[PATCH/RFC v3 06/19] video: display: OF support
Laurent Pinchart
laurent.pinchart+renesas at ideasonboard.com
Fri Aug 9 16:03:05 PDT 2013
Extend the notifier with DT node matching support, and add helper functions to
build the notifier and link entities based on a graph representation in
DT.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas at ideasonboard.com>
---
drivers/video/display/display-core.c | 334 +++++++++++++++++++++++++++++++
drivers/video/display/display-notifier.c | 187 +++++++++++++++++
include/video/display.h | 45 +++++
3 files changed, 566 insertions(+)
diff --git a/drivers/video/display/display-core.c b/drivers/video/display/display-core.c
index c3b47d3..328ead7 100644
--- a/drivers/video/display/display-core.c
+++ b/drivers/video/display/display-core.c
@@ -14,6 +14,7 @@
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/module.h>
+#include <linux/of.h>
#include <linux/slab.h>
#include <media/media-device.h>
@@ -315,6 +316,184 @@ void display_entity_unregister(struct display_entity *entity)
EXPORT_SYMBOL_GPL(display_entity_unregister);
/* -----------------------------------------------------------------------------
+ * OF Helpers
+ */
+
+#ifdef CONFIG_OF
+
+/**
+ * display_of_get_next_endpoint() - get next endpoint node
+ * @parent: pointer to the parent device node
+ * @prev: previous endpoint node, or NULL to get first
+ *
+ * Return: An 'endpoint' node pointer with refcount incremented. Refcount
+ * of the passed @prev node is not decremented, the caller have to use
+ * of_node_put() on it when done.
+ */
+struct device_node *
+display_of_get_next_endpoint(const struct device_node *parent,
+ struct device_node *prev)
+{
+ struct device_node *endpoint;
+ struct device_node *port = NULL;
+
+ if (!parent)
+ return NULL;
+
+ if (!prev) {
+ struct device_node *node;
+ /*
+ * It's the first call, we have to find a port subnode
+ * within this node or within an optional 'ports' node.
+ */
+ node = of_get_child_by_name(parent, "ports");
+ if (node)
+ parent = node;
+
+ port = of_get_child_by_name(parent, "port");
+
+ if (port) {
+ /* Found a port, get an endpoint. */
+ endpoint = of_get_next_child(port, NULL);
+ of_node_put(port);
+ } else {
+ endpoint = NULL;
+ }
+
+ if (!endpoint)
+ pr_err("%s(): no endpoint nodes specified for %s\n",
+ __func__, parent->full_name);
+ of_node_put(node);
+ } else {
+ port = of_get_parent(prev);
+ if (!port)
+ /* Hm, has someone given us the root node ?... */
+ return NULL;
+
+ /* Avoid dropping prev node refcount to 0. */
+ of_node_get(prev);
+ endpoint = of_get_next_child(port, prev);
+ if (endpoint) {
+ of_node_put(port);
+ return endpoint;
+ }
+
+ /* No more endpoints under this port, try the next one. */
+ do {
+ port = of_get_next_child(parent, port);
+ if (!port)
+ return NULL;
+ } while (of_node_cmp(port->name, "port"));
+
+ /* Pick up the first endpoint in this port. */
+ endpoint = of_get_next_child(port, NULL);
+ of_node_put(port);
+ }
+
+ return endpoint;
+}
+
+/**
+ * display_of_get_remote_port_parent() - get remote port's parent node
+ * @node: pointer to a local endpoint device_node
+ *
+ * Return: Remote device node associated with remote endpoint node linked
+ * to @node. Use of_node_put() on it when done.
+ */
+struct device_node *
+display_of_get_remote_port_parent(const struct device_node *node)
+{
+ struct device_node *np;
+ unsigned int depth;
+
+ /* Get remote endpoint node. */
+ np = of_parse_phandle(node, "remote-endpoint", 0);
+
+ /* Walk 3 levels up only if there is 'ports' node. */
+ for (depth = 3; depth && np; depth--) {
+ np = of_get_next_parent(np);
+ if (depth == 2 && of_node_cmp(np->name, "ports"))
+ break;
+ }
+ return np;
+}
+
+/**
+ * struct display_of_link - a link between two endpoints
+ * @local_node: pointer to device_node of this endpoint
+ * @local_port: identifier of the port this endpoint belongs to
+ * @remote_node: pointer to device_node of the remote endpoint
+ * @remote_port: identifier of the port the remote endpoint belongs to
+ */
+struct display_of_link {
+ struct device_node *local_node;
+ unsigned int local_port;
+ struct device_node *remote_node;
+ unsigned int remote_port;
+};
+
+/**
+ * display_of_parse_link() - parse a link between two endpoints
+ * @node: pointer to the endpoint at the local end of the link
+ * @link: pointer to the display OF link data structure
+ *
+ * Fill the link structure with the local and remote nodes and port numbers.
+ * The local_node and remote_node fields are set to point to the local and
+ * remote port parent nodes respectively (the port parent node being the parent
+ * node of the port node if that node isn't a 'ports' node, or the grand-parent
+ * node of the port node otherwise).
+ *
+ * A reference is taken to both the local and remote nodes, the caller must use
+ * display_of_put_link() to drop the references when done with the link.
+ *
+ * Return: 0 on success, or -ENOLINK if the remote endpoint can't be found.
+ */
+static int display_of_parse_link(const struct device_node *node,
+ struct display_of_link *link)
+{
+ struct device_node *np;
+
+ memset(link, 0, sizeof(*link));
+
+ np = of_get_parent(node);
+ of_property_read_u32(np, "reg", &link->local_port);
+ np = of_get_next_parent(np);
+ if (of_node_cmp(np->name, "ports") == 0)
+ np = of_get_next_parent(np);
+ link->local_node = np;
+
+ np = of_parse_phandle(node, "remote-endpoint", 0);
+ if (!np) {
+ of_node_put(link->local_node);
+ return -ENOLINK;
+ }
+
+ np = of_get_parent(np);
+ of_property_read_u32(np, "reg", &link->remote_port);
+ np = of_get_next_parent(np);
+ if (of_node_cmp(np->name, "ports") == 0)
+ np = of_get_next_parent(np);
+ link->remote_node = np;
+
+ return 0;
+}
+
+/**
+ * display_of_put_link() - drop references to nodes in a link
+ * @link: pointer to the display OF link data structure
+ *
+ * Drop references to the local and remote nodes in the link. This function must
+ * be called on every link parsed with display_of_parse_link().
+ */
+static void display_of_put_link(struct display_of_link *link)
+{
+ of_node_put(link->local_node);
+ of_node_put(link->remote_node);
+}
+
+#endif /* CONFIG_OF */
+
+/* -----------------------------------------------------------------------------
* Graph Helpers
*/
@@ -420,6 +599,161 @@ int display_entity_link_graph(struct device *dev, struct list_head *entities)
}
EXPORT_SYMBOL_GPL(display_entity_link_graph);
+#ifdef CONFIG_OF
+
+static int display_of_entity_link_entity(struct device *dev,
+ struct display_entity *entity,
+ struct list_head *entities,
+ struct display_entity *root)
+{
+ u32 link_flags = MEDIA_LNK_FL_IMMUTABLE | MEDIA_LNK_FL_ENABLED;
+ const struct device_node *node = entity->dev->of_node;
+ struct media_entity *local = &entity->entity;
+ struct device_node *ep = NULL;
+ int ret = 0;
+
+ dev_dbg(dev, "creating links for entity %s\n", local->name);
+
+ while (1) {
+ struct media_entity *remote = NULL;
+ struct media_pad *remote_pad;
+ struct media_pad *local_pad;
+ struct display_of_link link;
+ struct display_entity *ent;
+ struct device_node *next;
+
+ /* Get the next endpoint and parse its link. */
+ next = display_of_get_next_endpoint(node, ep);
+ if (next == NULL)
+ break;
+
+ of_node_put(ep);
+ ep = next;
+
+ dev_dbg(dev, "processing endpoint %s\n", ep->full_name);
+
+ ret = display_of_parse_link(ep, &link);
+ if (ret < 0) {
+ dev_err(dev, "failed to parse link for %s\n",
+ ep->full_name);
+ continue;
+ }
+
+ /* Skip source pads, they will be processed from the other end of
+ * the link.
+ */
+ if (link.local_port >= local->num_pads) {
+ dev_err(dev, "invalid port number %u on %s\n",
+ link.local_port, link.local_node->full_name);
+ display_of_put_link(&link);
+ ret = -EINVAL;
+ break;
+ }
+
+ local_pad = &local->pads[link.local_port];
+
+ if (local_pad->flags & MEDIA_PAD_FL_SOURCE) {
+ dev_dbg(dev, "skipping source port %s:%u\n",
+ link.local_node->full_name, link.local_port);
+ display_of_put_link(&link);
+ continue;
+ }
+
+ /* Find the remote entity. If not found, just skip the link as
+ * it goes out of scope of the entities handled by the notifier.
+ */
+ list_for_each_entry(ent, entities, list) {
+ if (ent->dev->of_node == link.remote_node) {
+ remote = &ent->entity;
+ break;
+ }
+ }
+
+ if (root->dev->of_node == link.remote_node)
+ remote = &root->entity;
+
+ if (remote == NULL) {
+ dev_dbg(dev, "no entity found for %s\n",
+ link.remote_node->full_name);
+ display_of_put_link(&link);
+ continue;
+ }
+
+ if (link.remote_port >= remote->num_pads) {
+ dev_err(dev, "invalid port number %u on %s\n",
+ link.remote_port, link.remote_node->full_name);
+ display_of_put_link(&link);
+ ret = -EINVAL;
+ break;
+ }
+
+ remote_pad = &remote->pads[link.remote_port];
+
+ display_of_put_link(&link);
+
+ /* Create the media link. */
+ dev_dbg(dev, "creating %s:%u -> %s:%u link\n",
+ remote->name, remote_pad->index,
+ local->name, local_pad->index);
+
+ ret = media_entity_create_link(remote, remote_pad->index,
+ local, local_pad->index,
+ link_flags);
+ if (ret < 0) {
+ dev_err(dev,
+ "failed to create %s:%u -> %s:%u link\n",
+ remote->name, remote_pad->index,
+ local->name, local_pad->index);
+ break;
+ }
+ }
+
+ of_node_put(ep);
+ return ret;
+}
+
+/**
+ * display_of_entity_link_graph - Link all entities in a graph
+ * @dev: device used to print debugging and error messages
+ * @root: optional root display entity
+ * @entities: list of display entities in the graph
+ *
+ * This function creates media controller links for all entities in a graph
+ * based on the device tree graph representation. It relies on all entities
+ * having been instantiated from the device tree.
+ *
+ * The list of entities is typically taken directly from a display notifier
+ * done list. It will thus not include any display entity not handled by the
+ * notifier, such as entities directly accessible by the caller without going
+ * through the notification process. The optional root entity parameter can be
+ * used to pass such a display entity and include it in the graph. For all
+ * practical purpose the root entity is handled is if it was part of the
+ * entities list.
+ *
+ * Return 0 on success or a negative error code otherwise.
+ */
+int display_of_entity_link_graph(struct device *dev, struct list_head *entities,
+ struct display_entity *root)
+{
+ struct display_entity *entity;
+ int ret;
+
+ list_for_each_entry(entity, entities, list) {
+ if (WARN_ON(entity->match->type != DISPLAY_ENTITY_BUS_DT))
+ return -EINVAL;
+
+ ret = display_of_entity_link_entity(dev, entity, entities,
+ root);
+ if (ret < 0)
+ return ret;
+ }
+
+ return display_of_entity_link_entity(dev, root, entities, root);
+}
+EXPORT_SYMBOL_GPL(display_of_entity_link_graph);
+
+#endif
+
MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart at ideasonboard.com>");
MODULE_DESCRIPTION("Display Core");
MODULE_LICENSE("GPL");
diff --git a/drivers/video/display/display-notifier.c b/drivers/video/display/display-notifier.c
index 2d752b3..6bede03 100644
--- a/drivers/video/display/display-notifier.c
+++ b/drivers/video/display/display-notifier.c
@@ -16,6 +16,7 @@
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/of.h>
+#include <linux/slab.h>
#include <video/display.h>
@@ -36,6 +37,14 @@ static bool match_platform(struct device *dev,
return !strcmp(match->match.platform.name, dev_name(dev));
}
+static bool match_dt(struct device *dev, struct display_entity_match *match)
+{
+ pr_debug("%s: matching device node '%s' with node '%s'\n", __func__,
+ dev->of_node->full_name, match->match.dt.node->full_name);
+
+ return match->match.dt.node == dev->of_node;
+}
+
static struct display_entity_match *
display_entity_notifier_match(struct display_entity_notifier *notifier,
struct display_entity *entity)
@@ -52,6 +61,9 @@ display_entity_notifier_match(struct display_entity_notifier *notifier,
case DISPLAY_ENTITY_BUS_PLATFORM:
match_func = match_platform;
break;
+ case DISPLAY_ENTITY_BUS_DT:
+ match_func = match_dt;
+ break;
}
if (match_func(entity->dev, match))
@@ -158,6 +170,7 @@ int display_entity_register_notifier(struct display_entity_notifier *notifier)
switch (match->type) {
case DISPLAY_ENTITY_BUS_PLATFORM:
+ case DISPLAY_ENTITY_BUS_DT:
break;
default:
dev_err(notifier->dev,
@@ -272,6 +285,180 @@ int display_entity_build_notifier(struct display_entity_notifier *notifier,
EXPORT_SYMBOL_GPL(display_entity_build_notifier);
/* -----------------------------------------------------------------------------
+ * OF Support
+ */
+
+#ifdef CONFIG_OF
+
+struct display_entity_of {
+ struct list_head list;
+ struct device_node *node;
+};
+
+static struct display_entity_of *
+display_of_find_entity(struct list_head *entities,
+ const struct device_node *node)
+{
+ struct display_entity_of *entity;
+
+ list_for_each_entry(entity, entities, list) {
+ if (entity->node == node)
+ return entity;
+ }
+
+ return NULL;
+}
+
+static int display_of_parse_dt(struct display_entity_notifier *notifier,
+ struct list_head *entities,
+ struct device_node *node)
+{
+ struct display_entity_of *entity;
+ struct device_node *remote;
+ struct device_node *ep = NULL;
+ struct device_node *next;
+ unsigned int num_entities = 0;
+ int ret = 0;
+
+ /* Walk the device tree and build a list of nodes. */
+ dev_dbg(notifier->dev, "parsing node %s\n", node->full_name);
+
+ while (1) {
+ next = display_of_get_next_endpoint(node, ep);
+ if (next == NULL)
+ break;
+
+ of_node_put(ep);
+ ep = next;
+
+ dev_dbg(notifier->dev, "handling endpoint %s\n", ep->full_name);
+
+ remote = display_of_get_remote_port_parent(ep);
+ if (remote == NULL)
+ continue;
+
+ /* Skip entities that we have already processed. */
+ if (display_of_find_entity(entities, remote) || remote == node) {
+ dev_dbg(notifier->dev,
+ "entity %s already in list, skipping\n",
+ remote->full_name);
+ continue;
+ }
+
+ entity = kzalloc(sizeof(*entity), GFP_KERNEL);
+ if (entity == NULL) {
+ of_node_put(remote);
+ ret = -ENOMEM;
+ break;
+ }
+
+ dev_dbg(notifier->dev, "adding remote entity %s to list\n",
+ remote->full_name);
+
+ entity->node = remote;
+ list_add_tail(&entity->list, entities);
+ num_entities++;
+ }
+
+ of_node_put(ep);
+
+ if (ret < 0)
+ return ret;
+
+ return num_entities;
+}
+
+/**
+ * display_of_entity_build_notifier - build a notifier from device tree
+ * @notifier: display entity notifier to be built
+ * @node: device tree node
+ *
+ * Before registering a notifier drivers must initialize the notifier's list of
+ * entities. This helper function simplifies building the list of entities for
+ * drivers that use a device tree representation of the graph.
+ *
+ * The function allocates an array of struct display_entity_match, initialize it
+ * from the device tree, and sets the notifier entities and num_entities fields.
+ *
+ * The entities array is allocated using the managed memory allocation API on
+ * the notifier device, which must be initialized before calling this function.
+ *
+ * Return 0 on success or a negative error code on error.
+ */
+int display_of_entity_build_notifier(struct display_entity_notifier *notifier,
+ struct device_node *node)
+{
+ struct display_entity_match *matches;
+ struct display_entity_of *entity;
+ struct display_entity_of *next;
+ unsigned int num_entities = 0;
+ LIST_HEAD(entities);
+ unsigned int i;
+ int ret;
+
+ /* Add an initial entity that stores the device tree node pointer to the
+ * list.
+ */
+ entity = kzalloc(sizeof(*entity), GFP_KERNEL);
+ if (entity == NULL)
+ return -ENOMEM;
+
+ entity->node = node;
+ list_add_tail(&entity->list, &entities);
+
+ /* Parse all entities in the list. New entities will be added at the
+ * tail when parsing the device tree and will just be processed by the
+ * next iterations.
+ */
+ list_for_each_entry(entity, &entities, list) {
+ ret = display_of_parse_dt(notifier, &entities, entity->node);
+ if (ret < 0)
+ goto error;
+
+ num_entities += ret;
+ }
+
+ /* Allocate the entity matches array and fill it. */
+ matches = devm_kzalloc(notifier->dev, sizeof(*notifier->entities) *
+ num_entities, GFP_KERNEL);
+ if (matches == NULL) {
+ ret = -ENOMEM;
+ goto error;
+ }
+
+ i = 0;
+ list_for_each_entry_safe(entity, next, &entities, list) {
+ struct display_entity_match *match;
+
+ /* Don't add the initial node to the matches array. */
+ if (entity->node != node) {
+ match = &matches[i++];
+ match->type = DISPLAY_ENTITY_BUS_DT;
+ match->match.dt.node = entity->node;
+ }
+
+ list_del(&entity->list);
+ kfree(entity);
+ }
+
+ notifier->num_entities = num_entities;
+ notifier->entities = matches;
+
+ return 0;
+
+error:
+ list_for_each_entry_safe(entity, next, &entities, list) {
+ list_del(&entity->list);
+ kfree(entity);
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(display_of_entity_build_notifier);
+
+#endif /* CONFIG_OF */
+
+/* -----------------------------------------------------------------------------
* Entity Registration
*/
diff --git a/include/video/display.h b/include/video/display.h
index 58ff0d1..36ff637 100644
--- a/include/video/display.h
+++ b/include/video/display.h
@@ -22,6 +22,7 @@
* Display Entity
*/
+struct device_node;
struct display_entity;
struct display_entity_match;
struct display_entity_notify;
@@ -145,12 +146,33 @@ int display_entity_get_params(struct display_entity *entity, unsigned int port,
int display_entity_set_stream(struct display_entity *entity, unsigned int port,
enum display_entity_stream_state state);
+#ifdef CONFIG_OF
+struct device_node *
+display_of_get_next_endpoint(const struct device_node *parent,
+ struct device_node *prev);
+struct device_node *
+display_of_get_remote_port_parent(const struct device_node *node);
+#else
+static inline struct device_node *
+display_of_get_next_endpoint(const struct device_node *parent,
+ struct device_node *prev)
+{
+ return NULL;
+}
+static inline struct device_node *
+display_of_get_remote_port_parent(const struct device_node *node)
+{
+ return NULL;
+}
+#endif
+
/* -----------------------------------------------------------------------------
* Notifier
*/
enum display_entity_bus_type {
DISPLAY_ENTITY_BUS_PLATFORM,
+ DISPLAY_ENTITY_BUS_DT,
};
/**
@@ -167,6 +189,9 @@ struct display_entity_match {
struct {
const char *name;
} platform;
+ struct {
+ const struct device_node *node;
+ } dt;
} match;
struct list_head list;
@@ -226,4 +251,24 @@ int display_entity_build_notifier(struct display_entity_notifier *notifier,
const struct display_entity_graph_data *graph);
int display_entity_link_graph(struct device *dev, struct list_head *entities);
+#ifdef CONFIG_OF
+int display_of_entity_build_notifier(struct display_entity_notifier *notifier,
+ struct device_node *node);
+int display_of_entity_link_graph(struct device *dev, struct list_head *entities,
+ struct display_entity *root);
+#else
+static inline int
+display_of_entity_build_notifier(struct display_entity_notifier *notifier,
+ struct device_node *node)
+{
+ return -ENOSYS;
+}
+static inline int
+display_of_entity_link_graph(struct device *dev,struct list_head *entities,
+ struct display_entity *root)
+{
+ return -ENOSYS;
+}
+#endif
+
#endif /* __DISPLAY_H__ */
--
1.8.1.5
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