diff options
Diffstat (limited to 'Documentation/acpi')
| -rw-r--r-- | Documentation/acpi/aml-debugger.txt | 66 | ||||
| -rw-r--r-- | Documentation/acpi/linuxized-acpica.txt | 262 | ||||
| -rw-r--r-- | Documentation/acpi/ssdt-overlays.txt | 172 |
3 files changed, 500 insertions, 0 deletions
diff --git a/Documentation/acpi/aml-debugger.txt b/Documentation/acpi/aml-debugger.txt new file mode 100644 index 000000000000..5f62aa4a493b --- /dev/null +++ b/Documentation/acpi/aml-debugger.txt @@ -0,0 +1,66 @@ +The AML Debugger + +Copyright (C) 2016, Intel Corporation +Author: Lv Zheng <lv.zheng@intel.com> + + +This document describes the usage of the AML debugger embedded in the Linux +kernel. + +1. Build the debugger + + The following kernel configuration items are required to enable the AML + debugger interface from the Linux kernel: + + CONFIG_ACPI_DEBUGGER=y + CONFIG_ACPI_DEBUGGER_USER=m + + The userspace utlities can be built from the kernel source tree using + the following commands: + + $ cd tools + $ make acpi + + The resultant userspace tool binary is then located at: + + tools/acpi/power/acpi/acpidbg/acpidbg + + It can be installed to system directories by running "make install" (as a + sufficiently privileged user). + +2. Start the userspace debugger interface + + After booting the kernel with the debugger built-in, the debugger can be + started by using the following commands: + + # mount -t debugfs none /sys/kernel/debug + # modprobe acpi_dbg + # tools/acpi/power/acpi/acpidbg/acpidbg + + That spawns the interactive AML debugger environment where you can execute + debugger commands. + + The commands are documented in the "ACPICA Overview and Programmer Reference" + that can be downloaded from + + https://acpica.org/documentation + + The detailed debugger commands reference is located in Chapter 12 "ACPICA + Debugger Reference". The "help" command can be used for a quick reference. + +3. Stop the userspace debugger interface + + The interactive debugger interface can be closed by pressing Ctrl+C or using + the "quit" or "exit" commands. When finished, unload the module with: + + # rmmod acpi_dbg + + The module unloading may fail if there is an acpidbg instance running. + +4. Run the debugger in a script + + It may be useful to run the AML debugger in a test script. "acpidbg" supports + this in a special "batch" mode. For example, the following command outputs + the entire ACPI namespace: + + # acpidbg -b "namespace" diff --git a/Documentation/acpi/linuxized-acpica.txt b/Documentation/acpi/linuxized-acpica.txt new file mode 100644 index 000000000000..defe2eec5331 --- /dev/null +++ b/Documentation/acpi/linuxized-acpica.txt @@ -0,0 +1,262 @@ +Linuxized ACPICA - Introduction to ACPICA Release Automation + +Copyright (C) 2013-2016, Intel Corporation +Author: Lv Zheng <lv.zheng@intel.com> + + +Abstract: + +This document describes the ACPICA project and the relationship between +ACPICA and Linux. It also describes how ACPICA code in drivers/acpi/acpica, +include/acpi and tools/power/acpi is automatically updated to follow the +upstream. + + +1. ACPICA Project + + The ACPI Component Architecture (ACPICA) project provides an operating + system (OS)-independent reference implementation of the Advanced + Configuration and Power Interface Specification (ACPI). It has been + adapted by various host OSes. By directly integrating ACPICA, Linux can + also benefit from the application experiences of ACPICA from other host + OSes. + + The homepage of ACPICA project is: www.acpica.org, it is maintained and + supported by Intel Corporation. + + The following figure depicts the Linux ACPI subystem where the ACPICA + adaptation is included: + + +---------------------------------------------------------+ + | | + | +---------------------------------------------------+ | + | | +------------------+ | | + | | | Table Management | | | + | | +------------------+ | | + | | +----------------------+ | | + | | | Namespace Management | | | + | | +----------------------+ | | + | | +------------------+ ACPICA Components | | + | | | Event Management | | | + | | +------------------+ | | + | | +---------------------+ | | + | | | Resource Management | | | + | | +---------------------+ | | + | | +---------------------+ | | + | | | Hardware Management | | | + | | +---------------------+ | | + | +---------------------------------------------------+ | | + | | | +------------------+ | | | + | | | | OS Service Layer | | | | + | | | +------------------+ | | | + | | +-------------------------------------------------|-+ | + | | +--------------------+ | | + | | | Device Enumeration | | | + | | +--------------------+ | | + | | +------------------+ | | + | | | Power Management | | | + | | +------------------+ Linux/ACPI Components | | + | | +--------------------+ | | + | | | Thermal Management | | | + | | +--------------------+ | | + | | +--------------------------+ | | + | | | Drivers for ACPI Devices | | | + | | +--------------------------+ | | + | | +--------+ | | + | | | ...... | | | + | | +--------+ | | + | +---------------------------------------------------+ | + | | + +---------------------------------------------------------+ + + Figure 1. Linux ACPI Software Components + + NOTE: + A. OS Service Layer - Provided by Linux to offer OS dependent + implementation of the predefined ACPICA interfaces (acpi_os_*). + include/acpi/acpiosxf.h + drivers/acpi/osl.c + include/acpi/platform + include/asm/acenv.h + B. ACPICA Functionality - Released from ACPICA code base to offer + OS independent implementation of the ACPICA interfaces (acpi_*). + drivers/acpi/acpica + include/acpi/ac*.h + tools/power/acpi + C. Linux/ACPI Functionality - Providing Linux specific ACPI + functionality to the other Linux kernel subsystems and user space + programs. + drivers/acpi + include/linux/acpi.h + include/linux/acpi*.h + include/acpi + tools/power/acpi + D. Architecture Specific ACPICA/ACPI Functionalities - Provided by the + ACPI subsystem to offer architecture specific implementation of the + ACPI interfaces. They are Linux specific components and are out of + the scope of this document. + include/asm/acpi.h + include/asm/acpi*.h + arch/*/acpi + +2. ACPICA Release + + The ACPICA project maintains its code base at the following repository URL: + https://github.com/acpica/acpica.git. As a rule, a release is made every + month. + + As the coding style adopted by the ACPICA project is not acceptable by + Linux, there is a release process to convert the ACPICA git commits into + Linux patches. The patches generated by this process are referred to as + "linuxized ACPICA patches". The release process is carried out on a local + copy the ACPICA git repository. Each commit in the monthly release is + converted into a linuxized ACPICA patch. Together, they form the montly + ACPICA release patchset for the Linux ACPI community. This process is + illustrated in the following figure: + + +-----------------------------+ + | acpica / master (-) commits | + +-----------------------------+ + /|\ | + | \|/ + | /---------------------\ +----------------------+ + | < Linuxize repo Utility >-->| old linuxized acpica |--+ + | \---------------------/ +----------------------+ | + | | + /---------\ | + < git reset > \ + \---------/ \ + /|\ /+-+ + | / | + +-----------------------------+ | | + | acpica / master (+) commits | | | + +-----------------------------+ | | + | | | + \|/ | | + /-----------------------\ +----------------------+ | | + < Linuxize repo Utilities >-->| new linuxized acpica |--+ | + \-----------------------/ +----------------------+ | + \|/ + +--------------------------+ /----------------------\ + | Linuxized ACPICA Patches |<----------------< Linuxize patch Utility > + +--------------------------+ \----------------------/ + | + \|/ + /---------------------------\ + < Linux ACPI Community Review > + \---------------------------/ + | + \|/ + +-----------------------+ /------------------\ +----------------+ + | linux-pm / linux-next |-->< Linux Merge Window >-->| linux / master | + +-----------------------+ \------------------/ +----------------+ + + Figure 2. ACPICA -> Linux Upstream Process + + NOTE: + A. Linuxize Utilities - Provided by the ACPICA repository, including a + utility located in source/tools/acpisrc folder and a number of + scripts located in generate/linux folder. + B. acpica / master - "master" branch of the git repository at + <https://github.com/acpica/acpica.git>. + C. linux-pm / linux-next - "linux-next" branch of the git repository at + <http://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git>. + D. linux / master - "master" branch of the git repository at + <http://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git>. + + Before the linuxized ACPICA patches are sent to the Linux ACPI community + for review, there is a quality ensurance build test process to reduce + porting issues. Currently this build process only takes care of the + following kernel configuration options: + CONFIG_ACPI/CONFIG_ACPI_DEBUG/CONFIG_ACPI_DEBUGGER + +3. ACPICA Divergences + + Ideally, all of the ACPICA commits should be converted into Linux patches + automatically without manual modifications, the "linux / master" tree should + contain the ACPICA code that exactly corresponds to the ACPICA code + contained in "new linuxized acpica" tree and it should be possible to run + the release process fully automatically. + + As a matter of fact, however, there are source code differences between + the ACPICA code in Linux and the upstream ACPICA code, referred to as + "ACPICA Divergences". + + The various sources of ACPICA divergences include: + 1. Legacy divergences - Before the current ACPICA release process was + established, there already had been divergences between Linux and + ACPICA. Over the past several years those divergences have been greatly + reduced, but there still are several ones and it takes time to figure + out the underlying reasons for their existence. + 2. Manual modifications - Any manual modification (eg. coding style fixes) + made directly in the Linux sources obviously hurts the ACPICA release + automation. Thus it is recommended to fix such issues in the ACPICA + upstream source code and generate the linuxized fix using the ACPICA + release utilities (please refer to Section 4 below for the details). + 3. Linux specific features - Sometimes it's impossible to use the + current ACPICA APIs to implement features required by the Linux kernel, + so Linux developers occasionaly have to change ACPICA code directly. + Those changes may not be acceptable by ACPICA upstream and in such cases + they are left as committed ACPICA divergences unless the ACPICA side can + implement new mechanisms as replacements for them. + 4. ACPICA release fixups - ACPICA only tests commits using a set of the + user space simulation utilies, thus the linuxized ACPICA patches may + break the Linux kernel, leaving us build/boot failures. In order to + avoid breaking Linux bisection, fixes are applied directly to the + linuxized ACPICA patches during the release process. When the release + fixups are backported to the upstream ACPICA sources, they must follow + the upstream ACPICA rules and so further modifications may appear. + That may result in the appearance of new divergences. + 5. Fast tracking of ACPICA commits - Some ACPICA commits are regression + fixes or stable-candidate material, so they are applied in advance with + respect to the ACPICA release process. If such commits are reverted or + rebased on the ACPICA side in order to offer better solutions, new ACPICA + divergences are generated. + +4. ACPICA Development + + This paragraph guides Linux developers to use the ACPICA upstream release + utilities to obtain Linux patches corresponding to upstream ACPICA commits + before they become available from the ACPICA release process. + + 1. Cherry-pick an ACPICA commit + + First you need to git clone the ACPICA repository and the ACPICA change + you want to cherry pick must be committed into the local repository. + + Then the gen-patch.sh command can help to cherry-pick an ACPICA commit + from the ACPICA local repository: + + $ git clone https://github.com/acpica/acpica + $ cd acpica + $ generate/linux/gen-patch.sh -u [commit ID] + + Here the commit ID is the ACPICA local repository commit ID you want to + cherry pick. It can be omitted if the commit is "HEAD". + + 2. Cherry-pick recent ACPICA commits + + Sometimes you need to rebase your code on top of the most recent ACPICA + changes that haven't been applied to Linux yet. + + You can generate the ACPICA release series yourself and rebase your code on + top of the generated ACPICA release patches: + + $ git clone https://github.com/acpica/acpica + $ cd acpica + $ generate/linux/make-patches.sh -u [commit ID] + + The commit ID should be the last ACPICA commit accepted by Linux. Usually, + it is the commit modifying ACPI_CA_VERSION. It can be found by executing + "git blame source/include/acpixf.h" and referencing the line that contains + "ACPI_CA_VERSION". + + 3. Inspect the current divergences + + If you have local copies of both Linux and upstream ACPICA, you can generate + a diff file indicating the state of the current divergences: + + # git clone https://github.com/acpica/acpica + # git clone http://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git + # cd acpica + # generate/linux/divergences.sh -s ../linux diff --git a/Documentation/acpi/ssdt-overlays.txt b/Documentation/acpi/ssdt-overlays.txt new file mode 100644 index 000000000000..5ae13f161ea2 --- /dev/null +++ b/Documentation/acpi/ssdt-overlays.txt @@ -0,0 +1,172 @@ + +In order to support ACPI open-ended hardware configurations (e.g. development +boards) we need a way to augment the ACPI configuration provided by the firmware +image. A common example is connecting sensors on I2C / SPI buses on development +boards. + +Although this can be accomplished by creating a kernel platform driver or +recompiling the firmware image with updated ACPI tables, neither is practical: +the former proliferates board specific kernel code while the latter requires +access to firmware tools which are often not publicly available. + +Because ACPI supports external references in AML code a more practical +way to augment firmware ACPI configuration is by dynamically loading +user defined SSDT tables that contain the board specific information. + +For example, to enumerate a Bosch BMA222E accelerometer on the I2C bus of the +Minnowboard MAX development board exposed via the LSE connector [1], the +following ASL code can be used: + +DefinitionBlock ("minnowmax.aml", "SSDT", 1, "Vendor", "Accel", 0x00000003) +{ + External (\_SB.I2C6, DeviceObj) + + Scope (\_SB.I2C6) + { + Device (STAC) + { + Name (_ADR, Zero) + Name (_HID, "BMA222E") + + Method (_CRS, 0, Serialized) + { + Name (RBUF, ResourceTemplate () + { + I2cSerialBus (0x0018, ControllerInitiated, 0x00061A80, + AddressingMode7Bit, "\\_SB.I2C6", 0x00, + ResourceConsumer, ,) + GpioInt (Edge, ActiveHigh, Exclusive, PullDown, 0x0000, + "\\_SB.GPO2", 0x00, ResourceConsumer, , ) + { // Pin list + 0 + } + }) + Return (RBUF) + } + } + } +} + +which can then be compiled to AML binary format: + +$ iasl minnowmax.asl + +Intel ACPI Component Architecture +ASL Optimizing Compiler version 20140214-64 [Mar 29 2014] +Copyright (c) 2000 - 2014 Intel Corporation + +ASL Input: minnomax.asl - 30 lines, 614 bytes, 7 keywords +AML Output: minnowmax.aml - 165 bytes, 6 named objects, 1 executable opcodes + +[1] http://wiki.minnowboard.org/MinnowBoard_MAX#Low_Speed_Expansion_Connector_.28Top.29 + +The resulting AML code can then be loaded by the kernel using one of the methods +below. + +== Loading ACPI SSDTs from initrd == + +This option allows loading of user defined SSDTs from initrd and it is useful +when the system does not support EFI or when there is not enough EFI storage. + +It works in a similar way with initrd based ACPI tables override/upgrade: SSDT +aml code must be placed in the first, uncompressed, initrd under the +"kernel/firmware/acpi" path. Multiple files can be used and this will translate +in loading multiple tables. Only SSDT and OEM tables are allowed. See +initrd_table_override.txt for more details. + +Here is an example: + +# Add the raw ACPI tables to an uncompressed cpio archive. +# They must be put into a /kernel/firmware/acpi directory inside the +# cpio archive. +# The uncompressed cpio archive must be the first. +# Other, typically compressed cpio archives, must be +# concatenated on top of the uncompressed one. +mkdir -p kernel/firmware/acpi +cp ssdt.aml kernel/firmware/acpi + +# Create the uncompressed cpio archive and concatenate the original initrd +# on top: +find kernel | cpio -H newc --create > /boot/instrumented_initrd +cat /boot/initrd >>/boot/instrumented_initrd + +== Loading ACPI SSDTs from EFI variables == + +This is the preferred method, when EFI is supported on the platform, because it +allows a persistent, OS independent way of storing the user defined SSDTs. There +is also work underway to implement EFI support for loading user defined SSDTs +and using this method will make it easier to convert to the EFI loading +mechanism when that will arrive. + +In order to load SSDTs from an EFI variable the efivar_ssdt kernel command line +parameter can be used. The argument for the option is the variable name to +use. If there are multiple variables with the same name but with different +vendor GUIDs, all of them will be loaded. + +In order to store the AML code in an EFI variable the efivarfs filesystem can be +used. It is enabled and mounted by default in /sys/firmware/efi/efivars in all +recent distribution. + +Creating a new file in /sys/firmware/efi/efivars will automatically create a new +EFI variable. Updating a file in /sys/firmware/efi/efivars will update the EFI +variable. Please note that the file name needs to be specially formatted as +"Name-GUID" and that the first 4 bytes in the file (little-endian format) +represent the attributes of the EFI variable (see EFI_VARIABLE_MASK in +include/linux/efi.h). Writing to the file must also be done with one write +operation. + +For example, you can use the following bash script to create/update an EFI +variable with the content from a given file: + +#!/bin/sh -e + +while ! [ -z "$1" ]; do + case "$1" in + "-f") filename="$2"; shift;; + "-g") guid="$2"; shift;; + *) name="$1";; + esac + shift +done + +usage() +{ + echo "Syntax: ${0##*/} -f filename [ -g guid ] name" + exit 1 +} + +[ -n "$name" -a -f "$filename" ] || usage + +EFIVARFS="/sys/firmware/efi/efivars" + +[ -d "$EFIVARFS" ] || exit 2 + +if stat -tf $EFIVARFS | grep -q -v de5e81e4; then + mount -t efivarfs none $EFIVARFS +fi + +# try to pick up an existing GUID +[ -n "$guid" ] || guid=$(find "$EFIVARFS" -name "$name-*" | head -n1 | cut -f2- -d-) + +# use a randomly generated GUID +[ -n "$guid" ] || guid="$(cat /proc/sys/kernel/random/uuid)" + +# efivarfs expects all of the data in one write +tmp=$(mktemp) +/bin/echo -ne "\007\000\000\000" | cat - $filename > $tmp +dd if=$tmp of="$EFIVARFS/$name-$guid" bs=$(stat -c %s $tmp) +rm $tmp + +== Loading ACPI SSDTs from configfs == + +This option allows loading of user defined SSDTs from userspace via the configfs +interface. The CONFIG_ACPI_CONFIGFS option must be select and configfs must be +mounted. In the following examples, we assume that configfs has been mounted in +/config. + +New tables can be loading by creating new directories in /config/acpi/table/ and +writing the SSDT aml code in the aml attribute: + +cd /config/acpi/table +mkdir my_ssdt +cat ~/ssdt.aml > my_ssdt/aml |