1 files changed, 112 insertions, 12 deletions

diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
index 552248b0005b..85e3b612bdc0 100644
--- a/drivers/acpi/utils.c
+++ b/drivers/acpi/utils.c
@@ -30,8 +30,6 @@
 #include <linux/types.h>
 #include <linux/hardirq.h>
 #include <linux/acpi.h>
-#include <acpi/acpi_bus.h>
-#include <acpi/acpi_drivers.h>
 
 #include "internal.h"
 
@@ -101,10 +99,6 @@ acpi_extract_package(union acpi_object *package,
 
 		union acpi_object *element = &(package->package.elements[i]);
 
-		if (!element) {
-			return AE_BAD_DATA;
-		}
-
 		switch (element->type) {
 
 		case ACPI_TYPE_INTEGER:
@@ -121,7 +115,7 @@ acpi_extract_package(union acpi_object *package,
 				break;
 			default:
 				printk(KERN_WARNING PREFIX "Invalid package element"
-					      " [%d]: got number, expecing"
+					      " [%d]: got number, expecting"
 					      " [%c]\n",
 					      i, format_string[i]);
 				return AE_BAD_DATA;
@@ -148,7 +142,7 @@ acpi_extract_package(union acpi_object *package,
 			default:
 				printk(KERN_WARNING PREFIX "Invalid package element"
 					      " [%d] got string/buffer,"
-					      " expecing [%c]\n",
+					      " expecting [%c]\n",
 					      i, format_string[i]);
 				return AE_BAD_DATA;
 				break;
@@ -169,11 +163,20 @@ acpi_extract_package(union acpi_object *package,
 	/*
 	 * Validate output buffer.
 	 */
-	if (buffer->length < size_required) {
+	if (buffer->length == ACPI_ALLOCATE_BUFFER) {
+		buffer->pointer = ACPI_ALLOCATE(size_required);
+		if (!buffer->pointer)
+			return AE_NO_MEMORY;
 		buffer->length = size_required;
-		return AE_BUFFER_OVERFLOW;
-	} else if (buffer->length != size_required || !buffer->pointer) {
-		return AE_BAD_PARAMETER;
+		memset(buffer->pointer, 0, size_required);
+	} else {
+		if (buffer->length < size_required) {
+			buffer->length = size_required;
+			return AE_BUFFER_OVERFLOW;
+		} else if (buffer->length != size_required ||
+			   !buffer->pointer) {
+			return AE_BAD_PARAMETER;
+		}
 	}
 
 	head = buffer->pointer;
@@ -565,3 +568,100 @@ 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);