Documentation: ACPI: move namespace.txt to firmware-guide/acpi and convert to reST

This converts the plain text documentation to reStructuredText format
and adds it to Sphinx TOC tree.

No essential content change.
Signed-off-by: Changbin Du <changbin.du@gmail.com>
Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Documentation/firmware-guide/acpi/index.rst

@@ -7,3 +7,4 @@ ACPI Support
 .. toctree::
    :maxdepth: 1
 
+   namespace

Documentation/acpi/namespace.txt → Documentation/firmware-guide/acpi/namespace.rst

+.. SPDX-License-Identifier: GPL-2.0
+.. include:: <isonum.txt>
+
+===================================================
 ACPI Device Tree - Representation of ACPI Namespace
+===================================================
 
-Copyright (C) 2013, Intel Corporation
-Author: Lv Zheng <lv.zheng@intel.com>
+:Copyright: |copy| 2013, Intel Corporation
 
+:Author: Lv Zheng <lv.zheng@intel.com>
 
-Abstract:
+:Credit:   Thanks for the help from Zhang Rui <rui.zhang@intel.com> and
+           Rafael J.Wysocki <rafael.j.wysocki@intel.com>.
 
+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
+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 <rui.zhang@intel.com> and Rafael J.
-Wysocki <rafael.j.wysocki@intel.com>.
-
-
-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.
+This document illustrates the structure of the ACPI device tree.
 
-   The relationships between ACPI System Definition Tables described above
-   are illustrated in the following diagram.
+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  |    |  +-------------------+ |
@@ -68,18 +71,20 @@ Wysocki <rafael.j.wysocki@intel.com>.
 
                   Figure 1. ACPI Definition Blocks
 
-   NOTE: RSDP can also contain a pointer to the RSDT (Root System
+.. 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
+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:
 
-   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 +96,7 @@ Wysocki <rafael.j.wysocki@intel.com>.
       (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 +189,20 @@ Wysocki <rafael.j.wysocki@intel.com>.
                      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 <bus_id:instance>, 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 <bus_id:instance>, 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 +232,11 @@ Wysocki <rafael.j.wysocki@intel.com>.
 
                  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 +256,14 @@ Wysocki <rafael.j.wysocki@intel.com>.
       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 +283,47 @@ Wysocki <rafael.j.wysocki@intel.com>.
       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 +387,14 @@ Wysocki <rafael.j.wysocki@intel.com>.
 
                   Figure 3. Example Linux ACPI Device Tree
 
-   NOTE: Each node is represented as "object/path/modalias", where:
+.. 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
+
+.. note:: N/A indicates the device object does not have the 'path' or the
    'modalias' attribute.