media: media-request: implement media requests

Add initial media request support:

1) Add MEDIA_IOC_REQUEST_ALLOC ioctl support to media-device.c
2) Add struct media_request to store request objects.
3) Add struct media_request_object to represent a request object.
4) Add MEDIA_REQUEST_IOC_QUEUE/REINIT ioctl support.

Basic lifecycle: the application allocates a request, adds
objects to it, queues the request, polls until it is completed
and can then read the final values of the objects at the time
of completion. When it closes the file descriptor the request
memory will be freed (actually, when the last user of that request
releases the request).

Drivers will bind an object to a request (the 'adds objects to it'
phase), when MEDIA_REQUEST_IOC_QUEUE is called the request is
validated (req_validate op), then queued (the req_queue op).

When done with an object it can either be unbound from the request
(e.g. when the driver has finished with a vb2 buffer) or marked as
completed (e.g. for controls associated with a buffer). When all
objects in the request are completed (or unbound), then the request
fd will signal an exception (poll).

Co-developed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Co-developed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Co-developed-by: Alexandre Courbot <acourbot@chromium.org>

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

1 files changed, 20 insertions, 4 deletions

diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
index 3bae24b15eaa..4dd2b1dae03d 100644
--- a/drivers/media/media-device.c
+++ b/drivers/media/media-device.c
@@ -30,6 +30,7 @@
 #include <media/media-device.h>
 #include <media/media-devnode.h>
 #include <media/media-entity.h>
+#include <media/media-request.h>
 
 #ifdef CONFIG_MEDIA_CONTROLLER
 
@@ -377,10 +378,19 @@ static long media_device_get_topology(struct media_device *mdev, void *arg)
 	return ret;
 }
 
+static long media_device_request_alloc(struct media_device *mdev,
+				       int *alloc_fd)
+{
+	if (!mdev->ops || !mdev->ops->req_validate || !mdev->ops->req_queue)
+		return -ENOTTY;
+
+	return media_request_alloc(mdev, alloc_fd);
+}
+
 static long copy_arg_from_user(void *karg, void __user *uarg, unsigned int cmd)
 {
-	/* All media IOCTLs are _IOWR() */
-	if (copy_from_user(karg, uarg, _IOC_SIZE(cmd)))
+	if ((_IOC_DIR(cmd) & _IOC_WRITE) &&
+	    copy_from_user(karg, uarg, _IOC_SIZE(cmd)))
 		return -EFAULT;
 
 	return 0;
@@ -388,8 +398,8 @@ static long copy_arg_from_user(void *karg, void __user *uarg, unsigned int cmd)
 
 static long copy_arg_to_user(void __user *uarg, void *karg, unsigned int cmd)
 {
-	/* All media IOCTLs are _IOWR() */
-	if (copy_to_user(uarg, karg, _IOC_SIZE(cmd)))
+	if ((_IOC_DIR(cmd) & _IOC_READ) &&
+	    copy_to_user(uarg, karg, _IOC_SIZE(cmd)))
 		return -EFAULT;
 
 	return 0;
@@ -425,6 +435,7 @@ static const struct media_ioctl_info ioctl_info[] = {
 	MEDIA_IOC(ENUM_LINKS, media_device_enum_links, MEDIA_IOC_FL_GRAPH_MUTEX),
 	MEDIA_IOC(SETUP_LINK, media_device_setup_link, MEDIA_IOC_FL_GRAPH_MUTEX),
 	MEDIA_IOC(G_TOPOLOGY, media_device_get_topology, MEDIA_IOC_FL_GRAPH_MUTEX),
+	MEDIA_IOC(REQUEST_ALLOC, media_device_request_alloc, 0),
 };
 
 static long media_device_ioctl(struct file *filp, unsigned int cmd,
@@ -691,9 +702,13 @@ void media_device_init(struct media_device *mdev)
 	INIT_LIST_HEAD(&mdev->pads);
 	INIT_LIST_HEAD(&mdev->links);
 	INIT_LIST_HEAD(&mdev->entity_notify);
+
+	mutex_init(&mdev->req_queue_mutex);
 	mutex_init(&mdev->graph_mutex);
 	ida_init(&mdev->entity_internal_idx);
 
+	atomic_set(&mdev->request_id, 0);
+
 	dev_dbg(mdev->dev, "Media device initialized\n");
 }
 EXPORT_SYMBOL_GPL(media_device_init);
@@ -704,6 +719,7 @@ void media_device_cleanup(struct media_device *mdev)
 	mdev->entity_internal_idx_max = 0;
 	media_graph_walk_cleanup(&mdev->pm_count_walk);
 	mutex_destroy(&mdev->graph_mutex);
+	mutex_destroy(&mdev->req_queue_mutex);
 }
 EXPORT_SYMBOL_GPL(media_device_cleanup);