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Commit 79389a83 authored by Mika Westerberg's avatar Mika Westerberg Committed by Rafael J. Wysocki
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ACPI / property: Add support for remote endpoints 



DT has had concept of remote endpoints for some time already. It makes
possible to reference another firmware node through a property called
remote-endpoint. This is already used by some subsystems like v4l2 for
parsing hardware properties related to camera.

This patch adds ACPI support for remote endpoints utilizing _DSD
hierarchical data extensions.

Signed-off-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: default avatarSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 21ea73f5

drivers/acpi/property.c

+138 −0
Original line number Original line Diff line number Diff line
@@ -969,3 +969,141 @@ struct fwnode_handle *acpi_node_get_parent(struct fwnode_handle *fwnode) 




	return NULL;

	return NULL;

}

}



/**

 * acpi_graph_get_next_endpoint - Get next endpoint ACPI firmware node

 * @fwnode: Pointer to the parent firmware node

 * @prev: Previous endpoint node or %NULL to get the first

 *

 * Looks up next endpoint ACPI firmware node below a given @fwnode. Returns

 * %NULL if there is no next endpoint, ERR_PTR() in case of error. In case

 * of success the next endpoint is returned.

 */

struct fwnode_handle *acpi_graph_get_next_endpoint(struct fwnode_handle *fwnode,

						   struct fwnode_handle *prev)

{

	struct fwnode_handle *port = NULL;

	struct fwnode_handle *endpoint;



	if (!prev) {

		do {

			port = fwnode_get_next_child_node(fwnode, port);

			/* Ports must have port property */

			if (fwnode_property_present(port, "port"))

				break;

		} while (port);

	} else {

		port = fwnode_get_parent(prev);

	}



	if (!port)

		return NULL;



	endpoint = fwnode_get_next_child_node(port, prev);

	while (!endpoint) {

		port = fwnode_get_next_child_node(fwnode, port);

		if (!port)

			break;

		if (fwnode_property_present(port, "port"))

			endpoint = fwnode_get_next_child_node(port, NULL);

	}



	if (endpoint) {

		/* Endpoints must have "endpoint" property */

		if (!fwnode_property_present(endpoint, "endpoint"))

			return ERR_PTR(-EPROTO);

	}



	return endpoint;

}



/**

 * acpi_graph_get_child_prop_value - Return a child with a given property value

 * @fwnode: device fwnode

 * @prop_name: The name of the property to look for

 * @val: the desired property value

 *

 * Return the port node corresponding to a given port number. Returns

 * the child node on success, NULL otherwise.

 */

static struct fwnode_handle *acpi_graph_get_child_prop_value(

	struct fwnode_handle *fwnode, const char *prop_name, unsigned int val)

{

	struct fwnode_handle *child;



	fwnode_for_each_child_node(fwnode, child) {

		u32 nr;



		if (!fwnode_property_read_u32(fwnode, prop_name, &nr))

			continue;



		if (val == nr)

			return child;

	}



	return NULL;

}





/**

 * acpi_graph_get_remote_enpoint - Parses and returns remote end of an endpoint

 * @fwnode: Endpoint firmware node pointing to a remote device

 * @parent: Firmware node of remote port parent is filled here if not %NULL

 * @port: Firmware node of remote port is filled here if not %NULL

 * @endpoint: Firmware node of remote endpoint is filled here if not %NULL

 *

 * Function parses remote end of ACPI firmware remote endpoint and fills in

 * fields requested by the caller. Returns %0 in case of success and

 * negative errno otherwise.

 */

int acpi_graph_get_remote_endpoint(struct fwnode_handle *fwnode,

				   struct fwnode_handle **parent,

				   struct fwnode_handle **port,

				   struct fwnode_handle **endpoint)

{

	unsigned int port_nr, endpoint_nr;

	struct acpi_reference_args args;

	int ret;



	memset(&args, 0, sizeof(args));

	ret = acpi_node_get_property_reference(fwnode, "remote-endpoint", 0,

					       &args);

	if (ret)

		return ret;



	/*

	 * Always require two arguments with the reference: port and

	 * endpoint indices.

	 */

	if (args.nargs != 2)

		return -EPROTO;



	fwnode = acpi_fwnode_handle(args.adev);

	port_nr = args.args[0];

	endpoint_nr = args.args[1];



	if (parent)

		*parent = fwnode;



	if (!port && !endpoint)

		return 0;



	fwnode = acpi_graph_get_child_prop_value(fwnode, "port", port_nr);

	if (!fwnode)

		return -EPROTO;



	if (port)

		*port = fwnode;



	if (!endpoint)

		return 0;



	fwnode = acpi_graph_get_child_prop_value(fwnode, "endpoint",

						 endpoint_nr);

	if (!fwnode)

		return -EPROTO;



	*endpoint = fwnode;



	return 0;

}

include/linux/acpi.h

+23 −0
Original line number Original line Diff line number Diff line
@@ -1001,6 +1001,13 @@ struct fwnode_handle *acpi_get_next_subnode(struct fwnode_handle *fwnode, 
					    struct fwnode_handle *child);

					    struct fwnode_handle *child);

struct fwnode_handle *acpi_node_get_parent(struct fwnode_handle *fwnode);

struct fwnode_handle *acpi_node_get_parent(struct fwnode_handle *fwnode);





struct fwnode_handle *acpi_graph_get_next_endpoint(struct fwnode_handle *fwnode,

						   struct fwnode_handle *prev);

int acpi_graph_get_remote_endpoint(struct fwnode_handle *fwnode,

				   struct fwnode_handle **remote,

				   struct fwnode_handle **port,

				   struct fwnode_handle **endpoint);



struct acpi_probe_entry;

struct acpi_probe_entry;

typedef bool (*acpi_probe_entry_validate_subtbl)(struct acpi_subtable_header *,

typedef bool (*acpi_probe_entry_validate_subtbl)(struct acpi_subtable_header *,

						 struct acpi_probe_entry *);

						 struct acpi_probe_entry *);
@@ -1128,6 +1135,22 @@ acpi_node_get_parent(struct fwnode_handle *fwnode) 
	return NULL;

	return NULL;

}

}





static inline struct fwnode_handle *

acpi_graph_get_next_endpoint(struct fwnode_handle *fwnode,

			     struct fwnode_handle *prev)

{

	return ERR_PTR(-ENXIO);

}



static inline int

acpi_graph_get_remote_endpoint(struct fwnode_handle *fwnode,

			       struct fwnode_handle **remote,

			       struct fwnode_handle **port,

			       struct fwnode_handle **endpoint)

{

	return -ENXIO;

}



#define ACPI_DECLARE_PROBE_ENTRY(table, name, table_id, subtable, valid, data, fn) \

#define ACPI_DECLARE_PROBE_ENTRY(table, name, table_id, subtable, valid, data, fn) \

	static const void * __acpi_table_##name[]			\

	static const void * __acpi_table_##name[]			\

		__attribute__((unused))					\

		__attribute__((unused))					\