The request API allows bundling media device parameters with request
objects and applying them atomically, either synchronously or
asynchronously.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
---
Changes since v0:
- Make the request ID 32 bits wide internally
---
drivers/media/media-device.c | 175 +++++++++++++++++++++++++++++++++++++++++++
include/media/media-device.h | 41 ++++++++++
include/uapi/linux/media.h | 12 +++
3 files changed, 228 insertions(+)
diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
index 285f7d79d848..37da26806ed8 100644
--- a/drivers/media/media-device.c
+++ b/drivers/media/media-device.c
@@ -33,6 +33,7 @@
struct media_device_fh {
struct media_devnode_fh fh;
+ struct list_head requests;
};
static inline struct media_device_fh *media_device_fh(struct file *filp)
@@ -41,6 +42,161 @@ static inline struct media_device_fh *media_device_fh(struct file *filp)
}
/* -----------------------------------------------------------------------------
+ * Requests
+ */
+
+/**
+ * media_device_request_find - Find a request based from its ID
+ * @mdev: The media device
+ * @reqid: The request ID
+ *
+ * Find and return the request associated with the given ID, or NULL if no such
+ * request exists.
+ *
+ * When the function returns a non-NULL request it increases its reference
+ * count. The caller is responsible for releasing the reference by calling
+ * media_device_request_put() on the request.
+ */
+struct media_device_request *
+media_device_request_find(struct media_device *mdev, u16 reqid)
+{
+ struct media_device_request *req;
+ unsigned long flags;
+ bool found = false;
+
+ spin_lock_irqsave(&mdev->req_lock, flags);
+ list_for_each_entry(req, &mdev->requests, list) {
+ if (req->id == reqid) {
+ kref_get(&req->kref);
+ found = true;
+ break;
+ }
+ }
+ spin_unlock_irqrestore(&mdev->req_lock, flags);
+
+ return found ? req : NULL;
+}
+EXPORT_SYMBOL_GPL(media_device_request_find);
+
+void media_device_request_get(struct media_device_request *req)
+{
+ kref_get(&req->kref);
+}
+EXPORT_SYMBOL_GPL(media_device_request_get);
+
+static void media_device_request_release(struct kref *kref)
+{
+ struct media_device_request *req =
+ container_of(kref, struct media_device_request, kref);
+ struct media_device *mdev = req->mdev;
+
+ mdev->ops->req_free(mdev, req);
+}
+
+void media_device_request_put(struct media_device_request *req)
+{
+ kref_put(&req->kref, media_device_request_release);
+}
+EXPORT_SYMBOL_GPL(media_device_request_put);
+
+static int media_device_request_alloc(struct media_device *mdev,
+ struct media_device_fh *fh,
+ struct media_request_cmd *cmd)
+{
+ struct media_device_request *req;
+ unsigned long flags;
+
+ req = mdev->ops->req_alloc(mdev);
+ if (!req)
+ return -ENOMEM;
+
+ req->mdev = mdev;
+ kref_init(&req->kref);
+
+ spin_lock_irqsave(&mdev->req_lock, flags);
+ req->id = ++mdev->req_id;
+ list_add_tail(&req->list, &mdev->requests);
+ list_add_tail(&req->fh_list, &fh->requests);
+ spin_unlock_irqrestore(&mdev->req_lock, flags);
+
+ cmd->request = req->id;
+ return 0;
+}
+
+static void media_device_request_delete(struct media_device *mdev,
+ struct media_device_request *req)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&mdev->req_lock, flags);
+ list_del(&req->list);
+ spin_unlock_irqrestore(&mdev->req_lock, flags);
+
+ media_device_request_put(req);
+}
+
+static long media_device_request_cmd(struct media_device *mdev,
+ struct media_device_fh *fh,
+ struct media_request_cmd __user *_cmd)
+{
+ struct media_device_request *req = NULL;
+ struct media_request_cmd cmd;
+ int ret;
+
+ if (!mdev->ops || !mdev->ops->req_alloc || !mdev->ops->req_free)
+ return -ENOTTY;
+
+ if (copy_from_user(&cmd, _cmd, sizeof(cmd)))
+ return -EFAULT;
+
+ if (cmd.cmd != MEDIA_REQ_CMD_ALLOC) {
+ req = media_device_request_find(mdev, cmd.request);
+ if (!req)
+ return -EINVAL;
+ }
+
+ switch (cmd.cmd) {
+ case MEDIA_REQ_CMD_ALLOC:
+ ret = media_device_request_alloc(mdev, fh, &cmd);
+ break;
+
+ case MEDIA_REQ_CMD_DELETE:
+ media_device_request_delete(mdev, req);
+ ret = 0;
+ break;
+
+ case MEDIA_REQ_CMD_APPLY:
+ if (!mdev->ops->req_apply)
+ return -ENOSYS;
+
+ ret = mdev->ops->req_apply(mdev, req);
+ break;
+
+ case MEDIA_REQ_CMD_QUEUE:
+ if (!mdev->ops->req_queue)
+ return -ENOSYS;
+
+ ret = mdev->ops->req_queue(mdev, req);
+ break;
+
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ if (req)
+ media_device_request_put(req);
+
+ if (ret < 0)
+ return ret;
+
+ if (copy_to_user(_cmd, &cmd, sizeof(cmd)))
+ return -EFAULT;
+
+ return 0;
+}
+
+/* -----------------------------------------------------------------------------
* Userspace API
*/
@@ -52,6 +208,7 @@ static int media_device_open(struct file *filp)
if (!fh)
return -ENOMEM;
+ INIT_LIST_HEAD(&fh->requests);
filp->private_data = &fh->fh;
return 0;
@@ -60,6 +217,15 @@ static int media_device_open(struct file *filp)
static int media_device_close(struct file *filp)
{
struct media_device_fh *fh = media_device_fh(filp);
+ struct media_device *mdev = to_media_device(fh->fh.devnode);
+ struct media_device_request *req, *next;
+
+ spin_lock_irq(&mdev->req_lock);
+ list_for_each_entry_safe(req, next, &fh->requests, fh_list) {
+ list_del(&req->fh_list);
+ media_device_request_put(req);
+ }
+ spin_unlock_irq(&mdev->req_lock);
kfree(fh);
@@ -257,6 +423,7 @@ static long media_device_ioctl(struct file *filp, unsigned int cmd,
{
struct media_devnode *devnode = media_devnode_data(filp);
struct media_device *dev = to_media_device(devnode);
+ struct media_device_fh *fh = media_device_fh(filp);
long ret;
switch (cmd) {
@@ -284,6 +451,11 @@ static long media_device_ioctl(struct file *filp, unsigned int cmd,
mutex_unlock(&dev->graph_mutex);
break;
+ case MEDIA_IOC_REQUEST_CMD:
+ ret = media_device_request_cmd(dev, fh,
+ (struct media_request_cmd __user *)arg);
+ break;
+
default:
ret = -ENOIOCTLCMD;
}
@@ -404,6 +576,9 @@ int __must_check __media_device_register(struct media_device *mdev,
spin_lock_init(&mdev->lock);
mutex_init(&mdev->graph_mutex);
+ spin_lock_init(&mdev->req_lock);
+ INIT_LIST_HEAD(&mdev->requests);
+
/* Register the device node. */
mdev->devnode.fops = &media_device_fops;
mdev->devnode.parent = mdev->dev;
diff --git a/include/media/media-device.h b/include/media/media-device.h
index 7e6de4dbf497..bc003bedf087 100644
--- a/include/media/media-device.h
+++ b/include/media/media-device.h
@@ -23,6 +23,7 @@
#ifndef _MEDIA_DEVICE_H
#define _MEDIA_DEVICE_H
+#include <linux/kref.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
@@ -31,14 +32,42 @@
#include <media/media-entity.h>
struct device;
+struct media_device;
+
+/**
+ * struct media_device_request - Media device request
+ * @id: Request ID
+ * @mdev: Media device this request belongs to
+ * @kref: Reference count
+ * @list: List entry in the media device requests list
+ * @fh_list: List entry in the media file handle requests list
+ */
+struct media_device_request {
+ u32 id;
+ struct media_device *mdev;
+ struct kref kref;
+ struct list_head list;
+ struct list_head fh_list;
+};
/**
* struct media_device_ops - Media device operations
* @link_notify: Link state change notification callback
+ * @req_alloc: Allocate a request
+ * @req_free: Free a request
+ * @req_apply: Apply a request
+ * @req_queue: Queue a request
*/
struct media_device_ops {
int (*link_notify)(struct media_link *link, u32 flags,
unsigned int notification);
+ struct media_device_request *(*req_alloc)(struct media_device *mdev);
+ void (*req_free)(struct media_device *mdev,
+ struct media_device_request *req);
+ int (*req_apply)(struct media_device *mdev,
+ struct media_device_request *req);
+ int (*req_queue)(struct media_device *mdev,
+ struct media_device_request *req);
};
/**
@@ -55,6 +84,9 @@ struct media_device_ops {
* @lock: Entities list lock
* @graph_mutex: Entities graph operation lock
* @ops: Operation handler callbacks
+ * @req_lock: Protects the req_id and requests fields
+ * @req_id: Last request ID that was allocated
+ * @requests: List of allocated requests
*
* This structure represents an abstract high-level media device. It allows easy
* access to entities and provides basic media device-level support. The
@@ -86,6 +118,10 @@ struct media_device {
struct mutex graph_mutex;
const struct media_device_ops *ops;
+
+ spinlock_t req_lock;
+ u32 req_id;
+ struct list_head requests;
};
/* Supported link_notify @notification values. */
@@ -108,4 +144,9 @@ void media_device_unregister_entity(struct media_entity *entity);
#define media_device_for_each_entity(entity, mdev) \
list_for_each_entry(entity, &(mdev)->entities, list)
+struct media_device_request *
+media_device_request_find(struct media_device *mdev, u16 reqid);
+void media_device_request_get(struct media_device_request *req);
+void media_device_request_put(struct media_device_request *req);
+
#endif
diff --git a/include/uapi/linux/media.h b/include/uapi/linux/media.h
index 4e816be3de39..fd8887a03988 100644
--- a/include/uapi/linux/media.h
+++ b/include/uapi/linux/media.h
@@ -167,9 +167,21 @@ struct media_links_enum {
__u32 reserved[4];
};
+#define MEDIA_REQ_CMD_ALLOC 0
+#define MEDIA_REQ_CMD_DELETE 1
+#define MEDIA_REQ_CMD_APPLY 2
+#define MEDIA_REQ_CMD_QUEUE 3
+
+struct media_request_cmd {
+ __u32 cmd;
+ __u32 request;
+ __u32 reserved[9];
+};
+
#define MEDIA_IOC_DEVICE_INFO _IOWR('|', 0x00, struct media_device_info)
#define MEDIA_IOC_ENUM_ENTITIES _IOWR('|', 0x01, struct media_entity_desc)
#define MEDIA_IOC_ENUM_LINKS _IOWR('|', 0x02, struct media_links_enum)
#define MEDIA_IOC_SETUP_LINK _IOWR('|', 0x03, struct media_link_desc)
+#define MEDIA_IOC_REQUEST_CMD _IOWR('|', 0x04, struct media_request_cmd)
#endif /* __LINUX_MEDIA_H */
--
2.4.10
--
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