Documentation: ACPI: move method-customizing.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/acpi/method-customizing.txt

-Linux ACPI Custom Control Method How To
-=======================================
-
-Written by Zhang Rui <rui.zhang@intel.com>
-
-
-Linux supports customizing ACPI control methods at runtime.
-
-Users can use this to
-1. override an existing method which may not work correctly,
-   or just for debugging purposes.
-2. insert a completely new method in order to create a missing
-   method such as _OFF, _ON, _STA, _INI, etc.
-For these cases, it is far simpler to dynamically install a single
-control method rather than override the entire DSDT, because kernel
-rebuild/reboot is not needed and test result can be got in minutes.
-
-Note: Only ACPI METHOD can be overridden, any other object types like
-      "Device", "OperationRegion", are not recognized. Methods
-      declared inside scope operators are also not supported.
-Note: The same ACPI control method can be overridden for many times,
-      and it's always the latest one that used by Linux/kernel.
-Note: To get the ACPI debug object output (Store (AAAA, Debug)),
-      please run "echo 1 > /sys/module/acpi/parameters/aml_debug_output".
-
-1. override an existing method
-   a) get the ACPI table via ACPI sysfs I/F. e.g. to get the DSDT,
-      just run "cat /sys/firmware/acpi/tables/DSDT > /tmp/dsdt.dat"
-   b) disassemble the table by running "iasl -d dsdt.dat".
-   c) rewrite the ASL code of the method and save it in a new file,
-   d) package the new file (psr.asl) to an ACPI table format.
-      Here is an example of a customized \_SB._AC._PSR method,
-
-      DefinitionBlock ("", "SSDT", 1, "", "", 0x20080715)
-      {
-	Method (\_SB_.AC._PSR, 0, NotSerialized)
-	{
-		Store ("In AC _PSR", Debug)
-		Return (ACON)
-	}
-      }
-      Note that the full pathname of the method in ACPI namespace
-      should be used.
-   e) assemble the file to generate the AML code of the method.
-      e.g. "iasl -vw 6084 psr.asl" (psr.aml is generated as a result)
-      If parameter "-vw 6084" is not supported by your iASL compiler,
-      please try a newer version.
-   f) mount debugfs by "mount -t debugfs none /sys/kernel/debug"
-   g) override the old method via the debugfs by running
-      "cat /tmp/psr.aml > /sys/kernel/debug/acpi/custom_method"
-
-2. insert a new method
-   This is easier than overriding an existing method.
-   We just need to create the ASL code of the method we want to
-   insert and then follow the step c) ~ g) in section 1.
-
-3. undo your changes
-   The "undo" operation is not supported for a new inserted method
-   right now, i.e. we can not remove a method currently.
-   For an overridden method, in order to undo your changes, please
-   save a copy of the method original ASL code in step c) section 1,
-   and redo step c) ~ g) to override the method with the original one.
-
-
-Note: We can use a kernel with multiple custom ACPI method running,
-      But each individual write to debugfs can implement a SINGLE
-      method override. i.e. if we want to insert/override multiple
-      ACPI methods, we need to redo step c) ~ g) for multiple times.
-
-Note: Be aware that root can mis-use this driver to modify arbitrary
-      memory and gain additional rights, if root's privileges got
-      restricted (for example if root is not allowed to load additional
-      modules after boot).

Documentation/firmware-guide/acpi/index.rst

@@ -10,5 +10,6 @@ ACPI Support
    namespace
    enumeration
    osi
+   method-customizing
    DSD-properties-rules
-   gpio-properties
+   gpio-properties
\ No newline at end of file

Documentation/firmware-guide/acpi/method-customizing.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+=======================================
+Linux ACPI Custom Control Method How To
+=======================================
+
+:Author: Zhang Rui <rui.zhang@intel.com>
+
+
+Linux supports customizing ACPI control methods at runtime.
+
+Users can use this to:
+
+1. override an existing method which may not work correctly,
+   or just for debugging purposes.
+2. insert a completely new method in order to create a missing
+   method such as _OFF, _ON, _STA, _INI, etc.
+
+For these cases, it is far simpler to dynamically install a single
+control method rather than override the entire DSDT, because kernel
+rebuild/reboot is not needed and test result can be got in minutes.
+
+.. note::
+
+  - Only ACPI METHOD can be overridden, any other object types like
+    "Device", "OperationRegion", are not recognized. Methods
+    declared inside scope operators are also not supported.
+
+  - The same ACPI control method can be overridden for many times,
+    and it's always the latest one that used by Linux/kernel.
+
+  - To get the ACPI debug object output (Store (AAAA, Debug)),
+    please run::
+
+      echo 1 > /sys/module/acpi/parameters/aml_debug_output
+
+
+1. override an existing method
+==============================
+a) get the ACPI table via ACPI sysfs I/F. e.g. to get the DSDT,
+   just run "cat /sys/firmware/acpi/tables/DSDT > /tmp/dsdt.dat"
+b) disassemble the table by running "iasl -d dsdt.dat".
+c) rewrite the ASL code of the method and save it in a new file,
+d) package the new file (psr.asl) to an ACPI table format.
+   Here is an example of a customized \_SB._AC._PSR method::
+
+      DefinitionBlock ("", "SSDT", 1, "", "", 0x20080715)
+      {
+         Method (\_SB_.AC._PSR, 0, NotSerialized)
+         {
+            Store ("In AC _PSR", Debug)
+            Return (ACON)
+         }
+      }
+
+   Note that the full pathname of the method in ACPI namespace
+   should be used.
+e) assemble the file to generate the AML code of the method.
+   e.g. "iasl -vw 6084 psr.asl" (psr.aml is generated as a result)
+   If parameter "-vw 6084" is not supported by your iASL compiler,
+   please try a newer version.
+f) mount debugfs by "mount -t debugfs none /sys/kernel/debug"
+g) override the old method via the debugfs by running
+   "cat /tmp/psr.aml > /sys/kernel/debug/acpi/custom_method"
+
+2. insert a new method
+======================
+This is easier than overriding an existing method.
+We just need to create the ASL code of the method we want to
+insert and then follow the step c) ~ g) in section 1.
+
+3. undo your changes
+====================
+The "undo" operation is not supported for a new inserted method
+right now, i.e. we can not remove a method currently.
+For an overridden method, in order to undo your changes, please
+save a copy of the method original ASL code in step c) section 1,
+and redo step c) ~ g) to override the method with the original one.
+
+
+.. note:: We can use a kernel with multiple custom ACPI method running,
+   But each individual write to debugfs can implement a SINGLE
+   method override. i.e. if we want to insert/override multiple
+   ACPI methods, we need to redo step c) ~ g) for multiple times.
+
+.. note:: Be aware that root can mis-use this driver to modify arbitrary
+   memory and gain additional rights, if root's privileges got
+   restricted (for example if root is not allowed to load additional
+   modules after boot).