docs: driver-api: add a series of orphaned documents

There are lots of documents under Documentation/*.txt and a few other
orphan documents elsehwere that belong to the driver-API book.

Move them to their right place.

Reviewed-by: Cornelia Huck <cohuck@redhat.com> # vfio-related parts
Acked-by: Logan Gunthorpe <logang@deltatee.com> # switchtec
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

27 files changed, 5692 insertions, 0 deletions

diff --git a/Documentation/driver-api/bt8xxgpio.rst b/Documentation/driver-api/bt8xxgpio.rst
new file mode 100644
index 000000000000..a845feb074de
--- /dev/null
+++ b/Documentation/driver-api/bt8xxgpio.rst
@@ -0,0 +1,62 @@
+===================================================================
+A driver for a selfmade cheap BT8xx based PCI GPIO-card (bt8xxgpio)
+===================================================================
+
+For advanced documentation, see http://www.bu3sch.de/btgpio.php
+
+A generic digital 24-port PCI GPIO card can be built out of an ordinary
+Brooktree bt848, bt849, bt878 or bt879 based analog TV tuner card. The
+Brooktree chip is used in old analog Hauppauge WinTV PCI cards. You can easily
+find them used for low prices on the net.
+
+The bt8xx chip does have 24 digital GPIO ports.
+These ports are accessible via 24 pins on the SMD chip package.
+
+
+How to physically access the GPIO pins
+======================================
+
+The are several ways to access these pins. One might unsolder the whole chip
+and put it on a custom PCI board, or one might only unsolder each individual
+GPIO pin and solder that to some tiny wire. As the chip package really is tiny
+there are some advanced soldering skills needed in any case.
+
+The physical pinouts are drawn in the following ASCII art.
+The GPIO pins are marked with G00-G23::
+
+                                           G G G G G G G G G G G G     G G G G G G
+                                           0 0 0 0 0 0 0 0 0 0 1 1     1 1 1 1 1 1
+                                           0 1 2 3 4 5 6 7 8 9 0 1     2 3 4 5 6 7
+           | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
+           ---------------------------------------------------------------------------
+         --|                               ^                                     ^   |--
+         --|                               pin 86                           pin 67   |--
+         --|                                                                         |--
+         --|                                                               pin 61 >  |-- G18
+         --|                                                                         |-- G19
+         --|                                                                         |-- G20
+         --|                                                                         |-- G21
+         --|                                                                         |-- G22
+         --|                                                               pin 56 >  |-- G23
+         --|                                                                         |--
+         --|                           Brooktree 878/879                             |--
+         --|                                                                         |--
+         --|                                                                         |--
+         --|                                                                         |--
+         --|                                                                         |--
+         --|                                                                         |--
+         --|                                                                         |--
+         --|                                                                         |--
+         --|                                                                         |--
+         --|                                                                         |--
+         --|                                                                         |--
+         --|                                                                         |--
+         --|                                                                         |--
+         --|                                                                         |--
+         --|   O                                                                     |--
+         --|                                                                         |--
+           ---------------------------------------------------------------------------
+           | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
+           ^
+           This is pin 1
+
diff --git a/Documentation/driver-api/connector.rst b/Documentation/driver-api/connector.rst
new file mode 100644
index 000000000000..c100c7482289
--- /dev/null
+++ b/Documentation/driver-api/connector.rst
@@ -0,0 +1,156 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+================
+Kernel Connector
+================
+
+Kernel connector - new netlink based userspace <-> kernel space easy
+to use communication module.
+
+The Connector driver makes it easy to connect various agents using a
+netlink based network.  One must register a callback and an identifier.
+When the driver receives a special netlink message with the appropriate
+identifier, the appropriate callback will be called.
+
+From the userspace point of view it's quite straightforward:
+
+	- socket();
+	- bind();
+	- send();
+	- recv();
+
+But if kernelspace wants to use the full power of such connections, the
+driver writer must create special sockets, must know about struct sk_buff
+handling, etc...  The Connector driver allows any kernelspace agents to use
+netlink based networking for inter-process communication in a significantly
+easier way::
+
+  int cn_add_callback(struct cb_id *id, char *name, void (*callback) (struct cn_msg *, struct netlink_skb_parms *));
+  void cn_netlink_send_multi(struct cn_msg *msg, u16 len, u32 portid, u32 __group, int gfp_mask);
+  void cn_netlink_send(struct cn_msg *msg, u32 portid, u32 __group, int gfp_mask);
+
+  struct cb_id
+  {
+	__u32			idx;
+	__u32			val;
+  };
+
+idx and val are unique identifiers which must be registered in the
+connector.h header for in-kernel usage.  `void (*callback) (void *)` is a
+callback function which will be called when a message with above idx.val
+is received by the connector core.  The argument for that function must
+be dereferenced to `struct cn_msg *`::
+
+  struct cn_msg
+  {
+	struct cb_id		id;
+
+	__u32			seq;
+	__u32			ack;
+
+	__u32			len;	/* Length of the following data */
+	__u8			data[0];
+  };
+
+Connector interfaces
+====================
+
+ .. kernel-doc:: include/linux/connector.h
+
+ Note:
+   When registering new callback user, connector core assigns
+   netlink group to the user which is equal to its id.idx.
+
+Protocol description
+====================
+
+The current framework offers a transport layer with fixed headers.  The
+recommended protocol which uses such a header is as following:
+
+msg->seq and msg->ack are used to determine message genealogy.  When
+someone sends a message, they use a locally unique sequence and random
+acknowledge number.  The sequence number may be copied into
+nlmsghdr->nlmsg_seq too.
+
+The sequence number is incremented with each message sent.
+
+If you expect a reply to the message, then the sequence number in the
+received message MUST be the same as in the original message, and the
+acknowledge number MUST be the same + 1.
+
+If we receive a message and its sequence number is not equal to one we
+are expecting, then it is a new message.  If we receive a message and
+its sequence number is the same as one we are expecting, but its
+acknowledge is not equal to the sequence number in the original
+message + 1, then it is a new message.
+
+Obviously, the protocol header contains the above id.
+
+The connector allows event notification in the following form: kernel
+driver or userspace process can ask connector to notify it when
+selected ids will be turned on or off (registered or unregistered its
+callback).  It is done by sending a special command to the connector
+driver (it also registers itself with id={-1, -1}).
+
+As example of this usage can be found in the cn_test.c module which
+uses the connector to request notification and to send messages.
+
+Reliability
+===========
+
+Netlink itself is not a reliable protocol.  That means that messages can
+be lost due to memory pressure or process' receiving queue overflowed,
+so caller is warned that it must be prepared.  That is why the struct
+cn_msg [main connector's message header] contains u32 seq and u32 ack
+fields.
+
+Userspace usage
+===============
+
+2.6.14 has a new netlink socket implementation, which by default does not
+allow people to send data to netlink groups other than 1.
+So, if you wish to use a netlink socket (for example using connector)
+with a different group number, the userspace application must subscribe to
+that group first.  It can be achieved by the following pseudocode::
+
+  s = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR);
+
+  l_local.nl_family = AF_NETLINK;
+  l_local.nl_groups = 12345;
+  l_local.nl_pid = 0;
+
+  if (bind(s, (struct sockaddr *)&l_local, sizeof(struct sockaddr_nl)) == -1) {
+	perror("bind");
+	close(s);
+	return -1;
+  }
+
+  {
+	int on = l_local.nl_groups;
+	setsockopt(s, 270, 1, &on, sizeof(on));
+  }
+
+Where 270 above is SOL_NETLINK, and 1 is a NETLINK_ADD_MEMBERSHIP socket
+option.  To drop a multicast subscription, one should call the above socket
+option with the NETLINK_DROP_MEMBERSHIP parameter which is defined as 0.
+
+2.6.14 netlink code only allows to select a group which is less or equal to
+the maximum group number, which is used at netlink_kernel_create() time.
+In case of connector it is CN_NETLINK_USERS + 0xf, so if you want to use
+group number 12345, you must increment CN_NETLINK_USERS to that number.
+Additional 0xf numbers are allocated to be used by non-in-kernel users.
+
+Due to this limitation, group 0xffffffff does not work now, so one can
+not use add/remove connector's group notifications, but as far as I know,
+only cn_test.c test module used it.
+
+Some work in netlink area is still being done, so things can be changed in
+2.6.15 timeframe, if it will happen, documentation will be updated for that
+kernel.
+
+Code samples
+============
+
+Sample code for a connector test module and user space can be found
+in samples/connector/. To build this code, enable CONFIG_CONNECTOR
+and CONFIG_SAMPLES.
diff --git a/Documentation/driver-api/console.rst b/Documentation/driver-api/console.rst
new file mode 100644
index 000000000000..8394ad7747ac
--- /dev/null
+++ b/Documentation/driver-api/console.rst
@@ -0,0 +1,152 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+===============
+Console Drivers
+===============
+
+The Linux kernel has 2 general types of console drivers.  The first type is
+assigned by the kernel to all the virtual consoles during the boot process.
+This type will be called 'system driver', and only one system driver is allowed
+to exist. The system driver is persistent and it can never be unloaded, though
+it may become inactive.
+
+The second type has to be explicitly loaded and unloaded. This will be called
+'modular driver' by this document. Multiple modular drivers can coexist at
+any time with each driver sharing the console with other drivers including
+the system driver. However, modular drivers cannot take over the console
+that is currently occupied by another modular driver. (Exception: Drivers that
+call do_take_over_console() will succeed in the takeover regardless of the type
+of driver occupying the consoles.) They can only take over the console that is
+occupied by the system driver. In the same token, if the modular driver is
+released by the console, the system driver will take over.
+
+Modular drivers, from the programmer's point of view, have to call::
+
+	 do_take_over_console() - load and bind driver to console layer
+	 give_up_console() - unload driver; it will only work if driver
+			     is fully unbound
+
+In newer kernels, the following are also available::
+
+	 do_register_con_driver()
+	 do_unregister_con_driver()
+
+If sysfs is enabled, the contents of /sys/class/vtconsole can be
+examined. This shows the console backends currently registered by the
+system which are named vtcon<n> where <n> is an integer from 0 to 15.
+Thus::
+
+       ls /sys/class/vtconsole
+       .  ..  vtcon0  vtcon1
+
+Each directory in /sys/class/vtconsole has 3 files::
+
+     ls /sys/class/vtconsole/vtcon0
+     .  ..  bind  name  uevent
+
+What do these files signify?
+
+     1. bind - this is a read/write file. It shows the status of the driver if
+        read, or acts to bind or unbind the driver to the virtual consoles
+        when written to. The possible values are:
+
+	0
+	  - means the driver is not bound and if echo'ed, commands the driver
+	    to unbind
+
+        1
+	  - means the driver is bound and if echo'ed, commands the driver to
+	    bind
+
+     2. name - read-only file. Shows the name of the driver in this format::
+
+	  cat /sys/class/vtconsole/vtcon0/name
+	  (S) VGA+
+
+	      '(S)' stands for a (S)ystem driver, i.e., it cannot be directly
+	      commanded to bind or unbind
+
+	      'VGA+' is the name of the driver
+
+	  cat /sys/class/vtconsole/vtcon1/name
+	  (M) frame buffer device
+
+	      In this case, '(M)' stands for a (M)odular driver, one that can be
+	      directly commanded to bind or unbind.
+
+     3. uevent - ignore this file
+
+When unbinding, the modular driver is detached first, and then the system
+driver takes over the consoles vacated by the driver. Binding, on the other
+hand, will bind the driver to the consoles that are currently occupied by a
+system driver.
+
+NOTE1:
+  Binding and unbinding must be selected in Kconfig. It's under::
+
+    Device Drivers ->
+	Character devices ->
+		Support for binding and unbinding console drivers
+
+NOTE2:
+  If any of the virtual consoles are in KD_GRAPHICS mode, then binding or
+  unbinding will not succeed. An example of an application that sets the
+  console to KD_GRAPHICS is X.
+
+How useful is this feature? This is very useful for console driver
+developers. By unbinding the driver from the console layer, one can unload the
+driver, make changes, recompile, reload and rebind the driver without any need
+for rebooting the kernel. For regular users who may want to switch from
+framebuffer console to VGA console and vice versa, this feature also makes
+this possible. (NOTE NOTE NOTE: Please read fbcon.txt under Documentation/fb
+for more details.)
+
+Notes for developers
+====================
+
+do_take_over_console() is now broken up into::
+
+     do_register_con_driver()
+     do_bind_con_driver() - private function
+
+give_up_console() is a wrapper to do_unregister_con_driver(), and a driver must
+be fully unbound for this call to succeed. con_is_bound() will check if the
+driver is bound or not.
+
+Guidelines for console driver writers
+=====================================
+
+In order for binding to and unbinding from the console to properly work,
+console drivers must follow these guidelines:
+
+1. All drivers, except system drivers, must call either do_register_con_driver()
+   or do_take_over_console(). do_register_con_driver() will just add the driver
+   to the console's internal list. It won't take over the
+   console. do_take_over_console(), as it name implies, will also take over (or
+   bind to) the console.
+
+2. All resources allocated during con->con_init() must be released in
+   con->con_deinit().
+
+3. All resources allocated in con->con_startup() must be released when the
+   driver, which was previously bound, becomes unbound.  The console layer
+   does not have a complementary call to con->con_startup() so it's up to the
+   driver to check when it's legal to release these resources. Calling
+   con_is_bound() in con->con_deinit() will help.  If the call returned
+   false(), then it's safe to release the resources.  This balance has to be
+   ensured because con->con_startup() can be called again when a request to
+   rebind the driver to the console arrives.
+
+4. Upon exit of the driver, ensure that the driver is totally unbound. If the
+   condition is satisfied, then the driver must call do_unregister_con_driver()
+   or give_up_console().
+
+5. do_unregister_con_driver() can also be called on conditions which make it
+   impossible for the driver to service console requests.  This can happen
+   with the framebuffer console that suddenly lost all of its drivers.
+
+The current crop of console drivers should still work correctly, but binding
+and unbinding them may cause problems. With minimal fixes, these drivers can
+be made to work correctly.
+
+Antonino Daplas <adaplas@pol.net>
diff --git a/Documentation/driver-api/dcdbas.rst b/Documentation/driver-api/dcdbas.rst
new file mode 100644
index 000000000000..309cc57a7c1c
--- /dev/null
+++ b/Documentation/driver-api/dcdbas.rst
@@ -0,0 +1,99 @@
+===================================
+Dell Systems Management Base Driver
+===================================
+
+Overview
+========
+
+The Dell Systems Management Base Driver provides a sysfs interface for
+systems management software such as Dell OpenManage to perform system
+management interrupts and host control actions (system power cycle or
+power off after OS shutdown) on certain Dell systems.
+
+Dell OpenManage requires this driver on the following Dell PowerEdge systems:
+300, 1300, 1400, 400SC, 500SC, 1500SC, 1550, 600SC, 1600SC, 650, 1655MC,
+700, and 750.  Other Dell software such as the open source libsmbios project
+is expected to make use of this driver, and it may include the use of this
+driver on other Dell systems.
+
+The Dell libsmbios project aims towards providing access to as much BIOS
+information as possible.  See http://linux.dell.com/libsmbios/main/ for
+more information about the libsmbios project.
+
+
+System Management Interrupt
+===========================
+
+On some Dell systems, systems management software must access certain
+management information via a system management interrupt (SMI).  The SMI data
+buffer must reside in 32-bit address space, and the physical address of the
+buffer is required for the SMI.  The driver maintains the memory required for
+the SMI and provides a way for the application to generate the SMI.
+The driver creates the following sysfs entries for systems management
+software to perform these system management interrupts::
+
+	/sys/devices/platform/dcdbas/smi_data
+	/sys/devices/platform/dcdbas/smi_data_buf_phys_addr
+	/sys/devices/platform/dcdbas/smi_data_buf_size
+	/sys/devices/platform/dcdbas/smi_request
+
+Systems management software must perform the following steps to execute
+a SMI using this driver:
+
+1) Lock smi_data.
+2) Write system management command to smi_data.
+3) Write "1" to smi_request to generate a calling interface SMI or
+   "2" to generate a raw SMI.
+4) Read system management command response from smi_data.
+5) Unlock smi_data.
+
+
+Host Control Action
+===================
+
+Dell OpenManage supports a host control feature that allows the administrator
+to perform a power cycle or power off of the system after the OS has finished
+shutting down.  On some Dell systems, this host control feature requires that
+a driver perform a SMI after the OS has finished shutting down.
+
+The driver creates the following sysfs entries for systems management software
+to schedule the driver to perform a power cycle or power off host control
+action after the system has finished shutting down:
+
+/sys/devices/platform/dcdbas/host_control_action
+/sys/devices/platform/dcdbas/host_control_smi_type
+/sys/devices/platform/dcdbas/host_control_on_shutdown
+
+Dell OpenManage performs the following steps to execute a power cycle or
+power off host control action using this driver:
+
+1) Write host control action to be performed to host_control_action.
+2) Write type of SMI that driver needs to perform to host_control_smi_type.
+3) Write "1" to host_control_on_shutdown to enable host control action.
+4) Initiate OS shutdown.
+   (Driver will perform host control SMI when it is notified that the OS
+   has finished shutting down.)
+
+
+Host Control SMI Type
+=====================
+
+The following table shows the value to write to host_control_smi_type to
+perform a power cycle or power off host control action:
+
+=================== =====================
+PowerEdge System    Host Control SMI Type
+=================== =====================
+      300             HC_SMITYPE_TYPE1
+     1300             HC_SMITYPE_TYPE1
+     1400             HC_SMITYPE_TYPE2
+      500SC           HC_SMITYPE_TYPE2
+     1500SC           HC_SMITYPE_TYPE2
+     1550             HC_SMITYPE_TYPE2
+      600SC           HC_SMITYPE_TYPE2
+     1600SC           HC_SMITYPE_TYPE2
+      650             HC_SMITYPE_TYPE2
+     1655MC           HC_SMITYPE_TYPE2
+      700             HC_SMITYPE_TYPE3
+      750             HC_SMITYPE_TYPE3
+=================== =====================
diff --git a/Documentation/driver-api/dell_rbu.rst b/Documentation/driver-api/dell_rbu.rst
new file mode 100644
index 000000000000..5d1ce7bcd04d
--- /dev/null
+++ b/Documentation/driver-api/dell_rbu.rst
@@ -0,0 +1,128 @@
+=============================================================
+Usage of the new open sourced rbu (Remote BIOS Update) driver
+=============================================================
+
+Purpose
+=======
+
+Document demonstrating the use of the Dell Remote BIOS Update driver.
+for updating BIOS images on Dell servers and desktops.
+
+Scope
+=====
+
+This document discusses the functionality of the rbu driver only.
+It does not cover the support needed from applications to enable the BIOS to
+update itself with the image downloaded in to the memory.
+
+Overview
+========
+
+This driver works with Dell OpenManage or Dell Update Packages for updating
+the BIOS on Dell servers (starting from servers sold since 1999), desktops
+and notebooks (starting from those sold in 2005).
+
+Please go to  http://support.dell.com register and you can find info on
+OpenManage and Dell Update packages (DUP).
+
+Libsmbios can also be used to update BIOS on Dell systems go to
+http://linux.dell.com/libsmbios/ for details.
+
+Dell_RBU driver supports BIOS update using the monolithic image and packetized
+image methods. In case of monolithic the driver allocates a contiguous chunk
+of physical pages having the BIOS image. In case of packetized the app
+using the driver breaks the image in to packets of fixed sizes and the driver
+would place each packet in contiguous physical memory. The driver also
+maintains a link list of packets for reading them back.
+
+If the dell_rbu driver is unloaded all the allocated memory is freed.
+
+The rbu driver needs to have an application (as mentioned above)which will
+inform the BIOS to enable the update in the next system reboot.
+
+The user should not unload the rbu driver after downloading the BIOS image
+or updating.
+
+The driver load creates the following directories under the /sys file system::
+
+	/sys/class/firmware/dell_rbu/loading
+	/sys/class/firmware/dell_rbu/data
+	/sys/devices/platform/dell_rbu/image_type
+	/sys/devices/platform/dell_rbu/data
+	/sys/devices/platform/dell_rbu/packet_size
+
+The driver supports two types of update mechanism; monolithic and packetized.
+These update mechanism depends upon the BIOS currently running on the system.
+Most of the Dell systems support a monolithic update where the BIOS image is
+copied to a single contiguous block of physical memory.
+
+In case of packet mechanism the single memory can be broken in smaller chunks
+of contiguous memory and the BIOS image is scattered in these packets.
+
+By default the driver uses monolithic memory for the update type. This can be
+changed to packets during the driver load time by specifying the load
+parameter image_type=packet.  This can also be changed later as below::
+
+	echo packet > /sys/devices/platform/dell_rbu/image_type
+
+In packet update mode the packet size has to be given before any packets can
+be downloaded. It is done as below::
+
+	echo XXXX > /sys/devices/platform/dell_rbu/packet_size
+
+In the packet update mechanism, the user needs to create a new file having
+packets of data arranged back to back. It can be done as follows
+The user creates packets header, gets the chunk of the BIOS image and
+places it next to the packetheader; now, the packetheader + BIOS image chunk
+added together should match the specified packet_size. This makes one
+packet, the user needs to create more such packets out of the entire BIOS
+image file and then arrange all these packets back to back in to one single
+file.
+
+This file is then copied to /sys/class/firmware/dell_rbu/data.
+Once this file gets to the driver, the driver extracts packet_size data from
+the file and spreads it across the physical memory in contiguous packet_sized
+space.
+
+This method makes sure that all the packets get to the driver in a single operation.
+
+In monolithic update the user simply get the BIOS image (.hdr file) and copies
+to the data file as is without any change to the BIOS image itself.
+
+Do the steps below to download the BIOS image.
+
+1) echo 1 > /sys/class/firmware/dell_rbu/loading
+2) cp bios_image.hdr /sys/class/firmware/dell_rbu/data
+3) echo 0 > /sys/class/firmware/dell_rbu/loading
+
+The /sys/class/firmware/dell_rbu/ entries will remain till the following is
+done.
+
+::
+
+	echo -1 > /sys/class/firmware/dell_rbu/loading
+
+Until this step is completed the driver cannot be unloaded.
+
+Also echoing either mono, packet or init in to image_type will free up the
+memory allocated by the driver.
+
+If a user by accident executes steps 1 and 3 above without executing step 2;
+it will make the /sys/class/firmware/dell_rbu/ entries disappear.
+
+The entries can be recreated by doing the following::
+
+	echo init > /sys/devices/platform/dell_rbu/image_type
+
+.. note:: echoing init in image_type does not change it original value.
+
+Also the driver provides /sys/devices/platform/dell_rbu/data readonly file to
+read back the image downloaded.
+
+.. note::
+
+   After updating the BIOS image a user mode application needs to execute
+   code which sends the BIOS update request to the BIOS. So on the next reboot
+   the BIOS knows about the new image downloaded and it updates itself.
+   Also don't unload the rbu driver if the image has to be updated.
+
diff --git a/Documentation/driver-api/edid.rst b/Documentation/driver-api/edid.rst
new file mode 100644
index 000000000000..b1b5acd501ed
--- /dev/null
+++ b/Documentation/driver-api/edid.rst
@@ -0,0 +1,58 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+====
+EDID
+====
+
+In the good old days when graphics parameters were configured explicitly
+in a file called xorg.conf, even broken hardware could be managed.
+
+Today, with the advent of Kernel Mode Setting, a graphics board is
+either correctly working because all components follow the standards -
+or the computer is unusable, because the screen remains dark after
+booting or it displays the wrong area. Cases when this happens are:
+- The graphics board does not recognize the monitor.
+- The graphics board is unable to detect any EDID data.
+- The graphics board incorrectly forwards EDID data to the driver.
+- The monitor sends no or bogus EDID data.
+- A KVM sends its own EDID data instead of querying the connected monitor.
+Adding the kernel parameter "nomodeset" helps in most cases, but causes
+restrictions later on.
+
+As a remedy for such situations, the kernel configuration item
+CONFIG_DRM_LOAD_EDID_FIRMWARE was introduced. It allows to provide an
+individually prepared or corrected EDID data set in the /lib/firmware
+directory from where it is loaded via the firmware interface. The code
+(see drivers/gpu/drm/drm_edid_load.c) contains built-in data sets for
+commonly used screen resolutions (800x600, 1024x768, 1280x1024, 1600x1200,
+1680x1050, 1920x1080) as binary blobs, but the kernel source tree does
+not contain code to create these data. In order to elucidate the origin
+of the built-in binary EDID blobs and to facilitate the creation of
+individual data for a specific misbehaving monitor, commented sources
+and a Makefile environment are given here.
+
+To create binary EDID and C source code files from the existing data
+material, simply type "make".
+
+If you want to create your own EDID file, copy the file 1024x768.S,
+replace the settings with your own data and add a new target to the
+Makefile. Please note that the EDID data structure expects the timing
+values in a different way as compared to the standard X11 format.
+
+X11:
+  HTimings:
+    hdisp hsyncstart hsyncend htotal
+  VTimings:
+    vdisp vsyncstart vsyncend vtotal
+
+EDID::
+
+  #define XPIX hdisp
+  #define XBLANK htotal-hdisp
+  #define XOFFSET hsyncstart-hdisp
+  #define XPULSE hsyncend-hsyncstart
+
+  #define YPIX vdisp
+  #define YBLANK vtotal-vdisp
+  #define YOFFSET vsyncstart-vdisp
+  #define YPULSE vsyncend-vsyncstart
diff --git a/Documentation/driver-api/eisa.rst b/Documentation/driver-api/eisa.rst
new file mode 100644
index 000000000000..c07565ba57da
--- /dev/null
+++ b/Documentation/driver-api/eisa.rst
@@ -0,0 +1,230 @@
+================
+EISA bus support
+================
+
+:Author: Marc Zyngier <maz@wild-wind.fr.eu.org>
+
+This document groups random notes about porting EISA drivers to the
+new EISA/sysfs API.
+
+Starting from version 2.5.59, the EISA bus is almost given the same
+status as other much more mainstream busses such as PCI or USB. This
+has been possible through sysfs, which defines a nice enough set of
+abstractions to manage busses, devices and drivers.
+
+Although the new API is quite simple to use, converting existing
+drivers to the new infrastructure is not an easy task (mostly because
+detection code is generally also used to probe ISA cards). Moreover,
+most EISA drivers are among the oldest Linux drivers so, as you can
+imagine, some dust has settled here over the years.
+
+The EISA infrastructure is made up of three parts:
+
+    - The bus code implements most of the generic code. It is shared
+      among all the architectures that the EISA code runs on. It
+      implements bus probing (detecting EISA cards available on the bus),
+      allocates I/O resources, allows fancy naming through sysfs, and
+      offers interfaces for driver to register.
+
+    - The bus root driver implements the glue between the bus hardware
+      and the generic bus code. It is responsible for discovering the
+      device implementing the bus, and setting it up to be latter probed
+      by the bus code. This can go from something as simple as reserving
+      an I/O region on x86, to the rather more complex, like the hppa
+      EISA code. This is the part to implement in order to have EISA
+      running on an "new" platform.
+
+    - The driver offers the bus a list of devices that it manages, and
+      implements the necessary callbacks to probe and release devices
+      whenever told to.
+
+Every function/structure below lives in <linux/eisa.h>, which depends
+heavily on <linux/device.h>.
+
+Bus root driver
+===============
+
+::
+
+	int eisa_root_register (struct eisa_root_device *root);
+
+The eisa_root_register function is used to declare a device as the
+root of an EISA bus. The eisa_root_device structure holds a reference
+to this device, as well as some parameters for probing purposes::
+
+	struct eisa_root_device {
+		struct device   *dev;	 /* Pointer to bridge device */
+		struct resource *res;
+		unsigned long    bus_base_addr;
+		int		 slots;  /* Max slot number */
+		int		 force_probe; /* Probe even when no slot 0 */
+		u64		 dma_mask; /* from bridge device */
+		int              bus_nr; /* Set by eisa_root_register */
+		struct resource  eisa_root_res;	/* ditto */
+	};
+
+============= ======================================================
+node          used for eisa_root_register internal purpose
+dev           pointer to the root device
+res           root device I/O resource
+bus_base_addr slot 0 address on this bus
+slots	      max slot number to probe
+force_probe   Probe even when slot 0 is empty (no EISA mainboard)
+dma_mask      Default DMA mask. Usually the bridge device dma_mask.
+bus_nr	      unique bus id, set by eisa_root_register
+============= ======================================================
+
+Driver
+======
+
+::
+
+	int eisa_driver_register (struct eisa_driver *edrv);
+	void eisa_driver_unregister (struct eisa_driver *edrv);
+
+Clear enough ?
+
+::
+
+	struct eisa_device_id {
+		char sig[EISA_SIG_LEN];
+		unsigned long driver_data;
+	};
+
+	struct eisa_driver {
+		const struct eisa_device_id *id_table;
+		struct device_driver         driver;
+	};
+
+=============== ====================================================
+id_table	an array of NULL terminated EISA id strings,
+		followed by an empty string. Each string can
+		optionally be paired with a driver-dependent value
+		(driver_data).
+
+driver		a generic driver, such as described in
+		Documentation/driver-api/driver-model/driver.rst. Only .name,
+		.probe and .remove members are mandatory.
+=============== ====================================================
+
+An example is the 3c59x driver::
+
+	static struct eisa_device_id vortex_eisa_ids[] = {
+		{ "TCM5920", EISA_3C592_OFFSET },
+		{ "TCM5970", EISA_3C597_OFFSET },
+		{ "" }
+	};
+
+	static struct eisa_driver vortex_eisa_driver = {
+		.id_table = vortex_eisa_ids,
+		.driver   = {
+			.name    = "3c59x",
+			.probe   = vortex_eisa_probe,
+			.remove  = vortex_eisa_remove
+		}
+	};
+
+Device
+======
+
+The sysfs framework calls .probe and .remove functions upon device
+discovery and removal (note that the .remove function is only called
+when driver is built as a module).
+
+Both functions are passed a pointer to a 'struct device', which is
+encapsulated in a 'struct eisa_device' described as follows::
+
+	struct eisa_device {
+		struct eisa_device_id id;
+		int                   slot;
+		int                   state;
+		unsigned long         base_addr;
+		struct resource       res[EISA_MAX_RESOURCES];
+		u64                   dma_mask;
+		struct device         dev; /* generic device */
+	};
+
+======== ============================================================
+id	 EISA id, as read from device. id.driver_data is set from the
+	 matching driver EISA id.
+slot	 slot number which the device was detected on
+state    set of flags indicating the state of the device. Current
+	 flags are EISA_CONFIG_ENABLED and EISA_CONFIG_FORCED.
+res	 set of four 256 bytes I/O regions allocated to this device
+dma_mask DMA mask set from the parent device.
+dev	 generic device (see Documentation/driver-api/driver-model/device.rst)
+======== ============================================================
+
+You can get the 'struct eisa_device' from 'struct device' using the
+'to_eisa_device' macro.
+
+Misc stuff
+==========
+
+::
+
+	void eisa_set_drvdata (struct eisa_device *edev, void *data);
+
+Stores data into the device's driver_data area.
+
+::
+
+	void *eisa_get_drvdata (struct eisa_device *edev):
+
+Gets the pointer previously stored into the device's driver_data area.
+
+::
+
+	int eisa_get_region_index (void *addr);
+
+Returns the region number (0 <= x < EISA_MAX_RESOURCES) of a given
+address.
+
+Kernel parameters
+=================
+
+eisa_bus.enable_dev
+	A comma-separated list of slots to be enabled, even if the firmware
+	set the card as disabled. The driver must be able to properly
+	initialize the device in such conditions.
+
+eisa_bus.disable_dev
+	A comma-separated list of slots to be enabled, even if the firmware
+	set the card as enabled. The driver won't be called to handle this
+	device.
+
+virtual_root.force_probe
+	Force the probing code to probe EISA slots even when it cannot find an
+	EISA compliant mainboard (nothing appears on slot 0). Defaults to 0
+	(don't force), and set to 1 (force probing) when either
+	CONFIG_ALPHA_JENSEN or CONFIG_EISA_VLB_PRIMING are set.
+
+Random notes
+============
+
+Converting an EISA driver to the new API mostly involves *deleting*
+code (since probing is now in the core EISA code). Unfortunately, most
+drivers share their probing routine between ISA, and EISA. Special
+care must be taken when ripping out the EISA code, so other busses
+won't suffer from these surgical strikes...
+
+You *must not* expect any EISA device to be detected when returning
+from eisa_driver_register, since the chances are that the bus has not
+yet been probed. In fact, that's what happens most of the time (the
+bus root driver usually kicks in rather late in the boot process).
+Unfortunately, most drivers are doing the probing by themselves, and
+expect to have explored the whole machine when they exit their probe
+routine.
+
+For example, switching your favorite EISA SCSI card to the "hotplug"
+model is "the right thing"(tm).
+
+Thanks
+======
+
+I'd like to thank the following people for their help:
+
+- Xavier Benigni for lending me a wonderful Alpha Jensen,
+- James Bottomley, Jeff Garzik for getting this stuff into the kernel,
+- Andries Brouwer for contributing numerous EISA ids,
+- Catrin Jones for coping with far too many machines at home.
diff --git a/Documentation/driver-api/index.rst b/Documentation/driver-api/index.rst
index 9fb03b7bdeb1..d1c6513dd20d 100644
--- a/Documentation/driver-api/index.rst
+++ b/Documentation/driver-api/index.rst
@@ -68,7 +68,33 @@ available subsections can be seen below.
    fpga/index
    acpi/index
    backlight/lp855x-driver.rst
+   bt8xxgpio
+   connector
+   console
+   dcdbas
+   dell_rbu
+   edid
+   eisa
+   isa
+   isapnp
    generic-counter
+   lightnvm-pblk
+   men-chameleon-bus
+   ntb
+   nvmem
+   parport-lowlevel
+   pti_intel_mid
+   pwm
+   rfkill
+   sgi-ioc4
+   sm501
+   smsc_ece1099
+   switchtec
+   sync_file
+   vfio-mediated-device
+   vfio
+   xillybus
+   zorro
 
 .. only::  subproject and html
 
diff --git a/Documentation/driver-api/isa.rst b/Documentation/driver-api/isa.rst
new file mode 100644
index 000000000000..def4a7b690b5
--- /dev/null
+++ b/Documentation/driver-api/isa.rst
@@ -0,0 +1,122 @@
+===========
+ISA Drivers
+===========
+
+The following text is adapted from the commit message of the initial
+commit of the ISA bus driver authored by Rene Herman.
+
+During the recent "isa drivers using platform devices" discussion it was
+pointed out that (ALSA) ISA drivers ran into the problem of not having
+the option to fail driver load (device registration rather) upon not
+finding their hardware due to a probe() error not being passed up
+through the driver model. In the course of that, I suggested a separate
+ISA bus might be best; Russell King agreed and suggested this bus could
+use the .match() method for the actual device discovery.
+
+The attached does this. For this old non (generically) discoverable ISA
+hardware only the driver itself can do discovery so as a difference with
+the platform_bus, this isa_bus also distributes match() up to the
+driver.
+
+As another difference: these devices only exist in the driver model due
+to the driver creating them because it might want to drive them, meaning
+that all device creation has been made internal as well.
+
+The usage model this provides is nice, and has been acked from the ALSA
+side by Takashi Iwai and Jaroslav Kysela. The ALSA driver module_init's
+now (for oldisa-only drivers) become::
+
+	static int __init alsa_card_foo_init(void)
+	{
+		return isa_register_driver(&snd_foo_isa_driver, SNDRV_CARDS);
+	}
+
+	static void __exit alsa_card_foo_exit(void)
+	{
+		isa_unregister_driver(&snd_foo_isa_driver);
+	}
+
+Quite like the other bus models therefore. This removes a lot of
+duplicated init code from the ALSA ISA drivers.
+
+The passed in isa_driver struct is the regular driver struct embedding a
+struct device_driver, the normal probe/remove/shutdown/suspend/resume
+callbacks, and as indicated that .match callback.
+
+The "SNDRV_CARDS" you see being passed in is a "unsigned int ndev"
+parameter, indicating how many devices to create and call our methods
+with.
+
+The platform_driver callbacks are called with a platform_device param;
+the isa_driver callbacks are being called with a ``struct device *dev,
+unsigned int id`` pair directly -- with the device creation completely
+internal to the bus it's much cleaner to not leak isa_dev's by passing
+them in at all. The id is the only thing we ever want other then the
+struct device anyways, and it makes for nicer code in the callbacks as
+well.
+
+With this additional .match() callback ISA drivers have all options. If
+ALSA would want to keep the old non-load behaviour, it could stick all
+of the old .probe in .match, which would only keep them registered after
+everything was found to be present and accounted for. If it wanted the
+behaviour of always loading as it inadvertently did for a bit after the
+changeover to platform devices, it could just not provide a .match() and
+do everything in .probe() as before.
+
+If it, as Takashi Iwai already suggested earlier as a way of following
+the model from saner buses more closely, wants to load when a later bind
+could conceivably succeed, it could use .match() for the prerequisites
+(such as checking the user wants the card enabled and that port/irq/dma
+values have been passed in) and .probe() for everything else. This is
+the nicest model.
+
+To the code...
+
+This exports only two functions; isa_{,un}register_driver().
+
+isa_register_driver() register's the struct device_driver, and then
+loops over the passed in ndev creating devices and registering them.
+This causes the bus match method to be called for them, which is::
+
+	int isa_bus_match(struct device *dev, struct device_driver *driver)
+	{
+		struct isa_driver *isa_driver = to_isa_driver(driver);
+
+		if (dev->platform_data == isa_driver) {
+			if (!isa_driver->match ||
+				isa_driver->match(dev, to_isa_dev(dev)->id))
+				return 1;
+			dev->platform_data = NULL;
+		}
+		return 0;
+	}
+
+The first thing this does is check if this device is in fact one of this
+driver's devices by seeing if the device's platform_data pointer is set
+to this driver. Platform devices compare strings, but we don't need to
+do that with everything being internal, so isa_register_driver() abuses
+dev->platform_data as a isa_driver pointer which we can then check here.
+I believe platform_data is available for this, but if rather not, moving
+the isa_driver pointer to the private struct isa_dev is ofcourse fine as
+well.
+
+Then, if the the driver did not provide a .match, it matches. If it did,
+the driver match() method is called to determine a match.
+
+If it did **not** match, dev->platform_data is reset to indicate this to
+isa_register_driver which can then unregister the device again.
+
+If during all this, there's any error, or no devices matched at all
+everything is backed out again and the error, or -ENODEV, is returned.
+
+isa_unregister_driver() just unregisters the matched devices and the
+driver itself.
+
+module_isa_driver is a helper macro for ISA drivers which do not do
+anything special in module init/exit. This eliminates a lot of
+boilerplate code. Each module may only use this macro once, and calling
+it replaces module_init and module_exit.
+
+max_num_isa_dev is a macro to determine the maximum possible number of
+ISA devices which may be registered in the I/O port address space given
+the address extent of the ISA devices.
diff --git a/Documentation/driver-api/isapnp.rst b/Documentation/driver-api/isapnp.rst
new file mode 100644
index 000000000000..8d0840ac847b
--- /dev/null
+++ b/Documentation/driver-api/isapnp.rst
@@ -0,0 +1,15 @@
+==========================================================
+ISA Plug & Play support by Jaroslav Kysela <perex@suse.cz>
+==========================================================
+
+Interface /proc/isapnp
+======================
+
+The interface has been removed. See pnp.txt for more details.
+
+Interface /proc/bus/isapnp
+==========================
+
+This directory allows access to ISA PnP cards and logical devices.
+The regular files contain the contents of ISA PnP registers for
+a logical device.
diff --git a/Documentation/driver-api/lightnvm-pblk.rst b/Documentation/driver-api/lightnvm-pblk.rst
new file mode 100644
index 000000000000..1040ed1cec81
--- /dev/null
+++ b/Documentation/driver-api/lightnvm-pblk.rst
@@ -0,0 +1,21 @@
+pblk: Physical Block Device Target
+==================================
+
+pblk implements a fully associative, host-based FTL that exposes a traditional
+block I/O interface. Its primary responsibilities are:
+
+  - Map logical addresses onto physical addresses (4KB granularity) in a
+    logical-to-physical (L2P) table.
+  - Maintain the integrity and consistency of the L2P table as well as its
+    recovery from normal tear down and power outage.
+  - Deal with controller- and media-specific constrains.
+  - Handle I/O errors.
+  - Implement garbage collection.
+  - Maintain consistency across the I/O stack during synchronization points.
+
+For more information please refer to:
+
+  http://lightnvm.io
+
+which maintains updated FAQs, manual pages, technical documentation, tools,
+contacts, etc.
diff --git a/Documentation/driver-api/men-chameleon-bus.rst b/Documentation/driver-api/men-chameleon-bus.rst
new file mode 100644
index 000000000000..1b1f048aa748
--- /dev/null
+++ b/Documentation/driver-api/men-chameleon-bus.rst
@@ -0,0 +1,175 @@
+=================
+MEN Chameleon Bus
+=================
+
+.. Table of Contents
+   =================
+   1 Introduction
+       1.1 Scope of this Document
+       1.2 Limitations of the current implementation
+   2 Architecture
+       2.1 MEN Chameleon Bus
+       2.2 Carrier Devices
+       2.3 Parser
+   3 Resource handling
+       3.1 Memory Resources
+       3.2 IRQs
+   4 Writing an MCB driver
+       4.1 The driver structure
+       4.2 Probing and attaching
+       4.3 Initializing the driver
+
+
+Introduction
+============
+
+This document describes the architecture and implementation of the MEN
+Chameleon Bus (called MCB throughout this document).
+
+Scope of this Document
+----------------------
+
+This document is intended to be a short overview of the current
+implementation and does by no means describe the complete possibilities of MCB
+based devices.
+
+Limitations of the current implementation
+-----------------------------------------
+
+The current implementation is limited to PCI and PCIe based carrier devices
+that only use a single memory resource and share the PCI legacy IRQ.  Not
+implemented are:
+
+- Multi-resource MCB devices like the VME Controller or M-Module carrier.
+- MCB devices that need another MCB device, like SRAM for a DMA Controller's
+  buffer descriptors or a video controller's video memory.
+- A per-carrier IRQ domain for carrier devices that have one (or more) IRQs
+  per MCB device like PCIe based carriers with MSI or MSI-X support.
+
+Architecture
+============
+
+MCB is divided into 3 functional blocks:
+
+- The MEN Chameleon Bus itself,
+- drivers for MCB Carrier Devices and
+- the parser for the Chameleon table.
+
+MEN Chameleon Bus
+-----------------
+
+The MEN Chameleon Bus is an artificial bus system that attaches to a so
+called Chameleon FPGA device found on some hardware produced my MEN Mikro
+Elektronik GmbH. These devices are multi-function devices implemented in a
+single FPGA and usually attached via some sort of PCI or PCIe link. Each
+FPGA contains a header section describing the content of the FPGA. The
+header lists the device id, PCI BAR, offset from the beginning of the PCI
+BAR, size in the FPGA, interrupt number and some other properties currently
+not handled by the MCB implementation.
+
+Carrier Devices
+---------------
+
+A carrier device is just an abstraction for the real world physical bus the
+Chameleon FPGA is attached to. Some IP Core drivers may need to interact with
+properties of the carrier device (like querying the IRQ number of a PCI
+device). To provide abstraction from the real hardware bus, an MCB carrier
+device provides callback methods to translate the driver's MCB function calls
+to hardware related function calls. For example a carrier device may
+implement the get_irq() method which can be translated into a hardware bus
+query for the IRQ number the device should use.
+
+Parser
+------
+
+The parser reads the first 512 bytes of a Chameleon device and parses the
+Chameleon table. Currently the parser only supports the Chameleon v2 variant
+of the Chameleon table but can easily be adopted to support an older or
+possible future variant. While parsing the table's entries new MCB devices
+are allocated and their resources are assigned according to the resource
+assignment in the Chameleon table. After resource assignment is finished, the
+MCB devices are registered at the MCB and thus at the driver core of the
+Linux kernel.
+
+Resource handling
+=================
+
+The current implementation assigns exactly one memory and one IRQ resource
+per MCB device. But this is likely going to change in the future.
+
+Memory Resources
+----------------
+
+Each MCB device has exactly one memory resource, which can be requested from
+the MCB bus. This memory resource is the physical address of the MCB device
+inside the carrier and is intended to be passed to ioremap() and friends. It
+is already requested from the kernel by calling request_mem_region().
+
+IRQs
+----
+
+Each MCB device has exactly one IRQ resource, which can be requested from the
+MCB bus. If a carrier device driver implements the ->get_irq() callback
+method, the IRQ number assigned by the carrier device will be returned,
+otherwise the IRQ number inside the Chameleon table will be returned. This
+number is suitable to be passed to request_irq().
+
+Writing an MCB driver
+=====================
+
+The driver structure
+--------------------
+
+Each MCB driver has a structure to identify the device driver as well as
+device ids which identify the IP Core inside the FPGA. The driver structure
+also contains callback methods which get executed on driver probe and
+removal from the system::
+
+	static const struct mcb_device_id foo_ids[] = {
+		{ .device = 0x123 },
+		{ }
+	};
+	MODULE_DEVICE_TABLE(mcb, foo_ids);
+
+	static struct mcb_driver foo_driver = {
+	driver = {
+		.name = "foo-bar",
+		.owner = THIS_MODULE,
+	},
+		.probe = foo_probe,
+		.remove = foo_remove,
+		.id_table = foo_ids,
+	};
+
+Probing and attaching
+---------------------
+
+When a driver is loaded and the MCB devices it services are found, the MCB
+core will call the driver's probe callback method. When the driver is removed
+from the system, the MCB core will call the driver's remove callback method::
+
+	static init foo_probe(struct mcb_device *mdev, const struct mcb_device_id *id);
+	static void foo_remove(struct mcb_device *mdev);
+
+Initializing the driver
+-----------------------
+
+When the kernel is booted or your foo driver module is inserted, you have to
+perform driver initialization. Usually it is enough to register your driver
+module at the MCB core::
+
+	static int __init foo_init(void)
+	{
+		return mcb_register_driver(&foo_driver);
+	}
+	module_init(foo_init);
+
+	static void __exit foo_exit(void)
+	{
+		mcb_unregister_driver(&foo_driver);
+	}
+	module_exit(foo_exit);
+
+The module_mcb_driver() macro can be used to reduce the above code::
+
+	module_mcb_driver(foo_driver);
diff --git a/Documentation/driver-api/ntb.rst b/Documentation/driver-api/ntb.rst
new file mode 100644
index 000000000000..074a423c853c
--- /dev/null
+++ b/Documentation/driver-api/ntb.rst
@@ -0,0 +1,236 @@
+===========
+NTB Drivers
+===========
+
+NTB (Non-Transparent Bridge) is a type of PCI-Express bridge chip that connects
+the separate memory systems of two or more computers to the same PCI-Express
+fabric. Existing NTB hardware supports a common feature set: doorbell
+registers and memory translation windows, as well as non common features like
+scratchpad and message registers. Scratchpad registers are read-and-writable
+registers that are accessible from either side of the device, so that peers can
+exchange a small amount of information at a fixed address. Message registers can
+be utilized for the same purpose. Additionally they are provided with with
+special status bits to make sure the information isn't rewritten by another
+peer. Doorbell registers provide a way for peers to send interrupt events.
+Memory windows allow translated read and write access to the peer memory.
+
+NTB Core Driver (ntb)
+=====================
+
+The NTB core driver defines an api wrapping the common feature set, and allows
+clients interested in NTB features to discover NTB the devices supported by
+hardware drivers.  The term "client" is used here to mean an upper layer
+component making use of the NTB api.  The term "driver," or "hardware driver,"
+is used here to mean a driver for a specific vendor and model of NTB hardware.
+
+NTB Client Drivers
+==================
+
+NTB client drivers should register with the NTB core driver.  After
+registering, the client probe and remove functions will be called appropriately
+as ntb hardware, or hardware drivers, are inserted and removed.  The
+registration uses the Linux Device framework, so it should feel familiar to
+anyone who has written a pci driver.
+
+NTB Typical client driver implementation
+----------------------------------------
+
+Primary purpose of NTB is to share some peace of memory between at least two
+systems. So the NTB device features like Scratchpad/Message registers are
+mainly used to perform the proper memory window initialization. Typically
+there are two types of memory window interfaces supported by the NTB API:
+inbound translation configured on the local ntb port and outbound translation
+configured by the peer, on the peer ntb port. The first type is
+depicted on the next figure::
+
+ Inbound translation:
+
+ Memory:              Local NTB Port:      Peer NTB Port:      Peer MMIO:
+  ____________
+ | dma-mapped |-ntb_mw_set_trans(addr)  |
+ | memory     |        _v____________   |   ______________
+ | (addr)     |<======| MW xlat addr |<====| MW base addr |<== memory-mapped IO
+ |------------|       |--------------|  |  |--------------|
+
+So typical scenario of the first type memory window initialization looks:
+1) allocate a memory region, 2) put translated address to NTB config,
+3) somehow notify a peer device of performed initialization, 4) peer device
+maps corresponding outbound memory window so to have access to the shared
+memory region.
+
+The second type of interface, that implies the shared windows being
+initialized by a peer device, is depicted on the figure::
+
+ Outbound translation:
+
+ Memory:        Local NTB Port:    Peer NTB Port:      Peer MMIO:
+  ____________                      ______________
+ | dma-mapped |                |   | MW base addr |<== memory-mapped IO
+ | memory     |                |   |--------------|
+ | (addr)     |<===================| MW xlat addr |<-ntb_peer_mw_set_trans(addr)
+ |------------|                |   |--------------|
+
+Typical scenario of the second type interface initialization would be:
+1) allocate a memory region, 2) somehow deliver a translated address to a peer
+device, 3) peer puts the translated address to NTB config, 4) peer device maps
+outbound memory window so to have access to the shared memory region.
+
+As one can see the described scenarios can be combined in one portable
+algorithm.
+
+ Local device:
+  1) Allocate memory for a shared window
+  2) Initialize memory window by translated address of the allocated region
+     (it may fail if local memory window initialization is unsupported)
+  3) Send the translated address and memory window index to a peer device
+
+ Peer device:
+  1) Initialize memory window with retrieved address of the allocated
+     by another device memory region (it may fail if peer memory window
+     initialization is unsupported)
+  2) Map outbound memory window
+
+In accordance with this scenario, the NTB Memory Window API can be used as
+follows:
+
+ Local device:
+  1) ntb_mw_count(pidx) - retrieve number of memory ranges, which can
+     be allocated for memory windows between local device and peer device
+     of port with specified index.
+  2) ntb_get_align(pidx, midx) - retrieve parameters restricting the
+     shared memory region alignment and size. Then memory can be properly
+     allocated.
+  3) Allocate physically contiguous memory region in compliance with
+     restrictions retrieved in 2).
+  4) ntb_mw_set_trans(pidx, midx) - try to set translation address of
+     the memory window with specified index for the defined peer device
+     (it may fail if local translated address setting is not supported)
+  5) Send translated base address (usually together with memory window
+     number) to the peer device using, for instance, scratchpad or message
+     registers.
+
+ Peer device:
+  1) ntb_peer_mw_set_trans(pidx, midx) - try to set received from other
+     device (related to pidx) translated address for specified memory
+     window. It may fail if retrieved address, for instance, exceeds
+     maximum possible address or isn't properly aligned.
+  2) ntb_peer_mw_get_addr(widx) - retrieve MMIO address to map the memory
+     window so to have an access to the shared memory.
+
+Also it is worth to note, that method ntb_mw_count(pidx) should return the
+same value as ntb_peer_mw_count() on the peer with port index - pidx.
+
+NTB Transport Client (ntb\_transport) and NTB Netdev (ntb\_netdev)
+------------------------------------------------------------------
+
+The primary client for NTB is the Transport client, used in tandem with NTB
+Netdev.  These drivers function together to create a logical link to the peer,
+across the ntb, to exchange packets of network data.  The Transport client
+establishes a logical link to the peer, and creates queue pairs to exchange
+messages and data.  The NTB Netdev then creates an ethernet device using a
+Transport queue pair.  Network data is copied between socket buffers and the
+Transport queue pair buffer.  The Transport client may be used for other things
+besides Netdev, however no other applications have yet been written.
+
+NTB Ping Pong Test Client (ntb\_pingpong)
+-----------------------------------------
+
+The Ping Pong test client serves as a demonstration to exercise the doorbell
+and scratchpad registers of NTB hardware, and as an example simple NTB client.
+Ping Pong enables the link when started, waits for the NTB link to come up, and
+then proceeds to read and write the doorbell scratchpad registers of the NTB.
+The peers interrupt each other using a bit mask of doorbell bits, which is
+shifted by one in each round, to test the behavior of multiple doorbell bits
+and interrupt vectors.  The Ping Pong driver also reads the first local
+scratchpad, and writes the value plus one to the first peer scratchpad, each
+round before writing the peer doorbell register.
+
+Module Parameters:
+
+* unsafe - Some hardware has known issues with scratchpad and doorbell
+	registers.  By default, Ping Pong will not attempt to exercise such
+	hardware.  You may override this behavior at your own risk by setting
+	unsafe=1.
+* delay\_ms - Specify the delay between receiving a doorbell
+	interrupt event and setting the peer doorbell register for the next
+	round.
+* init\_db - Specify the doorbell bits to start new series of rounds.  A new
+	series begins once all the doorbell bits have been shifted out of
+	range.
+* dyndbg - It is suggested to specify dyndbg=+p when loading this module, and
+	then to observe debugging output on the console.
+
+NTB Tool Test Client (ntb\_tool)
+--------------------------------
+
+The Tool test client serves for debugging, primarily, ntb hardware and drivers.
+The Tool provides access through debugfs for reading, setting, and clearing the
+NTB doorbell, and reading and writing scratchpads.
+
+The Tool does not currently have any module parameters.
+
+Debugfs Files:
+
+* *debugfs*/ntb\_tool/*hw*/
+	A directory in debugfs will be created for each
+	NTB device probed by the tool.  This directory is shortened to *hw*
+	below.
+* *hw*/db
+	This file is used to read, set, and clear the local doorbell.  Not
+	all operations may be supported by all hardware.  To read the doorbell,
+	read the file.  To set the doorbell, write `s` followed by the bits to
+	set (eg: `echo 's 0x0101' > db`).  To clear the doorbell, write `c`
+	followed by the bits to clear.
+* *hw*/mask
+	This file is used to read, set, and clear the local doorbell mask.
+	See *db* for details.
+* *hw*/peer\_db
+	This file is used to read, set, and clear the peer doorbell.
+	See *db* for details.
+* *hw*/peer\_mask
+	This file is used to read, set, and clear the peer doorbell
+	mask.  See *db* for details.
+* *hw*/spad
+	This file is used to read and write local scratchpads.  To read
+	the values of all scratchpads, read the file.  To write values, write a
+	series of pairs of scratchpad number and value
+	(eg: `echo '4 0x123 7 0xabc' > spad`
+	# to set scratchpads `4` and `7` to `0x123` and `0xabc`, respectively).
+* *hw*/peer\_spad
+	This file is used to read and write peer scratchpads.  See
+	*spad* for details.
+
+NTB Hardware Drivers
+====================
+
+NTB hardware drivers should register devices with the NTB core driver.  After
+registering, clients probe and remove functions will be called.
+
+NTB Intel Hardware Driver (ntb\_hw\_intel)
+------------------------------------------
+
+The Intel hardware driver supports NTB on Xeon and Atom CPUs.
+
+Module Parameters:
+
+* b2b\_mw\_idx
+	If the peer ntb is to be accessed via a memory window, then use
+	this memory window to access the peer ntb.  A value of zero or positive
+	starts from the first mw idx, and a negative value starts from the last
+	mw idx.  Both sides MUST set the same value here!  The default value is
+	`-1`.
+* b2b\_mw\_share
+	If the peer ntb is to be accessed via a memory window, and if
+	the memory window is large enough, still allow the client to use the
+	second half of the memory window for address translation to the peer.
+* xeon\_b2b\_usd\_bar2\_addr64
+	If using B2B topology on Xeon hardware, use
+	this 64 bit address on the bus between the NTB devices for the window
+	at BAR2, on the upstream side of the link.
+* xeon\_b2b\_usd\_bar4\_addr64 - See *xeon\_b2b\_bar2\_addr64*.
+* xeon\_b2b\_usd\_bar4\_addr32 - See *xeon\_b2b\_bar2\_addr64*.
+* xeon\_b2b\_usd\_bar5\_addr32 - See *xeon\_b2b\_bar2\_addr64*.
+* xeon\_b2b\_dsd\_bar2\_addr64 - See *xeon\_b2b\_bar2\_addr64*.
+* xeon\_b2b\_dsd\_bar4\_addr64 - See *xeon\_b2b\_bar2\_addr64*.
+* xeon\_b2b\_dsd\_bar4\_addr32 - See *xeon\_b2b\_bar2\_addr64*.
+* xeon\_b2b\_dsd\_bar5\_addr32 - See *xeon\_b2b\_bar2\_addr64*.
diff --git a/Documentation/driver-api/nvmem.rst b/Documentation/driver-api/nvmem.rst
new file mode 100644
index 000000000000..d9d958d5c824
--- /dev/null
+++ b/Documentation/driver-api/nvmem.rst
@@ -0,0 +1,189 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+===============
+NVMEM Subsystem
+===============
+
+ Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
+
+This document explains the NVMEM Framework along with the APIs provided,
+and how to use it.
+
+1. Introduction
+===============
+*NVMEM* is the abbreviation for Non Volatile Memory layer. It is used to
+retrieve configuration of SOC or Device specific data from non volatile
+memories like eeprom, efuses and so on.
+
+Before this framework existed, NVMEM drivers like eeprom were stored in
+drivers/misc, where they all had to duplicate pretty much the same code to
+register a sysfs file, allow in-kernel users to access the content of the
+devices they were driving, etc.
+
+This was also a problem as far as other in-kernel users were involved, since
+the solutions used were pretty much different from one driver to another, there
+was a rather big abstraction leak.
+
+This framework aims at solve these problems. It also introduces DT
+representation for consumer devices to go get the data they require (MAC
+Addresses, SoC/Revision ID, part numbers, and so on) from the NVMEMs. This
+framework is based on regmap, so that most of the abstraction available in
+regmap can be reused, across multiple types of buses.
+
+NVMEM Providers
++++++++++++++++
+
+NVMEM provider refers to an entity that implements methods to initialize, read
+and write the non-volatile memory.
+
+2. Registering/Unregistering the NVMEM provider
+===============================================
+
+A NVMEM provider can register with NVMEM core by supplying relevant
+nvmem configuration to nvmem_register(), on success core would return a valid
+nvmem_device pointer.
+
+nvmem_unregister(nvmem) is used to unregister a previously registered provider.
+
+For example, a simple qfprom case::
+
+  static struct nvmem_config econfig = {
+	.name = "qfprom",
+	.owner = THIS_MODULE,
+  };
+
+  static int qfprom_probe(struct platform_device *pdev)
+  {
+	...
+	econfig.dev = &pdev->dev;
+	nvmem = nvmem_register(&econfig);
+	...
+  }
+
+It is mandatory that the NVMEM provider has a regmap associated with its
+struct device. Failure to do would return error code from nvmem_register().
+
+Users of board files can define and register nvmem cells using the
+nvmem_cell_table struct::
+
+  static struct nvmem_cell_info foo_nvmem_cells[] = {
+	{
+		.name		= "macaddr",
+		.offset		= 0x7f00,
+		.bytes		= ETH_ALEN,
+	}
+  };
+
+  static struct nvmem_cell_table foo_nvmem_cell_table = {
+	.nvmem_name		= "i2c-eeprom",
+	.cells			= foo_nvmem_cells,
+	.ncells			= ARRAY_SIZE(foo_nvmem_cells),
+  };
+
+  nvmem_add_cell_table(&foo_nvmem_cell_table);
+
+Additionally it is possible to create nvmem cell lookup entries and register
+them with the nvmem framework from machine code as shown in the example below::
+
+  static struct nvmem_cell_lookup foo_nvmem_lookup = {
+	.nvmem_name		= "i2c-eeprom",
+	.cell_name		= "macaddr",
+	.dev_id			= "foo_mac.0",
+	.con_id			= "mac-address",
+  };
+
+  nvmem_add_cell_lookups(&foo_nvmem_lookup, 1);
+
+NVMEM Consumers
++++++++++++++++
+
+NVMEM consumers are the entities which make use of the NVMEM provider to
+read from and to NVMEM.
+
+3. NVMEM cell based consumer APIs
+=================================
+
+NVMEM cells are the data entries/fields in the NVMEM.
+The NVMEM framework provides 3 APIs to read/write NVMEM cells::
+
+  struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *name);
+  struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *name);
+
+  void nvmem_cell_put(struct nvmem_cell *cell);
+  void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell);
+
+  void *nvmem_cell_read(struct nvmem_cell *cell, ssize_t *len);
+  int nvmem_cell_write(struct nvmem_cell *cell, void *buf, ssize_t len);
+
+`*nvmem_cell_get()` apis will get a reference to nvmem cell for a given id,
+and nvmem_cell_read/write() can then read or write to the cell.
+Once the usage of the cell is finished the consumer should call
+`*nvmem_cell_put()` to free all the allocation memory for the cell.
+
+4. Direct NVMEM device based consumer APIs
+==========================================
+
+In some instances it is necessary to directly read/write the NVMEM.
+To facilitate such consumers NVMEM framework provides below apis::
+
+  struct nvmem_device *nvmem_device_get(struct device *dev, const char *name);
+  struct nvmem_device *devm_nvmem_device_get(struct device *dev,
+					   const char *name);
+  void nvmem_device_put(struct nvmem_device *nvmem);
+  int nvmem_device_read(struct nvmem_device *nvmem, unsigned int offset,
+		      size_t bytes, void *buf);
+  int nvmem_device_write(struct nvmem_device *nvmem, unsigned int offset,
+		       size_t bytes, void *buf);
+  int nvmem_device_cell_read(struct nvmem_device *nvmem,
+			   struct nvmem_cell_info *info, void *buf);
+  int nvmem_device_cell_write(struct nvmem_device *nvmem,
+			    struct nvmem_cell_info *info, void *buf);
+
+Before the consumers can read/write NVMEM directly, it should get hold
+of nvmem_controller from one of the `*nvmem_device_get()` api.
+
+The difference between these apis and cell based apis is that these apis always
+take nvmem_device as parameter.
+
+5. Releasing a reference to the NVMEM
+=====================================
+
+When a consumer no longer needs the NVMEM, it has to release the reference
+to the NVMEM it has obtained using the APIs mentioned in the above section.
+The NVMEM framework provides 2 APIs to release a reference to the NVMEM::
+
+  void nvmem_cell_put(struct nvmem_cell *cell);
+  void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell);
+  void nvmem_device_put(struct nvmem_device *nvmem);
+  void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem);
+
+Both these APIs are used to release a reference to the NVMEM and
+devm_nvmem_cell_put and devm_nvmem_device_put destroys the devres associated
+with this NVMEM.
+
+Userspace
++++++++++
+
+6. Userspace binary interface
+==============================
+
+Userspace can read/write the raw NVMEM file located at::
+
+	/sys/bus/nvmem/devices/*/nvmem
+
+ex::
+
+  hexdump /sys/bus/nvmem/devices/qfprom0/nvmem
+
+  0000000 0000 0000 0000 0000 0000 0000 0000 0000
+  *
+  00000a0 db10 2240 0000 e000 0c00 0c00 0000 0c00
+  0000000 0000 0000 0000 0000 0000 0000 0000 0000
+  ...
+  *
+  0001000
+
+7. DeviceTree Binding
+=====================
+
+See Documentation/devicetree/bindings/nvmem/nvmem.txt
diff --git a/Documentation/driver-api/parport-lowlevel.rst b/Documentation/driver-api/parport-lowlevel.rst
new file mode 100644
index 000000000000..0633d70ffda7
--- /dev/null
+++ b/Documentation/driver-api/parport-lowlevel.rst
@@ -0,0 +1,1832 @@
+===============================
+PARPORT interface documentation
+===============================
+
+:Time-stamp: <2000-02-24 13:30:20 twaugh>
+
+Described here are the following functions:
+
+Global functions::
+  parport_register_driver
+  parport_unregister_driver
+  parport_enumerate
+  parport_register_device
+  parport_unregister_device
+  parport_claim
+  parport_claim_or_block
+  parport_release
+  parport_yield
+  parport_yield_blocking
+  parport_wait_peripheral
+  parport_poll_peripheral
+  parport_wait_event
+  parport_negotiate
+  parport_read
+  parport_write
+  parport_open
+  parport_close
+  parport_device_id
+  parport_device_coords
+  parport_find_class
+  parport_find_device
+  parport_set_timeout
+
+Port functions (can be overridden by low-level drivers):
+
+  SPP::
+    port->ops->read_data
+    port->ops->write_data
+    port->ops->read_status
+    port->ops->read_control
+    port->ops->write_control
+    port->ops->frob_control
+    port->ops->enable_irq
+    port->ops->disable_irq
+    port->ops->data_forward
+    port->ops->data_reverse
+
+  EPP::
+    port->ops->epp_write_data
+    port->ops->epp_read_data
+    port->ops->epp_write_addr
+    port->ops->epp_read_addr
+
+  ECP::
+    port->ops->ecp_write_data
+    port->ops->ecp_read_data
+    port->ops->ecp_write_addr
+
+  Other::
+    port->ops->nibble_read_data
+    port->ops->byte_read_data
+    port->ops->compat_write_data
+
+The parport subsystem comprises ``parport`` (the core port-sharing
+code), and a variety of low-level drivers that actually do the port
+accesses.  Each low-level driver handles a particular style of port
+(PC, Amiga, and so on).
+
+The parport interface to the device driver author can be broken down
+into global functions and port functions.
+
+The global functions are mostly for communicating between the device
+driver and the parport subsystem: acquiring a list of available ports,
+claiming a port for exclusive use, and so on.  They also include
+``generic`` functions for doing standard things that will work on any
+IEEE 1284-capable architecture.
+
+The port functions are provided by the low-level drivers, although the
+core parport module provides generic ``defaults`` for some routines.
+The port functions can be split into three groups: SPP, EPP, and ECP.
+
+SPP (Standard Parallel Port) functions modify so-called ``SPP``
+registers: data, status, and control.  The hardware may not actually
+have registers exactly like that, but the PC does and this interface is
+modelled after common PC implementations.  Other low-level drivers may
+be able to emulate most of the functionality.
+
+EPP (Enhanced Parallel Port) functions are provided for reading and
+writing in IEEE 1284 EPP mode, and ECP (Extended Capabilities Port)
+functions are used for IEEE 1284 ECP mode. (What about BECP? Does
+anyone care?)
+
+Hardware assistance for EPP and/or ECP transfers may or may not be
+available, and if it is available it may or may not be used.  If
+hardware is not used, the transfer will be software-driven.  In order
+to cope with peripherals that only tenuously support IEEE 1284, a
+low-level driver specific function is provided, for altering 'fudge
+factors'.
+
+Global functions
+================
+
+parport_register_driver - register a device driver with parport
+---------------------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	struct parport_driver {
+		const char *name;
+		void (*attach) (struct parport *);
+		void (*detach) (struct parport *);
+		struct parport_driver *next;
+	};
+	int parport_register_driver (struct parport_driver *driver);
+
+DESCRIPTION
+^^^^^^^^^^^
+
+In order to be notified about parallel ports when they are detected,
+parport_register_driver should be called.  Your driver will
+immediately be notified of all ports that have already been detected,
+and of each new port as low-level drivers are loaded.
+
+A ``struct parport_driver`` contains the textual name of your driver,
+a pointer to a function to handle new ports, and a pointer to a
+function to handle ports going away due to a low-level driver
+unloading.  Ports will only be detached if they are not being used
+(i.e. there are no devices registered on them).
+
+The visible parts of the ``struct parport *`` argument given to
+attach/detach are::
+
+	struct parport
+	{
+		struct parport *next; /* next parport in list */
+		const char *name;     /* port's name */
+		unsigned int modes;   /* bitfield of hardware modes */
+		struct parport_device_info probe_info;
+				/* IEEE1284 info */
+		int number;           /* parport index */
+		struct parport_operations *ops;
+		...
+	};
+
+There are other members of the structure, but they should not be
+touched.
+
+The ``modes`` member summarises the capabilities of the underlying
+hardware.  It consists of flags which may be bitwise-ored together:
+
+  ============================= ===============================================
+  PARPORT_MODE_PCSPP		IBM PC registers are available,
+				i.e. functions that act on data,
+				control and status registers are
+				probably writing directly to the
+				hardware.
+  PARPORT_MODE_TRISTATE		The data drivers may be turned off.
+				This allows the data lines to be used
+				for reverse (peripheral to host)
+				transfers.
+  PARPORT_MODE_COMPAT		The hardware can assist with
+				compatibility-mode (printer)
+				transfers, i.e. compat_write_block.
+  PARPORT_MODE_EPP		The hardware can assist with EPP
+				transfers.
+  PARPORT_MODE_ECP		The hardware can assist with ECP
+				transfers.
+  PARPORT_MODE_DMA		The hardware can use DMA, so you might
+				want to pass ISA DMA-able memory
+				(i.e. memory allocated using the
+				GFP_DMA flag with kmalloc) to the
+				low-level driver in order to take
+				advantage of it.
+  ============================= ===============================================
+
+There may be other flags in ``modes`` as well.
+
+The contents of ``modes`` is advisory only.  For example, if the
+hardware is capable of DMA, and PARPORT_MODE_DMA is in ``modes``, it
+doesn't necessarily mean that DMA will always be used when possible.
+Similarly, hardware that is capable of assisting ECP transfers won't
+necessarily be used.
+
+RETURN VALUE
+^^^^^^^^^^^^
+
+Zero on success, otherwise an error code.
+
+ERRORS
+^^^^^^
+
+None. (Can it fail? Why return int?)
+
+EXAMPLE
+^^^^^^^
+
+::
+
+	static void lp_attach (struct parport *port)
+	{
+		...
+		private = kmalloc (...);
+		dev[count++] = parport_register_device (...);
+		...
+	}
+
+	static void lp_detach (struct parport *port)
+	{
+		...
+	}
+
+	static struct parport_driver lp_driver = {
+		"lp",
+		lp_attach,
+		lp_detach,
+		NULL /* always put NULL here */
+	};
+
+	int lp_init (void)
+	{
+		...
+		if (parport_register_driver (&lp_driver)) {
+			/* Failed; nothing we can do. */
+			return -EIO;
+		}
+		...
+	}
+
+
+SEE ALSO
+^^^^^^^^
+
+parport_unregister_driver, parport_register_device, parport_enumerate
+
+
+
+parport_unregister_driver - tell parport to forget about this driver
+--------------------------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	struct parport_driver {
+		const char *name;
+		void (*attach) (struct parport *);
+		void (*detach) (struct parport *);
+		struct parport_driver *next;
+	};
+	void parport_unregister_driver (struct parport_driver *driver);
+
+DESCRIPTION
+^^^^^^^^^^^
+
+This tells parport not to notify the device driver of new ports or of
+ports going away.  Registered devices belonging to that driver are NOT
+unregistered: parport_unregister_device must be used for each one.
+
+EXAMPLE
+^^^^^^^
+
+::
+
+	void cleanup_module (void)
+	{
+		...
+		/* Stop notifications. */
+		parport_unregister_driver (&lp_driver);
+
+		/* Unregister devices. */
+		for (i = 0; i < NUM_DEVS; i++)
+			parport_unregister_device (dev[i]);
+		...
+	}
+
+SEE ALSO
+^^^^^^^^
+
+parport_register_driver, parport_enumerate
+
+
+
+parport_enumerate - retrieve a list of parallel ports (DEPRECATED)
+------------------------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	struct parport *parport_enumerate (void);
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Retrieve the first of a list of valid parallel ports for this machine.
+Successive parallel ports can be found using the ``struct parport
+*next`` element of the ``struct parport *`` that is returned.  If ``next``
+is NULL, there are no more parallel ports in the list.  The number of
+ports in the list will not exceed PARPORT_MAX.
+
+RETURN VALUE
+^^^^^^^^^^^^
+
+A ``struct parport *`` describing a valid parallel port for the machine,
+or NULL if there are none.
+
+ERRORS
+^^^^^^
+
+This function can return NULL to indicate that there are no parallel
+ports to use.
+
+EXAMPLE
+^^^^^^^
+
+::
+
+	int detect_device (void)
+	{
+		struct parport *port;
+
+		for (port = parport_enumerate ();
+		port != NULL;
+		port = port->next) {
+			/* Try to detect a device on the port... */
+			...
+		}
+		}
+
+		...
+	}
+
+NOTES
+^^^^^
+
+parport_enumerate is deprecated; parport_register_driver should be
+used instead.
+
+SEE ALSO
+^^^^^^^^
+
+parport_register_driver, parport_unregister_driver
+
+
+
+parport_register_device - register to use a port
+------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	typedef int (*preempt_func) (void *handle);
+	typedef void (*wakeup_func) (void *handle);
+	typedef int (*irq_func) (int irq, void *handle, struct pt_regs *);
+
+	struct pardevice *parport_register_device(struct parport *port,
+						  const char *name,
+						  preempt_func preempt,
+						  wakeup_func wakeup,
+						  irq_func irq,
+						  int flags,
+						  void *handle);
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Use this function to register your device driver on a parallel port
+(``port``).  Once you have done that, you will be able to use
+parport_claim and parport_release in order to use the port.
+
+The (``name``) argument is the name of the device that appears in /proc
+filesystem. The string must be valid for the whole lifetime of the
+device (until parport_unregister_device is called).
+
+This function will register three callbacks into your driver:
+``preempt``, ``wakeup`` and ``irq``.  Each of these may be NULL in order to
+indicate that you do not want a callback.
+
+When the ``preempt`` function is called, it is because another driver
+wishes to use the parallel port.  The ``preempt`` function should return
+non-zero if the parallel port cannot be released yet -- if zero is
+returned, the port is lost to another driver and the port must be
+re-claimed before use.
+
+The ``wakeup`` function is called once another driver has released the
+port and no other driver has yet claimed it.  You can claim the
+parallel port from within the ``wakeup`` function (in which case the
+claim is guaranteed to succeed), or choose not to if you don't need it
+now.
+
+If an interrupt occurs on the parallel port your driver has claimed,
+the ``irq`` function will be called. (Write something about shared
+interrupts here.)
+
+The ``handle`` is a pointer to driver-specific data, and is passed to
+the callback functions.
+
+``flags`` may be a bitwise combination of the following flags:
+
+  ===================== =================================================
+        Flag            Meaning
+  ===================== =================================================
+  PARPORT_DEV_EXCL	The device cannot share the parallel port at all.
+			Use this only when absolutely necessary.
+  ===================== =================================================
+
+The typedefs are not actually defined -- they are only shown in order
+to make the function prototype more readable.
+
+The visible parts of the returned ``struct pardevice`` are::
+
+	struct pardevice {
+		struct parport *port;	/* Associated port */
+		void *private;		/* Device driver's 'handle' */
+		...
+	};
+
+RETURN VALUE
+^^^^^^^^^^^^
+
+A ``struct pardevice *``: a handle to the registered parallel port
+device that can be used for parport_claim, parport_release, etc.
+
+ERRORS
+^^^^^^
+
+A return value of NULL indicates that there was a problem registering
+a device on that port.
+
+EXAMPLE
+^^^^^^^
+
+::
+
+	static int preempt (void *handle)
+	{
+		if (busy_right_now)
+			return 1;
+
+		must_reclaim_port = 1;
+		return 0;
+	}
+
+	static void wakeup (void *handle)
+	{
+		struct toaster *private = handle;
+		struct pardevice *dev = private->dev;
+		if (!dev) return; /* avoid races */
+
+		if (want_port)
+			parport_claim (dev);
+	}
+
+	static int toaster_detect (struct toaster *private, struct parport *port)
+	{
+		private->dev = parport_register_device (port, "toaster", preempt,
+							wakeup, NULL, 0,
+							private);
+		if (!private->dev)
+			/* Couldn't register with parport. */
+			return -EIO;
+
+		must_reclaim_port = 0;
+		busy_right_now = 1;
+		parport_claim_or_block (private->dev);
+		...
+		/* Don't need the port while the toaster warms up. */
+		busy_right_now = 0;
+		...
+		busy_right_now = 1;
+		if (must_reclaim_port) {
+			parport_claim_or_block (private->dev);
+			must_reclaim_port = 0;
+		}
+		...
+	}
+
+SEE ALSO
+^^^^^^^^
+
+parport_unregister_device, parport_claim
+
+
+
+parport_unregister_device - finish using a port
+-----------------------------------------------
+
+SYNPOPSIS
+
+::
+
+	#include <linux/parport.h>
+
+	void parport_unregister_device (struct pardevice *dev);
+
+DESCRIPTION
+^^^^^^^^^^^
+
+This function is the opposite of parport_register_device.  After using
+parport_unregister_device, ``dev`` is no longer a valid device handle.
+
+You should not unregister a device that is currently claimed, although
+if you do it will be released automatically.
+
+EXAMPLE
+^^^^^^^
+
+::
+
+	...
+	kfree (dev->private); /* before we lose the pointer */
+	parport_unregister_device (dev);
+	...
+
+SEE ALSO
+^^^^^^^^
+
+
+parport_unregister_driver
+
+parport_claim, parport_claim_or_block - claim the parallel port for a device
+----------------------------------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	int parport_claim (struct pardevice *dev);
+	int parport_claim_or_block (struct pardevice *dev);
+
+DESCRIPTION
+^^^^^^^^^^^
+
+These functions attempt to gain control of the parallel port on which
+``dev`` is registered.  ``parport_claim`` does not block, but
+``parport_claim_or_block`` may do. (Put something here about blocking
+interruptibly or non-interruptibly.)
+
+You should not try to claim a port that you have already claimed.
+
+RETURN VALUE
+^^^^^^^^^^^^
+
+A return value of zero indicates that the port was successfully
+claimed, and the caller now has possession of the parallel port.
+
+If ``parport_claim_or_block`` blocks before returning successfully, the
+return value is positive.
+
+ERRORS
+^^^^^^
+
+========== ==========================================================
+  -EAGAIN  The port is unavailable at the moment, but another attempt
+           to claim it may succeed.
+========== ==========================================================
+
+SEE ALSO
+^^^^^^^^
+
+
+parport_release
+
+parport_release - release the parallel port
+-------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	void parport_release (struct pardevice *dev);
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Once a parallel port device has been claimed, it can be released using
+``parport_release``.  It cannot fail, but you should not release a
+device that you do not have possession of.
+
+EXAMPLE
+^^^^^^^
+
+::
+
+	static size_t write (struct pardevice *dev, const void *buf,
+			size_t len)
+	{
+		...
+		written = dev->port->ops->write_ecp_data (dev->port, buf,
+							len);
+		parport_release (dev);
+		...
+	}
+
+
+SEE ALSO
+^^^^^^^^
+
+change_mode, parport_claim, parport_claim_or_block, parport_yield
+
+
+
+parport_yield, parport_yield_blocking - temporarily release a parallel port
+---------------------------------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	int parport_yield (struct pardevice *dev)
+	int parport_yield_blocking (struct pardevice *dev);
+
+DESCRIPTION
+^^^^^^^^^^^
+
+When a driver has control of a parallel port, it may allow another
+driver to temporarily ``borrow`` it.  ``parport_yield`` does not block;
+``parport_yield_blocking`` may do.
+
+RETURN VALUE
+^^^^^^^^^^^^
+
+A return value of zero indicates that the caller still owns the port
+and the call did not block.
+
+A positive return value from ``parport_yield_blocking`` indicates that
+the caller still owns the port and the call blocked.
+
+A return value of -EAGAIN indicates that the caller no longer owns the
+port, and it must be re-claimed before use.
+
+ERRORS
+^^^^^^
+
+========= ==========================================================
+  -EAGAIN  Ownership of the parallel port was given away.
+========= ==========================================================
+
+SEE ALSO
+^^^^^^^^
+
+parport_release
+
+
+
+parport_wait_peripheral - wait for status lines, up to 35ms
+-----------------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	int parport_wait_peripheral (struct parport *port,
+				     unsigned char mask,
+				     unsigned char val);
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Wait for the status lines in mask to match the values in val.
+
+RETURN VALUE
+^^^^^^^^^^^^
+
+======== ==========================================================
+ -EINTR  a signal is pending
+      0  the status lines in mask have values in val
+      1  timed out while waiting (35ms elapsed)
+======== ==========================================================
+
+SEE ALSO
+^^^^^^^^
+
+parport_poll_peripheral
+
+
+
+parport_poll_peripheral - wait for status lines, in usec
+--------------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	int parport_poll_peripheral (struct parport *port,
+				     unsigned char mask,
+				     unsigned char val,
+				     int usec);
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Wait for the status lines in mask to match the values in val.
+
+RETURN VALUE
+^^^^^^^^^^^^
+
+======== ==========================================================
+ -EINTR  a signal is pending
+      0  the status lines in mask have values in val
+      1  timed out while waiting (usec microseconds have elapsed)
+======== ==========================================================
+
+SEE ALSO
+^^^^^^^^
+
+parport_wait_peripheral
+
+
+
+parport_wait_event - wait for an event on a port
+------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	int parport_wait_event (struct parport *port, signed long timeout)
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Wait for an event (e.g. interrupt) on a port.  The timeout is in
+jiffies.
+
+RETURN VALUE
+^^^^^^^^^^^^
+
+======= ==========================================================
+      0  success
+     <0  error (exit as soon as possible)
+     >0  timed out
+======= ==========================================================
+
+parport_negotiate - perform IEEE 1284 negotiation
+-------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	int parport_negotiate (struct parport *, int mode);
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Perform IEEE 1284 negotiation.
+
+RETURN VALUE
+^^^^^^^^^^^^
+
+======= ==========================================================
+     0  handshake OK; IEEE 1284 peripheral and mode available
+    -1  handshake failed; peripheral not compliant (or none present)
+     1  handshake OK; IEEE 1284 peripheral present but mode not
+        available
+======= ==========================================================
+
+SEE ALSO
+^^^^^^^^
+
+parport_read, parport_write
+
+
+
+parport_read - read data from device
+------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	ssize_t parport_read (struct parport *, void *buf, size_t len);
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Read data from device in current IEEE 1284 transfer mode.  This only
+works for modes that support reverse data transfer.
+
+RETURN VALUE
+^^^^^^^^^^^^
+
+If negative, an error code; otherwise the number of bytes transferred.
+
+SEE ALSO
+^^^^^^^^
+
+parport_write, parport_negotiate
+
+
+
+parport_write - write data to device
+------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	ssize_t parport_write (struct parport *, const void *buf, size_t len);
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Write data to device in current IEEE 1284 transfer mode.  This only
+works for modes that support forward data transfer.
+
+RETURN VALUE
+^^^^^^^^^^^^
+
+If negative, an error code; otherwise the number of bytes transferred.
+
+SEE ALSO
+^^^^^^^^
+
+parport_read, parport_negotiate
+
+
+
+parport_open - register device for particular device number
+-----------------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	struct pardevice *parport_open (int devnum, const char *name,
+				        int (*pf) (void *),
+					void (*kf) (void *),
+					void (*irqf) (int, void *,
+						      struct pt_regs *),
+					int flags, void *handle);
+
+DESCRIPTION
+^^^^^^^^^^^
+
+This is like parport_register_device but takes a device number instead
+of a pointer to a struct parport.
+
+RETURN VALUE
+^^^^^^^^^^^^
+
+See parport_register_device.  If no device is associated with devnum,
+NULL is returned.
+
+SEE ALSO
+^^^^^^^^
+
+parport_register_device
+
+
+
+parport_close - unregister device for particular device number
+--------------------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	void parport_close (struct pardevice *dev);
+
+DESCRIPTION
+^^^^^^^^^^^
+
+This is the equivalent of parport_unregister_device for parport_open.
+
+SEE ALSO
+^^^^^^^^
+
+parport_unregister_device, parport_open
+
+
+
+parport_device_id - obtain IEEE 1284 Device ID
+----------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	ssize_t parport_device_id (int devnum, char *buffer, size_t len);
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Obtains the IEEE 1284 Device ID associated with a given device.
+
+RETURN VALUE
+^^^^^^^^^^^^
+
+If negative, an error code; otherwise, the number of bytes of buffer
+that contain the device ID.  The format of the device ID is as
+follows::
+
+	[length][ID]
+
+The first two bytes indicate the inclusive length of the entire Device
+ID, and are in big-endian order.  The ID is a sequence of pairs of the
+form::
+
+	key:value;
+
+NOTES
+^^^^^
+
+Many devices have ill-formed IEEE 1284 Device IDs.
+
+SEE ALSO
+^^^^^^^^
+
+parport_find_class, parport_find_device
+
+
+
+parport_device_coords - convert device number to device coordinates
+-------------------------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	int parport_device_coords (int devnum, int *parport, int *mux,
+				   int *daisy);
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Convert between device number (zero-based) and device coordinates
+(port, multiplexor, daisy chain address).
+
+RETURN VALUE
+^^^^^^^^^^^^
+
+Zero on success, in which case the coordinates are (``*parport``, ``*mux``,
+``*daisy``).
+
+SEE ALSO
+^^^^^^^^
+
+parport_open, parport_device_id
+
+
+
+parport_find_class - find a device by its class
+-----------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	typedef enum {
+		PARPORT_CLASS_LEGACY = 0,       /* Non-IEEE1284 device */
+		PARPORT_CLASS_PRINTER,
+		PARPORT_CLASS_MODEM,
+		PARPORT_CLASS_NET,
+		PARPORT_CLASS_HDC,              /* Hard disk controller */
+		PARPORT_CLASS_PCMCIA,
+		PARPORT_CLASS_MEDIA,            /* Multimedia device */
+		PARPORT_CLASS_FDC,              /* Floppy disk controller */
+		PARPORT_CLASS_PORTS,
+		PARPORT_CLASS_SCANNER,
+		PARPORT_CLASS_DIGCAM,
+		PARPORT_CLASS_OTHER,            /* Anything else */
+		PARPORT_CLASS_UNSPEC,           /* No CLS field in ID */
+		PARPORT_CLASS_SCSIADAPTER
+	} parport_device_class;
+
+	int parport_find_class (parport_device_class cls, int from);
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Find a device by class.  The search starts from device number from+1.
+
+RETURN VALUE
+^^^^^^^^^^^^
+
+The device number of the next device in that class, or -1 if no such
+device exists.
+
+NOTES
+^^^^^
+
+Example usage::
+
+	int devnum = -1;
+	while ((devnum = parport_find_class (PARPORT_CLASS_DIGCAM, devnum)) != -1) {
+		struct pardevice *dev = parport_open (devnum, ...);
+		...
+	}
+
+SEE ALSO
+^^^^^^^^
+
+parport_find_device, parport_open, parport_device_id
+
+
+
+parport_find_device - find a device by its class
+------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	int parport_find_device (const char *mfg, const char *mdl, int from);
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Find a device by vendor and model.  The search starts from device
+number from+1.
+
+RETURN VALUE
+^^^^^^^^^^^^
+
+The device number of the next device matching the specifications, or
+-1 if no such device exists.
+
+NOTES
+^^^^^
+
+Example usage::
+
+	int devnum = -1;
+	while ((devnum = parport_find_device ("IOMEGA", "ZIP+", devnum)) != -1) {
+		struct pardevice *dev = parport_open (devnum, ...);
+		...
+	}
+
+SEE ALSO
+^^^^^^^^
+
+parport_find_class, parport_open, parport_device_id
+
+
+
+parport_set_timeout - set the inactivity timeout
+------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	long parport_set_timeout (struct pardevice *dev, long inactivity);
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Set the inactivity timeout, in jiffies, for a registered device.  The
+previous timeout is returned.
+
+RETURN VALUE
+^^^^^^^^^^^^
+
+The previous timeout, in jiffies.
+
+NOTES
+^^^^^
+
+Some of the port->ops functions for a parport may take time, owing to
+delays at the peripheral.  After the peripheral has not responded for
+``inactivity`` jiffies, a timeout will occur and the blocking function
+will return.
+
+A timeout of 0 jiffies is a special case: the function must do as much
+as it can without blocking or leaving the hardware in an unknown
+state.  If port operations are performed from within an interrupt
+handler, for instance, a timeout of 0 jiffies should be used.
+
+Once set for a registered device, the timeout will remain at the set
+value until set again.
+
+SEE ALSO
+^^^^^^^^
+
+port->ops->xxx_read/write_yyy
+
+
+
+
+PORT FUNCTIONS
+==============
+
+The functions in the port->ops structure (struct parport_operations)
+are provided by the low-level driver responsible for that port.
+
+port->ops->read_data - read the data register
+---------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	struct parport_operations {
+		...
+		unsigned char (*read_data) (struct parport *port);
+		...
+	};
+
+DESCRIPTION
+^^^^^^^^^^^
+
+If port->modes contains the PARPORT_MODE_TRISTATE flag and the
+PARPORT_CONTROL_DIRECTION bit in the control register is set, this
+returns the value on the data pins.  If port->modes contains the
+PARPORT_MODE_TRISTATE flag and the PARPORT_CONTROL_DIRECTION bit is
+not set, the return value _may_ be the last value written to the data
+register.  Otherwise the return value is undefined.
+
+SEE ALSO
+^^^^^^^^
+
+write_data, read_status, write_control
+
+
+
+port->ops->write_data - write the data register
+-----------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	struct parport_operations {
+		...
+		void (*write_data) (struct parport *port, unsigned char d);
+		...
+	};
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Writes to the data register.  May have side-effects (a STROBE pulse,
+for instance).
+
+SEE ALSO
+^^^^^^^^
+
+read_data, read_status, write_control
+
+
+
+port->ops->read_status - read the status register
+-------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	struct parport_operations {
+		...
+		unsigned char (*read_status) (struct parport *port);
+		...
+	};
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Reads from the status register.  This is a bitmask:
+
+- PARPORT_STATUS_ERROR (printer fault, "nFault")
+- PARPORT_STATUS_SELECT (on-line, "Select")
+- PARPORT_STATUS_PAPEROUT (no paper, "PError")
+- PARPORT_STATUS_ACK (handshake, "nAck")
+- PARPORT_STATUS_BUSY (busy, "Busy")
+
+There may be other bits set.
+
+SEE ALSO
+^^^^^^^^
+
+read_data, write_data, write_control
+
+
+
+port->ops->read_control - read the control register
+---------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	struct parport_operations {
+		...
+		unsigned char (*read_control) (struct parport *port);
+		...
+	};
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Returns the last value written to the control register (either from
+write_control or frob_control).  No port access is performed.
+
+SEE ALSO
+^^^^^^^^
+
+read_data, write_data, read_status, write_control
+
+
+
+port->ops->write_control - write the control register
+-----------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	struct parport_operations {
+		...
+		void (*write_control) (struct parport *port, unsigned char s);
+		...
+	};
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Writes to the control register. This is a bitmask::
+
+				  _______
+	- PARPORT_CONTROL_STROBE (nStrobe)
+				  _______
+	- PARPORT_CONTROL_AUTOFD (nAutoFd)
+				_____
+	- PARPORT_CONTROL_INIT (nInit)
+				  _________
+	- PARPORT_CONTROL_SELECT (nSelectIn)
+
+SEE ALSO
+^^^^^^^^
+
+read_data, write_data, read_status, frob_control
+
+
+
+port->ops->frob_control - write control register bits
+-----------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	struct parport_operations {
+		...
+		unsigned char (*frob_control) (struct parport *port,
+					unsigned char mask,
+					unsigned char val);
+		...
+	};
+
+DESCRIPTION
+^^^^^^^^^^^
+
+This is equivalent to reading from the control register, masking out
+the bits in mask, exclusive-or'ing with the bits in val, and writing
+the result to the control register.
+
+As some ports don't allow reads from the control port, a software copy
+of its contents is maintained, so frob_control is in fact only one
+port access.
+
+SEE ALSO
+^^^^^^^^
+
+read_data, write_data, read_status, write_control
+
+
+
+port->ops->enable_irq - enable interrupt generation
+---------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	struct parport_operations {
+		...
+		void (*enable_irq) (struct parport *port);
+		...
+	};
+
+DESCRIPTION
+^^^^^^^^^^^
+
+The parallel port hardware is instructed to generate interrupts at
+appropriate moments, although those moments are
+architecture-specific.  For the PC architecture, interrupts are
+commonly generated on the rising edge of nAck.
+
+SEE ALSO
+^^^^^^^^
+
+disable_irq
+
+
+
+port->ops->disable_irq - disable interrupt generation
+-----------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	struct parport_operations {
+		...
+		void (*disable_irq) (struct parport *port);
+		...
+	};
+
+DESCRIPTION
+^^^^^^^^^^^
+
+The parallel port hardware is instructed not to generate interrupts.
+The interrupt itself is not masked.
+
+SEE ALSO
+^^^^^^^^
+
+enable_irq
+
+
+
+port->ops->data_forward - enable data drivers
+---------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	struct parport_operations {
+		...
+		void (*data_forward) (struct parport *port);
+		...
+	};
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Enables the data line drivers, for 8-bit host-to-peripheral
+communications.
+
+SEE ALSO
+^^^^^^^^
+
+data_reverse
+
+
+
+port->ops->data_reverse - tristate the buffer
+---------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	struct parport_operations {
+		...
+		void (*data_reverse) (struct parport *port);
+		...
+	};
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Places the data bus in a high impedance state, if port->modes has the
+PARPORT_MODE_TRISTATE bit set.
+
+SEE ALSO
+^^^^^^^^
+
+data_forward
+
+
+
+port->ops->epp_write_data - write EPP data
+------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	struct parport_operations {
+		...
+		size_t (*epp_write_data) (struct parport *port, const void *buf,
+					size_t len, int flags);
+		...
+	};
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Writes data in EPP mode, and returns the number of bytes written.
+
+The ``flags`` parameter may be one or more of the following,
+bitwise-or'ed together:
+
+======================= =================================================
+PARPORT_EPP_FAST	Use fast transfers. Some chips provide 16-bit and
+			32-bit registers.  However, if a transfer
+			times out, the return value may be unreliable.
+======================= =================================================
+
+SEE ALSO
+^^^^^^^^
+
+epp_read_data, epp_write_addr, epp_read_addr
+
+
+
+port->ops->epp_read_data - read EPP data
+----------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	struct parport_operations {
+		...
+		size_t (*epp_read_data) (struct parport *port, void *buf,
+					size_t len, int flags);
+		...
+	};
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Reads data in EPP mode, and returns the number of bytes read.
+
+The ``flags`` parameter may be one or more of the following,
+bitwise-or'ed together:
+
+======================= =================================================
+PARPORT_EPP_FAST	Use fast transfers. Some chips provide 16-bit and
+			32-bit registers.  However, if a transfer
+			times out, the return value may be unreliable.
+======================= =================================================
+
+SEE ALSO
+^^^^^^^^
+
+epp_write_data, epp_write_addr, epp_read_addr
+
+
+
+port->ops->epp_write_addr - write EPP address
+---------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	struct parport_operations {
+		...
+		size_t (*epp_write_addr) (struct parport *port,
+					const void *buf, size_t len, int flags);
+		...
+	};
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Writes EPP addresses (8 bits each), and returns the number written.
+
+The ``flags`` parameter may be one or more of the following,
+bitwise-or'ed together:
+
+======================= =================================================
+PARPORT_EPP_FAST	Use fast transfers. Some chips provide 16-bit and
+			32-bit registers.  However, if a transfer
+			times out, the return value may be unreliable.
+======================= =================================================
+
+(Does PARPORT_EPP_FAST make sense for this function?)
+
+SEE ALSO
+^^^^^^^^
+
+epp_write_data, epp_read_data, epp_read_addr
+
+
+
+port->ops->epp_read_addr - read EPP address
+-------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	struct parport_operations {
+		...
+		size_t (*epp_read_addr) (struct parport *port, void *buf,
+					size_t len, int flags);
+		...
+	};
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Reads EPP addresses (8 bits each), and returns the number read.
+
+The ``flags`` parameter may be one or more of the following,
+bitwise-or'ed together:
+
+======================= =================================================
+PARPORT_EPP_FAST	Use fast transfers. Some chips provide 16-bit and
+			32-bit registers.  However, if a transfer
+			times out, the return value may be unreliable.
+======================= =================================================
+
+(Does PARPORT_EPP_FAST make sense for this function?)
+
+SEE ALSO
+^^^^^^^^
+
+epp_write_data, epp_read_data, epp_write_addr
+
+
+
+port->ops->ecp_write_data - write a block of ECP data
+-----------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	struct parport_operations {
+		...
+		size_t (*ecp_write_data) (struct parport *port,
+					const void *buf, size_t len, int flags);
+		...
+	};
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Writes a block of ECP data.  The ``flags`` parameter is ignored.
+
+RETURN VALUE
+^^^^^^^^^^^^
+
+The number of bytes written.
+
+SEE ALSO
+^^^^^^^^
+
+ecp_read_data, ecp_write_addr
+
+
+
+port->ops->ecp_read_data - read a block of ECP data
+---------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	struct parport_operations {
+		...
+		size_t (*ecp_read_data) (struct parport *port,
+					void *buf, size_t len, int flags);
+		...
+	};
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Reads a block of ECP data.  The ``flags`` parameter is ignored.
+
+RETURN VALUE
+^^^^^^^^^^^^
+
+The number of bytes read.  NB. There may be more unread data in a
+FIFO.  Is there a way of stunning the FIFO to prevent this?
+
+SEE ALSO
+^^^^^^^^
+
+ecp_write_block, ecp_write_addr
+
+
+
+port->ops->ecp_write_addr - write a block of ECP addresses
+----------------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	struct parport_operations {
+		...
+		size_t (*ecp_write_addr) (struct parport *port,
+					const void *buf, size_t len, int flags);
+		...
+	};
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Writes a block of ECP addresses.  The ``flags`` parameter is ignored.
+
+RETURN VALUE
+^^^^^^^^^^^^
+
+The number of bytes written.
+
+NOTES
+^^^^^
+
+This may use a FIFO, and if so shall not return until the FIFO is empty.
+
+SEE ALSO
+^^^^^^^^
+
+ecp_read_data, ecp_write_data
+
+
+
+port->ops->nibble_read_data - read a block of data in nibble mode
+-----------------------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	struct parport_operations {
+		...
+		size_t (*nibble_read_data) (struct parport *port,
+					void *buf, size_t len, int flags);
+		...
+	};
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Reads a block of data in nibble mode.  The ``flags`` parameter is ignored.
+
+RETURN VALUE
+^^^^^^^^^^^^
+
+The number of whole bytes read.
+
+SEE ALSO
+^^^^^^^^
+
+byte_read_data, compat_write_data
+
+
+
+port->ops->byte_read_data - read a block of data in byte mode
+-------------------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	struct parport_operations {
+		...
+		size_t (*byte_read_data) (struct parport *port,
+					void *buf, size_t len, int flags);
+		...
+	};
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Reads a block of data in byte mode.  The ``flags`` parameter is ignored.
+
+RETURN VALUE
+^^^^^^^^^^^^
+
+The number of bytes read.
+
+SEE ALSO
+^^^^^^^^
+
+nibble_read_data, compat_write_data
+
+
+
+port->ops->compat_write_data - write a block of data in compatibility mode
+--------------------------------------------------------------------------
+
+SYNOPSIS
+^^^^^^^^
+
+::
+
+	#include <linux/parport.h>
+
+	struct parport_operations {
+		...
+		size_t (*compat_write_data) (struct parport *port,
+					const void *buf, size_t len, int flags);
+		...
+	};
+
+DESCRIPTION
+^^^^^^^^^^^
+
+Writes a block of data in compatibility mode.  The ``flags`` parameter
+is ignored.
+
+RETURN VALUE
+^^^^^^^^^^^^
+
+The number of bytes written.
+
+SEE ALSO
+^^^^^^^^
+
+nibble_read_data, byte_read_data
diff --git a/Documentation/driver-api/pti_intel_mid.rst b/Documentation/driver-api/pti_intel_mid.rst
new file mode 100644
index 000000000000..20f1cff42d5f
--- /dev/null
+++ b/Documentation/driver-api/pti_intel_mid.rst
@@ -0,0 +1,106 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=============
+Intel MID PTI
+=============
+
+The Intel MID PTI project is HW implemented in Intel Atom
+system-on-a-chip designs based on the Parallel Trace
+Interface for MIPI P1149.7 cJTAG standard.  The kernel solution
+for this platform involves the following files::
+
+	./include/linux/pti.h
+	./drivers/.../n_tracesink.h
+	./drivers/.../n_tracerouter.c
+	./drivers/.../n_tracesink.c
+	./drivers/.../pti.c
+
+pti.c is the driver that enables various debugging features
+popular on platforms from certain mobile manufacturers.
+n_tracerouter.c and n_tracesink.c allow extra system information to
+be collected and routed to the pti driver, such as trace
+debugging data from a modem.  Although n_tracerouter
+and n_tracesink are a part of the complete PTI solution,
+these two line disciplines can work separately from
+pti.c and route any data stream from one /dev/tty node
+to another /dev/tty node via kernel-space.  This provides
+a stable, reliable connection that will not break unless
+the user-space application shuts down (plus avoids
+kernel->user->kernel context switch overheads of routing
+data).
+
+An example debugging usage for this driver system:
+
+  * Hook /dev/ttyPTI0 to syslogd.  Opening this port will also start
+    a console device to further capture debugging messages to PTI.
+  * Hook /dev/ttyPTI1 to modem debugging data to write to PTI HW.
+    This is where n_tracerouter and n_tracesink are used.
+  * Hook /dev/pti to a user-level debugging application for writing
+    to PTI HW.
+  * `Use mipi_` Kernel Driver API in other device drivers for
+    debugging to PTI by first requesting a PTI write address via
+    mipi_request_masterchannel(1).
+
+Below is example pseudo-code on how a 'privileged' application
+can hook up n_tracerouter and n_tracesink to any tty on
+a system.  'Privileged' means the application has enough
+privileges to successfully manipulate the ldisc drivers
+but is not just blindly executing as 'root'. Keep in mind
+the use of ioctl(,TIOCSETD,) is not specific to the n_tracerouter
+and n_tracesink line discpline drivers but is a generic
+operation for a program to use a line discpline driver
+on a tty port other than the default n_tty::
+
+  /////////// To hook up n_tracerouter and n_tracesink /////////
+
+  // Note that n_tracerouter depends on n_tracesink.
+  #include <errno.h>
+  #define ONE_TTY "/dev/ttyOne"
+  #define TWO_TTY "/dev/ttyTwo"
+
+  // needed global to hand onto ldisc connection
+  static int g_fd_source = -1;
+  static int g_fd_sink  = -1;
+
+  // these two vars used to grab LDISC values from loaded ldisc drivers
+  // in OS.  Look at /proc/tty/ldiscs to get the right numbers from
+  // the ldiscs loaded in the system.
+  int source_ldisc_num, sink_ldisc_num = -1;
+  int retval;
+
+  g_fd_source = open(ONE_TTY, O_RDWR); // must be R/W
+  g_fd_sink   = open(TWO_TTY, O_RDWR); // must be R/W
+
+  if (g_fd_source <= 0) || (g_fd_sink <= 0) {
+     // doubt you'll want to use these exact error lines of code
+     printf("Error on open(). errno: %d\n",errno);
+     return errno;
+  }
+
+  retval = ioctl(g_fd_sink, TIOCSETD, &sink_ldisc_num);
+  if (retval < 0) {
+     printf("Error on ioctl().  errno: %d\n", errno);
+     return errno;
+  }
+
+  retval = ioctl(g_fd_source, TIOCSETD, &source_ldisc_num);
+  if (retval < 0) {
+     printf("Error on ioctl().  errno: %d\n", errno);
+     return errno;
+  }
+
+  /////////// To disconnect n_tracerouter and n_tracesink ////////
+
+  // First make sure data through the ldiscs has stopped.
+
+  // Second, disconnect ldiscs.  This provides a
+  // little cleaner shutdown on tty stack.
+  sink_ldisc_num = 0;
+  source_ldisc_num = 0;
+  ioctl(g_fd_uart, TIOCSETD, &sink_ldisc_num);
+  ioctl(g_fd_gadget, TIOCSETD, &source_ldisc_num);
+
+  // Three, program closes connection, and cleanup:
+  close(g_fd_uart);
+  close(g_fd_gadget);
+  g_fd_uart = g_fd_gadget = NULL;
diff --git a/Documentation/driver-api/pwm.rst b/Documentation/driver-api/pwm.rst
new file mode 100644
index 000000000000..ab62f1bb0366
--- /dev/null
+++ b/Documentation/driver-api/pwm.rst
@@ -0,0 +1,165 @@
+======================================
+Pulse Width Modulation (PWM) interface
+======================================
+
+This provides an overview about the Linux PWM interface
+
+PWMs are commonly used for controlling LEDs, fans or vibrators in
+cell phones. PWMs with a fixed purpose have no need implementing
+the Linux PWM API (although they could). However, PWMs are often
+found as discrete devices on SoCs which have no fixed purpose. It's
+up to the board designer to connect them to LEDs or fans. To provide
+this kind of flexibility the generic PWM API exists.
+
+Identifying PWMs
+----------------
+
+Users of the legacy PWM API use unique IDs to refer to PWM devices.
+
+Instead of referring to a PWM device via its unique ID, board setup code
+should instead register a static mapping that can be used to match PWM
+consumers to providers, as given in the following example::
+
+	static struct pwm_lookup board_pwm_lookup[] = {
+		PWM_LOOKUP("tegra-pwm", 0, "pwm-backlight", NULL,
+			   50000, PWM_POLARITY_NORMAL),
+	};
+
+	static void __init board_init(void)
+	{
+		...
+		pwm_add_table(board_pwm_lookup, ARRAY_SIZE(board_pwm_lookup));
+		...
+	}
+
+Using PWMs
+----------
+
+Legacy users can request a PWM device using pwm_request() and free it
+after usage with pwm_free().
+
+New users should use the pwm_get() function and pass to it the consumer
+device or a consumer name. pwm_put() is used to free the PWM device. Managed
+variants of these functions, devm_pwm_get() and devm_pwm_put(), also exist.
+
+After being requested, a PWM has to be configured using::
+
+	int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state);
+
+This API controls both the PWM period/duty_cycle config and the
+enable/disable state.
+
+The pwm_config(), pwm_enable() and pwm_disable() functions are just wrappers
+around pwm_apply_state() and should not be used if the user wants to change
+several parameter at once. For example, if you see pwm_config() and
+pwm_{enable,disable}() calls in the same function, this probably means you
+should switch to pwm_apply_state().
+
+The PWM user API also allows one to query the PWM state with pwm_get_state().
+
+In addition to the PWM state, the PWM API also exposes PWM arguments, which
+are the reference PWM config one should use on this PWM.
+PWM arguments are usually platform-specific and allows the PWM user to only
+care about dutycycle relatively to the full period (like, duty = 50% of the
+period). struct pwm_args contains 2 fields (period and polarity) and should
+be used to set the initial PWM config (usually done in the probe function
+of the PWM user). PWM arguments are retrieved with pwm_get_args().
+
+All consumers should really be reconfiguring the PWM upon resume as
+appropriate. This is the only way to ensure that everything is resumed in
+the proper order.
+
+Using PWMs with the sysfs interface
+-----------------------------------
+
+If CONFIG_SYSFS is enabled in your kernel configuration a simple sysfs
+interface is provided to use the PWMs from userspace. It is exposed at
+/sys/class/pwm/. Each probed PWM controller/chip will be exported as
+pwmchipN, where N is the base of the PWM chip. Inside the directory you
+will find:
+
+  npwm
+    The number of PWM channels this chip supports (read-only).
+
+  export
+    Exports a PWM channel for use with sysfs (write-only).
+
+  unexport
+   Unexports a PWM channel from sysfs (write-only).
+
+The PWM channels are numbered using a per-chip index from 0 to npwm-1.
+
+When a PWM channel is exported a pwmX directory will be created in the
+pwmchipN directory it is associated with, where X is the number of the
+channel that was exported. The following properties will then be available:
+
+  period
+    The total period of the PWM signal (read/write).
+    Value is in nanoseconds and is the sum of the active and inactive
+    time of the PWM.
+
+  duty_cycle
+    The active time of the PWM signal (read/write).
+    Value is in nanoseconds and must be less than the period.
+
+  polarity
+    Changes the polarity of the PWM signal (read/write).
+    Writes to this property only work if the PWM chip supports changing
+    the polarity. The polarity can only be changed if the PWM is not
+    enabled. Value is the string "normal" or "inversed".
+
+  enable
+    Enable/disable the PWM signal (read/write).
+
+	- 0 - disabled
+	- 1 - enabled
+
+Implementing a PWM driver
+-------------------------
+
+Currently there are two ways to implement pwm drivers. Traditionally
+there only has been the barebone API meaning that each driver has
+to implement the pwm_*() functions itself. This means that it's impossible
+to have multiple PWM drivers in the system. For this reason it's mandatory
+for new drivers to use the generic PWM framework.
+
+A new PWM controller/chip can be added using pwmchip_add() and removed
+again with pwmchip_remove(). pwmchip_add() takes a filled in struct
+pwm_chip as argument which provides a description of the PWM chip, the
+number of PWM devices provided by the chip and the chip-specific
+implementation of the supported PWM operations to the framework.
+
+When implementing polarity support in a PWM driver, make sure to respect the
+signal conventions in the PWM framework. By definition, normal polarity
+characterizes a signal starts high for the duration of the duty cycle and
+goes low for the remainder of the period. Conversely, a signal with inversed
+polarity starts low for the duration of the duty cycle and goes high for the
+remainder of the period.
+
+Drivers are encouraged to implement ->apply() instead of the legacy
+->enable(), ->disable() and ->config() methods. Doing that should provide
+atomicity in the PWM config workflow, which is required when the PWM controls
+a critical device (like a regulator).
+
+The implementation of ->get_state() (a method used to retrieve initial PWM
+state) is also encouraged for the same reason: letting the PWM user know
+about the current PWM state would allow him to avoid glitches.
+
+Drivers should not implement any power management. In other words,
+consumers should implement it as described in the "Using PWMs" section.
+
+Locking
+-------
+
+The PWM core list manipulations are protected by a mutex, so pwm_request()
+and pwm_free() may not be called from an atomic context. Currently the
+PWM core does not enforce any locking to pwm_enable(), pwm_disable() and
+pwm_config(), so the calling context is currently driver specific. This
+is an issue derived from the former barebone API and should be fixed soon.
+
+Helpers
+-------
+
+Currently a PWM can only be configured with period_ns and duty_ns. For several
+use cases freq_hz and duty_percent might be better. Instead of calculating
+this in your driver please consider adding appropriate helpers to the framework.
diff --git a/Documentation/driver-api/rfkill.rst b/Documentation/driver-api/rfkill.rst
new file mode 100644
index 000000000000..7d3684e81df6
--- /dev/null
+++ b/Documentation/driver-api/rfkill.rst
@@ -0,0 +1,132 @@
+===============================
+rfkill - RF kill switch support
+===============================
+
+
+.. contents::
+   :depth: 2
+
+Introduction
+============
+
+The rfkill subsystem provides a generic interface for disabling any radio
+transmitter in the system. When a transmitter is blocked, it shall not
+radiate any power.
+
+The subsystem also provides the ability to react on button presses and
+disable all transmitters of a certain type (or all). This is intended for
+situations where transmitters need to be turned off, for example on
+aircraft.
+
+The rfkill subsystem has a concept of "hard" and "soft" block, which
+differ little in their meaning (block == transmitters off) but rather in
+whether they can be changed or not:
+
+ - hard block
+	read-only radio block that cannot be overridden by software
+
+ - soft block
+	writable radio block (need not be readable) that is set by
+        the system software.
+
+The rfkill subsystem has two parameters, rfkill.default_state and
+rfkill.master_switch_mode, which are documented in
+admin-guide/kernel-parameters.rst.
+
+
+Implementation details
+======================
+
+The rfkill subsystem is composed of three main components:
+
+ * the rfkill core,
+ * the deprecated rfkill-input module (an input layer handler, being
+   replaced by userspace policy code) and
+ * the rfkill drivers.
+
+The rfkill core provides API for kernel drivers to register their radio
+transmitter with the kernel, methods for turning it on and off, and letting
+the system know about hardware-disabled states that may be implemented on
+the device.
+
+The rfkill core code also notifies userspace of state changes, and provides
+ways for userspace to query the current states. See the "Userspace support"
+section below.
+
+When the device is hard-blocked (either by a call to rfkill_set_hw_state()
+or from query_hw_block), set_block() will be invoked for additional software
+block, but drivers can ignore the method call since they can use the return
+value of the function rfkill_set_hw_state() to sync the software state
+instead of keeping track of calls to set_block(). In fact, drivers should
+use the return value of rfkill_set_hw_state() unless the hardware actually
+keeps track of soft and hard block separately.
+
+
+Kernel API
+==========
+
+Drivers for radio transmitters normally implement an rfkill driver.
+
+Platform drivers might implement input devices if the rfkill button is just
+that, a button. If that button influences the hardware then you need to
+implement an rfkill driver instead. This also applies if the platform provides
+a way to turn on/off the transmitter(s).
+
+For some platforms, it is possible that the hardware state changes during
+suspend/hibernation, in which case it will be necessary to update the rfkill
+core with the current state at resume time.
+
+To create an rfkill driver, driver's Kconfig needs to have::
+
+	depends on RFKILL || !RFKILL
+
+to ensure the driver cannot be built-in when rfkill is modular. The !RFKILL
+case allows the driver to be built when rfkill is not configured, in which
+case all rfkill API can still be used but will be provided by static inlines
+which compile to almost nothing.
+
+Calling rfkill_set_hw_state() when a state change happens is required from
+rfkill drivers that control devices that can be hard-blocked unless they also
+assign the poll_hw_block() callback (then the rfkill core will poll the
+device). Don't do this unless you cannot get the event in any other way.
+
+rfkill provides per-switch LED triggers, which can be used to drive LEDs
+according to the switch state (LED_FULL when blocked, LED_OFF otherwise).
+
+
+Userspace support
+=================
+
+The recommended userspace interface to use is /dev/rfkill, which is a misc
+character device that allows userspace to obtain and set the state of rfkill
+devices and sets of devices. It also notifies userspace about device addition
+and removal. The API is a simple read/write API that is defined in
+linux/rfkill.h, with one ioctl that allows turning off the deprecated input
+handler in the kernel for the transition period.
+
+Except for the one ioctl, communication with the kernel is done via read()
+and write() of instances of 'struct rfkill_event'. In this structure, the
+soft and hard block are properly separated (unlike sysfs, see below) and
+userspace is able to get a consistent snapshot of all rfkill devices in the
+system. Also, it is possible to switch all rfkill drivers (or all drivers of
+a specified type) into a state which also updates the default state for
+hotplugged devices.
+
+After an application opens /dev/rfkill, it can read the current state of all
+devices. Changes can be obtained by either polling the descriptor for
+hotplug or state change events or by listening for uevents emitted by the
+rfkill core framework.
+
+Additionally, each rfkill device is registered in sysfs and emits uevents.
+
+rfkill devices issue uevents (with an action of "change"), with the following
+environment variables set::
+
+	RFKILL_NAME
+	RFKILL_STATE
+	RFKILL_TYPE
+
+The content of these variables corresponds to the "name", "state" and
+"type" sysfs files explained above.
+
+For further details consult Documentation/ABI/stable/sysfs-class-rfkill.
diff --git a/Documentation/driver-api/sgi-ioc4.rst b/Documentation/driver-api/sgi-ioc4.rst
new file mode 100644
index 000000000000..72709222d3c0
--- /dev/null
+++ b/Documentation/driver-api/sgi-ioc4.rst
@@ -0,0 +1,49 @@
+====================================
+SGI IOC4 PCI (multi function) device
+====================================
+
+The SGI IOC4 PCI device is a bit of a strange beast, so some notes on
+it are in order.
+
+First, even though the IOC4 performs multiple functions, such as an
+IDE controller, a serial controller, a PS/2 keyboard/mouse controller,
+and an external interrupt mechanism, it's not implemented as a
+multifunction device.  The consequence of this from a software
+standpoint is that all these functions share a single IRQ, and
+they can't all register to own the same PCI device ID.  To make
+matters a bit worse, some of the register blocks (and even registers
+themselves) present in IOC4 are mixed-purpose between these several
+functions, meaning that there's no clear "owning" device driver.
+
+The solution is to organize the IOC4 driver into several independent
+drivers, "ioc4", "sgiioc4", and "ioc4_serial".  Note that there is no
+PS/2 controller driver as this functionality has never been wired up
+on a shipping IO card.
+
+ioc4
+====
+This is the core (or shim) driver for IOC4.  It is responsible for
+initializing the basic functionality of the chip, and allocating
+the PCI resources that are shared between the IOC4 functions.
+
+This driver also provides registration functions that the other
+IOC4 drivers can call to make their presence known.  Each driver
+needs to provide a probe and remove function, which are invoked
+by the core driver at appropriate times.  The interface of these
+IOC4 function probe and remove operations isn't precisely the same
+as PCI device probe and remove operations, but is logically the
+same operation.
+
+sgiioc4
+=======
+This is the IDE driver for IOC4.  Its name isn't very descriptive
+simply for historical reasons (it used to be the only IOC4 driver
+component).  There's not much to say about it other than it hooks
+up to the ioc4 driver via the appropriate registration, probe, and
+remove functions.
+
+ioc4_serial
+===========
+This is the serial driver for IOC4.  There's not much to say about it
+other than it hooks up to the ioc4 driver via the appropriate registration,
+probe, and remove functions.
diff --git a/Documentation/driver-api/sm501.rst b/Documentation/driver-api/sm501.rst
new file mode 100644
index 000000000000..882507453ba4
--- /dev/null
+++ b/Documentation/driver-api/sm501.rst
@@ -0,0 +1,74 @@
+.. include:: <isonum.txt>
+
+============
+SM501 Driver
+============
+
+:Copyright: |copy| 2006, 2007 Simtec Electronics
+
+The Silicon Motion SM501 multimedia companion chip is a multifunction device
+which may provide numerous interfaces including USB host controller USB gadget,
+asynchronous serial ports, audio functions, and a dual display video interface.
+The device may be connected by PCI or local bus with varying functions enabled.
+
+Core
+----
+
+The core driver in drivers/mfd provides common services for the
+drivers which manage the specific hardware blocks. These services
+include locking for common registers, clock control and resource
+management.
+
+The core registers drivers for both PCI and generic bus based
+chips via the platform device and driver system.
+
+On detection of a device, the core initialises the chip (which may
+be specified by the platform data) and then exports the selected
+peripheral set as platform devices for the specific drivers.
+
+The core re-uses the platform device system as the platform device
+system provides enough features to support the drivers without the
+need to create a new bus-type and the associated code to go with it.
+
+
+Resources
+---------
+
+Each peripheral has a view of the device which is implicitly narrowed to
+the specific set of resources that peripheral requires in order to
+function correctly.
+
+The centralised memory allocation allows the driver to ensure that the
+maximum possible resource allocation can be made to the video subsystem
+as this is by-far the most resource-sensitive of the on-chip functions.
+
+The primary issue with memory allocation is that of moving the video
+buffers once a display mode is chosen. Indeed when a video mode change
+occurs the memory footprint of the video subsystem changes.
+
+Since video memory is difficult to move without changing the display
+(unless sufficient contiguous memory can be provided for the old and new
+modes simultaneously) the video driver fully utilises the memory area
+given to it by aligning fb0 to the start of the area and fb1 to the end
+of it. Any memory left over in the middle is used for the acceleration
+functions, which are transient and thus their location is less critical
+as it can be moved.
+
+
+Configuration
+-------------
+
+The platform device driver uses a set of platform data to pass
+configurations through to the core and the subsidiary drivers
+so that there can be support for more than one system carrying
+an SM501 built into a single kernel image.
+
+The PCI driver assumes that the PCI card behaves as per the Silicon
+Motion reference design.
+
+There is an errata (AB-5) affecting the selection of the
+of the M1XCLK and M1CLK frequencies. These two clocks
+must be sourced from the same PLL, although they can then
+be divided down individually. If this is not set, then SM501 may
+lock and hang the whole system. The driver will refuse to
+attach if the PLL selection is different.
diff --git a/Documentation/driver-api/smsc_ece1099.rst b/Documentation/driver-api/smsc_ece1099.rst
new file mode 100644
index 000000000000..079277421eaf
--- /dev/null
+++ b/Documentation/driver-api/smsc_ece1099.rst
@@ -0,0 +1,60 @@
+=================================================
+Msc Keyboard Scan Expansion/GPIO Expansion device
+=================================================
+
+What is smsc-ece1099?
+----------------------
+
+The ECE1099 is a 40-Pin 3.3V Keyboard Scan Expansion
+or GPIO Expansion device. The device supports a keyboard
+scan matrix of 23x8. The device is connected to a Master
+via the SMSC BC-Link interface or via the SMBus.
+Keypad scan Input(KSI) and Keypad Scan Output(KSO) signals
+are multiplexed with GPIOs.
+
+Interrupt generation
+--------------------
+
+Interrupts can be generated by an edge detection on a GPIO
+pin or an edge detection on one of the bus interface pins.
+Interrupts can also be detected on the keyboard scan interface.
+The bus interrupt pin (BC_INT# or SMBUS_INT#) is asserted if
+any bit in one of the Interrupt Status registers is 1 and
+the corresponding Interrupt Mask bit is also 1.
+
+In order for software to determine which device is the source
+of an interrupt, it should first read the Group Interrupt Status Register
+to determine which Status register group is a source for the interrupt.
+Software should read both the Status register and the associated Mask register,
+then AND the two values together. Bits that are 1 in the result of the AND
+are active interrupts. Software clears an interrupt by writing a 1 to the
+corresponding bit in the Status register.
+
+Communication Protocol
+----------------------
+
+- SMbus slave Interface
+	The host processor communicates with the ECE1099 device
+	through a series of read/write registers via the SMBus
+	interface. SMBus is a serial communication protocol between
+	a computer host and its peripheral devices. The SMBus data
+	rate is 10KHz minimum to 400 KHz maximum
+
+- Slave Bus Interface
+	The ECE1099 device SMBus implementation is a subset of the
+	SMBus interface to the host. The device is a slave-only SMBus device.
+	The implementation in the device is a subset of SMBus since it
+	only supports four protocols.
+
+	The Write Byte, Read Byte, Send Byte, and Receive Byte protocols are the
+	only valid SMBus protocols for the device.
+
+- BC-LinkTM Interface
+	The BC-Link is a proprietary bus that allows communication
+	between a Master device and a Companion device. The Master
+	device uses this serial bus to read and write registers
+	located on the Companion device. The bus comprises three signals,
+	BC_CLK, BC_DAT and BC_INT#. The Master device always provides the
+	clock, BC_CLK, and the Companion device is the source for an
+	independent asynchronous interrupt signal, BC_INT#. The ECE1099
+	supports BC-Link speeds up to 24MHz.
diff --git a/Documentation/driver-api/switchtec.rst b/Documentation/driver-api/switchtec.rst
new file mode 100644
index 000000000000..7611fdc53e19
--- /dev/null
+++ b/Documentation/driver-api/switchtec.rst
@@ -0,0 +1,102 @@
+========================
+Linux Switchtec Support
+========================
+
+Microsemi's "Switchtec" line of PCI switch devices is already
+supported by the kernel with standard PCI switch drivers. However, the
+Switchtec device advertises a special management endpoint which
+enables some additional functionality. This includes:
+
+* Packet and Byte Counters
+* Firmware Upgrades
+* Event and Error logs
+* Querying port link status
+* Custom user firmware commands
+
+The switchtec kernel module implements this functionality.
+
+
+Interface
+=========
+
+The primary means of communicating with the Switchtec management firmware is
+through the Memory-mapped Remote Procedure Call (MRPC) interface.
+Commands are submitted to the interface with a 4-byte command
+identifier and up to 1KB of command specific data. The firmware will
+respond with a 4-byte return code and up to 1KB of command-specific
+data. The interface only processes a single command at a time.
+
+
+Userspace Interface
+===================
+
+The MRPC interface will be exposed to userspace through a simple char
+device: /dev/switchtec#, one for each management endpoint in the system.
+
+The char device has the following semantics:
+
+* A write must consist of at least 4 bytes and no more than 1028 bytes.
+  The first 4 bytes will be interpreted as the Command ID and the
+  remainder will be used as the input data. A write will send the
+  command to the firmware to begin processing.
+
+* Each write must be followed by exactly one read. Any double write will
+  produce an error and any read that doesn't follow a write will
+  produce an error.
+
+* A read will block until the firmware completes the command and return
+  the 4-byte Command Return Value plus up to 1024 bytes of output
+  data. (The length will be specified by the size parameter of the read
+  call -- reading less than 4 bytes will produce an error.)
+
+* The poll call will also be supported for userspace applications that
+  need to do other things while waiting for the command to complete.
+
+The following IOCTLs are also supported by the device:
+
+* SWITCHTEC_IOCTL_FLASH_INFO - Retrieve firmware length and number
+  of partitions in the device.
+
+* SWITCHTEC_IOCTL_FLASH_PART_INFO - Retrieve address and lengeth for
+  any specified partition in flash.
+
+* SWITCHTEC_IOCTL_EVENT_SUMMARY - Read a structure of bitmaps
+  indicating all uncleared events.
+
+* SWITCHTEC_IOCTL_EVENT_CTL - Get the current count, clear and set flags
+  for any event. This ioctl takes in a switchtec_ioctl_event_ctl struct
+  with the event_id, index and flags set (index being the partition or PFF
+  number for non-global events). It returns whether the event has
+  occurred, the number of times and any event specific data. The flags
+  can be used to clear the count or enable and disable actions to
+  happen when the event occurs.
+  By using the SWITCHTEC_IOCTL_EVENT_FLAG_EN_POLL flag,
+  you can set an event to trigger a poll command to return with
+  POLLPRI. In this way, userspace can wait for events to occur.
+
+* SWITCHTEC_IOCTL_PFF_TO_PORT and SWITCHTEC_IOCTL_PORT_TO_PFF convert
+  between PCI Function Framework number (used by the event system)
+  and Switchtec Logic Port ID and Partition number (which is more
+  user friendly).
+
+
+Non-Transparent Bridge (NTB) Driver
+===================================
+
+An NTB hardware driver is provided for the Switchtec hardware in
+ntb_hw_switchtec. Currently, it only supports switches configured with
+exactly 2 NT partitions and zero or more non-NT partitions. It also requires
+the following configuration settings:
+
+* Both NT partitions must be able to access each other's GAS spaces.
+  Thus, the bits in the GAS Access Vector under Management Settings
+  must be set to support this.
+* Kernel configuration MUST include support for NTB (CONFIG_NTB needs
+  to be set)
+
+NT EP BAR 2 will be dynamically configured as a Direct Window, and
+the configuration file does not need to configure it explicitly.
+
+Please refer to Documentation/driver-api/ntb.rst in Linux source tree for an overall
+understanding of the Linux NTB stack. ntb_hw_switchtec works as an NTB
+Hardware Driver in this stack.
diff --git a/Documentation/driver-api/sync_file.rst b/Documentation/driver-api/sync_file.rst
new file mode 100644
index 000000000000..496fb2c3b3e6
--- /dev/null
+++ b/Documentation/driver-api/sync_file.rst
@@ -0,0 +1,86 @@
+===================
+Sync File API Guide
+===================
+
+:Author: Gustavo Padovan <gustavo at padovan dot org>
+
+This document serves as a guide for device drivers writers on what the
+sync_file API is, and how drivers can support it. Sync file is the carrier of
+the fences(struct dma_fence) that are needed to synchronize between drivers or
+across process boundaries.
+
+The sync_file API is meant to be used to send and receive fence information
+to/from userspace. It enables userspace to do explicit fencing, where instead
+of attaching a fence to the buffer a producer driver (such as a GPU or V4L
+driver) sends the fence related to the buffer to userspace via a sync_file.
+
+The sync_file then can be sent to the consumer (DRM driver for example), that
+will not use the buffer for anything before the fence(s) signals, i.e., the
+driver that issued the fence is not using/processing the buffer anymore, so it
+signals that the buffer is ready to use. And vice-versa for the consumer ->
+producer part of the cycle.
+
+Sync files allows userspace awareness on buffer sharing synchronization between
+drivers.
+
+Sync file was originally added in the Android kernel but current Linux Desktop
+can benefit a lot from it.
+
+in-fences and out-fences
+------------------------
+
+Sync files can go either to or from userspace. When a sync_file is sent from
+the driver to userspace we call the fences it contains 'out-fences'. They are
+related to a buffer that the driver is processing or is going to process, so
+the driver creates an out-fence to be able to notify, through
+dma_fence_signal(), when it has finished using (or processing) that buffer.
+Out-fences are fences that the driver creates.
+
+On the other hand if the driver receives fence(s) through a sync_file from
+userspace we call these fence(s) 'in-fences'. Receiving in-fences means that
+we need to wait for the fence(s) to signal before using any buffer related to
+the in-fences.
+
+Creating Sync Files
+-------------------
+
+When a driver needs to send an out-fence userspace it creates a sync_file.
+
+Interface::
+
+	struct sync_file *sync_file_create(struct dma_fence *fence);
+
+The caller pass the out-fence and gets back the sync_file. That is just the
+first step, next it needs to install an fd on sync_file->file. So it gets an
+fd::
+
+	fd = get_unused_fd_flags(O_CLOEXEC);
+
+and installs it on sync_file->file::
+
+	fd_install(fd, sync_file->file);
+
+The sync_file fd now can be sent to userspace.
+
+If the creation process fail, or the sync_file needs to be released by any
+other reason fput(sync_file->file) should be used.
+
+Receiving Sync Files from Userspace
+-----------------------------------
+
+When userspace needs to send an in-fence to the driver it passes file descriptor
+of the Sync File to the kernel. The kernel can then retrieve the fences
+from it.
+
+Interface::
+
+	struct dma_fence *sync_file_get_fence(int fd);
+
+
+The returned reference is owned by the caller and must be disposed of
+afterwards using dma_fence_put(). In case of error, a NULL is returned instead.
+
+References:
+
+1. struct sync_file in include/linux/sync_file.h
+2. All interfaces mentioned above defined in include/linux/sync_file.h
diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst
new file mode 100644
index 000000000000..25eb7d5b834b
--- /dev/null
+++ b/Documentation/driver-api/vfio-mediated-device.rst
@@ -0,0 +1,414 @@
+.. include:: <isonum.txt>
+
+=====================
+VFIO Mediated devices
+=====================
+
+:Copyright: |copy| 2016, NVIDIA CORPORATION. All rights reserved.
+:Author: Neo Jia <cjia@nvidia.com>
+:Author: Kirti Wankhede <kwankhede@nvidia.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License version 2 as
+published by the Free Software Foundation.
+
+
+Virtual Function I/O (VFIO) Mediated devices[1]
+===============================================
+
+The number of use cases for virtualizing DMA devices that do not have built-in
+SR_IOV capability is increasing. Previously, to virtualize such devices,
+developers had to create their own management interfaces and APIs, and then
+integrate them with user space software. To simplify integration with user space
+software, we have identified common requirements and a unified management
+interface for such devices.
+
+The VFIO driver framework provides unified APIs for direct device access. It is
+an IOMMU/device-agnostic framework for exposing direct device access to user
+space in a secure, IOMMU-protected environment. This framework is used for
+multiple devices, such as GPUs, network adapters, and compute accelerators. With
+direct device access, virtual machines or user space applications have direct
+access to the physical device. This framework is reused for mediated devices.
+
+The mediated core driver provides a common interface for mediated device
+management that can be used by drivers of different devices. This module
+provides a generic interface to perform these operations:
+
+* Create and destroy a mediated device
+* Add a mediated device to and remove it from a mediated bus driver
+* Add a mediated device to and remove it from an IOMMU group
+
+The mediated core driver also provides an interface to register a bus driver.
+For example, the mediated VFIO mdev driver is designed for mediated devices and
+supports VFIO APIs. The mediated bus driver adds a mediated device to and
+removes it from a VFIO group.
+
+The following high-level block diagram shows the main components and interfaces
+in the VFIO mediated driver framework. The diagram shows NVIDIA, Intel, and IBM
+devices as examples, as these devices are the first devices to use this module::
+
+     +---------------+
+     |               |
+     | +-----------+ |  mdev_register_driver() +--------------+
+     | |           | +<------------------------+              |
+     | |  mdev     | |                         |              |
+     | |  bus      | +------------------------>+ vfio_mdev.ko |<-> VFIO user
+     | |  driver   | |     probe()/remove()    |              |    APIs
+     | |           | |                         +--------------+
+     | +-----------+ |
+     |               |
+     |  MDEV CORE    |
+     |   MODULE      |
+     |   mdev.ko     |
+     | +-----------+ |  mdev_register_device() +--------------+
+     | |           | +<------------------------+              |
+     | |           | |                         |  nvidia.ko   |<-> physical
+     | |           | +------------------------>+              |    device
+     | |           | |        callbacks        +--------------+
+     | | Physical  | |
+     | |  device   | |  mdev_register_device() +--------------+
+     | | interface | |<------------------------+              |
+     | |           | |                         |  i915.ko     |<-> physical
+     | |           | +------------------------>+              |    device
+     | |           | |        callbacks        +--------------+
+     | |           | |
+     | |           | |  mdev_register_device() +--------------+
+     | |           | +<------------------------+              |
+     | |           | |                         | ccw_device.ko|<-> physical
+     | |           | +------------------------>+              |    device
+     | |           | |        callbacks        +--------------+
+     | +-----------+ |
+     +---------------+
+
+
+Registration Interfaces
+=======================
+
+The mediated core driver provides the following types of registration
+interfaces:
+
+* Registration interface for a mediated bus driver
+* Physical device driver interface
+
+Registration Interface for a Mediated Bus Driver
+------------------------------------------------
+
+The registration interface for a mediated bus driver provides the following
+structure to represent a mediated device's driver::
+
+     /*
+      * struct mdev_driver [2] - Mediated device's driver
+      * @name: driver name
+      * @probe: called when new device created
+      * @remove: called when device removed
+      * @driver: device driver structure
+      */
+     struct mdev_driver {
+	     const char *name;
+	     int  (*probe)  (struct device *dev);
+	     void (*remove) (struct device *dev);
+	     struct device_driver    driver;
+     };
+
+A mediated bus driver for mdev should use this structure in the function calls
+to register and unregister itself with the core driver:
+
+* Register::
+
+    extern int  mdev_register_driver(struct mdev_driver *drv,
+				   struct module *owner);
+
+* Unregister::
+
+    extern void mdev_unregister_driver(struct mdev_driver *drv);
+
+The mediated bus driver is responsible for adding mediated devices to the VFIO
+group when devices are bound to the driver and removing mediated devices from
+the VFIO when devices are unbound from the driver.
+
+
+Physical Device Driver Interface
+--------------------------------
+
+The physical device driver interface provides the mdev_parent_ops[3] structure
+to define the APIs to manage work in the mediated core driver that is related
+to the physical device.
+
+The structures in the mdev_parent_ops structure are as follows:
+
+* dev_attr_groups: attributes of the parent device
+* mdev_attr_groups: attributes of the mediated device
+* supported_config: attributes to define supported configurations
+
+The functions in the mdev_parent_ops structure are as follows:
+
+* create: allocate basic resources in a driver for a mediated device
+* remove: free resources in a driver when a mediated device is destroyed
+
+(Note that mdev-core provides no implicit serialization of create/remove
+callbacks per mdev parent device, per mdev type, or any other categorization.
+Vendor drivers are expected to be fully asynchronous in this respect or
+provide their own internal resource protection.)
+
+The callbacks in the mdev_parent_ops structure are as follows:
+
+* open: open callback of mediated device
+* close: close callback of mediated device
+* ioctl: ioctl callback of mediated device
+* read : read emulation callback
+* write: write emulation callback
+* mmap: mmap emulation callback
+
+A driver should use the mdev_parent_ops structure in the function call to
+register itself with the mdev core driver::
+
+	extern int  mdev_register_device(struct device *dev,
+	                                 const struct mdev_parent_ops *ops);
+
+However, the mdev_parent_ops structure is not required in the function call
+that a driver should use to unregister itself with the mdev core driver::
+
+	extern void mdev_unregister_device(struct device *dev);
+
+
+Mediated Device Management Interface Through sysfs
+==================================================
+
+The management interface through sysfs enables user space software, such as
+libvirt, to query and configure mediated devices in a hardware-agnostic fashion.
+This management interface provides flexibility to the underlying physical
+device's driver to support features such as:
+
+* Mediated device hot plug
+* Multiple mediated devices in a single virtual machine
+* Multiple mediated devices from different physical devices
+
+Links in the mdev_bus Class Directory
+-------------------------------------
+The /sys/class/mdev_bus/ directory contains links to devices that are registered
+with the mdev core driver.
+
+Directories and files under the sysfs for Each Physical Device
+--------------------------------------------------------------
+
+::
+
+  |- [parent physical device]
+  |--- Vendor-specific-attributes [optional]
+  |--- [mdev_supported_types]
+  |     |--- [<type-id>]
+  |     |   |--- create
+  |     |   |--- name
+  |     |   |--- available_instances
+  |     |   |--- device_api
+  |     |   |--- description
+  |     |   |--- [devices]
+  |     |--- [<type-id>]
+  |     |   |--- create
+  |     |   |--- name
+  |     |   |--- available_instances
+  |     |   |--- device_api
+  |     |   |--- description
+  |     |   |--- [devices]
+  |     |--- [<type-id>]
+  |          |--- create
+  |          |--- name
+  |          |--- available_instances
+  |          |--- device_api
+  |          |--- description
+  |          |--- [devices]
+
+* [mdev_supported_types]
+
+  The list of currently supported mediated device types and their details.
+
+  [<type-id>], device_api, and available_instances are mandatory attributes
+  that should be provided by vendor driver.
+
+* [<type-id>]
+
+  The [<type-id>] name is created by adding the device driver string as a prefix
+  to the string provided by the vendor driver. This format of this name is as
+  follows::
+
+	sprintf(buf, "%s-%s", dev_driver_string(parent->dev), group->name);
+
+  (or using mdev_parent_dev(mdev) to arrive at the parent device outside
+  of the core mdev code)
+
+* device_api
+
+  This attribute should show which device API is being created, for example,
+  "vfio-pci" for a PCI device.
+
+* available_instances
+
+  This attribute should show the number of devices of type <type-id> that can be
+  created.
+
+* [device]
+
+  This directory contains links to the devices of type <type-id> that have been
+  created.
+
+* name
+
+  This attribute should show human readable name. This is optional attribute.
+
+* description
+
+  This attribute should show brief features/description of the type. This is
+  optional attribute.
+
+Directories and Files Under the sysfs for Each mdev Device
+----------------------------------------------------------
+
+::
+
+  |- [parent phy device]
+  |--- [$MDEV_UUID]
+         |--- remove
+         |--- mdev_type {link to its type}
+         |--- vendor-specific-attributes [optional]
+
+* remove (write only)
+
+Writing '1' to the 'remove' file destroys the mdev device. The vendor driver can
+fail the remove() callback if that device is active and the vendor driver
+doesn't support hot unplug.
+
+Example::
+
+	# echo 1 > /sys/bus/mdev/devices/$mdev_UUID/remove
+
+Mediated device Hot plug
+------------------------
+
+Mediated devices can be created and assigned at runtime. The procedure to hot
+plug a mediated device is the same as the procedure to hot plug a PCI device.
+
+Translation APIs for Mediated Devices
+=====================================
+
+The following APIs are provided for translating user pfn to host pfn in a VFIO
+driver::
+
+	extern int vfio_pin_pages(struct device *dev, unsigned long *user_pfn,
+				  int npage, int prot, unsigned long *phys_pfn);
+
+	extern int vfio_unpin_pages(struct device *dev, unsigned long *user_pfn,
+				    int npage);
+
+These functions call back into the back-end IOMMU module by using the pin_pages
+and unpin_pages callbacks of the struct vfio_iommu_driver_ops[4]. Currently
+these callbacks are supported in the TYPE1 IOMMU module. To enable them for
+other IOMMU backend modules, such as PPC64 sPAPR module, they need to provide
+these two callback functions.
+
+Using the Sample Code
+=====================
+
+mtty.c in samples/vfio-mdev/ directory is a sample driver program to
+demonstrate how to use the mediated device framework.
+
+The sample driver creates an mdev device that simulates a serial port over a PCI
+card.
+
+1. Build and load the mtty.ko module.
+
+   This step creates a dummy device, /sys/devices/virtual/mtty/mtty/
+
+   Files in this device directory in sysfs are similar to the following::
+
+     # tree /sys/devices/virtual/mtty/mtty/
+        /sys/devices/virtual/mtty/mtty/
+        |-- mdev_supported_types
+        |   |-- mtty-1
+        |   |   |-- available_instances
+        |   |   |-- create
+        |   |   |-- device_api
+        |   |   |-- devices
+        |   |   `-- name
+        |   `-- mtty-2
+        |       |-- available_instances
+        |       |-- create
+        |       |-- device_api
+        |       |-- devices
+        |       `-- name
+        |-- mtty_dev
+        |   `-- sample_mtty_dev
+        |-- power
+        |   |-- autosuspend_delay_ms
+        |   |-- control
+        |   |-- runtime_active_time
+        |   |-- runtime_status
+        |   `-- runtime_suspended_time
+        |-- subsystem -> ../../../../class/mtty
+        `-- uevent
+
+2. Create a mediated device by using the dummy device that you created in the
+   previous step::
+
+     # echo "83b8f4f2-509f-382f-3c1e-e6bfe0fa1001" >	\
+              /sys/devices/virtual/mtty/mtty/mdev_supported_types/mtty-2/create
+
+3. Add parameters to qemu-kvm::
+
+     -device vfio-pci,\
+      sysfsdev=/sys/bus/mdev/devices/83b8f4f2-509f-382f-3c1e-e6bfe0fa1001
+
+4. Boot the VM.
+
+   In the Linux guest VM, with no hardware on the host, the device appears
+   as  follows::
+
+     # lspci -s 00:05.0 -xxvv
+     00:05.0 Serial controller: Device 4348:3253 (rev 10) (prog-if 02 [16550])
+             Subsystem: Device 4348:3253
+             Physical Slot: 5
+             Control: I/O+ Mem- BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr-
+     Stepping- SERR- FastB2B- DisINTx-
+             Status: Cap- 66MHz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort-
+     <TAbort- <MAbort- >SERR- <PERR- INTx-
+             Interrupt: pin A routed to IRQ 10
+             Region 0: I/O ports at c150 [size=8]
+             Region 1: I/O ports at c158 [size=8]
+             Kernel driver in use: serial
+     00: 48 43 53 32 01 00 00 02 10 02 00 07 00 00 00 00
+     10: 51 c1 00 00 59 c1 00 00 00 00 00 00 00 00 00 00
+     20: 00 00 00 00 00 00 00 00 00 00 00 00 48 43 53 32
+     30: 00 00 00 00 00 00 00 00 00 00 00 00 0a 01 00 00
+
+     In the Linux guest VM, dmesg output for the device is as follows:
+
+     serial 0000:00:05.0: PCI INT A -> Link[LNKA] -> GSI 10 (level, high) -> IRQ 10
+     0000:00:05.0: ttyS1 at I/O 0xc150 (irq = 10) is a 16550A
+     0000:00:05.0: ttyS2 at I/O 0xc158 (irq = 10) is a 16550A
+
+
+5. In the Linux guest VM, check the serial ports::
+
+     # setserial -g /dev/ttyS*
+     /dev/ttyS0, UART: 16550A, Port: 0x03f8, IRQ: 4
+     /dev/ttyS1, UART: 16550A, Port: 0xc150, IRQ: 10
+     /dev/ttyS2, UART: 16550A, Port: 0xc158, IRQ: 10
+
+6. Using minicom or any terminal emulation program, open port /dev/ttyS1 or
+   /dev/ttyS2 with hardware flow control disabled.
+
+7. Type data on the minicom terminal or send data to the terminal emulation
+   program and read the data.
+
+   Data is loop backed from hosts mtty driver.
+
+8. Destroy the mediated device that you created::
+
+     # echo 1 > /sys/bus/mdev/devices/83b8f4f2-509f-382f-3c1e-e6bfe0fa1001/remove
+
+References
+==========
+
+1. See Documentation/driver-api/vfio.rst for more information on VFIO.
+2. struct mdev_driver in include/linux/mdev.h
+3. struct mdev_parent_ops in include/linux/mdev.h
+4. struct vfio_iommu_driver_ops in include/linux/vfio.h
diff --git a/Documentation/driver-api/vfio.rst b/Documentation/driver-api/vfio.rst
new file mode 100644
index 000000000000..f1a4d3c3ba0b
--- /dev/null
+++ b/Documentation/driver-api/vfio.rst
@@ -0,0 +1,520 @@
+==================================
+VFIO - "Virtual Function I/O" [1]_
+==================================
+
+Many modern system now provide DMA and interrupt remapping facilities
+to help ensure I/O devices behave within the boundaries they've been
+allotted.  This includes x86 hardware with AMD-Vi and Intel VT-d,
+POWER systems with Partitionable Endpoints (PEs) and embedded PowerPC
+systems such as Freescale PAMU.  The VFIO driver is an IOMMU/device
+agnostic framework for exposing direct device access to userspace, in
+a secure, IOMMU protected environment.  In other words, this allows
+safe [2]_, non-privileged, userspace drivers.
+
+Why do we want that?  Virtual machines often make use of direct device
+access ("device assignment") when configured for the highest possible
+I/O performance.  From a device and host perspective, this simply
+turns the VM into a userspace driver, with the benefits of
+significantly reduced latency, higher bandwidth, and direct use of
+bare-metal device drivers [3]_.
+
+Some applications, particularly in the high performance computing
+field, also benefit from low-overhead, direct device access from
+userspace.  Examples include network adapters (often non-TCP/IP based)
+and compute accelerators.  Prior to VFIO, these drivers had to either
+go through the full development cycle to become proper upstream
+driver, be maintained out of tree, or make use of the UIO framework,
+which has no notion of IOMMU protection, limited interrupt support,
+and requires root privileges to access things like PCI configuration
+space.
+
+The VFIO driver framework intends to unify these, replacing both the
+KVM PCI specific device assignment code as well as provide a more
+secure, more featureful userspace driver environment than UIO.
+
+Groups, Devices, and IOMMUs
+---------------------------
+
+Devices are the main target of any I/O driver.  Devices typically
+create a programming interface made up of I/O access, interrupts,
+and DMA.  Without going into the details of each of these, DMA is
+by far the most critical aspect for maintaining a secure environment
+as allowing a device read-write access to system memory imposes the
+greatest risk to the overall system integrity.
+
+To help mitigate this risk, many modern IOMMUs now incorporate
+isolation properties into what was, in many cases, an interface only
+meant for translation (ie. solving the addressing problems of devices
+with limited address spaces).  With this, devices can now be isolated
+from each other and from arbitrary memory access, thus allowing
+things like secure direct assignment of devices into virtual machines.
+
+This isolation is not always at the granularity of a single device
+though.  Even when an IOMMU is capable of this, properties of devices,
+interconnects, and IOMMU topologies can each reduce this isolation.
+For instance, an individual device may be part of a larger multi-
+function enclosure.  While the IOMMU may be able to distinguish
+between devices within the enclosure, the enclosure may not require
+transactions between devices to reach the IOMMU.  Examples of this
+could be anything from a multi-function PCI device with backdoors
+between functions to a non-PCI-ACS (Access Control Services) capable
+bridge allowing redirection without reaching the IOMMU.  Topology
+can also play a factor in terms of hiding devices.  A PCIe-to-PCI
+bridge masks the devices behind it, making transaction appear as if
+from the bridge itself.  Obviously IOMMU design plays a major factor
+as well.
+
+Therefore, while for the most part an IOMMU may have device level
+granularity, any system is susceptible to reduced granularity.  The
+IOMMU API therefore supports a notion of IOMMU groups.  A group is
+a set of devices which is isolatable from all other devices in the
+system.  Groups are therefore the unit of ownership used by VFIO.
+
+While the group is the minimum granularity that must be used to
+ensure secure user access, it's not necessarily the preferred
+granularity.  In IOMMUs which make use of page tables, it may be
+possible to share a set of page tables between different groups,
+reducing the overhead both to the platform (reduced TLB thrashing,
+reduced duplicate page tables), and to the user (programming only
+a single set of translations).  For this reason, VFIO makes use of
+a container class, which may hold one or more groups.  A container
+is created by simply opening the /dev/vfio/vfio character device.
+
+On its own, the container provides little functionality, with all
+but a couple version and extension query interfaces locked away.
+The user needs to add a group into the container for the next level
+of functionality.  To do this, the user first needs to identify the
+group associated with the desired device.  This can be done using
+the sysfs links described in the example below.  By unbinding the
+device from the host driver and binding it to a VFIO driver, a new
+VFIO group will appear for the group as /dev/vfio/$GROUP, where
+$GROUP is the IOMMU group number of which the device is a member.
+If the IOMMU group contains multiple devices, each will need to
+be bound to a VFIO driver before operations on the VFIO group
+are allowed (it's also sufficient to only unbind the device from
+host drivers if a VFIO driver is unavailable; this will make the
+group available, but not that particular device).  TBD - interface
+for disabling driver probing/locking a device.
+
+Once the group is ready, it may be added to the container by opening
+the VFIO group character device (/dev/vfio/$GROUP) and using the
+VFIO_GROUP_SET_CONTAINER ioctl, passing the file descriptor of the
+previously opened container file.  If desired and if the IOMMU driver
+supports sharing the IOMMU context between groups, multiple groups may
+be set to the same container.  If a group fails to set to a container
+with existing groups, a new empty container will need to be used
+instead.
+
+With a group (or groups) attached to a container, the remaining
+ioctls become available, enabling access to the VFIO IOMMU interfaces.
+Additionally, it now becomes possible to get file descriptors for each
+device within a group using an ioctl on the VFIO group file descriptor.
+
+The VFIO device API includes ioctls for describing the device, the I/O
+regions and their read/write/mmap offsets on the device descriptor, as
+well as mechanisms for describing and registering interrupt
+notifications.
+
+VFIO Usage Example
+------------------
+
+Assume user wants to access PCI device 0000:06:0d.0::
+
+	$ readlink /sys/bus/pci/devices/0000:06:0d.0/iommu_group
+	../../../../kernel/iommu_groups/26
+
+This device is therefore in IOMMU group 26.  This device is on the
+pci bus, therefore the user will make use of vfio-pci to manage the
+group::
+
+	# modprobe vfio-pci
+
+Binding this device to the vfio-pci driver creates the VFIO group
+character devices for this group::
+
+	$ lspci -n -s 0000:06:0d.0
+	06:0d.0 0401: 1102:0002 (rev 08)
+	# echo 0000:06:0d.0 > /sys/bus/pci/devices/0000:06:0d.0/driver/unbind
+	# echo 1102 0002 > /sys/bus/pci/drivers/vfio-pci/new_id
+
+Now we need to look at what other devices are in the group to free
+it for use by VFIO::
+
+	$ ls -l /sys/bus/pci/devices/0000:06:0d.0/iommu_group/devices
+	total 0
+	lrwxrwxrwx. 1 root root 0 Apr 23 16:13 0000:00:1e.0 ->
+		../../../../devices/pci0000:00/0000:00:1e.0
+	lrwxrwxrwx. 1 root root 0 Apr 23 16:13 0000:06:0d.0 ->
+		../../../../devices/pci0000:00/0000:00:1e.0/0000:06:0d.0
+	lrwxrwxrwx. 1 root root 0 Apr 23 16:13 0000:06:0d.1 ->
+		../../../../devices/pci0000:00/0000:00:1e.0/0000:06:0d.1
+
+This device is behind a PCIe-to-PCI bridge [4]_, therefore we also
+need to add device 0000:06:0d.1 to the group following the same
+procedure as above.  Device 0000:00:1e.0 is a bridge that does
+not currently have a host driver, therefore it's not required to
+bind this device to the vfio-pci driver (vfio-pci does not currently
+support PCI bridges).
+
+The final step is to provide the user with access to the group if
+unprivileged operation is desired (note that /dev/vfio/vfio provides
+no capabilities on its own and is therefore expected to be set to
+mode 0666 by the system)::
+
+	# chown user:user /dev/vfio/26
+
+The user now has full access to all the devices and the iommu for this
+group and can access them as follows::
+
+	int container, group, device, i;
+	struct vfio_group_status group_status =
+					{ .argsz = sizeof(group_status) };
+	struct vfio_iommu_type1_info iommu_info = { .argsz = sizeof(iommu_info) };
+	struct vfio_iommu_type1_dma_map dma_map = { .argsz = sizeof(dma_map) };
+	struct vfio_device_info device_info = { .argsz = sizeof(device_info) };
+
+	/* Create a new container */
+	container = open("/dev/vfio/vfio", O_RDWR);
+
+	if (ioctl(container, VFIO_GET_API_VERSION) != VFIO_API_VERSION)
+		/* Unknown API version */
+
+	if (!ioctl(container, VFIO_CHECK_EXTENSION, VFIO_TYPE1_IOMMU))
+		/* Doesn't support the IOMMU driver we want. */
+
+	/* Open the group */
+	group = open("/dev/vfio/26", O_RDWR);
+
+	/* Test the group is viable and available */
+	ioctl(group, VFIO_GROUP_GET_STATUS, &group_status);
+
+	if (!(group_status.flags & VFIO_GROUP_FLAGS_VIABLE))
+		/* Group is not viable (ie, not all devices bound for vfio) */
+
+	/* Add the group to the container */
+	ioctl(group, VFIO_GROUP_SET_CONTAINER, &container);
+
+	/* Enable the IOMMU model we want */
+	ioctl(container, VFIO_SET_IOMMU, VFIO_TYPE1_IOMMU);
+
+	/* Get addition IOMMU info */
+	ioctl(container, VFIO_IOMMU_GET_INFO, &iommu_info);
+
+	/* Allocate some space and setup a DMA mapping */
+	dma_map.vaddr = mmap(0, 1024 * 1024, PROT_READ | PROT_WRITE,
+			     MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
+	dma_map.size = 1024 * 1024;
+	dma_map.iova = 0; /* 1MB starting at 0x0 from device view */
+	dma_map.flags = VFIO_DMA_MAP_FLAG_READ | VFIO_DMA_MAP_FLAG_WRITE;
+
+	ioctl(container, VFIO_IOMMU_MAP_DMA, &dma_map);
+
+	/* Get a file descriptor for the device */
+	device = ioctl(group, VFIO_GROUP_GET_DEVICE_FD, "0000:06:0d.0");
+
+	/* Test and setup the device */
+	ioctl(device, VFIO_DEVICE_GET_INFO, &device_info);
+
+	for (i = 0; i < device_info.num_regions; i++) {
+		struct vfio_region_info reg = { .argsz = sizeof(reg) };
+
+		reg.index = i;
+
+		ioctl(device, VFIO_DEVICE_GET_REGION_INFO, &reg);
+
+		/* Setup mappings... read/write offsets, mmaps
+		 * For PCI devices, config space is a region */
+	}
+
+	for (i = 0; i < device_info.num_irqs; i++) {
+		struct vfio_irq_info irq = { .argsz = sizeof(irq) };
+
+		irq.index = i;
+
+		ioctl(device, VFIO_DEVICE_GET_IRQ_INFO, &irq);
+
+		/* Setup IRQs... eventfds, VFIO_DEVICE_SET_IRQS */
+	}
+
+	/* Gratuitous device reset and go... */
+	ioctl(device, VFIO_DEVICE_RESET);
+
+VFIO User API
+-------------------------------------------------------------------------------
+
+Please see include/linux/vfio.h for complete API documentation.
+
+VFIO bus driver API
+-------------------------------------------------------------------------------
+
+VFIO bus drivers, such as vfio-pci make use of only a few interfaces
+into VFIO core.  When devices are bound and unbound to the driver,
+the driver should call vfio_add_group_dev() and vfio_del_group_dev()
+respectively::
+
+	extern int vfio_add_group_dev(struct device *dev,
+				      const struct vfio_device_ops *ops,
+				      void *device_data);
+
+	extern void *vfio_del_group_dev(struct device *dev);
+
+vfio_add_group_dev() indicates to the core to begin tracking the
+iommu_group of the specified dev and register the dev as owned by
+a VFIO bus driver.  The driver provides an ops structure for callbacks
+similar to a file operations structure::
+
+	struct vfio_device_ops {
+		int	(*open)(void *device_data);
+		void	(*release)(void *device_data);
+		ssize_t	(*read)(void *device_data, char __user *buf,
+				size_t count, loff_t *ppos);
+		ssize_t	(*write)(void *device_data, const char __user *buf,
+				 size_t size, loff_t *ppos);
+		long	(*ioctl)(void *device_data, unsigned int cmd,
+				 unsigned long arg);
+		int	(*mmap)(void *device_data, struct vm_area_struct *vma);
+	};
+
+Each function is passed the device_data that was originally registered
+in the vfio_add_group_dev() call above.  This allows the bus driver
+an easy place to store its opaque, private data.  The open/release
+callbacks are issued when a new file descriptor is created for a
+device (via VFIO_GROUP_GET_DEVICE_FD).  The ioctl interface provides
+a direct pass through for VFIO_DEVICE_* ioctls.  The read/write/mmap
+interfaces implement the device region access defined by the device's
+own VFIO_DEVICE_GET_REGION_INFO ioctl.
+
+
+PPC64 sPAPR implementation note
+-------------------------------
+
+This implementation has some specifics:
+
+1) On older systems (POWER7 with P5IOC2/IODA1) only one IOMMU group per
+   container is supported as an IOMMU table is allocated at the boot time,
+   one table per a IOMMU group which is a Partitionable Endpoint (PE)
+   (PE is often a PCI domain but not always).
+
+   Newer systems (POWER8 with IODA2) have improved hardware design which allows
+   to remove this limitation and have multiple IOMMU groups per a VFIO
+   container.
+
+2) The hardware supports so called DMA windows - the PCI address range
+   within which DMA transfer is allowed, any attempt to access address space
+   out of the window leads to the whole PE isolation.
+
+3) PPC64 guests are paravirtualized but not fully emulated. There is an API
+   to map/unmap pages for DMA, and it normally maps 1..32 pages per call and
+   currently there is no way to reduce the number of calls. In order to make
+   things faster, the map/unmap handling has been implemented in real mode
+   which provides an excellent performance which has limitations such as
+   inability to do locked pages accounting in real time.
+
+4) According to sPAPR specification, A Partitionable Endpoint (PE) is an I/O
+   subtree that can be treated as a unit for the purposes of partitioning and
+   error recovery. A PE may be a single or multi-function IOA (IO Adapter), a
+   function of a multi-function IOA, or multiple IOAs (possibly including
+   switch and bridge structures above the multiple IOAs). PPC64 guests detect
+   PCI errors and recover from them via EEH RTAS services, which works on the
+   basis of additional ioctl commands.
+
+   So 4 additional ioctls have been added:
+
+	VFIO_IOMMU_SPAPR_TCE_GET_INFO
+		returns the size and the start of the DMA window on the PCI bus.
+
+	VFIO_IOMMU_ENABLE
+		enables the container. The locked pages accounting
+		is done at this point. This lets user first to know what
+		the DMA window is and adjust rlimit before doing any real job.
+
+	VFIO_IOMMU_DISABLE
+		disables the container.
+
+	VFIO_EEH_PE_OP
+		provides an API for EEH setup, error detection and recovery.
+
+   The code flow from the example above should be slightly changed::
+
+	struct vfio_eeh_pe_op pe_op = { .argsz = sizeof(pe_op), .flags = 0 };
+
+	.....
+	/* Add the group to the container */
+	ioctl(group, VFIO_GROUP_SET_CONTAINER, &container);
+
+	/* Enable the IOMMU model we want */
+	ioctl(container, VFIO_SET_IOMMU, VFIO_SPAPR_TCE_IOMMU)
+
+	/* Get addition sPAPR IOMMU info */
+	vfio_iommu_spapr_tce_info spapr_iommu_info;
+	ioctl(container, VFIO_IOMMU_SPAPR_TCE_GET_INFO, &spapr_iommu_info);
+
+	if (ioctl(container, VFIO_IOMMU_ENABLE))
+		/* Cannot enable container, may be low rlimit */
+
+	/* Allocate some space and setup a DMA mapping */
+	dma_map.vaddr = mmap(0, 1024 * 1024, PROT_READ | PROT_WRITE,
+			     MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
+
+	dma_map.size = 1024 * 1024;
+	dma_map.iova = 0; /* 1MB starting at 0x0 from device view */
+	dma_map.flags = VFIO_DMA_MAP_FLAG_READ | VFIO_DMA_MAP_FLAG_WRITE;
+
+	/* Check here is .iova/.size are within DMA window from spapr_iommu_info */
+	ioctl(container, VFIO_IOMMU_MAP_DMA, &dma_map);
+
+	/* Get a file descriptor for the device */
+	device = ioctl(group, VFIO_GROUP_GET_DEVICE_FD, "0000:06:0d.0");
+
+	....
+
+	/* Gratuitous device reset and go... */
+	ioctl(device, VFIO_DEVICE_RESET);
+
+	/* Make sure EEH is supported */
+	ioctl(container, VFIO_CHECK_EXTENSION, VFIO_EEH);
+
+	/* Enable the EEH functionality on the device */
+	pe_op.op = VFIO_EEH_PE_ENABLE;
+	ioctl(container, VFIO_EEH_PE_OP, &pe_op);
+
+	/* You're suggested to create additional data struct to represent
+	 * PE, and put child devices belonging to same IOMMU group to the
+	 * PE instance for later reference.
+	 */
+
+	/* Check the PE's state and make sure it's in functional state */
+	pe_op.op = VFIO_EEH_PE_GET_STATE;
+	ioctl(container, VFIO_EEH_PE_OP, &pe_op);
+
+	/* Save device state using pci_save_state().
+	 * EEH should be enabled on the specified device.
+	 */
+
+	....
+
+	/* Inject EEH error, which is expected to be caused by 32-bits
+	 * config load.
+	 */
+	pe_op.op = VFIO_EEH_PE_INJECT_ERR;
+	pe_op.err.type = EEH_ERR_TYPE_32;
+	pe_op.err.func = EEH_ERR_FUNC_LD_CFG_ADDR;
+	pe_op.err.addr = 0ul;
+	pe_op.err.mask = 0ul;
+	ioctl(container, VFIO_EEH_PE_OP, &pe_op);
+
+	....
+
+	/* When 0xFF's returned from reading PCI config space or IO BARs
+	 * of the PCI device. Check the PE's state to see if that has been
+	 * frozen.
+	 */
+	ioctl(container, VFIO_EEH_PE_OP, &pe_op);
+
+	/* Waiting for pending PCI transactions to be completed and don't
+	 * produce any more PCI traffic from/to the affected PE until
+	 * recovery is finished.
+	 */
+
+	/* Enable IO for the affected PE and collect logs. Usually, the
+	 * standard part of PCI config space, AER registers are dumped
+	 * as logs for further analysis.
+	 */
+	pe_op.op = VFIO_EEH_PE_UNFREEZE_IO;
+	ioctl(container, VFIO_EEH_PE_OP, &pe_op);
+
+	/*
+	 * Issue PE reset: hot or fundamental reset. Usually, hot reset
+	 * is enough. However, the firmware of some PCI adapters would
+	 * require fundamental reset.
+	 */
+	pe_op.op = VFIO_EEH_PE_RESET_HOT;
+	ioctl(container, VFIO_EEH_PE_OP, &pe_op);
+	pe_op.op = VFIO_EEH_PE_RESET_DEACTIVATE;
+	ioctl(container, VFIO_EEH_PE_OP, &pe_op);
+
+	/* Configure the PCI bridges for the affected PE */
+	pe_op.op = VFIO_EEH_PE_CONFIGURE;
+	ioctl(container, VFIO_EEH_PE_OP, &pe_op);
+
+	/* Restored state we saved at initialization time. pci_restore_state()
+	 * is good enough as an example.
+	 */
+
+	/* Hopefully, error is recovered successfully. Now, you can resume to
+	 * start PCI traffic to/from the affected PE.
+	 */
+
+	....
+
+5) There is v2 of SPAPR TCE IOMMU. It deprecates VFIO_IOMMU_ENABLE/
+   VFIO_IOMMU_DISABLE and implements 2 new ioctls:
+   VFIO_IOMMU_SPAPR_REGISTER_MEMORY and VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY
+   (which are unsupported in v1 IOMMU).
+
+   PPC64 paravirtualized guests generate a lot of map/unmap requests,
+   and the handling of those includes pinning/unpinning pages and updating
+   mm::locked_vm counter to make sure we do not exceed the rlimit.
+   The v2 IOMMU splits accounting and pinning into separate operations:
+
+   - VFIO_IOMMU_SPAPR_REGISTER_MEMORY/VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY ioctls
+     receive a user space address and size of the block to be pinned.
+     Bisecting is not supported and VFIO_IOMMU_UNREGISTER_MEMORY is expected to
+     be called with the exact address and size used for registering
+     the memory block. The userspace is not expected to call these often.
+     The ranges are stored in a linked list in a VFIO container.
+
+   - VFIO_IOMMU_MAP_DMA/VFIO_IOMMU_UNMAP_DMA ioctls only update the actual
+     IOMMU table and do not do pinning; instead these check that the userspace
+     address is from pre-registered range.
+
+   This separation helps in optimizing DMA for guests.
+
+6) sPAPR specification allows guests to have an additional DMA window(s) on
+   a PCI bus with a variable page size. Two ioctls have been added to support
+   this: VFIO_IOMMU_SPAPR_TCE_CREATE and VFIO_IOMMU_SPAPR_TCE_REMOVE.
+   The platform has to support the functionality or error will be returned to
+   the userspace. The existing hardware supports up to 2 DMA windows, one is
+   2GB long, uses 4K pages and called "default 32bit window"; the other can
+   be as big as entire RAM, use different page size, it is optional - guests
+   create those in run-time if the guest driver supports 64bit DMA.
+
+   VFIO_IOMMU_SPAPR_TCE_CREATE receives a page shift, a DMA window size and
+   a number of TCE table levels (if a TCE table is going to be big enough and
+   the kernel may not be able to allocate enough of physically contiguous
+   memory). It creates a new window in the available slot and returns the bus
+   address where the new window starts. Due to hardware limitation, the user
+   space cannot choose the location of DMA windows.
+
+   VFIO_IOMMU_SPAPR_TCE_REMOVE receives the bus start address of the window
+   and removes it.
+
+-------------------------------------------------------------------------------
+
+.. [1] VFIO was originally an acronym for "Virtual Function I/O" in its
+   initial implementation by Tom Lyon while as Cisco.  We've since
+   outgrown the acronym, but it's catchy.
+
+.. [2] "safe" also depends upon a device being "well behaved".  It's
+   possible for multi-function devices to have backdoors between
+   functions and even for single function devices to have alternative
+   access to things like PCI config space through MMIO registers.  To
+   guard against the former we can include additional precautions in the
+   IOMMU driver to group multi-function PCI devices together
+   (iommu=group_mf).  The latter we can't prevent, but the IOMMU should
+   still provide isolation.  For PCI, SR-IOV Virtual Functions are the
+   best indicator of "well behaved", as these are designed for
+   virtualization usage models.
+
+.. [3] As always there are trade-offs to virtual machine device
+   assignment that are beyond the scope of VFIO.  It's expected that
+   future IOMMU technologies will reduce some, but maybe not all, of
+   these trade-offs.
+
+.. [4] In this case the device is below a PCI bridge, so transactions
+   from either function of the device are indistinguishable to the iommu::
+
+	-[0000:00]-+-1e.0-[06]--+-0d.0
+				\-0d.1
+
+	00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev 90)
diff --git a/Documentation/driver-api/xillybus.rst b/Documentation/driver-api/xillybus.rst
new file mode 100644
index 000000000000..2446ee303c09
--- /dev/null
+++ b/Documentation/driver-api/xillybus.rst
@@ -0,0 +1,379 @@
+==========================================
+Xillybus driver for generic FPGA interface
+==========================================
+
+:Author: Eli Billauer, Xillybus Ltd. (http://xillybus.com)
+:Email:  eli.billauer@gmail.com or as advertised on Xillybus' site.
+
+.. Contents:
+
+ - Introduction
+  -- Background
+  -- Xillybus Overview
+
+ - Usage
+  -- User interface
+  -- Synchronization
+  -- Seekable pipes
+
+ - Internals
+  -- Source code organization
+  -- Pipe attributes
+  -- Host never reads from the FPGA
+  -- Channels, pipes, and the message channel
+  -- Data streaming
+  -- Data granularity
+  -- Probing
+  -- Buffer allocation
+  -- The "nonempty" message (supporting poll)
+
+
+Introduction
+============
+
+Background
+----------
+
+An FPGA (Field Programmable Gate Array) is a piece of logic hardware, which
+can be programmed to become virtually anything that is usually found as a
+dedicated chipset: For instance, a display adapter, network interface card,
+or even a processor with its peripherals. FPGAs are the LEGO of hardware:
+Based upon certain building blocks, you make your own toys the way you like
+them. It's usually pointless to reimplement something that is already
+available on the market as a chipset, so FPGAs are mostly used when some
+special functionality is needed, and the production volume is relatively low
+(hence not justifying the development of an ASIC).
+
+The challenge with FPGAs is that everything is implemented at a very low
+level, even lower than assembly language. In order to allow FPGA designers to
+focus on their specific project, and not reinvent the wheel over and over
+again, pre-designed building blocks, IP cores, are often used. These are the
+FPGA parallels of library functions. IP cores may implement certain
+mathematical functions, a functional unit (e.g. a USB interface), an entire
+processor (e.g. ARM) or anything that might come handy. Think of them as a
+building block, with electrical wires dangling on the sides for connection to
+other blocks.
+
+One of the daunting tasks in FPGA design is communicating with a fullblown
+operating system (actually, with the processor running it): Implementing the
+low-level bus protocol and the somewhat higher-level interface with the host
+(registers, interrupts, DMA etc.) is a project in itself. When the FPGA's
+function is a well-known one (e.g. a video adapter card, or a NIC), it can
+make sense to design the FPGA's interface logic specifically for the project.
+A special driver is then written to present the FPGA as a well-known interface
+to the kernel and/or user space. In that case, there is no reason to treat the
+FPGA differently than any device on the bus.
+
+It's however common that the desired data communication doesn't fit any well-
+known peripheral function. Also, the effort of designing an elegant
+abstraction for the data exchange is often considered too big. In those cases,
+a quicker and possibly less elegant solution is sought: The driver is
+effectively written as a user space program, leaving the kernel space part
+with just elementary data transport. This still requires designing some
+interface logic for the FPGA, and write a simple ad-hoc driver for the kernel.
+
+Xillybus Overview
+-----------------
+
+Xillybus is an IP core and a Linux driver. Together, they form a kit for
+elementary data transport between an FPGA and the host, providing pipe-like
+data streams with a straightforward user interface. It's intended as a low-
+effort solution for mixed FPGA-host projects, for which it makes sense to
+have the project-specific part of the driver running in a user-space program.
+
+Since the communication requirements may vary significantly from one FPGA
+project to another (the number of data pipes needed in each direction and
+their attributes), there isn't one specific chunk of logic being the Xillybus
+IP core. Rather, the IP core is configured and built based upon a
+specification given by its end user.
+
+Xillybus presents independent data streams, which resemble pipes or TCP/IP
+communication to the user. At the host side, a character device file is used
+just like any pipe file. On the FPGA side, hardware FIFOs are used to stream
+the data. This is contrary to a common method of communicating through fixed-
+sized buffers (even though such buffers are used by Xillybus under the hood).
+There may be more than a hundred of these streams on a single IP core, but
+also no more than one, depending on the configuration.
+
+In order to ease the deployment of the Xillybus IP core, it contains a simple
+data structure which completely defines the core's configuration. The Linux
+driver fetches this data structure during its initialization process, and sets
+up the DMA buffers and character devices accordingly. As a result, a single
+driver is used to work out of the box with any Xillybus IP core.
+
+The data structure just mentioned should not be confused with PCI's
+configuration space or the Flattened Device Tree.
+
+Usage
+=====
+
+User interface
+--------------
+
+On the host, all interface with Xillybus is done through /dev/xillybus_*
+device files, which are generated automatically as the drivers loads. The
+names of these files depend on the IP core that is loaded in the FPGA (see
+Probing below). To communicate with the FPGA, open the device file that
+corresponds to the hardware FIFO you want to send data or receive data from,
+and use plain write() or read() calls, just like with a regular pipe. In
+particular, it makes perfect sense to go::
+
+	$ cat mydata > /dev/xillybus_thisfifo
+
+	$ cat /dev/xillybus_thatfifo > hisdata
+
+possibly pressing CTRL-C as some stage, even though the xillybus_* pipes have
+the capability to send an EOF (but may not use it).
+
+The driver and hardware are designed to behave sensibly as pipes, including:
+
+* Supporting non-blocking I/O (by setting O_NONBLOCK on open() ).
+
+* Supporting poll() and select().
+
+* Being bandwidth efficient under load (using DMA) but also handle small
+  pieces of data sent across (like TCP/IP) by autoflushing.
+
+A device file can be read only, write only or bidirectional. Bidirectional
+device files are treated like two independent pipes (except for sharing a
+"channel" structure in the implementation code).
+
+Synchronization
+---------------
+
+Xillybus pipes are configured (on the IP core) to be either synchronous or
+asynchronous. For a synchronous pipe, write() returns successfully only after
+some data has been submitted and acknowledged by the FPGA. This slows down
+bulk data transfers, and is nearly impossible for use with streams that
+require data at a constant rate: There is no data transmitted to the FPGA
+between write() calls, in particular when the process loses the CPU.
+
+When a pipe is configured asynchronous, write() returns if there was enough
+room in the buffers to store any of the data in the buffers.
+
+For FPGA to host pipes, asynchronous pipes allow data transfer from the FPGA
+as soon as the respective device file is opened, regardless of if the data
+has been requested by a read() call. On synchronous pipes, only the amount
+of data requested by a read() call is transmitted.
+
+In summary, for synchronous pipes, data between the host and FPGA is
+transmitted only to satisfy the read() or write() call currently handled
+by the driver, and those calls wait for the transmission to complete before
+returning.
+
+Note that the synchronization attribute has nothing to do with the possibility
+that read() or write() completes less bytes than requested. There is a
+separate configuration flag ("allowpartial") that determines whether such a
+partial completion is allowed.
+
+Seekable pipes
+--------------
+
+A synchronous pipe can be configured to have the stream's position exposed
+to the user logic at the FPGA. Such a pipe is also seekable on the host API.
+With this feature, a memory or register interface can be attached on the
+FPGA side to the seekable stream. Reading or writing to a certain address in
+the attached memory is done by seeking to the desired address, and calling
+read() or write() as required.
+
+
+Internals
+=========
+
+Source code organization
+------------------------
+
+The Xillybus driver consists of a core module, xillybus_core.c, and modules
+that depend on the specific bus interface (xillybus_of.c and xillybus_pcie.c).
+
+The bus specific modules are those probed when a suitable device is found by
+the kernel. Since the DMA mapping and synchronization functions, which are bus
+dependent by their nature, are used by the core module, a
+xilly_endpoint_hardware structure is passed to the core module on
+initialization. This structure is populated with pointers to wrapper functions
+which execute the DMA-related operations on the bus.
+
+Pipe attributes
+---------------
+
+Each pipe has a number of attributes which are set when the FPGA component
+(IP core) is built. They are fetched from the IDT (the data structure which
+defines the core's configuration, see Probing below) by xilly_setupchannels()
+in xillybus_core.c as follows:
+
+* is_writebuf: The pipe's direction. A non-zero value means it's an FPGA to
+  host pipe (the FPGA "writes").
+
+* channelnum: The pipe's identification number in communication between the
+  host and FPGA.
+
+* format: The underlying data width. See Data Granularity below.
+
+* allowpartial: A non-zero value means that a read() or write() (whichever
+  applies) may return with less than the requested number of bytes. The common
+  choice is a non-zero value, to match standard UNIX behavior.
+
+* synchronous: A non-zero value means that the pipe is synchronous. See
+  Synchronization above.
+
+* bufsize: Each DMA buffer's size. Always a power of two.
+
+* bufnum: The number of buffers allocated for this pipe. Always a power of two.
+
+* exclusive_open: A non-zero value forces exclusive opening of the associated
+  device file. If the device file is bidirectional, and already opened only in
+  one direction, the opposite direction may be opened once.
+
+* seekable: A non-zero value indicates that the pipe is seekable. See
+  Seekable pipes above.
+
+* supports_nonempty: A non-zero value (which is typical) indicates that the
+  hardware will send the messages that are necessary to support select() and
+  poll() for this pipe.
+
+Host never reads from the FPGA
+------------------------------
+
+Even though PCI Express is hotpluggable in general, a typical motherboard
+doesn't expect a card to go away all of the sudden. But since the PCIe card
+is based upon reprogrammable logic, a sudden disappearance from the bus is
+quite likely as a result of an accidental reprogramming of the FPGA while the
+host is up. In practice, nothing happens immediately in such a situation. But
+if the host attempts to read from an address that is mapped to the PCI Express
+device, that leads to an immediate freeze of the system on some motherboards,
+even though the PCIe standard requires a graceful recovery.
+
+In order to avoid these freezes, the Xillybus driver refrains completely from
+reading from the device's register space. All communication from the FPGA to
+the host is done through DMA. In particular, the Interrupt Service Routine
+doesn't follow the common practice of checking a status register when it's
+invoked. Rather, the FPGA prepares a small buffer which contains short
+messages, which inform the host what the interrupt was about.
+
+This mechanism is used on non-PCIe buses as well for the sake of uniformity.
+
+
+Channels, pipes, and the message channel
+----------------------------------------
+
+Each of the (possibly bidirectional) pipes presented to the user is allocated
+a data channel between the FPGA and the host. The distinction between channels
+and pipes is necessary only because of channel 0, which is used for interrupt-
+related messages from the FPGA, and has no pipe attached to it.
+
+Data streaming
+--------------
+
+Even though a non-segmented data stream is presented to the user at both
+sides, the implementation relies on a set of DMA buffers which is allocated
+for each channel. For the sake of illustration, let's take the FPGA to host
+direction: As data streams into the respective channel's interface in the
+FPGA, the Xillybus IP core writes it to one of the DMA buffers. When the
+buffer is full, the FPGA informs the host about that (appending a
+XILLYMSG_OPCODE_RELEASEBUF message channel 0 and sending an interrupt if
+necessary). The host responds by making the data available for reading through
+the character device. When all data has been read, the host writes on the
+the FPGA's buffer control register, allowing the buffer's overwriting. Flow
+control mechanisms exist on both sides to prevent underflows and overflows.
+
+This is not good enough for creating a TCP/IP-like stream: If the data flow
+stops momentarily before a DMA buffer is filled, the intuitive expectation is
+that the partial data in buffer will arrive anyhow, despite the buffer not
+being completed. This is implemented by adding a field in the
+XILLYMSG_OPCODE_RELEASEBUF message, through which the FPGA informs not just
+which buffer is submitted, but how much data it contains.
+
+But the FPGA will submit a partially filled buffer only if directed to do so
+by the host. This situation occurs when the read() method has been blocking
+for XILLY_RX_TIMEOUT jiffies (currently 10 ms), after which the host commands
+the FPGA to submit a DMA buffer as soon as it can. This timeout mechanism
+balances between bus bandwidth efficiency (preventing a lot of partially
+filled buffers being sent) and a latency held fairly low for tails of data.
+
+A similar setting is used in the host to FPGA direction. The handling of
+partial DMA buffers is somewhat different, though. The user can tell the
+driver to submit all data it has in the buffers to the FPGA, by issuing a
+write() with the byte count set to zero. This is similar to a flush request,
+but it doesn't block. There is also an autoflushing mechanism, which triggers
+an equivalent flush roughly XILLY_RX_TIMEOUT jiffies after the last write().
+This allows the user to be oblivious about the underlying buffering mechanism
+and yet enjoy a stream-like interface.
+
+Note that the issue of partial buffer flushing is irrelevant for pipes having
+the "synchronous" attribute nonzero, since synchronous pipes don't allow data
+to lay around in the DMA buffers between read() and write() anyhow.
+
+Data granularity
+----------------
+
+The data arrives or is sent at the FPGA as 8, 16 or 32 bit wide words, as
+configured by the "format" attribute. Whenever possible, the driver attempts
+to hide this when the pipe is accessed differently from its natural alignment.
+For example, reading single bytes from a pipe with 32 bit granularity works
+with no issues. Writing single bytes to pipes with 16 or 32 bit granularity
+will also work, but the driver can't send partially completed words to the
+FPGA, so the transmission of up to one word may be held until it's fully
+occupied with user data.
+
+This somewhat complicates the handling of host to FPGA streams, because
+when a buffer is flushed, it may contain up to 3 bytes don't form a word in
+the FPGA, and hence can't be sent. To prevent loss of data, these leftover
+bytes need to be moved to the next buffer. The parts in xillybus_core.c
+that mention "leftovers" in some way are related to this complication.
+
+Probing
+-------
+
+As mentioned earlier, the number of pipes that are created when the driver
+loads and their attributes depend on the Xillybus IP core in the FPGA. During
+the driver's initialization, a blob containing configuration info, the
+Interface Description Table (IDT), is sent from the FPGA to the host. The
+bootstrap process is done in three phases:
+
+1. Acquire the length of the IDT, so a buffer can be allocated for it. This
+   is done by sending a quiesce command to the device, since the acknowledge
+   for this command contains the IDT's buffer length.
+
+2. Acquire the IDT itself.
+
+3. Create the interfaces according to the IDT.
+
+Buffer allocation
+-----------------
+
+In order to simplify the logic that prevents illegal boundary crossings of
+PCIe packets, the following rule applies: If a buffer is smaller than 4kB,
+it must not cross a 4kB boundary. Otherwise, it must be 4kB aligned. The
+xilly_setupchannels() functions allocates these buffers by requesting whole
+pages from the kernel, and diving them into DMA buffers as necessary. Since
+all buffers' sizes are powers of two, it's possible to pack any set of such
+buffers, with a maximal waste of one page of memory.
+
+All buffers are allocated when the driver is loaded. This is necessary,
+since large continuous physical memory segments are sometimes requested,
+which are more likely to be available when the system is freshly booted.
+
+The allocation of buffer memory takes place in the same order they appear in
+the IDT. The driver relies on a rule that the pipes are sorted with decreasing
+buffer size in the IDT. If a requested buffer is larger or equal to a page,
+the necessary number of pages is requested from the kernel, and these are
+used for this buffer. If the requested buffer is smaller than a page, one
+single page is requested from the kernel, and that page is partially used.
+Or, if there already is a partially used page at hand, the buffer is packed
+into that page. It can be shown that all pages requested from the kernel
+(except possibly for the last) are 100% utilized this way.
+
+The "nonempty" message (supporting poll)
+----------------------------------------
+
+In order to support the "poll" method (and hence select() ), there is a small
+catch regarding the FPGA to host direction: The FPGA may have filled a DMA
+buffer with some data, but not submitted that buffer. If the host waited for
+the buffer's submission by the FPGA, there would be a possibility that the
+FPGA side has sent data, but a select() call would still block, because the
+host has not received any notification about this. This is solved with
+XILLYMSG_OPCODE_NONEMPTY messages sent by the FPGA when a channel goes from
+completely empty to containing some data.
+
+These messages are used only to support poll() and select(). The IP core can
+be configured not to send them for a slight reduction of bandwidth.
diff --git a/Documentation/driver-api/zorro.rst b/Documentation/driver-api/zorro.rst
new file mode 100644
index 000000000000..664072b017e3
--- /dev/null
+++ b/Documentation/driver-api/zorro.rst
@@ -0,0 +1,104 @@
+========================================
+Writing Device Drivers for Zorro Devices
+========================================
+
+:Author: Written by Geert Uytterhoeven <geert@linux-m68k.org>
+:Last revised: September 5, 2003
+
+
+Introduction
+------------
+
+The Zorro bus is the bus used in the Amiga family of computers. Thanks to
+AutoConfig(tm), it's 100% Plug-and-Play.
+
+There are two types of Zorro buses, Zorro II and Zorro III:
+
+  - The Zorro II address space is 24-bit and lies within the first 16 MB of the
+    Amiga's address map.
+
+  - Zorro III is a 32-bit extension of Zorro II, which is backwards compatible
+    with Zorro II. The Zorro III address space lies outside the first 16 MB.
+
+
+Probing for Zorro Devices
+-------------------------
+
+Zorro devices are found by calling ``zorro_find_device()``, which returns a
+pointer to the ``next`` Zorro device with the specified Zorro ID. A probe loop
+for the board with Zorro ID ``ZORRO_PROD_xxx`` looks like::
+
+    struct zorro_dev *z = NULL;
+
+    while ((z = zorro_find_device(ZORRO_PROD_xxx, z))) {
+	if (!zorro_request_region(z->resource.start+MY_START, MY_SIZE,
+				  "My explanation"))
+	...
+    }
+
+``ZORRO_WILDCARD`` acts as a wildcard and finds any Zorro device. If your driver
+supports different types of boards, you can use a construct like::
+
+    struct zorro_dev *z = NULL;
+
+    while ((z = zorro_find_device(ZORRO_WILDCARD, z))) {
+	if (z->id != ZORRO_PROD_xxx1 && z->id != ZORRO_PROD_xxx2 && ...)
+	    continue;
+	if (!zorro_request_region(z->resource.start+MY_START, MY_SIZE,
+				  "My explanation"))
+	...
+    }
+
+
+Zorro Resources
+---------------
+
+Before you can access a Zorro device's registers, you have to make sure it's
+not yet in use. This is done using the I/O memory space resource management
+functions::
+
+    request_mem_region()
+    release_mem_region()
+
+Shortcuts to claim the whole device's address space are provided as well::
+
+    zorro_request_device
+    zorro_release_device
+
+
+Accessing the Zorro Address Space
+---------------------------------
+
+The address regions in the Zorro device resources are Zorro bus address
+regions. Due to the identity bus-physical address mapping on the Zorro bus,
+they are CPU physical addresses as well.
+
+The treatment of these regions depends on the type of Zorro space:
+
+  - Zorro II address space is always mapped and does not have to be mapped
+    explicitly using z_ioremap().
+    
+    Conversion from bus/physical Zorro II addresses to kernel virtual addresses
+    and vice versa is done using::
+
+	virt_addr = ZTWO_VADDR(bus_addr);
+	bus_addr = ZTWO_PADDR(virt_addr);
+
+  - Zorro III address space must be mapped explicitly using z_ioremap() first
+    before it can be accessed::
+ 
+	virt_addr = z_ioremap(bus_addr, size);
+	...
+	z_iounmap(virt_addr);
+
+
+References
+----------
+
+#. linux/include/linux/zorro.h
+#. linux/include/uapi/linux/zorro.h
+#. linux/include/uapi/linux/zorro_ids.h
+#. linux/arch/m68k/include/asm/zorro.h
+#. linux/drivers/zorro
+#. /proc/bus/zorro
+