1 files changed, 176 insertions, 0 deletions

diff --git a/extras/recipes-kernel/linux/linux-omap/media/0012-media-Entity-use-count.patch b/extras/recipes-kernel/linux/linux-omap/media/0012-media-Entity-use-count.patch
new file mode 100644
index 00000000..bc850e44
--- /dev/null
+++ b/extras/recipes-kernel/linux/linux-omap/media/0012-media-Entity-use-count.patch
@@ -0,0 +1,176 @@
+From 3be6a2d10ff0cad0b240c65054da28395b014f82 Mon Sep 17 00:00:00 2001
+From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
+Date: Sun, 7 Mar 2010 20:04:59 +0200
+Subject: [PATCH 12/43] media: Entity use count
+
+Due to the wide differences between drivers regarding power management
+needs, the media controller does not implement power management.
+However, the media_entity structure includes a use_count field that
+media drivers can use to track the number of users of every entity for
+power management needs.
+
+The use_count field is owned by media drivers and must not be touched by
+entity drivers. Access to the field must be protected by the media
+device graph_mutex lock.
+
+Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
+---
+ Documentation/media-framework.txt |   13 ++++++++++
+ drivers/media/media-device.c      |    1 +
+ drivers/media/media-entity.c      |   46 +++++++++++++++++++++++++++++++++++++
+ include/media/media-device.h      |    4 +++
+ include/media/media-entity.h      |    5 ++++
+ 5 files changed, 69 insertions(+), 0 deletions(-)
+
+diff --git a/Documentation/media-framework.txt b/Documentation/media-framework.txt
+index 88fe379..9017a41 100644
+--- a/Documentation/media-framework.txt
++++ b/Documentation/media-framework.txt
+@@ -258,3 +258,16 @@ When the graph traversal is complete the function will return NULL.
+ 
+ Graph traversal can be interrupted at any moment. No cleanup function call is
+ required and the graph structure can be freed normally.
++
++
++Use count and power handling
++----------------------------
++
++Due to the wide differences between drivers regarding power management needs,
++the media controller does not implement power management. However, the
++media_entity structure includes a use_count field that media drivers can use to
++track the number of users of every entity for power management needs.
++
++The use_count field is owned by media drivers and must not be touched by entity
++drivers. Access to the field must be protected by the media device graph_mutex
++lock.
+diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
+index b8a3ace..e4c2157 100644
+--- a/drivers/media/media-device.c
++++ b/drivers/media/media-device.c
+@@ -73,6 +73,7 @@ int __must_check media_device_register(struct media_device *mdev)
+        mdev->entity_id = 1;
+        INIT_LIST_HEAD(&mdev->entities);
+        spin_lock_init(&mdev->lock);
++       mutex_init(&mdev->graph_mutex);
+ 
+        /* Register the device node. */
+        mdev->devnode.fops = &media_device_fops;
+diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c
+index a805f20..fe6bfd2 100644
+--- a/drivers/media/media-entity.c
++++ b/drivers/media/media-entity.c
+@@ -23,6 +23,7 @@
+ #include <linux/module.h>
+ #include <linux/slab.h>
+ #include <media/media-entity.h>
++#include <media/media-device.h>
+ 
+ /**
+  * media_entity_init - Initialize a media entity
+@@ -196,6 +197,51 @@ media_entity_graph_walk_next(struct media_entity_graph *graph)
+ EXPORT_SYMBOL_GPL(media_entity_graph_walk_next);
+ 
+ /* -----------------------------------------------------------------------------
++ * Module use count
++ */
++
++/*
++ * media_entity_get - Get a reference to the parent module
++ * @entity: The entity
++ *
++ * Get a reference to the parent media device module.
++ *
++ * The function will return immediately if @entity is NULL.
++ *
++ * Return a pointer to the entity on success or NULL on failure.
++ */
++struct media_entity *media_entity_get(struct media_entity *entity)
++{
++       if (entity == NULL)
++               return NULL;
++
++       if (entity->parent->dev &&
++           !try_module_get(entity->parent->dev->driver->owner))
++               return NULL;
++
++       return entity;
++}
++EXPORT_SYMBOL_GPL(media_entity_get);
++
++/*
++ * media_entity_put - Release the reference to the parent module
++ * @entity: The entity
++ *
++ * Release the reference count acquired by media_entity_get().
++ *
++ * The function will return immediately if @entity is NULL.
++ */
++void media_entity_put(struct media_entity *entity)
++{
++       if (entity == NULL)
++               return;
++
++       if (entity->parent->dev)
++               module_put(entity->parent->dev->driver->owner);
++}
++EXPORT_SYMBOL_GPL(media_entity_put);
++
++/* -----------------------------------------------------------------------------
+  * Links management
+  */
+ 
+diff --git a/include/media/media-device.h b/include/media/media-device.h
+index 0b1ecf5..260d59c 100644
+--- a/include/media/media-device.h
++++ b/include/media/media-device.h
+@@ -25,6 +25,7 @@
+ 
+ #include <linux/device.h>
+ #include <linux/list.h>
++#include <linux/mutex.h>
+ #include <linux/spinlock.h>
+ 
+ #include <media/media-devnode.h>
+@@ -42,6 +43,7 @@
+  * @entity_id: ID of the next entity to be registered
+  * @entities:  List of registered entities
+  * @lock:      Entities list lock
++ * @graph_mutex: Entities graph operation lock
+  *
+  * This structure represents an abstract high-level media device. It allows easy
+  * access to entities and provides basic media device-level support. The
+@@ -69,6 +71,8 @@ struct media_device {
+ 
+        /* Protects the entities list */
+        spinlock_t lock;
++       /* Serializes graph operations. */
++       struct mutex graph_mutex;
+ };
+ 
+ /* media_devnode to media_device */
+diff --git a/include/media/media-entity.h b/include/media/media-entity.h
+index b82f824..114541a 100644
+--- a/include/media/media-entity.h
++++ b/include/media/media-entity.h
+@@ -81,6 +81,8 @@ struct media_entity {
+        struct media_pad *pads;         /* Pads array (num_pads elements) */
+        struct media_link *links;       /* Links array (max_links elements)*/
+ 
++       int use_count;                  /* Use count for the entity. */
++
+        union {
+                /* Node specifications */
+                struct {
+@@ -129,6 +131,9 @@ void media_entity_cleanup(struct media_entity *entity);
+ int media_entity_create_link(struct media_entity *source, u16 source_pad,
+                struct media_entity *sink, u16 sink_pad, u32 flags);
+ 
++struct media_entity *media_entity_get(struct media_entity *entity);
++void media_entity_put(struct media_entity *entity);
++
+ void media_entity_graph_walk_start(struct media_entity_graph *graph,
+                struct media_entity *entity);
+ struct media_entity *
+-- 
+1.6.6.1
+