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: Jiang Liu <jiang....@linux.intel.com>
---
drivers/acpi/utils.c | 98 +++++++++++++++++++++++++++++++++++++++++++++++
include/acpi/acpi_bus.h | 26 +++++++++++++
2 files changed, 124 insertions(+)
diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
index 6d408bf..9517b0a 100644
--- a/drivers/acpi/utils.c
+++ b/drivers/acpi/utils.c
@@ -574,3 +574,101 @@ 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 method (0x%x)\n", ret);
+
+ return NULL;
+}
+EXPORT_SYMBOL(acpi_evaluate_dsm);
+
+/**
+ * acpi_check_dsm: check whether _DSM method under @handle 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);
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index c602c77..efccf39 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -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) \
+ { \
+ .type = ACPI_TYPE_PACKAGE, \
+ .package.count = (cnt), \
+ .package.elements = (eles) \
+ }
+
#ifdef CONFIG_ACPI
#include <linux/proc_fs.h>
--
1.7.10.4
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