ACPICA: Add acpi_get_properties() public interface

In order to support extracting Device Tree style properties from ACPI
devices a new method _PRP was introduced. This method, when present, is
expected to return a package containing packages with name-value pairs
analogous to their Device Tree counterparts.

A sample _PRP method migh look like this:

  Method (_PRP, 0, NotSerialized)
  {
	  Return (Package () {
		  Package () { "integer-property", 10 },
		  Package () { "string-property", "mystring" },
	  })
  }

Calling acpi_get_properties() will evaluate the _PRP method, validate the
result and return it to the caller if everything went fine.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

4 files changed, 226 insertions, 0 deletions

diff --git a/drivers/acpi/acpica/Makefile b/drivers/acpi/acpica/Makefile
index b7ed86a20427..4a0d60deb082 100644
--- a/drivers/acpi/acpica/Makefile
+++ b/drivers/acpi/acpica/Makefile
@@ -176,3 +176,5 @@ acpi-y +=		\
 
 acpi-$(ACPI_FUTURE_USAGE) += uttrack.o utcache.o
 
+acpi-y +=		\
+	prxface.o
diff --git a/drivers/acpi/acpica/prxface.c b/drivers/acpi/acpica/prxface.c
new file mode 100644
index 000000000000..4e52b5143374
--- /dev/null
+++ b/drivers/acpi/acpica/prxface.c
@@ -0,0 +1,217 @@
+/*******************************************************************************
+ *
+ * Module Name: prxface - Public interface to ACPI device properties
+ *
+ ******************************************************************************/
+
+/*
+ * Copyright (C) 2013, Intel Corp.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions, and the following disclaimer,
+ *    without modification.
+ * 2. Redistributions in binary form must reproduce at minimum a disclaimer
+ *    substantially similar to the "NO WARRANTY" disclaimer below
+ *    ("Disclaimer") and any redistribution must be conditioned upon
+ *    including a substantially similar Disclaimer requirement for further
+ *    binary redistribution.
+ * 3. Neither the names of the above-listed copyright holders nor the names
+ *    of any contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * NO WARRANTY
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGES.
+ */
+
+#include <linux/export.h>
+#include <acpi/acpi.h>
+#include "accommon.h"
+#include "acnamesp.h"
+
+#define _COMPONENT          ACPI_RESOURCES
+ACPI_MODULE_NAME("prxface")
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_pr_validate_parameters
+ *
+ * PARAMETERS:  device_handle   - Handle to a device
+ *              buffer          - Pointer to a data buffer
+ *              return_node     - Pointer to where the device node is returned
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Checks validity of the parameters passed to
+ *              acpi_get_device_properties().
+ *
+ ******************************************************************************/
+static acpi_status
+acpi_pr_validate_parameters(acpi_handle device_handle,
+			    struct acpi_buffer *buffer,
+			    struct acpi_namespace_node **return_node)
+{
+	struct acpi_namespace_node *node;
+	acpi_status status;
+
+	ACPI_FUNCTION_TRACE(acpi_pr_validate_parameters);
+
+	if (!device_handle) {
+		return_ACPI_STATUS(AE_BAD_PARAMETER);
+	}
+
+	node = acpi_ns_validate_handle(device_handle);
+	if (!node) {
+		return_ACPI_STATUS(AE_BAD_PARAMETER);
+	}
+
+	if (node->type != ACPI_TYPE_DEVICE) {
+		return_ACPI_STATUS(AE_TYPE);
+	}
+
+	/* Make sure the buffer is valid */
+	status = acpi_ut_validate_buffer(buffer);
+	if (ACPI_FAILURE(status)) {
+		return_ACPI_STATUS(status);
+	}
+
+	*return_node = node;
+	return_ACPI_STATUS(AE_OK);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_get_prp_method_data
+ *
+ * PARAMETERS:  node            - Device node
+ *              ret_buffer      - Pointer to a buffer structure where the
+ *                                resulting properties are stored
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: This function is called to evaluate _PRP method for a given
+ *              device. In case of success resulting package is stored in
+ *              ret_buffer.
+ *
+ *              If the function fails an appropriate status will be returned and
+ *              the contents of the callers buffer is undefined.
+ *
+ ******************************************************************************/
+static acpi_status
+acpi_pr_get_prp_method_data(struct acpi_namespace_node *node,
+			    struct acpi_buffer *ret_buffer)
+{
+	union acpi_operand_object *obj_desc;
+	union acpi_operand_object **properties;
+	acpi_status status;
+	acpi_size size;
+	int i;
+
+	ACPI_FUNCTION_TRACE(acpi_pr_get_prp_method_data);
+
+	status = acpi_ut_evaluate_object(node, METHOD_NAME__PRP,
+					 ACPI_BTYPE_PACKAGE, &obj_desc);
+	if (ACPI_FAILURE(status)) {
+		return_ACPI_STATUS(status);
+	}
+
+	/*
+	 * Validate that the returned package is in correct format:
+	 *  1) Each property is a package itself holding { key, value }
+	 *  2) Key is mandatory
+	 *  3) Key must be string.
+	 */
+	properties = obj_desc->package.elements;
+	for (i = 0; i < obj_desc->package.count; i++) {
+		union acpi_operand_object **property;
+
+		if (properties[i]->common.type != ACPI_TYPE_PACKAGE) {
+			status = AE_BAD_DATA;
+			goto out;
+		}
+		if (properties[i]->package.count < 1) {
+			status = AE_BAD_DATA;
+			goto out;
+		}
+
+		property = properties[i]->package.elements;
+		if (property[0]->common.type != ACPI_TYPE_STRING) {
+			status = AE_BAD_DATA;
+			goto out;
+		}
+	}
+
+	/* Copy the internal buffer to ret_buffer */
+	status = acpi_ut_get_object_size(obj_desc, &size);
+	if (ACPI_FAILURE(status)) {
+		goto out;
+	}
+
+	status = acpi_ut_initialize_buffer(ret_buffer, size);
+	if (ACPI_SUCCESS(status)) {
+		status = acpi_ut_copy_iobject_to_eobject(obj_desc, ret_buffer);
+	}
+
+      out:
+	acpi_ut_remove_reference(obj_desc);
+	return_ACPI_STATUS(status);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_get_properties
+ *
+ * PARAMETERS:  device_handle   - Handle to the device object for the
+ *                                device we are querying
+ *              ret_buffer      - Pointer to a buffer to receive the
+ *                                properties for the device
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: This function is called to get properties for
+ *              a specific device The caller must first acquire a handle for the
+ *              desired device The property data is placed in the buffer pointed
+ *              to by the ret_buffer variable parameter.
+ *
+ *              If the function fails an appropriate status will be returned
+ *              and the value of ret_buffer is undefined.
+ *
+ *              This function attempts to execute the _PRP method contained in
+ *              the object indicated by the passed device_handle.
+ *
+ ******************************************************************************/
+acpi_status
+acpi_get_properties(acpi_handle device_handle, struct acpi_buffer *ret_buffer)
+{
+	struct acpi_namespace_node *node;
+	acpi_status status;
+
+	ACPI_FUNCTION_TRACE(acpi_get_device_properties);
+
+	status = acpi_pr_validate_parameters(device_handle, ret_buffer, &node);
+	if (ACPI_FAILURE(status)) {
+		return_ACPI_STATUS(status);
+	}
+
+	status = acpi_pr_get_prp_method_data(node, ret_buffer);
+	return_ACPI_STATUS(status);
+}
+
+ACPI_EXPORT_SYMBOL(acpi_get_properties)
diff --git a/include/acpi/acnames.h b/include/acpi/acnames.h
index 3dd6e838dc30..ac7e598c8b43 100644
--- a/include/acpi/acnames.h
+++ b/include/acpi/acnames.h
@@ -65,6 +65,7 @@
 #define METHOD_NAME__STA        "_STA"
 #define METHOD_NAME__SUB        "_SUB"
 #define METHOD_NAME__UID        "_UID"
+#define METHOD_NAME__PRP        "_PRP"
 
 /* Method names - these methods must appear at the namespace root */
 
diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h
index 44f5e9749601..c8c0748887b5 100644
--- a/include/acpi/acpixf.h
+++ b/include/acpi/acpixf.h
@@ -478,6 +478,12 @@ acpi_buffer_to_resource(u8 *aml_buffer,
 			struct acpi_resource **resource_ptr);
 
 /*
+ * ACPI device properties
+ */
+acpi_status
+acpi_get_properties(acpi_handle device_handle, struct acpi_buffer *ret_buffer);
+
+/*
  * Hardware (ACPI device) interfaces
  */
 acpi_status acpi_reset(void);