/*
* uvc_queue.c -- USB Video Class driver - Buffers management
*
* Copyright (C) 2005-2010
* Laurent Pinchart (laurent.pinchart@ideasonboard.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#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-vmalloc.h>
#include "uvc.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.
*/
/* -----------------------------------------------------------------------------
* videobuf2 queue operations
*/
static int uvc_queue_setup(struct vb2_queue *vq, const struct v4l2_format *fmt,
unsigned int *nbuffers, unsigned int *nplanes,
unsigned int sizes[], void *alloc_ctxs[])
{
struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
struct uvc_video *video = container_of(queue, struct uvc_video, queue);
if (*nbuffers > UVC_MAX_VIDEO_BUFFERS)
*nbuffers = UVC_MAX_VIDEO_BUFFERS;
*nplanes = 1;
sizes[0] = video->imagesize;
return 0;
}
static int uvc_buffer_prepare(struct vb2_buffer *vb)
{
struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
struct uvc_buffer *buf = container_of(vb, struct uvc_buffer, buf);
if (vb->v4l2_buf.type == V4L2_BUF_TYPE_VIDEO_OUTPUT &&
vb2_get_plane_payload(vb, 0) > vb2_plane_size(vb, 0)) {
uvc_trace(UVC_TRACE_CAPTURE, "[E] Bytes used out of bounds.\n");
return -EINVAL;
}
if (unlikely(queue->flags & UVC_QUEUE_DISCONNECTED))
return -ENODEV;
buf->state = UVC_BUF_STATE_QUEUED;
buf->mem = vb2_plane_vaddr(vb, 0);
buf->length = vb2_plane_size(vb, 0);
if (vb->v4l2_buf.type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
buf->bytesused = 0;
else
buf->bytesused = vb2_get_plane_payload(vb, 0);
return 0;
}
static void uvc_buffer_queue(struct vb2_buffer *vb)
{
struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
struct uvc_buffer *buf = container_of(vb, struct uvc_buffer, buf);
unsigned long flags;
spin_lock_irqsave(&queue->irqlock, flags);
if (likely(!(queue->flags & UVC_QUEUE_DISCONNECTED))) {
list_add_tail(&buf->queue, &queue->irqqueue);
} else {
/* If the device is disconnected return the buffer to userspace
* directly. The next QBUF call will fail with -ENODEV.
*/
buf->state = UVC_BUF_STATE_ERROR;
vb2_buffer_done(&buf->buf, VB2_BUF_STATE_ERROR);
}
spin_unlock_irqrestore(&queue->irqlock, flags);
}
static void uvc_wait_prepare(struct vb2_queue *vq)
{
struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
mutex_unlock(&queue->mutex);
}
static void uvc_wait_finish(struct vb2_queue *vq)
{
struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
mutex_lock(&queue->mutex);
}
static struct vb2_ops uvc_queue_qops = {
.queue_setup = uvc_queue_setup,
.buf_prepare = uvc_buffer_prepare,
.buf_queue = uvc_buffer_queue,
.wait_prepare = uvc_wait_prepare,
.wait_finish = uvc_wait_finish,
};
static int uvc_queue_init(struct uvc_video_queue *queue,
enum v4l2_buf_type type)
{
int ret;
queue->queue.type = type;
queue->queue.io_modes = VB2_MMAP | VB2_USERPTR;
queue->queue.drv_priv = queue;
queue->queue.buf_struct_size = sizeof(struct uvc_buffer);
queue->queue.ops = &uvc_queue_qops;
queue->queue.mem_ops = &vb2_vmalloc_memops;
ret = vb2_queue_init(&queue->queue);
if (ret)
return ret;
mutex_init(&queue->mutex);
spin_lock_init(&queue->irqlock);
INIT_LIST_HEAD(&queue->irqqueue);
queue->flags = 0;
return 0;
}
/*
* Free the video buffers.
*/
static void uvc_free_buffers(struct uvc_video_queue *queue)
{
mutex_lock(&queue->mutex);
vb2_queue_release(&queue->queue);
mutex_unlock(&queue->mutex);
}
/*
* Allocate the video buffers.
*/
static int uvc_alloc_buffers(struct uvc_video_queue *queue,
struct v4l2_requestbuffers *rb)
{
int ret;
mutex_lock(&queue->mutex);
ret = vb2_reqbufs(&queue->queue, rb);
mutex_unlock(&queue->mutex);
return ret ? ret : rb->count;
}
static int uvc_query_buffer(struct uvc_video_queue *queue,
struct v4l2_buffer *buf)
{
int ret;
mutex_lock(&queue->mutex);
ret = vb2_querybuf(&queue->queue, buf);
mutex_unlock(&queue->mutex);
return ret;
}
static int uvc_queue_buffer(struct uvc_video_queue *queue,
struct v4l2_buffer *buf)
{
unsigned long flags;
int ret;
mutex_lock(&queue->mutex);
ret = vb2_qbuf(&queue->queue, buf);
if (ret < 0)
goto done;
spin_lock_irqsave(&queue->irqlock, flags);
ret = (queue->flags & UVC_QUEUE_PAUSED) != 0;
queue->flags &= ~UVC_QUEUE_PAUSED;
spin_unlock_irqrestore(&queue->irqlock, flags);
done:
mutex_unlock(&queue->mutex);
return ret;
}
/*
* Dequeue a video buffer. If nonblocking is false, block until a buffer is
* available.
*/
static int uvc_dequeue_buffer(struct uvc_video_queue *queue,
struct v4l2_buffer *buf, int nonblocking)
{
int ret;
mutex_lock(&queue->mutex);
ret = vb2_dqbuf(&queue->queue, buf, nonblocking);
mutex_unlock(&queue->mutex);
return ret;
}
/*
* Poll the video queue.
*
* This function implements video queue polling and is intended to be used by
* the device poll handler.
*/
static unsigned int uvc_queue_poll(struct uvc_video_queue *queue,
struct file *file, poll_table *wait)
{
unsigned int ret;
mutex_lock(&queue->mutex);
ret = vb2_poll(&queue->queue, file, wait);
mutex_unlock(&queue->mutex);
return ret;
}
static int uvc_queue_mmap(struct uvc_video_queue *queue,
struct vm_area_struct *vma)
{
int ret;
mutex_lock(&queue->mutex);
ret = vb2_mmap(&queue->queue, vma);
mutex_unlock(&queue->mutex);
return ret;
}
#ifndef CONFIG_MMU
/*
* Get unmapped area.
*
* NO-MMU arch need this function to make mmap() work correctly.
*/
static unsigned long uvc_queue_get_unmapped_area(struct uvc_video_queue *queue,
unsigned long pgoff)
{
unsigned long ret;
mutex_lock(&queue->mutex);
ret = vb2_get_unmapped_area(&queue->queue, 0, 0, pgoff, 0);
mutex_unlock(&queue->mutex);
return ret;
}
#endif
/*
* 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.
*/
static void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect)
{
struct uvc_buffer *buf;
unsigned long flags;
spin_lock_irqsave(&queue->irqlock, flags);
while (!list_empty(&queue->irqqueue)) {
buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
queue);
list_del(&buf->queue);
buf->state = UVC_BUF_STATE_ERROR;
vb2_buffer_done(&buf->buf, VB2_BUF_STATE_ERROR);
}
/* This must be protected by the irqlock spinlock to avoid race
* conditions between uvc_queue_buffer and the disconnection event that
* could result in an interruptible wait in uvc_dequeue_buffer. Do not
* blindly replace this logic by checking for the UVC_DEV_DISCONNECTED
* state outside the queue code.
*/
if (disconnect)
queue->flags |= UVC_QUEUE_DISCONNECTED;
spin_unlock_irqrestore(&queue->irqlock, flags);
}
/*
* Enable or disable the video buffers queue.
*
* The queue must be enabled before starting video acquisition and must be
* disabled after stopping it. This ensures that the video buffers queue
* state can be properly initialized before buffers are accessed from the
* interrupt handler.
*
* Enabling the video queue initializes parameters (such as sequence number,
* sync pattern, ...). If the queue is already enabled, return -EBUSY.
*
* Disabling the video queue cancels the queue and removes all buffers from
* the main queue.
*
* This function can't be called from interrupt context. Use
* uvc_queue_cancel() instead.
*/
static int uvc_queue_enable(struct uvc_video_queue *queue, int enable)
{
unsigned long flags;
int ret = 0;
mutex_lock(&queue->mutex);
if (enable) {
ret = vb2_streamon(&queue->queue, queue->queue.type);
if (ret < 0)
goto done;
queue->sequence = 0;
queue->buf_used = 0;
} else {
ret = vb2_streamoff(&queue->queue, queue->queue.type);
if (ret < 0)
goto done;
spin_lock_irqsave(&queue->irqlock, flags);
INIT_LIST_HEAD(&queue->irqqueue);
/*
* FIXME: We need to clear the DISCONNECTED flag to ensure that
* applications will be able to queue buffers for the next
* streaming run. However, clearing it here doesn't guarantee
* that the device will be reconnected in the meantime.
*/
queue->flags &= ~UVC_QUEUE_DISCONNECTED;
spin_unlock_irqrestore(&queue->irqlock, flags);
}
done:
mutex_unlock(&queue->mutex);
return ret;
}
/* called with &queue_irqlock held.. */
static struct uvc_buffer *uvc_queue_next_buffer(struct uvc_video_queue *queue,
struct uvc_buffer *buf)
{
struct uvc_buffer *nextbuf;
if ((queue->flags & UVC_QUEUE_DROP_INCOMPLETE) &&
buf->length != buf->bytesused) {
buf->state = UVC_BUF_STATE_QUEUED;
vb2_set_plane_payload(&buf->buf, 0, 0);
return buf;
}
list_del(&buf->queue);
if (!list_empty(&queue->irqqueue))
nextbuf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
queue);
else
nextbuf = NULL;
/*
* FIXME: with videobuf2, the sequence number or timestamp fields
* are valid only for video capture devices and the UVC gadget usually
* is a video output device. Keeping these until the specs are clear on
* this aspect.
*/
buf->buf.v4l2_buf.sequence = queue->sequence++;
do_gettimeofday(&buf->buf.v4l2_buf.timestamp);
vb2_set_plane_payload(&buf->buf, 0, buf->bytesused);
vb2_buffer_done(&buf->buf, VB2_BUF_STATE_DONE);
return nextbuf;
}
static struct uvc_buffer *uvc_queue_head(struct uvc_video_queue *queue)
{
struct uvc_buffer *buf = NULL;
if (!list_empty(&queue->irqqueue))
buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
queue);
else
queue->flags |= UVC_QUEUE_PAUSED;
return buf;
}
