ACPICA: Utilities: Add _CLS processing

ACPICA commit 9a2b638acb3a7215209432e070c6bd0312374229

ACPI Device object often contains a _CLS object to supply PCI-defined class
code for the device. This patch introduces logic to process the _CLS
object. Suravee Suthikulpanit, Lv Zheng.

Link: https://github.com/acpica/acpica/commit/9a2b638a
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/acpica/utids.c

@@ -1,6 +1,6 @@
 /******************************************************************************
  *
- * Module Name: utids - support for device Ids - HID, UID, CID
+ * Module Name: utids - support for device Ids - HID, UID, CID, SUB, CLS
  *
  *****************************************************************************/
 
@@ -416,3 +416,92 @@ cleanup:
 	acpi_ut_remove_reference(obj_desc);
 	return_ACPI_STATUS(status);
 }
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_execute_CLS
+ *
+ * PARAMETERS:  device_node         - Node for the device
+ *              return_id           - Where the _CLS is returned
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Executes the _CLS control method that returns PCI-defined
+ *              class code of the device. The _CLS value is always a package
+ *              containing PCI class information as a list of integers.
+ *              The returned string has format "BBSSPP", where:
+ *                BB = Base-class code
+ *                SS = Sub-class code
+ *                PP = Programming Interface code
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_ut_execute_CLS(struct acpi_namespace_node *device_node,
+		    struct acpi_pnp_device_id **return_id)
+{
+	union acpi_operand_object *obj_desc;
+	union acpi_operand_object **cls_objects;
+	u32 count;
+	struct acpi_pnp_device_id *cls;
+	u32 length;
+	acpi_status status;
+	u8 class_code[3] = { 0, 0, 0 };
+
+	ACPI_FUNCTION_TRACE(ut_execute_CLS);
+
+	status = acpi_ut_evaluate_object(device_node, METHOD_NAME__CLS,
+					 ACPI_BTYPE_PACKAGE, &obj_desc);
+	if (ACPI_FAILURE(status)) {
+		return_ACPI_STATUS(status);
+	}
+
+	/* Get the size of the String to be returned, includes null terminator */
+
+	length = ACPI_PCICLS_STRING_SIZE;
+	cls_objects = obj_desc->package.elements;
+	count = obj_desc->package.count;
+
+	if (obj_desc->common.type == ACPI_TYPE_PACKAGE) {
+		if (count > 0
+		    && cls_objects[0]->common.type == ACPI_TYPE_INTEGER) {
+			class_code[0] = (u8)cls_objects[0]->integer.value;
+		}
+		if (count > 1
+		    && cls_objects[1]->common.type == ACPI_TYPE_INTEGER) {
+			class_code[1] = (u8)cls_objects[1]->integer.value;
+		}
+		if (count > 2
+		    && cls_objects[2]->common.type == ACPI_TYPE_INTEGER) {
+			class_code[2] = (u8)cls_objects[2]->integer.value;
+		}
+	}
+
+	/* Allocate a buffer for the CLS */
+
+	cls =
+	    ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_pnp_device_id) +
+				 (acpi_size) length);
+	if (!cls) {
+		status = AE_NO_MEMORY;
+		goto cleanup;
+	}
+
+	/* Area for the string starts after PNP_DEVICE_ID struct */
+
+	cls->string =
+	    ACPI_ADD_PTR(char, cls, sizeof(struct acpi_pnp_device_id));
+
+	/* Simply copy existing string */
+
+	acpi_ex_pci_cls_to_string(cls->string, class_code);
+	cls->length = length;
+	*return_id = cls;
+
+cleanup:
+
+	/* On exit, we must delete the return object */
+
+	acpi_ut_remove_reference(obj_desc);
+	return_ACPI_STATUS(status);
+}