From patchwork Tue Apr 23 16:28:31 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Changbin Du X-Patchwork-Id: 10913335 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0CE661390 for ; Tue, 23 Apr 2019 16:31:24 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EF91F286BF for ; Tue, 23 Apr 2019 16:31:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E27E928701; Tue, 23 Apr 2019 16:31:23 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AC201286A0 for ; Tue, 23 Apr 2019 16:31:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728544AbfDWQas (ORCPT ); Tue, 23 Apr 2019 12:30:48 -0400 Received: from mail-pl1-f195.google.com ([209.85.214.195]:41300 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728457AbfDWQas (ORCPT ); Tue, 23 Apr 2019 12:30:48 -0400 Received: by mail-pl1-f195.google.com with SMTP id d9so1859820pls.8; Tue, 23 Apr 2019 09:30:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=ncWoEeVc7E3SQTuKBjvA5OE9SZ5yGvMgjp5vCjVSzLU=; b=cOTOFFA03ZaJ7loM/zufuZcw4ULz2+ZzcBcEEGAsJSuHeVL3nkDHGi/Mwgt1sx4Hj5 oj1j63mOIU2uCIDUus3DGqjLKDy8uoim6olEJYeSJG2Zb4yW9PpVk1pT47ItP4UCePBs idFm6pWQU6pMZy0+FLT8ybyml6ks80umWn1mk2lT1ay3yzVIHjAu4IOZhNtoTshNqpRp lN2qPKT7NnbrwaajUkcqF0qPsHLv7EO8yeIeg5E9K8A3aHQbYAlDoi4Gy6Nu1HIm8GB+ sQmRYo9NwkrxzuZakmvv0wZe/VPQRjx/4PaRrGPvM9jQzbYo5tBgGt9+KpWVZyvPoQCz 4ONw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=ncWoEeVc7E3SQTuKBjvA5OE9SZ5yGvMgjp5vCjVSzLU=; b=TOQQhdita8zQXrtDm6lo8by07EHNn+fX/UGR6JbidpxIGzNQMXyExr6c5HqeviXaW6 IEmWZjQ37TS60J5kTreGzT9ggMu4JRwTNyTjyNhLq5rB/9PQqeTONpM4PLDB0Cyhfvy6 mJ0ZPeNHPmP/1Y2AklzmKJ7txXk6Bb+naYksKRQ8bU+SHOhWpkAa/Vjf3Yp3CHNb2ZAd 0EkPg7e54hPjNJDFe4052Fa2Nf5NfwDcYWexBR+/Z+8QKoEgEmzp6yghUV+i3mldKpJ/ N7oa/FhtIOvj4pbkzXb9aJo/nA1EFnz3zx3zv11BpoA5UtZdNmlj4pGaZxqAthfCweIl NpeQ== X-Gm-Message-State: APjAAAUJXhPYDcB+wwVuLChgvsGnUYRsJv19XZ1uW83v8xbtyyr1aehk inhDAykqNoIc/4KSIkcOugw= X-Google-Smtp-Source: APXvYqylW0MM40iUb34DEC75H9bN9P6vFlInL6meiInFdGGAJpEMeDqMPIYRE4xYR0wbJmv+Ovngsg== X-Received: by 2002:a17:902:61:: with SMTP id 88mr26747008pla.166.1556037046375; Tue, 23 Apr 2019 09:30:46 -0700 (PDT) Received: from localhost.localdomain ([104.238.181.70]) by smtp.gmail.com with ESMTPSA id v1sm24364801pff.81.2019.04.23.09.30.37 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 23 Apr 2019 09:30:45 -0700 (PDT) From: Changbin Du To: Jonathan Corbet Cc: Bjorn Helgaas , rjw@rjwysocki.net, linux-pci@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, x86@kernel.org, fenghua.yu@intel.com, linuxppc-dev@lists.ozlabs.org, linux-acpi@vger.kernel.org, linux-gpio@vger.kernel.org, mchehab+samsung@kernel.org, Changbin Du Subject: [PATCH v4 02/63] Documentation: ACPI: move namespace.txt to firmware-guide/acpi and convert to reST Date: Wed, 24 Apr 2019 00:28:31 +0800 Message-Id: <20190423162932.21428-3-changbin.du@gmail.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190423162932.21428-1-changbin.du@gmail.com> References: <20190423162932.21428-1-changbin.du@gmail.com> MIME-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This converts the plain text documentation to reStructuredText format and add it to Sphinx TOC tree. No essential content change. Signed-off-by: Changbin Du Reviewed-by: Mauro Carvalho Chehab --- Documentation/firmware-guide/acpi/index.rst | 1 + .../acpi/namespace.rst} | 310 +++++++++--------- 2 files changed, 161 insertions(+), 150 deletions(-) rename Documentation/{acpi/namespace.txt => firmware-guide/acpi/namespace.rst} (54%) diff --git a/Documentation/firmware-guide/acpi/index.rst b/Documentation/firmware-guide/acpi/index.rst index 0ec7d072ba22..210ad8acd6df 100644 --- a/Documentation/firmware-guide/acpi/index.rst +++ b/Documentation/firmware-guide/acpi/index.rst @@ -7,3 +7,4 @@ ACPI Support .. toctree:: :maxdepth: 1 + namespace diff --git a/Documentation/acpi/namespace.txt b/Documentation/firmware-guide/acpi/namespace.rst similarity index 54% rename from Documentation/acpi/namespace.txt rename to Documentation/firmware-guide/acpi/namespace.rst index 1860cb3865c6..443f0e5d0617 100644 --- a/Documentation/acpi/namespace.txt +++ b/Documentation/firmware-guide/acpi/namespace.rst @@ -1,85 +1,88 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. include:: + +=================================================== ACPI Device Tree - Representation of ACPI Namespace +=================================================== + +:Copyright: |copy| 2013, Intel Corporation + +:Author: Lv Zheng + +:Abstract: The Linux ACPI subsystem converts ACPI namespace objects into a Linux + device tree under the /sys/devices/LNXSYSTEM:00 and updates it upon + receiving ACPI hotplug notification events. For each device object + in this hierarchy there is a corresponding symbolic link in the + /sys/bus/acpi/devices. + This document illustrates the structure of the ACPI device tree. + +:Credit: Thanks for the help from Zhang Rui and + Rafael J.Wysocki . + + +ACPI Definition Blocks +====================== + +The ACPI firmware sets up RSDP (Root System Description Pointer) in the +system memory address space pointing to the XSDT (Extended System +Description Table). The XSDT always points to the FADT (Fixed ACPI +Description Table) using its first entry, the data within the FADT +includes various fixed-length entries that describe fixed ACPI features +of the hardware. The FADT contains a pointer to the DSDT +(Differentiated System Descripition Table). The XSDT also contains +entries pointing to possibly multiple SSDTs (Secondary System +Description Table). + +The DSDT and SSDT data is organized in data structures called definition +blocks that contain definitions of various objects, including ACPI +control methods, encoded in AML (ACPI Machine Language). The data block +of the DSDT along with the contents of SSDTs represents a hierarchical +data structure called the ACPI namespace whose topology reflects the +structure of the underlying hardware platform. + +The relationships between ACPI System Definition Tables described above +are illustrated in the following diagram:: + + +---------+ +-------+ +--------+ +------------------------+ + | RSDP | +->| XSDT | +->| FADT | | +-------------------+ | + +---------+ | +-------+ | +--------+ +-|->| DSDT | | + | Pointer | | | Entry |-+ | ...... | | | +-------------------+ | + +---------+ | +-------+ | X_DSDT |--+ | | Definition Blocks | | + | Pointer |-+ | ..... | | ...... | | +-------------------+ | + +---------+ +-------+ +--------+ | +-------------------+ | + | Entry |------------------|->| SSDT | | + +- - - -+ | +-------------------| | + | Entry | - - - - - - - -+ | | Definition Blocks | | + +- - - -+ | | +-------------------+ | + | | +- - - - - - - - - -+ | + +-|->| SSDT | | + | +-------------------+ | + | | Definition Blocks | | + | +- - - - - - - - - -+ | + +------------------------+ + | + OSPM Loading | + \|/ + +----------------+ + | ACPI Namespace | + +----------------+ + + Figure 1. ACPI Definition Blocks + +.. note:: RSDP can also contain a pointer to the RSDT (Root System + Description Table). Platforms provide RSDT to enable + compatibility with ACPI 1.0 operating systems. The OS is expected + to use XSDT, if present. + + +Example ACPI Namespace +====================== + +All definition blocks are loaded into a single namespace. The namespace +is a hierarchy of objects identified by names and paths. +The following naming conventions apply to object names in the ACPI +namespace: -Copyright (C) 2013, Intel Corporation -Author: Lv Zheng - - -Abstract: - -The Linux ACPI subsystem converts ACPI namespace objects into a Linux -device tree under the /sys/devices/LNXSYSTEM:00 and updates it upon -receiving ACPI hotplug notification events. For each device object in this -hierarchy there is a corresponding symbolic link in the -/sys/bus/acpi/devices. -This document illustrates the structure of the ACPI device tree. - - -Credit: - -Thanks for the help from Zhang Rui and Rafael J. -Wysocki . - - -1. ACPI Definition Blocks - - The ACPI firmware sets up RSDP (Root System Description Pointer) in the - system memory address space pointing to the XSDT (Extended System - Description Table). The XSDT always points to the FADT (Fixed ACPI - Description Table) using its first entry, the data within the FADT - includes various fixed-length entries that describe fixed ACPI features - of the hardware. The FADT contains a pointer to the DSDT - (Differentiated System Descripition Table). The XSDT also contains - entries pointing to possibly multiple SSDTs (Secondary System - Description Table). - - The DSDT and SSDT data is organized in data structures called definition - blocks that contain definitions of various objects, including ACPI - control methods, encoded in AML (ACPI Machine Language). The data block - of the DSDT along with the contents of SSDTs represents a hierarchical - data structure called the ACPI namespace whose topology reflects the - structure of the underlying hardware platform. - - The relationships between ACPI System Definition Tables described above - are illustrated in the following diagram. - - +---------+ +-------+ +--------+ +------------------------+ - | RSDP | +->| XSDT | +->| FADT | | +-------------------+ | - +---------+ | +-------+ | +--------+ +-|->| DSDT | | - | Pointer | | | Entry |-+ | ...... | | | +-------------------+ | - +---------+ | +-------+ | X_DSDT |--+ | | Definition Blocks | | - | Pointer |-+ | ..... | | ...... | | +-------------------+ | - +---------+ +-------+ +--------+ | +-------------------+ | - | Entry |------------------|->| SSDT | | - +- - - -+ | +-------------------| | - | Entry | - - - - - - - -+ | | Definition Blocks | | - +- - - -+ | | +-------------------+ | - | | +- - - - - - - - - -+ | - +-|->| SSDT | | - | +-------------------+ | - | | Definition Blocks | | - | +- - - - - - - - - -+ | - +------------------------+ - | - OSPM Loading | - \|/ - +----------------+ - | ACPI Namespace | - +----------------+ - - Figure 1. ACPI Definition Blocks - - NOTE: RSDP can also contain a pointer to the RSDT (Root System - Description Table). Platforms provide RSDT to enable - compatibility with ACPI 1.0 operating systems. The OS is expected - to use XSDT, if present. - - -2. Example ACPI Namespace - - All definition blocks are loaded into a single namespace. The namespace - is a hierarchy of objects identified by names and paths. - The following naming conventions apply to object names in the ACPI - namespace: 1. All names are 32 bits long. 2. The first byte of a name must be one of 'A' - 'Z', '_'. 3. Each of the remaining bytes of a name must be one of 'A' - 'Z', '0' @@ -91,7 +94,7 @@ Wysocki . (i.e. names prepended with '^' are relative to the parent of the current namespace node). - The figure below shows an example ACPI namespace. +The figure below shows an example ACPI namespace:: +------+ | \ | Root @@ -184,19 +187,20 @@ Wysocki . Figure 2. Example ACPI Namespace -3. Linux ACPI Device Objects +Linux ACPI Device Objects +========================= - The Linux kernel's core ACPI subsystem creates struct acpi_device - objects for ACPI namespace objects representing devices, power resources - processors, thermal zones. Those objects are exported to user space via - sysfs as directories in the subtree under /sys/devices/LNXSYSTM:00. The - format of their names is , where 'bus_id' refers to the - ACPI namespace representation of the given object and 'instance' is used - for distinguishing different object of the same 'bus_id' (it is - two-digit decimal representation of an unsigned integer). +The Linux kernel's core ACPI subsystem creates struct acpi_device +objects for ACPI namespace objects representing devices, power resources +processors, thermal zones. Those objects are exported to user space via +sysfs as directories in the subtree under /sys/devices/LNXSYSTM:00. The +format of their names is , where 'bus_id' refers to the +ACPI namespace representation of the given object and 'instance' is used +for distinguishing different object of the same 'bus_id' (it is +two-digit decimal representation of an unsigned integer). - The value of 'bus_id' depends on the type of the object whose name it is - part of as listed in the table below. +The value of 'bus_id' depends on the type of the object whose name it is +part of as listed in the table below:: +---+-----------------+-------+----------+ | | Object/Feature | Table | bus_id | @@ -226,10 +230,11 @@ Wysocki . Table 1. ACPI Namespace Objects Mapping - The following rules apply when creating struct acpi_device objects on - the basis of the contents of ACPI System Description Tables (as - indicated by the letter in the first column and the notation in the - second column of the table above): +The following rules apply when creating struct acpi_device objects on +the basis of the contents of ACPI System Description Tables (as +indicated by the letter in the first column and the notation in the +second column of the table above): + N: The object's source is an ACPI namespace node (as indicated by the named object's type in the second column). In that case the object's @@ -249,13 +254,14 @@ Wysocki . struct acpi_device object with LNXVIDEO 'bus_id' will be created for it. - The third column of the above table indicates which ACPI System - Description Tables contain information used for the creation of the - struct acpi_device objects represented by the given row (xSDT means DSDT - or SSDT). +The third column of the above table indicates which ACPI System +Description Tables contain information used for the creation of the +struct acpi_device objects represented by the given row (xSDT means DSDT +or SSDT). + +The forth column of the above table indicates the 'bus_id' generation +rule of the struct acpi_device object: - The forth column of the above table indicates the 'bus_id' generation - rule of the struct acpi_device object: _HID: _HID in the last column of the table means that the object's bus_id is derived from the _HID/_CID identification objects present under @@ -275,45 +281,47 @@ Wysocki . object's bus_id. -4. Linux ACPI Physical Device Glue - - ACPI device (i.e. struct acpi_device) objects may be linked to other - objects in the Linux' device hierarchy that represent "physical" devices - (for example, devices on the PCI bus). If that happens, it means that - the ACPI device object is a "companion" of a device otherwise - represented in a different way and is used (1) to provide configuration - information on that device which cannot be obtained by other means and - (2) to do specific things to the device with the help of its ACPI - control methods. One ACPI device object may be linked this way to - multiple "physical" devices. - - If an ACPI device object is linked to a "physical" device, its sysfs - directory contains the "physical_node" symbolic link to the sysfs - directory of the target device object. In turn, the target device's - sysfs directory will then contain the "firmware_node" symbolic link to - the sysfs directory of the companion ACPI device object. - The linking mechanism relies on device identification provided by the - ACPI namespace. For example, if there's an ACPI namespace object - representing a PCI device (i.e. a device object under an ACPI namespace - object representing a PCI bridge) whose _ADR returns 0x00020000 and the - bus number of the parent PCI bridge is 0, the sysfs directory - representing the struct acpi_device object created for that ACPI - namespace object will contain the 'physical_node' symbolic link to the - /sys/devices/pci0000:00/0000:00:02:0/ sysfs directory of the - corresponding PCI device. - - The linking mechanism is generally bus-specific. The core of its - implementation is located in the drivers/acpi/glue.c file, but there are - complementary parts depending on the bus types in question located - elsewhere. For example, the PCI-specific part of it is located in - drivers/pci/pci-acpi.c. - - -5. Example Linux ACPI Device Tree - - The sysfs hierarchy of struct acpi_device objects corresponding to the - example ACPI namespace illustrated in Figure 2 with the addition of - fixed PWR_BUTTON/SLP_BUTTON devices is shown below. +Linux ACPI Physical Device Glue +=============================== + +ACPI device (i.e. struct acpi_device) objects may be linked to other +objects in the Linux' device hierarchy that represent "physical" devices +(for example, devices on the PCI bus). If that happens, it means that +the ACPI device object is a "companion" of a device otherwise +represented in a different way and is used (1) to provide configuration +information on that device which cannot be obtained by other means and +(2) to do specific things to the device with the help of its ACPI +control methods. One ACPI device object may be linked this way to +multiple "physical" devices. + +If an ACPI device object is linked to a "physical" device, its sysfs +directory contains the "physical_node" symbolic link to the sysfs +directory of the target device object. In turn, the target device's +sysfs directory will then contain the "firmware_node" symbolic link to +the sysfs directory of the companion ACPI device object. +The linking mechanism relies on device identification provided by the +ACPI namespace. For example, if there's an ACPI namespace object +representing a PCI device (i.e. a device object under an ACPI namespace +object representing a PCI bridge) whose _ADR returns 0x00020000 and the +bus number of the parent PCI bridge is 0, the sysfs directory +representing the struct acpi_device object created for that ACPI +namespace object will contain the 'physical_node' symbolic link to the +/sys/devices/pci0000:00/0000:00:02:0/ sysfs directory of the +corresponding PCI device. + +The linking mechanism is generally bus-specific. The core of its +implementation is located in the drivers/acpi/glue.c file, but there are +complementary parts depending on the bus types in question located +elsewhere. For example, the PCI-specific part of it is located in +drivers/pci/pci-acpi.c. + + +Example Linux ACPI Device Tree +================================= + +The sysfs hierarchy of struct acpi_device objects corresponding to the +example ACPI namespace illustrated in Figure 2 with the addition of +fixed PWR_BUTTON/SLP_BUTTON devices is shown below:: +--------------+---+-----------------+ | LNXSYSTEM:00 | \ | acpi:LNXSYSTEM: | @@ -377,12 +385,14 @@ Wysocki . Figure 3. Example Linux ACPI Device Tree - NOTE: Each node is represented as "object/path/modalias", where: - 1. 'object' is the name of the object's directory in sysfs. - 2. 'path' is the ACPI namespace path of the corresponding - ACPI namespace object, as returned by the object's 'path' - sysfs attribute. - 3. 'modalias' is the value of the object's 'modalias' sysfs - attribute (as described earlier in this document). - NOTE: N/A indicates the device object does not have the 'path' or the - 'modalias' attribute. +.. note:: Each node is represented as "object/path/modalias", where: + + 1. 'object' is the name of the object's directory in sysfs. + 2. 'path' is the ACPI namespace path of the corresponding + ACPI namespace object, as returned by the object's 'path' + sysfs attribute. + 3. 'modalias' is the value of the object's 'modalias' sysfs + attribute (as described earlier in this document). + +.. note:: N/A indicates the device object does not have the 'path' or the + 'modalias' attribute.