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ACPI / property: Add support for remote endpoints

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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: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Mika Westerberg 2017-03-28 10:52:20 +03:00 committed by Rafael J. Wysocki
parent 21ea73f54c
commit 79389a83bc
2 changed files with 161 additions and 0 deletions
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138
drivers/acpi/property.c
View File

@ -969,3 +969,141 @@ struct fwnode_handle *acpi_node_get_parent(struct fwnode_handle *fwnode)
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;
}

23
include/linux/acpi.h
View File

@ -1001,6 +1001,13 @@ struct fwnode_handle *acpi_get_next_subnode(struct fwnode_handle *fwnode,
struct fwnode_handle *child);
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;
typedef bool (*acpi_probe_entry_validate_subtbl)(struct acpi_subtable_header *,
struct acpi_probe_entry *);
@ -1128,6 +1135,22 @@ acpi_node_get_parent(struct fwnode_handle *fwnode)
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) \
static const void * __acpi_table_##name[] \
__attribute__((unused)) \