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https://github.com/edk2-porting/linux-next.git
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d692522577
This patch reworks the videobuffer management logic present in the UVC webcam gadget and ports it to use the "more apt" videobuf2 framework for video buffer management. To support routing video data captured from a real V4L2 video capture device with a "zero copy" operation on videobuffers (as they pass from the V4L2 domain to UVC domain via a user-space application), we need to support USER_PTR IO method at the UVC gadget side. So the V4L2 capture device driver can still continue to use MMAP IO method and now the user-space application can just pass a pointer to the video buffers being dequeued from the V4L2 device side while queueing them at the UVC gadget end. This ensures that we have a "zero-copy" design as the videobuffers pass from the V4L2 capture device to the UVC gadget. Note that there will still be a need to apply UVC specific payload headers on top of each UVC payload data, which will still require a copy operation to be performed in the 'encode' routines of the UVC gadget. This patch also addresses one issue found out while porting the UVC gadget to videobuf2 framework: - In case the usb requests queued by the gadget get completed with a status of -ESHUTDOWN (disconnected from host), the queue of videobuf2 should be cancelled to ensure that the application space daemon is not left in a state waiting for a vb2 to be successfully absorbed at the USB side. Signed-off-by: Bhupesh Sharma <bhupesh.sharma@st.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
64 lines
1.3 KiB
C
64 lines
1.3 KiB
C
#ifndef _UVC_QUEUE_H_
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#define _UVC_QUEUE_H_
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#ifdef __KERNEL__
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#include <linux/kernel.h>
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#include <linux/poll.h>
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#include <linux/videodev2.h>
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#include <media/videobuf2-core.h>
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/* Maximum frame size in bytes, for sanity checking. */
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#define UVC_MAX_FRAME_SIZE (16*1024*1024)
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/* Maximum number of video buffers. */
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#define UVC_MAX_VIDEO_BUFFERS 32
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/* ------------------------------------------------------------------------
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* Structures.
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*/
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enum uvc_buffer_state {
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UVC_BUF_STATE_IDLE = 0,
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UVC_BUF_STATE_QUEUED = 1,
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UVC_BUF_STATE_ACTIVE = 2,
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UVC_BUF_STATE_DONE = 3,
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UVC_BUF_STATE_ERROR = 4,
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};
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struct uvc_buffer {
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struct vb2_buffer buf;
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struct list_head queue;
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enum uvc_buffer_state state;
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void *mem;
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unsigned int length;
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unsigned int bytesused;
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};
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#define UVC_QUEUE_DISCONNECTED (1 << 0)
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#define UVC_QUEUE_DROP_INCOMPLETE (1 << 1)
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#define UVC_QUEUE_PAUSED (1 << 2)
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struct uvc_video_queue {
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struct vb2_queue queue;
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struct mutex mutex; /* Protects queue */
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unsigned int flags;
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__u32 sequence;
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unsigned int buf_used;
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spinlock_t irqlock; /* Protects flags and irqqueue */
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struct list_head irqqueue;
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};
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static inline int uvc_queue_streaming(struct uvc_video_queue *queue)
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{
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return vb2_is_streaming(&queue->queue);
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}
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#endif /* __KERNEL__ */
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#endif /* _UVC_QUEUE_H_ */
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