linux/drivers/media/usb/uvc/uvc_queue.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *      uvc_queue.c  --  USB Video Class driver - Buffers management
 *
 *      Copyright (C) 2005-2010
 *          Laurent Pinchart ([email protected])
 */

#include <linux/atomic.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/usb.h>
#include <linux/videodev2.h>
#include <linux/vmalloc.h>
#include <linux/wait.h>
#include <media/videobuf2-v4l2.h>
#include <media/videobuf2-vmalloc.h>

#include "uvcvideo.h"

/* ------------------------------------------------------------------------
 * Video buffers queue management.
 *
 * Video queues is initialized by uvc_queue_init(). The function performs
 * basic initialization of the uvc_video_queue struct and never fails.
 *
 * Video buffers are managed by videobuf2. The driver uses a mutex to protect
 * the videobuf2 queue operations by serializing calls to videobuf2 and a
 * spinlock to protect the IRQ queue that holds the buffers to be processed by
 * the driver.
 */

static inline struct uvc_buffer *uvc_vbuf_to_buffer(struct vb2_v4l2_buffer *buf)
{ … }

/*
 * Return all queued buffers to videobuf2 in the requested state.
 *
 * This function must be called with the queue spinlock held.
 */
static void uvc_queue_return_buffers(struct uvc_video_queue *queue,
			       enum uvc_buffer_state state)
{ … }

/* -----------------------------------------------------------------------------
 * videobuf2 queue operations
 */

static int uvc_queue_setup(struct vb2_queue *vq,
			   unsigned int *nbuffers, unsigned int *nplanes,
			   unsigned int sizes[], struct device *alloc_devs[])
{ … }

static int uvc_buffer_prepare(struct vb2_buffer *vb)
{ … }

static void uvc_buffer_queue(struct vb2_buffer *vb)
{ … }

static void uvc_buffer_finish(struct vb2_buffer *vb)
{ … }

static int uvc_start_streaming(struct vb2_queue *vq, unsigned int count)
{ … }

static void uvc_stop_streaming(struct vb2_queue *vq)
{ … }

static const struct vb2_ops uvc_queue_qops = …;

static const struct vb2_ops uvc_meta_queue_qops = …;

int uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type,
		    int drop_corrupted)
{ … }

void uvc_queue_release(struct uvc_video_queue *queue)
{ … }

/* -----------------------------------------------------------------------------
 * V4L2 queue operations
 */

int uvc_request_buffers(struct uvc_video_queue *queue,
			struct v4l2_requestbuffers *rb)
{ … }

int uvc_query_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf)
{ … }

int uvc_create_buffers(struct uvc_video_queue *queue,
		       struct v4l2_create_buffers *cb)
{ … }

int uvc_queue_buffer(struct uvc_video_queue *queue,
		     struct media_device *mdev, struct v4l2_buffer *buf)
{ … }

int uvc_export_buffer(struct uvc_video_queue *queue,
		      struct v4l2_exportbuffer *exp)
{ … }

int uvc_dequeue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf,
		       int nonblocking)
{ … }

int uvc_queue_streamon(struct uvc_video_queue *queue, enum v4l2_buf_type type)
{ … }

int uvc_queue_streamoff(struct uvc_video_queue *queue, enum v4l2_buf_type type)
{ … }

int uvc_queue_mmap(struct uvc_video_queue *queue, struct vm_area_struct *vma)
{ … }

#ifndef CONFIG_MMU
unsigned long uvc_queue_get_unmapped_area(struct uvc_video_queue *queue,
		unsigned long pgoff)
{
	return vb2_get_unmapped_area(&queue->queue, 0, 0, pgoff, 0);
}
#endif

__poll_t uvc_queue_poll(struct uvc_video_queue *queue, struct file *file,
			    poll_table *wait)
{ … }

/* -----------------------------------------------------------------------------
 *
 */

/*
 * Check if buffers have been allocated.
 */
int uvc_queue_allocated(struct uvc_video_queue *queue)
{ … }

/*
 * Cancel the video buffers queue.
 *
 * Cancelling the queue marks all buffers on the irq queue as erroneous,
 * wakes them up and removes them from the queue.
 *
 * If the disconnect parameter is set, further calls to uvc_queue_buffer will
 * fail with -ENODEV.
 *
 * This function acquires the irq spinlock and can be called from interrupt
 * context.
 */
void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect)
{ … }

/*
 * uvc_queue_get_current_buffer: Obtain the current working output buffer
 *
 * Buffers may span multiple packets, and even URBs, therefore the active buffer
 * remains on the queue until the EOF marker.
 */
static struct uvc_buffer *
__uvc_queue_get_current_buffer(struct uvc_video_queue *queue)
{ … }

struct uvc_buffer *uvc_queue_get_current_buffer(struct uvc_video_queue *queue)
{ … }

/*
 * uvc_queue_buffer_requeue: Requeue a buffer on our internal irqqueue
 *
 * Reuse a buffer through our internal queue without the need to 'prepare'.
 * The buffer will be returned to userspace through the uvc_buffer_queue call if
 * the device has been disconnected.
 */
static void uvc_queue_buffer_requeue(struct uvc_video_queue *queue,
		struct uvc_buffer *buf)
{ … }

static void uvc_queue_buffer_complete(struct kref *ref)
{ … }

/*
 * Release a reference on the buffer. Complete the buffer when the last
 * reference is released.
 */
void uvc_queue_buffer_release(struct uvc_buffer *buf)
{ … }

/*
 * Remove this buffer from the queue. Lifetime will persist while async actions
 * are still running (if any), and uvc_queue_buffer_release will give the buffer
 * back to VB2 when all users have completed.
 */
struct uvc_buffer *uvc_queue_next_buffer(struct uvc_video_queue *queue,
		struct uvc_buffer *buf)
{ … }