diff mbox series

[v2] ACPI: PCC: Implement OperationRegion handler for the PCC Type 3 subtype

Message ID 20220103155838.616580-1-sudeep.holla@arm.com
State Superseded
Headers show
Series [v2] ACPI: PCC: Implement OperationRegion handler for the PCC Type 3 subtype | expand

Commit Message

Sudeep Holla Jan. 3, 2022, 3:58 p.m. UTC 
PCC OpRegion provides a mechanism to communicate with the platform
directly from the AML. PCCT provides the list of PCC channel available
in the platform, a subset or all of them can be used in PCC Opregion.

This patch registers the PCC OpRegion handler before ACPI tables are
loaded. This relies on the special context data passed to identify and
set up the PCC channel before the OpRegion handler is executed for the
first time.

Typical PCC Opregion declaration looks like this:

OperationRegion (PFRM, PCC, 2, 0x74)
Field (PFRM, ByteAcc, NoLock, Preserve)
{
    SIGN,   32,
    FLGS,   32,
    LEN,    32,
    CMD,    32,
    DATA,   800
}

It contains four named double words followed by 100 bytes of buffer
names DATA.

ASL can fill out the buffer something like:

    /* Create global or local buffer */
    Name (BUFF, Buffer (0x0C){})
    /* Create double word fields over the buffer */
    CreateDWordField (BUFF, 0x0, WD0)
    CreateDWordField (BUFF, 0x04, WD1)
    CreateDWordField (BUFF, 0x08, WD2)

    /* Fill the named fields */
    WD0 = 0x50434300
    SIGN = BUFF
    WD0 = 1
    FLGS = BUFF
    WD0 = 0x10
    LEN = BUFF

    /* Fill the payload in the DATA buffer */
    WD0 = 0
    WD1 = 0x08
    WD2 = 0
    DATA = BUFF

    /* Write to CMD field to trigger handler */
    WD0 = 0x4404
    CMD = BUFF

This buffer is received by acpi_pcc_opregion_space_handler. This
handler will fetch the complete buffer via internal_pcc_buffer.

The setup handler will receive the special PCC context data which will
contain the PCC channel index which used to set up the channel. The
buffer pointer and length is saved in region context which is then used
in the handler.

Cc: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
---
 drivers/acpi/Kconfig    |  17 ++++++
 drivers/acpi/Makefile   |   1 +
 drivers/acpi/acpi_pcc.c | 120 ++++++++++++++++++++++++++++++++++++++++
 drivers/acpi/bus.c      |   1 +
 include/linux/acpi.h    |   6 ++
 5 files changed, 145 insertions(+)
 create mode 100644 drivers/acpi/acpi_pcc.c

v1[0]-v2:
	- Addressed all the comments from Rafael[1]

[0] https://lore.kernel.org/r/20211222190919.137550-1-sudeep.holla@arm.com/
[1] https://lore.kernel.org/r/CAJZ5v0jWJVSFS3KTavfCTzxWq-Q361nGDCWf+VLXRu-9Z4MJsQ@mail.gmail.com

--
2.25.1

Comments

kernel test robot Jan. 4, 2022, 8:01 a.m. UTC | #1 
Hi Sudeep,

I love your patch! Yet something to improve:

[auto build test ERROR on rafael-pm/linux-next]
[also build test ERROR on linux/master linus/master v5.16-rc8 next-20211224]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Sudeep-Holla/ACPI-PCC-Implement-OperationRegion-handler-for-the-PCC-Type-3-subtype/20220104-000003
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
config: i386-allyesconfig (https://download.01.org/0day-ci/archive/20220104/202201041539.feAV0l27-lkp@intel.com/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/1dbcdc47eadc8c55659410fc03d067f3438a386a
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Sudeep-Holla/ACPI-PCC-Implement-OperationRegion-handler-for-the-PCC-Type-3-subtype/20220104-000003
        git checkout 1dbcdc47eadc8c55659410fc03d067f3438a386a
        # save the config file to linux build tree
        mkdir build_dir
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   In file included from include/acpi/acpi.h:29,
                    from include/linux/acpi.h:22,
                    from drivers/acpi/acpi_pcc.c:19:
   drivers/acpi/acpi_pcc.c: In function 'acpi_pcc_address_space_setup':
>> include/acpi/acoutput.h:398:19: error: implicit declaration of function 'acpi_ut_status_exit'; did you mean 'acpi_irq_stats_init'? [-Werror=implicit-function-declaration]
     398 |  ACPI_TRACE_EXIT (acpi_ut_status_exit, acpi_status, status)
         |                   ^~~~~~~~~~~~~~~~~~~
   include/acpi/acoutput.h:281:44: note: in definition of macro 'ACPI_DO_WHILE0'
     281 | #define ACPI_DO_WHILE0(a)               do a while(0)
         |                                            ^
   include/acpi/acoutput.h:398:2: note: in expansion of macro 'ACPI_TRACE_EXIT'
     398 |  ACPI_TRACE_EXIT (acpi_ut_status_exit, acpi_status, status)
         |  ^~~~~~~~~~~~~~~
   drivers/acpi/acpi_pcc.c:53:3: note: in expansion of macro 'return_ACPI_STATUS'
      53 |   return_ACPI_STATUS(AE_NO_MEMORY);
         |   ^~~~~~~~~~~~~~~~~~
>> include/acpi/acoutput.h:258:36: error: '_acpi_module_name' undeclared (first use in this function); did you mean 'acpi_dev_name'?
     258 |  __LINE__, ACPI_GET_FUNCTION_NAME, _acpi_module_name, _COMPONENT
         |                                    ^~~~~~~~~~~~~~~~~
   include/acpi/acoutput.h:281:44: note: in definition of macro 'ACPI_DO_WHILE0'
     281 | #define ACPI_DO_WHILE0(a)               do a while(0)
         |                                            ^
   include/acpi/acoutput.h:375:13: note: in expansion of macro 'ACPI_DEBUG_PARAMETERS'
     375 |   function (ACPI_DEBUG_PARAMETERS, _param); \
         |             ^~~~~~~~~~~~~~~~~~~~~
   include/acpi/acoutput.h:398:2: note: in expansion of macro 'ACPI_TRACE_EXIT'
     398 |  ACPI_TRACE_EXIT (acpi_ut_status_exit, acpi_status, status)
         |  ^~~~~~~~~~~~~~~
   drivers/acpi/acpi_pcc.c:53:3: note: in expansion of macro 'return_ACPI_STATUS'
      53 |   return_ACPI_STATUS(AE_NO_MEMORY);
         |   ^~~~~~~~~~~~~~~~~~
   include/acpi/acoutput.h:258:36: note: each undeclared identifier is reported only once for each function it appears in
     258 |  __LINE__, ACPI_GET_FUNCTION_NAME, _acpi_module_name, _COMPONENT
         |                                    ^~~~~~~~~~~~~~~~~
   include/acpi/acoutput.h:281:44: note: in definition of macro 'ACPI_DO_WHILE0'
     281 | #define ACPI_DO_WHILE0(a)               do a while(0)
         |                                            ^
   include/acpi/acoutput.h:375:13: note: in expansion of macro 'ACPI_DEBUG_PARAMETERS'
     375 |   function (ACPI_DEBUG_PARAMETERS, _param); \
         |             ^~~~~~~~~~~~~~~~~~~~~
   include/acpi/acoutput.h:398:2: note: in expansion of macro 'ACPI_TRACE_EXIT'
     398 |  ACPI_TRACE_EXIT (acpi_ut_status_exit, acpi_status, status)
         |  ^~~~~~~~~~~~~~~
   drivers/acpi/acpi_pcc.c:53:3: note: in expansion of macro 'return_ACPI_STATUS'
      53 |   return_ACPI_STATUS(AE_NO_MEMORY);
         |   ^~~~~~~~~~~~~~~~~~
>> include/acpi/acoutput.h:258:55: error: '_COMPONENT' undeclared (first use in this function)
     258 |  __LINE__, ACPI_GET_FUNCTION_NAME, _acpi_module_name, _COMPONENT
         |                                                       ^~~~~~~~~~
   include/acpi/acoutput.h:281:44: note: in definition of macro 'ACPI_DO_WHILE0'
     281 | #define ACPI_DO_WHILE0(a)               do a while(0)
         |                                            ^
   include/acpi/acoutput.h:375:13: note: in expansion of macro 'ACPI_DEBUG_PARAMETERS'
     375 |   function (ACPI_DEBUG_PARAMETERS, _param); \
         |             ^~~~~~~~~~~~~~~~~~~~~
   include/acpi/acoutput.h:398:2: note: in expansion of macro 'ACPI_TRACE_EXIT'
     398 |  ACPI_TRACE_EXIT (acpi_ut_status_exit, acpi_status, status)
         |  ^~~~~~~~~~~~~~~
   drivers/acpi/acpi_pcc.c:53:3: note: in expansion of macro 'return_ACPI_STATUS'
      53 |   return_ACPI_STATUS(AE_NO_MEMORY);
         |   ^~~~~~~~~~~~~~~~~~
   drivers/acpi/acpi_pcc.c: In function 'acpi_pcc_address_space_handler':
>> include/acpi/acoutput.h:258:36: error: '_acpi_module_name' undeclared (first use in this function); did you mean 'acpi_dev_name'?
     258 |  __LINE__, ACPI_GET_FUNCTION_NAME, _acpi_module_name, _COMPONENT
         |                                    ^~~~~~~~~~~~~~~~~
   include/acpi/acoutput.h:281:44: note: in definition of macro 'ACPI_DO_WHILE0'
     281 | #define ACPI_DO_WHILE0(a)               do a while(0)
         |                                            ^
   include/acpi/acoutput.h:375:13: note: in expansion of macro 'ACPI_DEBUG_PARAMETERS'
     375 |   function (ACPI_DEBUG_PARAMETERS, _param); \
         |             ^~~~~~~~~~~~~~~~~~~~~
   include/acpi/acoutput.h:398:2: note: in expansion of macro 'ACPI_TRACE_EXIT'
     398 |  ACPI_TRACE_EXIT (acpi_ut_status_exit, acpi_status, status)
         |  ^~~~~~~~~~~~~~~
   drivers/acpi/acpi_pcc.c:97:3: note: in expansion of macro 'return_ACPI_STATUS'
      97 |   return_ACPI_STATUS(AE_ERROR);
         |   ^~~~~~~~~~~~~~~~~~
>> include/acpi/acoutput.h:258:55: error: '_COMPONENT' undeclared (first use in this function)
     258 |  __LINE__, ACPI_GET_FUNCTION_NAME, _acpi_module_name, _COMPONENT
         |                                                       ^~~~~~~~~~
   include/acpi/acoutput.h:281:44: note: in definition of macro 'ACPI_DO_WHILE0'
     281 | #define ACPI_DO_WHILE0(a)               do a while(0)
         |                                            ^
   include/acpi/acoutput.h:375:13: note: in expansion of macro 'ACPI_DEBUG_PARAMETERS'
     375 |   function (ACPI_DEBUG_PARAMETERS, _param); \
         |             ^~~~~~~~~~~~~~~~~~~~~
   include/acpi/acoutput.h:398:2: note: in expansion of macro 'ACPI_TRACE_EXIT'
     398 |  ACPI_TRACE_EXIT (acpi_ut_status_exit, acpi_status, status)
         |  ^~~~~~~~~~~~~~~
   drivers/acpi/acpi_pcc.c:97:3: note: in expansion of macro 'return_ACPI_STATUS'
      97 |   return_ACPI_STATUS(AE_ERROR);
         |   ^~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +398 include/acpi/acoutput.h

50df4d8b0f6e19 Bob Moore      2008-12-31  252  
50df4d8b0f6e19 Bob Moore      2008-12-31  253  /*
50df4d8b0f6e19 Bob Moore      2008-12-31  254   * Common parameters used for debug output functions:
50df4d8b0f6e19 Bob Moore      2008-12-31  255   * line number, function name, module(file) name, component ID
50df4d8b0f6e19 Bob Moore      2008-12-31  256   */
ad5a06f2969763 Bob Moore      2012-12-31  257  #define ACPI_DEBUG_PARAMETERS \
ad5a06f2969763 Bob Moore      2012-12-31 @258  	__LINE__, ACPI_GET_FUNCTION_NAME, _acpi_module_name, _COMPONENT
50df4d8b0f6e19 Bob Moore      2008-12-31  259  
e81a52b8b642aa Bob Moore      2012-12-31  260  /* Check if debug output is currently dynamically enabled */
e81a52b8b642aa Bob Moore      2012-12-31  261  
e81a52b8b642aa Bob Moore      2012-12-31  262  #define ACPI_IS_DEBUG_ENABLED(level, component) \
e81a52b8b642aa Bob Moore      2012-12-31  263  	((level & acpi_dbg_level) && (component & acpi_dbg_layer))
e81a52b8b642aa Bob Moore      2012-12-31  264  
50df4d8b0f6e19 Bob Moore      2008-12-31  265  /*
50df4d8b0f6e19 Bob Moore      2008-12-31  266   * Master debug print macros
50df4d8b0f6e19 Bob Moore      2008-12-31  267   * Print message if and only if:
50df4d8b0f6e19 Bob Moore      2008-12-31  268   *    1) Debug print for the current component is enabled
50df4d8b0f6e19 Bob Moore      2008-12-31  269   *    2) Debug error level or trace level for the print statement is enabled
ad5a06f2969763 Bob Moore      2012-12-31  270   *
ad5a06f2969763 Bob Moore      2012-12-31  271   * November 2012: Moved the runtime check for whether to actually emit the
ad5a06f2969763 Bob Moore      2012-12-31  272   * debug message outside of the print function itself. This improves overall
ad5a06f2969763 Bob Moore      2012-12-31  273   * performance at a relatively small code cost. Implementation involves the
ad5a06f2969763 Bob Moore      2012-12-31  274   * use of variadic macros supported by C99.
6e1888fdcaad17 Bob Moore      2013-01-08  275   *
6e1888fdcaad17 Bob Moore      2013-01-08  276   * Note: the ACPI_DO_WHILE0 macro is used to prevent some compilers from
6e1888fdcaad17 Bob Moore      2013-01-08  277   * complaining about these constructs. On other compilers the do...while
6e1888fdcaad17 Bob Moore      2013-01-08  278   * adds some extra code, so this feature is optional.
50df4d8b0f6e19 Bob Moore      2008-12-31  279   */
6e1888fdcaad17 Bob Moore      2013-01-08  280  #ifdef ACPI_USE_DO_WHILE_0
6e1888fdcaad17 Bob Moore      2013-01-08  281  #define ACPI_DO_WHILE0(a)               do a while(0)
6e1888fdcaad17 Bob Moore      2013-01-08  282  #else
6e1888fdcaad17 Bob Moore      2013-01-08  283  #define ACPI_DO_WHILE0(a)               a
6e1888fdcaad17 Bob Moore      2013-01-08  284  #endif
ad5a06f2969763 Bob Moore      2012-12-31  285  
ad5a06f2969763 Bob Moore      2012-12-31  286  /* DEBUG_PRINT functions */
ad5a06f2969763 Bob Moore      2012-12-31  287  
7b09d8fdede65e Lv Zheng       2015-07-01  288  #ifndef COMPILER_VA_MACRO
7b09d8fdede65e Lv Zheng       2015-07-01  289  
7b09d8fdede65e Lv Zheng       2015-07-01  290  #define ACPI_DEBUG_PRINT(plist)         acpi_debug_print plist
7b09d8fdede65e Lv Zheng       2015-07-01  291  #define ACPI_DEBUG_PRINT_RAW(plist)     acpi_debug_print_raw plist
7b09d8fdede65e Lv Zheng       2015-07-01  292  
7b09d8fdede65e Lv Zheng       2015-07-01  293  #else
ad5a06f2969763 Bob Moore      2012-12-31  294  
ad5a06f2969763 Bob Moore      2012-12-31  295  /* Helper macros for DEBUG_PRINT */
ad5a06f2969763 Bob Moore      2012-12-31  296  
6e1888fdcaad17 Bob Moore      2013-01-08  297  #define ACPI_DO_DEBUG_PRINT(function, level, line, filename, modulename, component, ...) \
6e1888fdcaad17 Bob Moore      2013-01-08  298  	ACPI_DO_WHILE0 ({ \
ad5a06f2969763 Bob Moore      2012-12-31  299  		if (ACPI_IS_DEBUG_ENABLED (level, component)) \
ad5a06f2969763 Bob Moore      2012-12-31  300  		{ \
ad5a06f2969763 Bob Moore      2012-12-31  301  			function (level, line, filename, modulename, component, __VA_ARGS__); \
6e1888fdcaad17 Bob Moore      2013-01-08  302  		} \
6e1888fdcaad17 Bob Moore      2013-01-08  303  	})
ad5a06f2969763 Bob Moore      2012-12-31  304  
ad5a06f2969763 Bob Moore      2012-12-31  305  #define ACPI_ACTUAL_DEBUG(level, line, filename, modulename, component, ...) \
6e1888fdcaad17 Bob Moore      2013-01-08  306  	ACPI_DO_DEBUG_PRINT (acpi_debug_print, level, line, \
6e1888fdcaad17 Bob Moore      2013-01-08  307  		filename, modulename, component, __VA_ARGS__)
ad5a06f2969763 Bob Moore      2012-12-31  308  
ad5a06f2969763 Bob Moore      2012-12-31  309  #define ACPI_ACTUAL_DEBUG_RAW(level, line, filename, modulename, component, ...) \
6e1888fdcaad17 Bob Moore      2013-01-08  310  	ACPI_DO_DEBUG_PRINT (acpi_debug_print_raw, level, line, \
6e1888fdcaad17 Bob Moore      2013-01-08  311  		filename, modulename, component, __VA_ARGS__)
50df4d8b0f6e19 Bob Moore      2008-12-31  312  
7b09d8fdede65e Lv Zheng       2015-07-01  313  #define ACPI_DEBUG_PRINT(plist)         ACPI_ACTUAL_DEBUG plist
7b09d8fdede65e Lv Zheng       2015-07-01  314  #define ACPI_DEBUG_PRINT_RAW(plist)     ACPI_ACTUAL_DEBUG_RAW plist
7b09d8fdede65e Lv Zheng       2015-07-01  315  
7b09d8fdede65e Lv Zheng       2015-07-01  316  #endif
7b09d8fdede65e Lv Zheng       2015-07-01  317  
0377b5acba2f25 Bob Moore      2012-12-31  318  /*
0377b5acba2f25 Bob Moore      2012-12-31  319   * Function entry tracing
0377b5acba2f25 Bob Moore      2012-12-31  320   *
0377b5acba2f25 Bob Moore      2012-12-31  321   * The name of the function is emitted as a local variable that is
0377b5acba2f25 Bob Moore      2012-12-31  322   * intended to be used by both the entry trace and the exit trace.
0377b5acba2f25 Bob Moore      2012-12-31  323   */
0377b5acba2f25 Bob Moore      2012-12-31  324  
0377b5acba2f25 Bob Moore      2012-12-31  325  /* Helper macro */
0377b5acba2f25 Bob Moore      2012-12-31  326  
fd1af7126fb626 Bob Moore      2013-03-08  327  #define ACPI_TRACE_ENTRY(name, function, type, param) \
0377b5acba2f25 Bob Moore      2012-12-31  328  	ACPI_FUNCTION_NAME (name) \
fd1af7126fb626 Bob Moore      2013-03-08  329  	function (ACPI_DEBUG_PARAMETERS, (type) (param))
0377b5acba2f25 Bob Moore      2012-12-31  330  
0377b5acba2f25 Bob Moore      2012-12-31  331  /* The actual entry trace macros */
0377b5acba2f25 Bob Moore      2012-12-31  332  
0377b5acba2f25 Bob Moore      2012-12-31  333  #define ACPI_FUNCTION_TRACE(name) \
0377b5acba2f25 Bob Moore      2012-12-31  334  	ACPI_FUNCTION_NAME(name) \
0377b5acba2f25 Bob Moore      2012-12-31  335  	acpi_ut_trace (ACPI_DEBUG_PARAMETERS)
0377b5acba2f25 Bob Moore      2012-12-31  336  
0377b5acba2f25 Bob Moore      2012-12-31  337  #define ACPI_FUNCTION_TRACE_PTR(name, pointer) \
fd1af7126fb626 Bob Moore      2013-03-08  338  	ACPI_TRACE_ENTRY (name, acpi_ut_trace_ptr, void *, pointer)
0377b5acba2f25 Bob Moore      2012-12-31  339  
0377b5acba2f25 Bob Moore      2012-12-31  340  #define ACPI_FUNCTION_TRACE_U32(name, value) \
fd1af7126fb626 Bob Moore      2013-03-08  341  	ACPI_TRACE_ENTRY (name, acpi_ut_trace_u32, u32, value)
0377b5acba2f25 Bob Moore      2012-12-31  342  
0377b5acba2f25 Bob Moore      2012-12-31  343  #define ACPI_FUNCTION_TRACE_STR(name, string) \
4857a94de17a3c Jung-uk Kim    2016-08-04  344  	ACPI_TRACE_ENTRY (name, acpi_ut_trace_str, const char *, string)
0377b5acba2f25 Bob Moore      2012-12-31  345  
0377b5acba2f25 Bob Moore      2012-12-31  346  #define ACPI_FUNCTION_ENTRY() \
0377b5acba2f25 Bob Moore      2012-12-31  347  	acpi_ut_track_stack_ptr()
0377b5acba2f25 Bob Moore      2012-12-31  348  
0377b5acba2f25 Bob Moore      2012-12-31  349  /*
0377b5acba2f25 Bob Moore      2012-12-31  350   * Function exit tracing
0377b5acba2f25 Bob Moore      2012-12-31  351   *
0377b5acba2f25 Bob Moore      2012-12-31  352   * These macros include a return statement. This is usually considered
0377b5acba2f25 Bob Moore      2012-12-31  353   * bad form, but having a separate exit macro before the actual return
0377b5acba2f25 Bob Moore      2012-12-31  354   * is very ugly and difficult to maintain.
0377b5acba2f25 Bob Moore      2012-12-31  355   *
0377b5acba2f25 Bob Moore      2012-12-31  356   * One of the FUNCTION_TRACE macros above must be used in conjunction
0377b5acba2f25 Bob Moore      2012-12-31  357   * with these macros so that "_AcpiFunctionName" is defined.
fd1af7126fb626 Bob Moore      2013-03-08  358   *
fd1af7126fb626 Bob Moore      2013-03-08  359   * There are two versions of most of the return macros. The default version is
fd1af7126fb626 Bob Moore      2013-03-08  360   * safer, since it avoids side-effects by guaranteeing that the argument will
fd1af7126fb626 Bob Moore      2013-03-08  361   * not be evaluated twice.
fd1af7126fb626 Bob Moore      2013-03-08  362   *
fd1af7126fb626 Bob Moore      2013-03-08  363   * A less-safe version of the macros is provided for optional use if the
fd1af7126fb626 Bob Moore      2013-03-08  364   * compiler uses excessive CPU stack (for example, this may happen in the
e527db8f39d4c7 Colin Ian King 2021-04-06  365   * debug case if code optimization is disabled.)
0377b5acba2f25 Bob Moore      2012-12-31  366   */
0377b5acba2f25 Bob Moore      2012-12-31  367  
0377b5acba2f25 Bob Moore      2012-12-31  368  /* Exit trace helper macro */
0377b5acba2f25 Bob Moore      2012-12-31  369  
fd1af7126fb626 Bob Moore      2013-03-08  370  #ifndef ACPI_SIMPLE_RETURN_MACROS
fd1af7126fb626 Bob Moore      2013-03-08  371  
fd1af7126fb626 Bob Moore      2013-03-08  372  #define ACPI_TRACE_EXIT(function, type, param) \
fd1af7126fb626 Bob Moore      2013-03-08  373  	ACPI_DO_WHILE0 ({ \
fd1af7126fb626 Bob Moore      2013-03-08  374  		register type _param = (type) (param); \
fd1af7126fb626 Bob Moore      2013-03-08  375  		function (ACPI_DEBUG_PARAMETERS, _param); \
fd1af7126fb626 Bob Moore      2013-03-08  376  		return (_param); \
fd1af7126fb626 Bob Moore      2013-03-08  377  	})
fd1af7126fb626 Bob Moore      2013-03-08  378  
fd1af7126fb626 Bob Moore      2013-03-08  379  #else				/* Use original less-safe macros */
fd1af7126fb626 Bob Moore      2013-03-08  380  
fd1af7126fb626 Bob Moore      2013-03-08  381  #define ACPI_TRACE_EXIT(function, type, param) \
0377b5acba2f25 Bob Moore      2012-12-31  382  	ACPI_DO_WHILE0 ({ \
fd1af7126fb626 Bob Moore      2013-03-08  383  		function (ACPI_DEBUG_PARAMETERS, (type) (param)); \
fd1af7126fb626 Bob Moore      2013-03-08  384  		return (param); \
0377b5acba2f25 Bob Moore      2012-12-31  385  	})
0377b5acba2f25 Bob Moore      2012-12-31  386  
fd1af7126fb626 Bob Moore      2013-03-08  387  #endif				/* ACPI_SIMPLE_RETURN_MACROS */
fd1af7126fb626 Bob Moore      2013-03-08  388  
0377b5acba2f25 Bob Moore      2012-12-31  389  /* The actual exit macros */
0377b5acba2f25 Bob Moore      2012-12-31  390  
0377b5acba2f25 Bob Moore      2012-12-31  391  #define return_VOID \
0377b5acba2f25 Bob Moore      2012-12-31  392  	ACPI_DO_WHILE0 ({ \
0377b5acba2f25 Bob Moore      2012-12-31  393  		acpi_ut_exit (ACPI_DEBUG_PARAMETERS); \
0377b5acba2f25 Bob Moore      2012-12-31  394  		return; \
0377b5acba2f25 Bob Moore      2012-12-31  395  	})
0377b5acba2f25 Bob Moore      2012-12-31  396  
0377b5acba2f25 Bob Moore      2012-12-31  397  #define return_ACPI_STATUS(status) \
fd1af7126fb626 Bob Moore      2013-03-08 @398  	ACPI_TRACE_EXIT (acpi_ut_status_exit, acpi_status, status)
0377b5acba2f25 Bob Moore      2012-12-31  399  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
kernel test robot Jan. 5, 2022, 5:50 p.m. UTC | #2 
Hi Sudeep,

I love your patch! Perhaps something to improve:

[auto build test WARNING on rafael-pm/linux-next]
[also build test WARNING on next-20220105]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Sudeep-Holla/ACPI-PCC-Implement-OperationRegion-handler-for-the-PCC-Type-3-subtype/20220104-000003
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
config: x86_64-rhel-8.3-kselftests (https://download.01.org/0day-ci/archive/20220106/202201060154.xBYcdXiV-lkp@intel.com/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce:
        # apt-get install sparse
        # sparse version: v0.6.4-dirty
        # https://github.com/0day-ci/linux/commit/1dbcdc47eadc8c55659410fc03d067f3438a386a
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Sudeep-Holla/ACPI-PCC-Implement-OperationRegion-handler-for-the-PCC-Type-3-subtype/20220104-000003
        git checkout 1dbcdc47eadc8c55659410fc03d067f3438a386a
        # save the config file to linux build tree
        mkdir build_dir
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=x86_64 SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>


sparse warnings: (new ones prefixed by >>)
>> drivers/acpi/acpi_pcc.c:34:22: sparse: sparse: symbol 'pcc_ctx' was not declared. Should it be static?

Please review and possibly fold the followup patch.

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
kernel test robot Jan. 5, 2022, 9:46 p.m. UTC | #3 
Hi Sudeep,

I love your patch! Yet something to improve:

[auto build test ERROR on rafael-pm/linux-next]
[also build test ERROR on linux/master linus/master v5.16-rc8 next-20220105]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Sudeep-Holla/ACPI-PCC-Implement-OperationRegion-handler-for-the-PCC-Type-3-subtype/20220104-000003
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
config: x86_64-randconfig-a012-20220105 (https://download.01.org/0day-ci/archive/20220106/202201060524.QF2PbOn8-lkp@intel.com/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project d5b6e30ed3acad794dd0aec400e617daffc6cc3d)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/1dbcdc47eadc8c55659410fc03d067f3438a386a
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Sudeep-Holla/ACPI-PCC-Implement-OperationRegion-handler-for-the-PCC-Type-3-subtype/20220104-000003
        git checkout 1dbcdc47eadc8c55659410fc03d067f3438a386a
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> drivers/acpi/acpi_pcc.c:53:3: error: implicit declaration of function 'acpi_ut_status_exit' [-Werror,-Wimplicit-function-declaration]
                   return_ACPI_STATUS(AE_NO_MEMORY);
                   ^
   include/acpi/acoutput.h:398:19: note: expanded from macro 'return_ACPI_STATUS'
           ACPI_TRACE_EXIT (acpi_ut_status_exit, acpi_status, status)
                            ^
   drivers/acpi/acpi_pcc.c:53:3: note: did you mean 'acpi_irq_stats_init'?
   include/acpi/acoutput.h:398:19: note: expanded from macro 'return_ACPI_STATUS'
           ACPI_TRACE_EXIT (acpi_ut_status_exit, acpi_status, status)
                            ^
   include/linux/acpi.h:320:6: note: 'acpi_irq_stats_init' declared here
   void acpi_irq_stats_init(void);
        ^
>> drivers/acpi/acpi_pcc.c:53:3: error: use of undeclared identifier '_acpi_module_name'
                   return_ACPI_STATUS(AE_NO_MEMORY);
                   ^
   include/acpi/acoutput.h:398:2: note: expanded from macro 'return_ACPI_STATUS'
           ACPI_TRACE_EXIT (acpi_ut_status_exit, acpi_status, status)
           ^
   include/acpi/acoutput.h:375:13: note: expanded from macro 'ACPI_TRACE_EXIT'
                   function (ACPI_DEBUG_PARAMETERS, _param); \
                             ^
   include/acpi/acoutput.h:258:36: note: expanded from macro 'ACPI_DEBUG_PARAMETERS'
           __LINE__, ACPI_GET_FUNCTION_NAME, _acpi_module_name, _COMPONENT
                                             ^
>> drivers/acpi/acpi_pcc.c:53:3: error: use of undeclared identifier '_COMPONENT'
   include/acpi/acoutput.h:398:2: note: expanded from macro 'return_ACPI_STATUS'
           ACPI_TRACE_EXIT (acpi_ut_status_exit, acpi_status, status)
           ^
   include/acpi/acoutput.h:375:13: note: expanded from macro 'ACPI_TRACE_EXIT'
                   function (ACPI_DEBUG_PARAMETERS, _param); \
                             ^
   include/acpi/acoutput.h:258:55: note: expanded from macro 'ACPI_DEBUG_PARAMETERS'
           __LINE__, ACPI_GET_FUNCTION_NAME, _acpi_module_name, _COMPONENT
                                                                ^
   drivers/acpi/acpi_pcc.c:66:3: error: implicit declaration of function 'acpi_ut_status_exit' [-Werror,-Wimplicit-function-declaration]
                   return_ACPI_STATUS(AE_NOT_FOUND);
                   ^
   include/acpi/acoutput.h:398:19: note: expanded from macro 'return_ACPI_STATUS'
           ACPI_TRACE_EXIT (acpi_ut_status_exit, acpi_status, status)
                            ^
   drivers/acpi/acpi_pcc.c:66:3: error: use of undeclared identifier '_acpi_module_name'
   include/acpi/acoutput.h:398:2: note: expanded from macro 'return_ACPI_STATUS'
           ACPI_TRACE_EXIT (acpi_ut_status_exit, acpi_status, status)
           ^
   include/acpi/acoutput.h:375:13: note: expanded from macro 'ACPI_TRACE_EXIT'
                   function (ACPI_DEBUG_PARAMETERS, _param); \
                             ^
   include/acpi/acoutput.h:258:36: note: expanded from macro 'ACPI_DEBUG_PARAMETERS'
           __LINE__, ACPI_GET_FUNCTION_NAME, _acpi_module_name, _COMPONENT
                                             ^
   drivers/acpi/acpi_pcc.c:66:3: error: use of undeclared identifier '_COMPONENT'
   include/acpi/acoutput.h:398:2: note: expanded from macro 'return_ACPI_STATUS'
           ACPI_TRACE_EXIT (acpi_ut_status_exit, acpi_status, status)
           ^
   include/acpi/acoutput.h:375:13: note: expanded from macro 'ACPI_TRACE_EXIT'
                   function (ACPI_DEBUG_PARAMETERS, _param); \
                             ^
   include/acpi/acoutput.h:258:55: note: expanded from macro 'ACPI_DEBUG_PARAMETERS'
           __LINE__, ACPI_GET_FUNCTION_NAME, _acpi_module_name, _COMPONENT
                                                                ^
   drivers/acpi/acpi_pcc.c:75:3: error: implicit declaration of function 'acpi_ut_status_exit' [-Werror,-Wimplicit-function-declaration]
                   return_ACPI_STATUS(AE_NO_MEMORY);
                   ^
   include/acpi/acoutput.h:398:19: note: expanded from macro 'return_ACPI_STATUS'
           ACPI_TRACE_EXIT (acpi_ut_status_exit, acpi_status, status)
                            ^
   drivers/acpi/acpi_pcc.c:75:3: error: use of undeclared identifier '_acpi_module_name'
   include/acpi/acoutput.h:398:2: note: expanded from macro 'return_ACPI_STATUS'
           ACPI_TRACE_EXIT (acpi_ut_status_exit, acpi_status, status)
           ^
   include/acpi/acoutput.h:375:13: note: expanded from macro 'ACPI_TRACE_EXIT'
                   function (ACPI_DEBUG_PARAMETERS, _param); \
                             ^
   include/acpi/acoutput.h:258:36: note: expanded from macro 'ACPI_DEBUG_PARAMETERS'
           __LINE__, ACPI_GET_FUNCTION_NAME, _acpi_module_name, _COMPONENT
                                             ^
   drivers/acpi/acpi_pcc.c:75:3: error: use of undeclared identifier '_COMPONENT'
   include/acpi/acoutput.h:398:2: note: expanded from macro 'return_ACPI_STATUS'
           ACPI_TRACE_EXIT (acpi_ut_status_exit, acpi_status, status)
           ^
   include/acpi/acoutput.h:375:13: note: expanded from macro 'ACPI_TRACE_EXIT'
                   function (ACPI_DEBUG_PARAMETERS, _param); \
                             ^
   include/acpi/acoutput.h:258:55: note: expanded from macro 'ACPI_DEBUG_PARAMETERS'
           __LINE__, ACPI_GET_FUNCTION_NAME, _acpi_module_name, _COMPONENT
                                                                ^
   drivers/acpi/acpi_pcc.c:79:2: error: implicit declaration of function 'acpi_ut_status_exit' [-Werror,-Wimplicit-function-declaration]
           return_ACPI_STATUS(AE_OK);
           ^
   include/acpi/acoutput.h:398:19: note: expanded from macro 'return_ACPI_STATUS'
           ACPI_TRACE_EXIT (acpi_ut_status_exit, acpi_status, status)
                            ^
   drivers/acpi/acpi_pcc.c:79:2: error: use of undeclared identifier '_acpi_module_name'
   include/acpi/acoutput.h:398:2: note: expanded from macro 'return_ACPI_STATUS'
           ACPI_TRACE_EXIT (acpi_ut_status_exit, acpi_status, status)
           ^
   include/acpi/acoutput.h:375:13: note: expanded from macro 'ACPI_TRACE_EXIT'
                   function (ACPI_DEBUG_PARAMETERS, _param); \
                             ^
   include/acpi/acoutput.h:258:36: note: expanded from macro 'ACPI_DEBUG_PARAMETERS'
           __LINE__, ACPI_GET_FUNCTION_NAME, _acpi_module_name, _COMPONENT
                                             ^
   drivers/acpi/acpi_pcc.c:79:2: error: use of undeclared identifier '_COMPONENT'
   include/acpi/acoutput.h:398:2: note: expanded from macro 'return_ACPI_STATUS'
           ACPI_TRACE_EXIT (acpi_ut_status_exit, acpi_status, status)
           ^
   include/acpi/acoutput.h:375:13: note: expanded from macro 'ACPI_TRACE_EXIT'
                   function (ACPI_DEBUG_PARAMETERS, _param); \
                             ^
   include/acpi/acoutput.h:258:55: note: expanded from macro 'ACPI_DEBUG_PARAMETERS'
           __LINE__, ACPI_GET_FUNCTION_NAME, _acpi_module_name, _COMPONENT
                                                                ^
   drivers/acpi/acpi_pcc.c:97:3: error: implicit declaration of function 'acpi_ut_status_exit' [-Werror,-Wimplicit-function-declaration]
                   return_ACPI_STATUS(AE_ERROR);
                   ^
   include/acpi/acoutput.h:398:19: note: expanded from macro 'return_ACPI_STATUS'
           ACPI_TRACE_EXIT (acpi_ut_status_exit, acpi_status, status)
                            ^
   drivers/acpi/acpi_pcc.c:97:3: error: use of undeclared identifier '_acpi_module_name'
   include/acpi/acoutput.h:398:2: note: expanded from macro 'return_ACPI_STATUS'
           ACPI_TRACE_EXIT (acpi_ut_status_exit, acpi_status, status)
           ^
   include/acpi/acoutput.h:375:13: note: expanded from macro 'ACPI_TRACE_EXIT'
                   function (ACPI_DEBUG_PARAMETERS, _param); \
                             ^


vim +/acpi_ut_status_exit +53 drivers/acpi/acpi_pcc.c

    42	
    43	static acpi_status
    44	acpi_pcc_address_space_setup(acpi_handle region_handle, u32 function,
    45				     void *handler_context,  void **region_context)
    46	{
    47		struct pcc_data *data;
    48		struct acpi_pcc_info *ctx = handler_context;
    49		struct pcc_mbox_chan *pcc_chan;
    50	
    51		data = kzalloc(sizeof(*data), GFP_KERNEL);
    52		if (!data)
  > 53			return_ACPI_STATUS(AE_NO_MEMORY);
    54	
    55		data->cl.rx_callback = pcc_rx_callback;
    56		data->cl.knows_txdone = true;
    57		data->ctx.length = ctx->length;
    58		data->ctx.subspace_id = ctx->subspace_id;
    59		data->ctx.internal_buffer = ctx->internal_buffer;
    60	
    61		init_completion(&data->done);
    62		data->pcc_chan = pcc_mbox_request_channel(&data->cl, ctx->subspace_id);
    63		if (IS_ERR(data->pcc_chan)) {
    64			pr_err("Failed to find PCC channel for subspace %d\n",
    65			       ctx->subspace_id);
    66			return_ACPI_STATUS(AE_NOT_FOUND);
    67		}
    68	
    69		pcc_chan = data->pcc_chan;
    70		data->pcc_comm_addr = acpi_os_ioremap(pcc_chan->shmem_base_addr,
    71						      pcc_chan->shmem_size);
    72		if (!data->pcc_comm_addr) {
    73			pr_err("Failed to ioremap PCC comm region mem for %d\n",
    74			       ctx->subspace_id);
    75			return_ACPI_STATUS(AE_NO_MEMORY);
    76		}
    77	
    78		*region_context = data;
    79		return_ACPI_STATUS(AE_OK);
    80	}
    81	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Sudeep Holla Jan. 6, 2022, 2:12 p.m. UTC | #4 
Hi,

On Thu, Jan 06, 2022 at 01:45:56AM +0800, kernel test robot wrote:
> drivers/acpi/acpi_pcc.c:34:22: warning: symbol 'pcc_ctx' was not declared. Should it be static?
>
> Reported-by: kernel test robot <lkp@intel.com>

Thanks for the fix and sorry for not noticing this before it was merged.

Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Rafael J. Wysocki Jan. 12, 2022, 6:42 p.m. UTC | #5 
On Thu, Jan 6, 2022 at 3:12 PM Sudeep Holla <sudeep.holla@arm.com> wrote:
>
> Hi,
>
> On Thu, Jan 06, 2022 at 01:45:56AM +0800, kernel test robot wrote:
> > drivers/acpi/acpi_pcc.c:34:22: warning: symbol 'pcc_ctx' was not declared. Should it be static?
> >
> > Reported-by: kernel test robot <lkp@intel.com>
>
> Thanks for the fix and sorry for not noticing this before it was merged.
>
> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>

Applied, thanks!
diff mbox series

Patch

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 91f1da16934d..8cdc7860b6e6 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -546,6 +546,23 @@  config ACPI_PPTT
 	bool
 endif

+config ACPI_PCC
+	bool "ACPI PCC Address Space"
+	depends on PCC
+	default y
+	help
+	  The PCC Address Space also referred as PCC Operation Region pertains
+	  to the region of PCC subspace that succeeds the PCC signature.
+
+	  The PCC Operation Region works in conjunction with the PCC Table
+	  (Platform Communications Channel Table). PCC subspaces that are
+	  marked for use as PCC Operation Regions must not be used as PCC
+	  subspaces for the standard ACPI features such as CPPC, RASF, PDTT and
+	  MPST. These standard features must always use the PCC Table instead.
+
+	  Enable this feature if you want to set up and install the PCC Address
+	  Space handler to handle PCC OpRegion in the firmware.
+
 source "drivers/acpi/pmic/Kconfig"

 config ACPI_VIOT
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index d3dc79298ce3..f47032769f69 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -67,6 +67,7 @@  acpi-$(CONFIG_ACPI_LPIT)	+= acpi_lpit.o
 acpi-$(CONFIG_ACPI_GENERIC_GSI) += irq.o
 acpi-$(CONFIG_ACPI_WATCHDOG)	+= acpi_watchdog.o
 acpi-$(CONFIG_ACPI_PRMT)	+= prmt.o
+acpi-$(CONFIG_ACPI_PCC)		+= acpi_pcc.o

 # Address translation
 acpi-$(CONFIG_ACPI_ADXL)	+= acpi_adxl.o
diff --git a/drivers/acpi/acpi_pcc.c b/drivers/acpi/acpi_pcc.c
new file mode 100644
index 000000000000..64552fdb7347
--- /dev/null
+++ b/drivers/acpi/acpi_pcc.c
@@ -0,0 +1,120 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Author: Sudeep Holla <sudeep.holla@arm.com>
+ * Copyright 2021 Arm Limited
+ *
+ * The PCC Address Space also referred as PCC Operation Region pertains to the
+ * region of PCC subspace that succeeds the PCC signature. The PCC Operation
+ * Region works in conjunction with the PCC Table(Platform Communications
+ * Channel Table). PCC subspaces that are marked for use as PCC Operation
+ * Regions must not be used as PCC subspaces for the standard ACPI features
+ * such as CPPC, RASF, PDTT and MPST. These standard features must always use
+ * the PCC Table instead.
+ *
+ * This driver sets up the PCC Address Space and installs an handler to enable
+ * handling of PCC OpRegion in the firmware.
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/acpi.h>
+#include <linux/completion.h>
+#include <linux/idr.h>
+#include <linux/io.h>
+
+#include <acpi/pcc.h>
+
+struct pcc_data {
+	struct pcc_mbox_chan *pcc_chan;
+	void __iomem *pcc_comm_addr;
+	struct completion done;
+	struct mbox_client cl;
+	struct acpi_pcc_info ctx;
+};
+
+struct acpi_pcc_info pcc_ctx;
+
+static void pcc_rx_callback(struct mbox_client *cl, void *m)
+{
+	struct pcc_data *data = container_of(cl, struct pcc_data, cl);
+
+	complete(&data->done);
+}
+
+static acpi_status
+acpi_pcc_address_space_setup(acpi_handle region_handle, u32 function,
+			     void *handler_context,  void **region_context)
+{
+	struct pcc_data *data;
+	struct acpi_pcc_info *ctx = handler_context;
+	struct pcc_mbox_chan *pcc_chan;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return_ACPI_STATUS(AE_NO_MEMORY);
+
+	data->cl.rx_callback = pcc_rx_callback;
+	data->cl.knows_txdone = true;
+	data->ctx.length = ctx->length;
+	data->ctx.subspace_id = ctx->subspace_id;
+	data->ctx.internal_buffer = ctx->internal_buffer;
+
+	init_completion(&data->done);
+	data->pcc_chan = pcc_mbox_request_channel(&data->cl, ctx->subspace_id);
+	if (IS_ERR(data->pcc_chan)) {
+		pr_err("Failed to find PCC channel for subspace %d\n",
+		       ctx->subspace_id);
+		return_ACPI_STATUS(AE_NOT_FOUND);
+	}
+
+	pcc_chan = data->pcc_chan;
+	data->pcc_comm_addr = acpi_os_ioremap(pcc_chan->shmem_base_addr,
+					      pcc_chan->shmem_size);
+	if (!data->pcc_comm_addr) {
+		pr_err("Failed to ioremap PCC comm region mem for %d\n",
+		       ctx->subspace_id);
+		return_ACPI_STATUS(AE_NO_MEMORY);
+	}
+
+	*region_context = data;
+	return_ACPI_STATUS(AE_OK);
+}
+
+static acpi_status
+acpi_pcc_address_space_handler(u32 function, acpi_physical_address addr,
+			       u32 bits, acpi_integer *value,
+			       void *handler_context, void *region_context)
+{
+	int ret;
+	struct pcc_data *data = region_context;
+
+	reinit_completion(&data->done);
+
+	/* Write to Shared Memory */
+	memcpy_toio(data->pcc_comm_addr, (void *)value, data->ctx.length);
+
+	ret = mbox_send_message(data->pcc_chan->mchan, NULL);
+	if (ret < 0)
+		return_ACPI_STATUS(AE_ERROR);
+
+	if (data->pcc_chan->mchan->mbox->txdone_irq)
+		wait_for_completion(&data->done);
+
+	mbox_client_txdone(data->pcc_chan->mchan, ret);
+
+	memcpy_fromio(value, data->pcc_comm_addr, data->ctx.length);
+
+	return_ACPI_STATUS(AE_OK);
+}
+
+void __init acpi_init_pcc(void)
+{
+	acpi_status status;
+
+	status = acpi_install_address_space_handler(ACPI_ROOT_OBJECT,
+						    ACPI_ADR_SPACE_PLATFORM_COMM,
+						    &acpi_pcc_address_space_handler,
+						    &acpi_pcc_address_space_setup,
+						    &pcc_ctx);
+	if (ACPI_FAILURE(status))
+		pr_alert("OperationRegion handler could not be installed\n");
+}
diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index dd535b4b9a16..75a61626eddd 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -1320,6 +1320,7 @@  static int __init acpi_init(void)
 		pr_debug("%s: kset create error\n", __func__);

 	init_prmt();
+	acpi_init_pcc();
 	result = acpi_bus_init();
 	if (result) {
 		kobject_put(acpi_kobj);
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 6c0798db6bde..eaeb4b9255bc 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -1389,6 +1389,12 @@  static inline int find_acpi_cpu_cache_topology(unsigned int cpu, int level)
 }
 #endif

+#ifdef CONFIG_ACPI_PCC
+void acpi_init_pcc(void);
+#else
+static inline void acpi_init_pcc(void) { }
+#endif
+
 #ifdef CONFIG_ACPI
 extern void acpi_device_notify(struct device *dev);
 extern void acpi_device_notify_remove(struct device *dev);