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

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
......@@ -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);
......@@ -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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