Commit a65ac520 authored by Jiang Liu's avatar Jiang Liu Committed by Rafael J. Wysocki
Browse files

ACPI: introduce helper interfaces for _DSM method 



There are several drivers making use of ACPI _DSM method to detect
and invoke device specific methods. Currently every driver has
implemented its private version to support ACPI _DSM method.
So this patch introduces three helper functions to support ACPI _DSM
method, which will be used to replace open-coded versions.

It helps to simplify code and improve code readability.

Signed-off-by: default avatarJiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent e73be4a7

drivers/acpi/utils.c

+97 −0
Original line number Diff line number Diff line
@@ -574,3 +574,100 @@ acpi_status acpi_evaluate_lck(acpi_handle handle, int lock) 


	return status;

}



/**

 * acpi_evaluate_dsm - evaluate device's _DSM method

 * @handle: ACPI device handle

 * @uuid: UUID of requested functions, should be 16 bytes

 * @rev: revision number of requested function

 * @func: requested function number

 * @argv4: the function specific parameter

 *

 * Evaluate device's _DSM method with specified UUID, revision id and

 * function number. Caller needs to free the returned object.

 *

 * Though ACPI defines the fourth parameter for _DSM should be a package,

 * some old BIOSes do expect a buffer or an integer etc.

 */

union acpi_object *

acpi_evaluate_dsm(acpi_handle handle, const u8 *uuid, int rev, int func,

		  union acpi_object *argv4)

{

	acpi_status ret;

	struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};

	union acpi_object params[4];

	struct acpi_object_list input = {

		.count = 4,

		.pointer = params,

	};



	params[0].type = ACPI_TYPE_BUFFER;

	params[0].buffer.length = 16;

	params[0].buffer.pointer = (char *)uuid;

	params[1].type = ACPI_TYPE_INTEGER;

	params[1].integer.value = rev;

	params[2].type = ACPI_TYPE_INTEGER;

	params[2].integer.value = func;

	if (argv4) {

		params[3] = *argv4;

	} else {

		params[3].type = ACPI_TYPE_PACKAGE;

		params[3].package.count = 0;

		params[3].package.elements = NULL;

	}



	ret = acpi_evaluate_object(handle, "_DSM", &input, &buf);

	if (ACPI_SUCCESS(ret))

		return (union acpi_object *)buf.pointer;



	if (ret != AE_NOT_FOUND)

		acpi_handle_warn(handle,

				"failed to evaluate _DSM (0x%x)\n", ret);



	return NULL;

}

EXPORT_SYMBOL(acpi_evaluate_dsm);



/**

 * acpi_check_dsm - check if _DSM method supports requested functions.

 * @handle: ACPI device handle

 * @uuid: UUID of requested functions, should be 16 bytes at least

 * @rev: revision number of requested functions

 * @funcs: bitmap of requested functions

 * @exclude: excluding special value, used to support i915 and nouveau

 *

 * Evaluate device's _DSM method to check whether it supports requested

 * functions. Currently only support 64 functions at maximum, should be

 * enough for now.

 */

bool acpi_check_dsm(acpi_handle handle, const u8 *uuid, int rev, u64 funcs)

{

	int i;

	u64 mask = 0;

	union acpi_object *obj;



	if (funcs == 0)

		return false;



	obj = acpi_evaluate_dsm(handle, uuid, rev, 0, NULL);

	if (!obj)

		return false;



	/* For compatibility, old BIOSes may return an integer */

	if (obj->type == ACPI_TYPE_INTEGER)

		mask = obj->integer.value;

	else if (obj->type == ACPI_TYPE_BUFFER)

		for (i = 0; i < obj->buffer.length && i < 8; i++)

			mask |= (((u8)obj->buffer.pointer[i]) << (i * 8));

	ACPI_FREE(obj);



	/*

	 * Bit 0 indicates whether there's support for any functions other than

	 * function 0 for the specified UUID and revision.

	 */

	if ((mask & 0x1) && (mask & funcs) == funcs)

		return true;



	return false;

}

EXPORT_SYMBOL(acpi_check_dsm);

include/acpi/acpi_bus.h

+26 −0
Original line number Diff line number Diff line
@@ -66,6 +66,32 @@ bool acpi_ata_match(acpi_handle handle); 
bool acpi_bay_match(acpi_handle handle);

bool acpi_dock_match(acpi_handle handle);



bool acpi_check_dsm(acpi_handle handle, const u8 *uuid, int rev, u64 funcs);

union acpi_object *acpi_evaluate_dsm(acpi_handle handle, const u8 *uuid,

			int rev, int func, union acpi_object *argv4);



static inline union acpi_object *

acpi_evaluate_dsm_typed(acpi_handle handle, const u8 *uuid, int rev, int func,

			union acpi_object *argv4, acpi_object_type type)

{

	union acpi_object *obj;



	obj = acpi_evaluate_dsm(handle, uuid, rev, func, argv4);

	if (obj && obj->type != type) {

		ACPI_FREE(obj);

		obj = NULL;

	}



	return obj;

}



#define	ACPI_INIT_DSM_ARGV4(cnt, eles)			\

	{						\

	  .package.type = ACPI_TYPE_PACKAGE,		\

	  .package.count = (cnt),			\

	  .package.elements = (eles)			\

	}



#ifdef CONFIG_ACPI



#include <linux/proc_fs.h>

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