docs: move m68k architecture documentation under Documentation/arch/

Architecture-specific documentation is being moved into Documentation/arch/
as a way of cleaning up the top-level documentation directory and making
the docs hierarchy more closely match the source hierarchy.  Move
Documentation/m68k into arch/ and fix all in-tree references.

Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

4 files changed, 0 insertions, 1143 deletions

diff --git a/Documentation/m68k/buddha-driver.rst b/Documentation/m68k/buddha-driver.rst
deleted file mode 100644
index 20e401413991..000000000000
--- a/Documentation/m68k/buddha-driver.rst
+++ /dev/null
@@ -1,209 +0,0 @@
-=====================================
-Amiga Buddha and Catweasel IDE Driver
-=====================================
-
-The Amiga Buddha and Catweasel IDE Driver (part of ide.c) was written by
-Geert Uytterhoeven based on the following specifications:
-
-------------------------------------------------------------------------
-
-Register map of the Buddha IDE controller and the
-Buddha-part of the Catweasel Zorro-II version
-
-The Autoconfiguration has been implemented just as Commodore
-described  in  their  manuals, no tricks have been used (for
-example leaving some address lines out of the equations...).
-If you want to configure the board yourself (for example let
-a  Linux  kernel  configure the card), look at the Commodore
-Docs.  Reading the nibbles should give this information::
-
-  Vendor number: 4626 ($1212)
-  product number: 0 (42 for Catweasel Z-II)
-  Serial number: 0
-  Rom-vector: $1000
-
-The  card  should be a Z-II board, size 64K, not for freemem
-list, Rom-Vektor is valid, no second Autoconfig-board on the
-same card, no space preference, supports "Shutup_forever".
-
-Setting  the  base address should be done in two steps, just
-as  the Amiga Kickstart does:  The lower nibble of the 8-Bit
-address is written to $4a, then the whole Byte is written to
-$48, while it doesn't matter how often you're writing to $4a
-as  long as $48 is not touched.  After $48 has been written,
-the  whole card disappears from $e8 and is mapped to the new
-address just written.  Make sure $4a is written before $48,
-otherwise your chance is only 1:16 to find the board :-).
-
-The local memory-map is even active when mapped to $e8:
-
-==============  ===========================================
-$0-$7e		Autokonfig-space, see Z-II docs.
-
-$80-$7fd	reserved
-
-$7fe		Speed-select Register: Read & Write
-		(description see further down)
-
-$800-$8ff	IDE-Select 0 (Port 0, Register set 0)
-
-$900-$9ff	IDE-Select 1 (Port 0, Register set 1)
-
-$a00-$aff	IDE-Select 2 (Port 1, Register set 0)
-
-$b00-$bff	IDE-Select 3 (Port 1, Register set 1)
-
-$c00-$cff	IDE-Select 4 (Port 2, Register set 0,
-                Catweasel only!)
-
-$d00-$dff	IDE-Select 5 (Port 3, Register set 1,
-		Catweasel only!)
-
-$e00-$eff	local expansion port, on Catweasel Z-II the
-		Catweasel registers are also mapped here.
-		Never touch, use multidisk.device!
-
-$f00		read only, Byte-access: Bit 7 shows the
-		level of the IRQ-line of IDE port 0.
-
-$f01-$f3f	mirror of $f00
-
-$f40		read only, Byte-access: Bit 7 shows the
-		level of the IRQ-line of IDE port 1.
-
-$f41-$f7f	mirror of $f40
-
-$f80		read only, Byte-access: Bit 7 shows the
-		level of the IRQ-line of IDE port 2.
-		(Catweasel only!)
-
-$f81-$fbf	mirror of $f80
-
-$fc0		write-only: Writing any value to this
-		register enables IRQs to be passed from the
-		IDE ports to the Zorro bus. This mechanism
-		has been implemented to be compatible with
-		harddisks that are either defective or have
-		a buggy firmware and pull the IRQ line up
-		while starting up. If interrupts would
-		always be passed to the bus, the computer
-		might not start up. Once enabled, this flag
-		can not be disabled again. The level of the
-		flag can not be determined by software
-		(what for? Write to me if it's necessary!).
-
-$fc1-$fff	mirror of $fc0
-
-$1000-$ffff	Buddha-Rom with offset $1000 in the rom
-		chip. The addresses $0 to $fff of the rom
-		chip cannot be read. Rom is Byte-wide and
-		mapped to even addresses.
-==============  ===========================================
-
-The  IDE ports issue an INT2.  You can read the level of the
-IRQ-lines  of  the  IDE-ports by reading from the three (two
-for  Buddha-only)  registers  $f00, $f40 and $f80.  This way
-more  than one I/O request can be handled and you can easily
-determine  what  driver  has  to serve the INT2.  Buddha and
-Catweasel  expansion  boards  can issue an INT6.  A separate
-memory  map  is available for the I/O module and the sysop's
-I/O module.
-
-The IDE ports are fed by the address lines A2 to A4, just as
-the  Amiga  1200  and  Amiga  4000  IDE ports are.  This way
-existing  drivers  can be easily ported to Buddha.  A move.l
-polls  two  words  out of the same address of IDE port since
-every  word  is  mirrored  once.  movem is not possible, but
-it's  not  necessary  either,  because  you can only speedup
-68000  systems  with  this  technique.   A 68020 system with
-fastmem is faster with move.l.
-
-If you're using the mirrored registers of the IDE-ports with
-A6=1,  the Buddha doesn't care about the speed that you have
-selected  in  the  speed  register (see further down).  With
-A6=1  (for example $840 for port 0, register set 0), a 780ns
-access  is being made.  These registers should be used for a
-command   access   to  the  harddisk/CD-Rom,  since  command
-accesses  are Byte-wide and have to be made slower according
-to the ATA-X3T9 manual.
-
-Now  for the speed-register:  The register is byte-wide, and
-only  the  upper  three  bits are used (Bits 7 to 5).  Bit 4
-must  always  be set to 1 to be compatible with later Buddha
-versions  (if  I'll  ever  update this one).  I presume that
-I'll  never use the lower four bits, but they have to be set
-to 1 by definition.
-
-The  values in this table have to be shifted 5 bits to the
-left and or'd with $1f (this sets the lower 5 bits).
-
-All  the timings have in common:  Select and IOR/IOW rise at
-the  same  time.   IOR  and  IOW have a propagation delay of
-about  30ns  to  the clocks on the Zorro bus, that's why the
-values  are no multiple of 71.  One clock-cycle is 71ns long
-(exactly 70,5 at 14,18 Mhz on PAL systems).
-
-value 0 (Default after reset)
-  497ns Select (7 clock cycles) , IOR/IOW after 172ns (2 clock cycles)
-  (same timing as the Amiga 1200 does on it's IDE port without
-  accelerator card)
-
-value 1
-  639ns Select (9 clock cycles), IOR/IOW after 243ns (3 clock cycles)
-
-value 2
-  781ns Select (11 clock cycles), IOR/IOW after 314ns (4 clock cycles)
-
-value 3
-  355ns Select (5 clock cycles), IOR/IOW after 101ns (1 clock cycle)
-
-value 4
-  355ns Select (5 clock cycles), IOR/IOW after 172ns (2 clock cycles)
-
-value 5
-  355ns Select (5 clock cycles), IOR/IOW after 243ns (3 clock cycles)
-
-value 6
-  1065ns Select (15 clock cycles), IOR/IOW after 314ns (4 clock cycles)
-
-value 7
-  355ns Select, (5 clock cycles), IOR/IOW after 101ns (1 clock cycle)
-
-When accessing IDE registers with A6=1 (for example $84x),
-the timing will always be mode 0 8-bit compatible, no matter
-what you have selected in the speed register:
-
-781ns select, IOR/IOW after 4 clock cycles (=314ns) aktive.
-
-All  the  timings with a very short select-signal (the 355ns
-fast  accesses)  depend  on the accelerator card used in the
-system:  Sometimes two more clock cycles are inserted by the
-bus  interface,  making  the  whole access 497ns long.  This
-doesn't  affect  the  reliability  of the controller nor the
-performance  of  the  card,  since  this doesn't happen very
-often.
-
-All  the  timings  are  calculated  and  only  confirmed  by
-measurements  that allowed me to count the clock cycles.  If
-the  system  is clocked by an oscillator other than 28,37516
-Mhz  (for  example  the  NTSC-frequency  28,63636 Mhz), each
-clock  cycle is shortened to a bit less than 70ns (not worth
-mentioning).   You  could think of a small performance boost
-by  overclocking  the  system,  but  you would either need a
-multisync  monitor,  or  a  graphics card, and your internal
-diskdrive would go crazy, that's why you shouldn't tune your
-Amiga this way.
-
-Giving  you  the  possibility  to  write  software  that  is
-compatible  with both the Buddha and the Catweasel Z-II, The
-Buddha  acts  just  like  a  Catweasel  Z-II  with no device
-connected  to  the  third  IDE-port.   The IRQ-register $f80
-always  shows a "no IRQ here" on the Buddha, and accesses to
-the  third  IDE  port  are  going into data's Nirwana on the
-Buddha.
-
-Jens Schönfeld february 19th, 1997
-
-updated may 27th, 1997
-
-eMail: sysop@nostlgic.tng.oche.de
diff --git a/Documentation/m68k/features.rst b/Documentation/m68k/features.rst
deleted file mode 100644
index 5107a2119472..000000000000
--- a/Documentation/m68k/features.rst
+++ /dev/null
@@ -1,3 +0,0 @@
-.. SPDX-License-Identifier: GPL-2.0
-
-.. kernel-feat:: $srctree/Documentation/features m68k
diff --git a/Documentation/m68k/index.rst b/Documentation/m68k/index.rst
deleted file mode 100644
index 0f890dbb5fe2..000000000000
--- a/Documentation/m68k/index.rst
+++ /dev/null
@@ -1,20 +0,0 @@
-.. SPDX-License-Identifier: GPL-2.0
-
-=================
-m68k Architecture
-=================
-
-.. toctree::
-   :maxdepth: 2
-
-   kernel-options
-   buddha-driver
-
-   features
-
-.. only::  subproject and html
-
-   Indices
-   =======
-
-   * :ref:`genindex`
diff --git a/Documentation/m68k/kernel-options.rst b/Documentation/m68k/kernel-options.rst
deleted file mode 100644
index 2008a20b4329..000000000000
--- a/Documentation/m68k/kernel-options.rst
+++ /dev/null
@@ -1,911 +0,0 @@
-===================================
-Command Line Options for Linux/m68k
-===================================
-
-Last Update: 2 May 1999
-
-Linux/m68k version: 2.2.6
-
-Author: Roman.Hodek@informatik.uni-erlangen.de (Roman Hodek)
-
-Update: jds@kom.auc.dk (Jes Sorensen) and faq@linux-m68k.org (Chris Lawrence)
-
-0) Introduction
-===============
-
-Often I've been asked which command line options the Linux/m68k
-kernel understands, or how the exact syntax for the ... option is, or
-... about the option ... . I hope, this document supplies all the
-answers...
-
-Note that some options might be outdated, their descriptions being
-incomplete or missing. Please update the information and send in the
-patches.
-
-
-1) Overview of the Kernel's Option Processing
-=============================================
-
-The kernel knows three kinds of options on its command line:
-
-  1) kernel options
-  2) environment settings
-  3) arguments for init
-
-To which of these classes an argument belongs is determined as
-follows: If the option is known to the kernel itself, i.e. if the name
-(the part before the '=') or, in some cases, the whole argument string
-is known to the kernel, it belongs to class 1. Otherwise, if the
-argument contains an '=', it is of class 2, and the definition is put
-into init's environment. All other arguments are passed to init as
-command line options.
-
-This document describes the valid kernel options for Linux/m68k in
-the version mentioned at the start of this file. Later revisions may
-add new such options, and some may be missing in older versions.
-
-In general, the value (the part after the '=') of an option is a
-list of values separated by commas. The interpretation of these values
-is up to the driver that "owns" the option. This association of
-options with drivers is also the reason that some are further
-subdivided.
-
-
-2) General Kernel Options
-=========================
-
-2.1) root=
-----------
-
-:Syntax: root=/dev/<device>
-:or:     root=<hex_number>
-
-This tells the kernel which device it should mount as the root
-filesystem. The device must be a block device with a valid filesystem
-on it.
-
-The first syntax gives the device by name. These names are converted
-into a major/minor number internally in the kernel in an unusual way.
-Normally, this "conversion" is done by the device files in /dev, but
-this isn't possible here, because the root filesystem (with /dev)
-isn't mounted yet... So the kernel parses the name itself, with some
-hardcoded name to number mappings. The name must always be a
-combination of two or three letters, followed by a decimal number.
-Valid names are::
-
-  /dev/ram: -> 0x0100 (initial ramdisk)
-  /dev/hda: -> 0x0300 (first IDE disk)
-  /dev/hdb: -> 0x0340 (second IDE disk)
-  /dev/sda: -> 0x0800 (first SCSI disk)
-  /dev/sdb: -> 0x0810 (second SCSI disk)
-  /dev/sdc: -> 0x0820 (third SCSI disk)
-  /dev/sdd: -> 0x0830 (forth SCSI disk)
-  /dev/sde: -> 0x0840 (fifth SCSI disk)
-  /dev/fd : -> 0x0200 (floppy disk)
-
-The name must be followed by a decimal number, that stands for the
-partition number. Internally, the value of the number is just
-added to the device number mentioned in the table above. The
-exceptions are /dev/ram and /dev/fd, where /dev/ram refers to an
-initial ramdisk loaded by your bootstrap program (please consult the
-instructions for your bootstrap program to find out how to load an
-initial ramdisk). As of kernel version 2.0.18 you must specify
-/dev/ram as the root device if you want to boot from an initial
-ramdisk. For the floppy devices, /dev/fd, the number stands for the
-floppy drive number (there are no partitions on floppy disks). I.e.,
-/dev/fd0 stands for the first drive, /dev/fd1 for the second, and so
-on. Since the number is just added, you can also force the disk format
-by adding a number greater than 3. If you look into your /dev
-directory, use can see the /dev/fd0D720 has major 2 and minor 16. You
-can specify this device for the root FS by writing "root=/dev/fd16" on
-the kernel command line.
-
-[Strange and maybe uninteresting stuff ON]
-
-This unusual translation of device names has some strange
-consequences: If, for example, you have a symbolic link from /dev/fd
-to /dev/fd0D720 as an abbreviation for floppy driver #0 in DD format,
-you cannot use this name for specifying the root device, because the
-kernel cannot see this symlink before mounting the root FS and it
-isn't in the table above. If you use it, the root device will not be
-set at all, without an error message. Another example: You cannot use a
-partition on e.g. the sixth SCSI disk as the root filesystem, if you
-want to specify it by name. This is, because only the devices up to
-/dev/sde are in the table above, but not /dev/sdf. Although, you can
-use the sixth SCSI disk for the root FS, but you have to specify the
-device by number... (see below). Or, even more strange, you can use the
-fact that there is no range checking of the partition number, and your
-knowledge that each disk uses 16 minors, and write "root=/dev/sde17"
-(for /dev/sdf1).
-
-[Strange and maybe uninteresting stuff OFF]
-
-If the device containing your root partition isn't in the table
-above, you can also specify it by major and minor numbers. These are
-written in hex, with no prefix and no separator between. E.g., if you
-have a CD with contents appropriate as a root filesystem in the first
-SCSI CD-ROM drive, you boot from it by "root=0b00". Here, hex "0b" =
-decimal 11 is the major of SCSI CD-ROMs, and the minor 0 stands for
-the first of these. You can find out all valid major numbers by
-looking into include/linux/major.h.
-
-In addition to major and minor numbers, if the device containing your
-root partition uses a partition table format with unique partition
-identifiers, then you may use them.  For instance,
-"root=PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF".  It is also
-possible to reference another partition on the same device using a
-known partition UUID as the starting point.  For example,
-if partition 5 of the device has the UUID of
-00112233-4455-6677-8899-AABBCCDDEEFF then partition 3 may be found as
-follows:
-
-  PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF/PARTNROFF=-2
-
-Authoritative information can be found in
-"Documentation/admin-guide/kernel-parameters.rst".
-
-
-2.2) ro, rw
------------
-
-:Syntax: ro
-:or:     rw
-
-These two options tell the kernel whether it should mount the root
-filesystem read-only or read-write. The default is read-only, except
-for ramdisks, which default to read-write.
-
-
-2.3) debug
-----------
-
-:Syntax: debug
-
-This raises the kernel log level to 10 (the default is 7). This is the
-same level as set by the "dmesg" command, just that the maximum level
-selectable by dmesg is 8.
-
-
-2.4) debug=
------------
-
-:Syntax: debug=<device>
-
-This option causes certain kernel messages be printed to the selected
-debugging device. This can aid debugging the kernel, since the
-messages can be captured and analyzed on some other machine. Which
-devices are possible depends on the machine type. There are no checks
-for the validity of the device name. If the device isn't implemented,
-nothing happens.
-
-Messages logged this way are in general stack dumps after kernel
-memory faults or bad kernel traps, and kernel panics. To be exact: all
-messages of level 0 (panic messages) and all messages printed while
-the log level is 8 or more (their level doesn't matter). Before stack
-dumps, the kernel sets the log level to 10 automatically. A level of
-at least 8 can also be set by the "debug" command line option (see
-2.3) and at run time with "dmesg -n 8".
-
-Devices possible for Amiga:
-
- - "ser":
-	  built-in serial port; parameters: 9600bps, 8N1
- - "mem":
-	  Save the messages to a reserved area in chip mem. After
-          rebooting, they can be read under AmigaOS with the tool
-          'dmesg'.
-
-Devices possible for Atari:
-
- - "ser1":
-	   ST-MFP serial port ("Modem1"); parameters: 9600bps, 8N1
- - "ser2":
-	   SCC channel B serial port ("Modem2"); parameters: 9600bps, 8N1
- - "ser" :
-	   default serial port
-           This is "ser2" for a Falcon, and "ser1" for any other machine
- - "midi":
-	   The MIDI port; parameters: 31250bps, 8N1
- - "par" :
-	   parallel port
-
-           The printing routine for this implements a timeout for the
-           case there's no printer connected (else the kernel would
-           lock up). The timeout is not exact, but usually a few
-           seconds.
-
-
-2.6) ramdisk_size=
-------------------
-
-:Syntax: ramdisk_size=<size>
-
-This option instructs the kernel to set up a ramdisk of the given
-size in KBytes. Do not use this option if the ramdisk contents are
-passed by bootstrap! In this case, the size is selected automatically
-and should not be overwritten.
-
-The only application is for root filesystems on floppy disks, that
-should be loaded into memory. To do that, select the corresponding
-size of the disk as ramdisk size, and set the root device to the disk
-drive (with "root=").
-
-
-2.7) swap=
-
-  I can't find any sign of this option in 2.2.6.
-
-2.8) buff=
------------
-
-  I can't find any sign of this option in 2.2.6.
-
-
-3) General Device Options (Amiga and Atari)
-===========================================
-
-3.1) ether=
------------
-
-:Syntax: ether=[<irq>[,<base_addr>[,<mem_start>[,<mem_end>]]]],<dev-name>
-
-<dev-name> is the name of a net driver, as specified in
-drivers/net/Space.c in the Linux source. Most prominent are eth0, ...
-eth3, sl0, ... sl3, ppp0, ..., ppp3, dummy, and lo.
-
-The non-ethernet drivers (sl, ppp, dummy, lo) obviously ignore the
-settings by this options. Also, the existing ethernet drivers for
-Linux/m68k (ariadne, a2065, hydra) don't use them because Zorro boards
-are really Plug-'n-Play, so the "ether=" option is useless altogether
-for Linux/m68k.
-
-
-3.2) hd=
---------
-
-:Syntax: hd=<cylinders>,<heads>,<sectors>
-
-This option sets the disk geometry of an IDE disk. The first hd=
-option is for the first IDE disk, the second for the second one.
-(I.e., you can give this option twice.) In most cases, you won't have
-to use this option, since the kernel can obtain the geometry data
-itself. It exists just for the case that this fails for one of your
-disks.
-
-
-3.3) max_scsi_luns=
--------------------
-
-:Syntax: max_scsi_luns=<n>
-
-Sets the maximum number of LUNs (logical units) of SCSI devices to
-be scanned. Valid values for <n> are between 1 and 8. Default is 8 if
-"Probe all LUNs on each SCSI device" was selected during the kernel
-configuration, else 1.
-
-
-3.4) st=
---------
-
-:Syntax: st=<buffer_size>,[<write_thres>,[<max_buffers>]]
-
-Sets several parameters of the SCSI tape driver. <buffer_size> is
-the number of 512-byte buffers reserved for tape operations for each
-device. <write_thres> sets the number of blocks which must be filled
-to start an actual write operation to the tape. Maximum value is the
-total number of buffers. <max_buffer> limits the total number of
-buffers allocated for all tape devices.
-
-
-3.5) dmasound=
---------------
-
-:Syntax: dmasound=[<buffers>,<buffer-size>[,<catch-radius>]]
-
-This option controls some configurations of the Linux/m68k DMA sound
-driver (Amiga and Atari): <buffers> is the number of buffers you want
-to use (minimum 4, default 4), <buffer-size> is the size of each
-buffer in kilobytes (minimum 4, default 32) and <catch-radius> says
-how much percent of error will be tolerated when setting a frequency
-(maximum 10, default 0). For example with 3% you can play 8000Hz
-AU-Files on the Falcon with its hardware frequency of 8195Hz and thus
-don't need to expand the sound.
-
-
-
-4) Options for Atari Only
-=========================
-
-4.1) video=
------------
-
-:Syntax: video=<fbname>:<sub-options...>
-
-The <fbname> parameter specifies the name of the frame buffer,
-eg. most atari users will want to specify `atafb` here. The
-<sub-options> is a comma-separated list of the sub-options listed
-below.
-
-NB:
-    Please notice that this option was renamed from `atavideo` to
-    `video` during the development of the 1.3.x kernels, thus you
-    might need to update your boot-scripts if upgrading to 2.x from
-    an 1.2.x kernel.
-
-NBB:
-    The behavior of video= was changed in 2.1.57 so the recommended
-    option is to specify the name of the frame buffer.
-
-4.1.1) Video Mode
------------------
-
-This sub-option may be any of the predefined video modes, as listed
-in atari/atafb.c in the Linux/m68k source tree. The kernel will
-activate the given video mode at boot time and make it the default
-mode, if the hardware allows. Currently defined names are:
-
- - stlow           : 320x200x4
- - stmid, default5 : 640x200x2
- - sthigh, default4: 640x400x1
- - ttlow           : 320x480x8, TT only
- - ttmid, default1 : 640x480x4, TT only
- - tthigh, default2: 1280x960x1, TT only
- - vga2            : 640x480x1, Falcon only
- - vga4            : 640x480x2, Falcon only
- - vga16, default3 : 640x480x4, Falcon only
- - vga256          : 640x480x8, Falcon only
- - falh2           : 896x608x1, Falcon only
- - falh16          : 896x608x4, Falcon only
-
-If no video mode is given on the command line, the kernel tries the
-modes names "default<n>" in turn, until one is possible with the
-hardware in use.
-
-A video mode setting doesn't make sense, if the external driver is
-activated by a "external:" sub-option.
-
-4.1.2) inverse
---------------
-
-Invert the display. This affects only text consoles.
-Usually, the background is chosen to be black. With this
-option, you can make the background white.
-
-4.1.3) font
------------
-
-:Syntax: font:<fontname>
-
-Specify the font to use in text modes. Currently you can choose only
-between `VGA8x8`, `VGA8x16` and `PEARL8x8`. `VGA8x8` is default, if the
-vertical size of the display is less than 400 pixel rows. Otherwise, the
-`VGA8x16` font is the default.
-
-4.1.4) `hwscroll_`
-------------------
-
-:Syntax: `hwscroll_<n>`
-
-The number of additional lines of video memory to reserve for
-speeding up the scrolling ("hardware scrolling"). Hardware scrolling
-is possible only if the kernel can set the video base address in steps
-fine enough. This is true for STE, MegaSTE, TT, and Falcon. It is not
-possible with plain STs and graphics cards (The former because the
-base address must be on a 256 byte boundary there, the latter because
-the kernel doesn't know how to set the base address at all.)
-
-By default, <n> is set to the number of visible text lines on the
-display. Thus, the amount of video memory is doubled, compared to no
-hardware scrolling. You can turn off the hardware scrolling altogether
-by setting <n> to 0.
-
-4.1.5) internal:
-----------------
-
-:Syntax: internal:<xres>;<yres>[;<xres_max>;<yres_max>;<offset>]
-
-This option specifies the capabilities of some extended internal video
-hardware, like e.g. OverScan. <xres> and <yres> give the (extended)
-dimensions of the screen.
-
-If your OverScan needs a black border, you have to write the last
-three arguments of the "internal:". <xres_max> is the maximum line
-length the hardware allows, <yres_max> the maximum number of lines.
-<offset> is the offset of the visible part of the screen memory to its
-physical start, in bytes.
-
-Often, extended interval video hardware has to be activated somehow.
-For this, see the "sw_*" options below.
-
-4.1.6) external:
-----------------
-
-:Syntax:
-  external:<xres>;<yres>;<depth>;<org>;<scrmem>[;<scrlen>[;<vgabase>
-  [;<colw>[;<coltype>[;<xres_virtual>]]]]]
-
-.. I had to break this line...
-
-This is probably the most complicated parameter... It specifies that
-you have some external video hardware (a graphics board), and how to
-use it under Linux/m68k. The kernel cannot know more about the hardware
-than you tell it here! The kernel also is unable to set or change any
-video modes, since it doesn't know about any board internal. So, you
-have to switch to that video mode before you start Linux, and cannot
-switch to another mode once Linux has started.
-
-The first 3 parameters of this sub-option should be obvious: <xres>,
-<yres> and <depth> give the dimensions of the screen and the number of
-planes (depth). The depth is the logarithm to base 2 of the number
-of colors possible. (Or, the other way round: The number of colors is
-2^depth).
-
-You have to tell the kernel furthermore how the video memory is
-organized. This is done by a letter as <org> parameter:
-
- 'n':
-      "normal planes", i.e. one whole plane after another
- 'i':
-      "interleaved planes", i.e. 16 bit of the first plane, than 16 bit
-      of the next, and so on... This mode is used only with the
-      built-in Atari video modes, I think there is no card that
-      supports this mode.
- 'p':
-      "packed pixels", i.e. <depth> consecutive bits stand for all
-      planes of one pixel; this is the most common mode for 8 planes
-      (256 colors) on graphic cards
- 't':
-      "true color" (more or less packed pixels, but without a color
-      lookup table); usually depth is 24
-
-For monochrome modes (i.e., <depth> is 1), the <org> letter has a
-different meaning:
-
- 'n':
-      normal colors, i.e. 0=white, 1=black
- 'i':
-      inverted colors, i.e. 0=black, 1=white
-
-The next important information about the video hardware is the base
-address of the video memory. That is given in the <scrmem> parameter,
-as a hexadecimal number with a "0x" prefix. You have to find out this
-address in the documentation of your hardware.
-
-The next parameter, <scrlen>, tells the kernel about the size of the
-video memory. If it's missing, the size is calculated from <xres>,
-<yres>, and <depth>. For now, it is not useful to write a value here.
-It would be used only for hardware scrolling (which isn't possible
-with the external driver, because the kernel cannot set the video base
-address), or for virtual resolutions under X (which the X server
-doesn't support yet). So, it's currently best to leave this field
-empty, either by ending the "external:" after the video address or by
-writing two consecutive semicolons, if you want to give a <vgabase>
-(it is allowed to leave this parameter empty).
-
-The <vgabase> parameter is optional. If it is not given, the kernel
-cannot read or write any color registers of the video hardware, and
-thus you have to set appropriate colors before you start Linux. But if
-your card is somehow VGA compatible, you can tell the kernel the base
-address of the VGA register set, so it can change the color lookup
-table. You have to look up this address in your board's documentation.
-To avoid misunderstandings: <vgabase> is the _base_ address, i.e. a 4k
-aligned address. For read/writing the color registers, the kernel
-uses the addresses vgabase+0x3c7...vgabase+0x3c9. The <vgabase>
-parameter is written in hexadecimal with a "0x" prefix, just as
-<scrmem>.
-
-<colw> is meaningful only if <vgabase> is specified. It tells the
-kernel how wide each of the color register is, i.e. the number of bits
-per single color (red/green/blue). Default is 6, another quite usual
-value is 8.
-
-Also <coltype> is used together with <vgabase>. It tells the kernel
-about the color register model of your gfx board. Currently, the types
-"vga" (which is also the default) and "mv300" (SANG MV300) are
-implemented.
-
-Parameter <xres_virtual> is required for ProMST or ET4000 cards where
-the physical linelength differs from the visible length. With ProMST,
-xres_virtual must be set to 2048. For ET4000, xres_virtual depends on the
-initialisation of the video-card.
-If you're missing a corresponding yres_virtual: the external part is legacy,
-therefore we don't support hardware-dependent functions like hardware-scroll,
-panning or blanking.
-
-4.1.7) eclock:
---------------
-
-The external pixel clock attached to the Falcon VIDEL shifter. This
-currently works only with the ScreenWonder!
-
-4.1.8) monitorcap:
--------------------
-
-:Syntax: monitorcap:<vmin>;<vmax>;<hmin>;<hmax>
-
-This describes the capabilities of a multisync monitor. Don't use it
-with a fixed-frequency monitor! For now, only the Falcon frame buffer
-uses the settings of "monitorcap:".
-
-<vmin> and <vmax> are the minimum and maximum, resp., vertical frequencies
-your monitor can work with, in Hz. <hmin> and <hmax> are the same for
-the horizontal frequency, in kHz.
-
-  The defaults are 58;62;31;32 (VGA compatible).
-
-  The defaults for TV/SC1224/SC1435 cover both PAL and NTSC standards.
-
-4.1.9) keep
-------------
-
-If this option is given, the framebuffer device doesn't do any video
-mode calculations and settings on its own. The only Atari fb device
-that does this currently is the Falcon.
-
-What you reach with this: Settings for unknown video extensions
-aren't overridden by the driver, so you can still use the mode found
-when booting, when the driver doesn't know to set this mode itself.
-But this also means, that you can't switch video modes anymore...
-
-An example where you may want to use "keep" is the ScreenBlaster for
-the Falcon.
-
-
-4.2) atamouse=
---------------
-
-:Syntax: atamouse=<x-threshold>,[<y-threshold>]
-
-With this option, you can set the mouse movement reporting threshold.
-This is the number of pixels of mouse movement that have to accumulate
-before the IKBD sends a new mouse packet to the kernel. Higher values
-reduce the mouse interrupt load and thus reduce the chance of keyboard
-overruns. Lower values give a slightly faster mouse responses and
-slightly better mouse tracking.
-
-You can set the threshold in x and y separately, but usually this is
-of little practical use. If there's just one number in the option, it
-is used for both dimensions. The default value is 2 for both
-thresholds.
-
-
-4.3) ataflop=
--------------
-
-:Syntax: ataflop=<drive type>[,<trackbuffering>[,<steprateA>[,<steprateB>]]]
-
-   The drive type may be 0, 1, or 2, for DD, HD, and ED, resp. This
-   setting affects how many buffers are reserved and which formats are
-   probed (see also below). The default is 1 (HD). Only one drive type
-   can be selected. If you have two disk drives, select the "better"
-   type.
-
-   The second parameter <trackbuffer> tells the kernel whether to use
-   track buffering (1) or not (0). The default is machine-dependent:
-   no for the Medusa and yes for all others.
-
-   With the two following parameters, you can change the default
-   steprate used for drive A and B, resp.
-
-
-4.4) atascsi=
--------------
-
-:Syntax: atascsi=<can_queue>[,<cmd_per_lun>[,<scat-gat>[,<host-id>[,<tagged>]]]]
-
-This option sets some parameters for the Atari native SCSI driver.
-Generally, any number of arguments can be omitted from the end. And
-for each of the numbers, a negative value means "use default". The
-defaults depend on whether TT-style or Falcon-style SCSI is used.
-Below, defaults are noted as n/m, where the first value refers to
-TT-SCSI and the latter to Falcon-SCSI. If an illegal value is given
-for one parameter, an error message is printed and that one setting is
-ignored (others aren't affected).
-
-  <can_queue>:
-    This is the maximum number of SCSI commands queued internally to the
-    Atari SCSI driver. A value of 1 effectively turns off the driver
-    internal multitasking (if it causes problems). Legal values are >=
-    1. <can_queue> can be as high as you like, but values greater than
-    <cmd_per_lun> times the number of SCSI targets (LUNs) you have
-    don't make sense. Default: 16/8.
-
-  <cmd_per_lun>:
-    Maximum number of SCSI commands issued to the driver for one
-    logical unit (LUN, usually one SCSI target). Legal values start
-    from 1. If tagged queuing (see below) is not used, values greater
-    than 2 don't make sense, but waste memory. Otherwise, the maximum
-    is the number of command tags available to the driver (currently
-    32). Default: 8/1. (Note: Values > 1 seem to cause problems on a
-    Falcon, cause not yet known.)
-
-    The <cmd_per_lun> value at a great part determines the amount of
-    memory SCSI reserves for itself. The formula is rather
-    complicated, but I can give you some hints:
-
-      no scatter-gather:
-	cmd_per_lun * 232 bytes
-      full scatter-gather:
-	cmd_per_lun * approx. 17 Kbytes
-
-  <scat-gat>:
-    Size of the scatter-gather table, i.e. the number of requests
-    consecutive on the disk that can be merged into one SCSI command.
-    Legal values are between 0 and 255. Default: 255/0. Note: This
-    value is forced to 0 on a Falcon, since scatter-gather isn't
-    possible with the ST-DMA. Not using scatter-gather hurts
-    performance significantly.
-
-  <host-id>:
-    The SCSI ID to be used by the initiator (your Atari). This is
-    usually 7, the highest possible ID. Every ID on the SCSI bus must
-    be unique. Default: determined at run time: If the NV-RAM checksum
-    is valid, and bit 7 in byte 30 of the NV-RAM is set, the lower 3
-    bits of this byte are used as the host ID. (This method is defined
-    by Atari and also used by some TOS HD drivers.) If the above
-    isn't given, the default ID is 7. (both, TT and Falcon).
-
-  <tagged>:
-    0 means turn off tagged queuing support, all other values > 0 mean
-    use tagged queuing for targets that support it. Default: currently
-    off, but this may change when tagged queuing handling has been
-    proved to be reliable.
-
-    Tagged queuing means that more than one command can be issued to
-    one LUN, and the SCSI device itself orders the requests so they
-    can be performed in optimal order. Not all SCSI devices support
-    tagged queuing (:-().
-
-4.5 switches=
--------------
-
-:Syntax: switches=<list of switches>
-
-With this option you can switch some hardware lines that are often
-used to enable/disable certain hardware extensions. Examples are
-OverScan, overclocking, ...
-
-The <list of switches> is a comma-separated list of the following
-items:
-
-  ikbd:
-	set RTS of the keyboard ACIA high
-  midi:
-	set RTS of the MIDI ACIA high
-  snd6:
-	set bit 6 of the PSG port A
-  snd7:
-	set bit 6 of the PSG port A
-
-It doesn't make sense to mention a switch more than once (no
-difference to only once), but you can give as many switches as you
-want to enable different features. The switch lines are set as early
-as possible during kernel initialization (even before determining the
-present hardware.)
-
-All of the items can also be prefixed with `ov_`, i.e. `ov_ikbd`,
-`ov_midi`, ... These options are meant for switching on an OverScan
-video extension. The difference to the bare option is that the
-switch-on is done after video initialization, and somehow synchronized
-to the HBLANK. A speciality is that ov_ikbd and ov_midi are switched
-off before rebooting, so that OverScan is disabled and TOS boots
-correctly.
-
-If you give an option both, with and without the `ov_` prefix, the
-earlier initialization (`ov_`-less) takes precedence. But the
-switching-off on reset still happens in this case.
-
-5) Options for Amiga Only:
-==========================
-
-5.1) video=
------------
-
-:Syntax: video=<fbname>:<sub-options...>
-
-The <fbname> parameter specifies the name of the frame buffer, valid
-options are `amifb`, `cyber`, 'virge', `retz3` and `clgen`, provided
-that the respective frame buffer devices have been compiled into the
-kernel (or compiled as loadable modules). The behavior of the <fbname>
-option was changed in 2.1.57 so it is now recommended to specify this
-option.
-
-The <sub-options> is a comma-separated list of the sub-options listed
-below. This option is organized similar to the Atari version of the
-"video"-option (4.1), but knows fewer sub-options.
-
-5.1.1) video mode
------------------
-
-Again, similar to the video mode for the Atari (see 4.1.1). Predefined
-modes depend on the used frame buffer device.
-
-OCS, ECS and AGA machines all use the color frame buffer. The following
-predefined video modes are available:
-
-NTSC modes:
- - ntsc            : 640x200, 15 kHz, 60 Hz
- - ntsc-lace       : 640x400, 15 kHz, 60 Hz interlaced
-
-PAL modes:
- - pal             : 640x256, 15 kHz, 50 Hz
- - pal-lace        : 640x512, 15 kHz, 50 Hz interlaced
-
-ECS modes:
- - multiscan       : 640x480, 29 kHz, 57 Hz
- - multiscan-lace  : 640x960, 29 kHz, 57 Hz interlaced
- - euro36          : 640x200, 15 kHz, 72 Hz
- - euro36-lace     : 640x400, 15 kHz, 72 Hz interlaced
- - euro72          : 640x400, 29 kHz, 68 Hz
- - euro72-lace     : 640x800, 29 kHz, 68 Hz interlaced
- - super72         : 800x300, 23 kHz, 70 Hz
- - super72-lace    : 800x600, 23 kHz, 70 Hz interlaced
- - dblntsc-ff      : 640x400, 27 kHz, 57 Hz
- - dblntsc-lace    : 640x800, 27 kHz, 57 Hz interlaced
- - dblpal-ff       : 640x512, 27 kHz, 47 Hz
- - dblpal-lace     : 640x1024, 27 kHz, 47 Hz interlaced
- - dblntsc         : 640x200, 27 kHz, 57 Hz doublescan
- - dblpal          : 640x256, 27 kHz, 47 Hz doublescan
-
-VGA modes:
- - vga             : 640x480, 31 kHz, 60 Hz
- - vga70           : 640x400, 31 kHz, 70 Hz
-
-Please notice that the ECS and VGA modes require either an ECS or AGA
-chipset, and that these modes are limited to 2-bit color for the ECS
-chipset and 8-bit color for the AGA chipset.
-
-5.1.2) depth
-------------
-
-:Syntax: depth:<nr. of bit-planes>
-
-Specify the number of bit-planes for the selected video-mode.
-
-5.1.3) inverse
---------------
-
-Use inverted display (black on white). Functionally the same as the
-"inverse" sub-option for the Atari.
-
-5.1.4) font
------------
-
-:Syntax: font:<fontname>
-
-Specify the font to use in text modes. Functionally the same as the
-"font" sub-option for the Atari, except that `PEARL8x8` is used instead
-of `VGA8x8` if the vertical size of the display is less than 400 pixel
-rows.
-
-5.1.5) monitorcap:
--------------------
-
-:Syntax: monitorcap:<vmin>;<vmax>;<hmin>;<hmax>
-
-This describes the capabilities of a multisync monitor. For now, only
-the color frame buffer uses the settings of "monitorcap:".
-
-<vmin> and <vmax> are the minimum and maximum, resp., vertical frequencies
-your monitor can work with, in Hz. <hmin> and <hmax> are the same for
-the horizontal frequency, in kHz.
-
-The defaults are 50;90;15;38 (Generic Amiga multisync monitor).
-
-
-5.2) fd_def_df0=
-----------------
-
-:Syntax: fd_def_df0=<value>
-
-Sets the df0 value for "silent" floppy drives. The value should be in
-hexadecimal with "0x" prefix.
-
-
-5.3) wd33c93=
--------------
-
-:Syntax: wd33c93=<sub-options...>
-
-These options affect the A590/A2091, A3000 and GVP Series II SCSI
-controllers.
-
-The <sub-options> is a comma-separated list of the sub-options listed
-below.
-
-5.3.1) nosync
--------------
-
-:Syntax: nosync:bitmask
-
-bitmask is a byte where the 1st 7 bits correspond with the 7
-possible SCSI devices. Set a bit to prevent sync negotiation on that
-device. To maintain backwards compatibility, a command-line such as
-"wd33c93=255" will be automatically translated to
-"wd33c93=nosync:0xff". The default is to disable sync negotiation for
-all devices, eg. nosync:0xff.
-
-5.3.2) period
--------------
-
-:Syntax: period:ns
-
-`ns` is the minimum # of nanoseconds in a SCSI data transfer
-period. Default is 500; acceptable values are 250 - 1000.
-
-5.3.3) disconnect
------------------
-
-:Syntax: disconnect:x
-
-Specify x = 0 to never allow disconnects, 2 to always allow them.
-x = 1 does 'adaptive' disconnects, which is the default and generally
-the best choice.
-
-5.3.4) debug
-------------
-
-:Syntax: debug:x
-
-If `DEBUGGING_ON` is defined, x is a bit mask that causes various
-types of debug output to printed - see the DB_xxx defines in
-wd33c93.h.
-
-5.3.5) clock
-------------
-
-:Syntax: clock:x
-
-x = clock input in MHz for WD33c93 chip. Normal values would be from
-8 through 20. The default value depends on your hostadapter(s),
-default for the A3000 internal controller is 14, for the A2091 it's 8
-and for the GVP hostadapters it's either 8 or 14, depending on the
-hostadapter and the SCSI-clock jumper present on some GVP
-hostadapters.
-
-5.3.6) next
------------
-
-No argument. Used to separate blocks of keywords when there's more
-than one wd33c93-based host adapter in the system.
-
-5.3.7) nodma
-------------
-
-:Syntax: nodma:x
-
-If x is 1 (or if the option is just written as "nodma"), the WD33c93
-controller will not use DMA (= direct memory access) to access the
-Amiga's memory.  This is useful for some systems (like A3000's and
-A4000's with the A3640 accelerator, revision 3.0) that have problems
-using DMA to chip memory.  The default is 0, i.e. to use DMA if
-possible.
-
-
-5.4) gvp11=
------------
-
-:Syntax: gvp11=<addr-mask>
-
-The earlier versions of the GVP driver did not handle DMA
-address-mask settings correctly which made it necessary for some
-people to use this option, in order to get their GVP controller
-running under Linux. These problems have hopefully been solved and the
-use of this option is now highly unrecommended!
-
-Incorrect use can lead to unpredictable behavior, so please only use
-this option if you *know* what you are doing and have a reason to do
-so. In any case if you experience problems and need to use this
-option, please inform us about it by mailing to the Linux/68k kernel
-mailing list.
-
-The address mask set by this option specifies which addresses are
-valid for DMA with the GVP Series II SCSI controller. An address is
-valid, if no bits are set except the bits that are set in the mask,
-too.
-
-Some versions of the GVP can only DMA into a 24 bit address range,
-some can address a 25 bit address range while others can use the whole
-32 bit address range for DMA. The correct setting depends on your
-controller and should be autodetected by the driver. An example is the
-24 bit region which is specified by a mask of 0x00fffffe.