diff options
Diffstat (limited to 'drivers/media/video/uvc/uvc_queue.c')
| -rw-r--r-- | drivers/media/video/uvc/uvc_queue.c | 513 |
1 files changed, 0 insertions, 513 deletions
diff --git a/drivers/media/video/uvc/uvc_queue.c b/drivers/media/video/uvc/uvc_queue.c deleted file mode 100644 index ed6d5449741..00000000000 --- a/drivers/media/video/uvc/uvc_queue.c +++ /dev/null @@ -1,513 +0,0 @@ -/* - * 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/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 <asm/atomic.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 buffer allocation and freeing are performed by uvc_alloc_buffers and - * uvc_free_buffers respectively. The former acquires the video queue lock, - * while the later must be called with the lock held (so that allocation can - * free previously allocated buffers). Trying to free buffers that are mapped - * to user space will return -EBUSY. - * - * Video buffers are managed using two queues. However, unlike most USB video - * drivers that use an in queue and an out queue, we use a main queue to hold - * all queued buffers (both 'empty' and 'done' buffers), and an irq queue to - * hold empty buffers. This design (copied from video-buf) minimizes locking - * in interrupt, as only one queue is shared between interrupt and user - * contexts. - * - * Use cases - * --------- - * - * Unless stated otherwise, all operations that modify the irq buffers queue - * are protected by the irq spinlock. - * - * 1. The user queues the buffers, starts streaming and dequeues a buffer. - * - * The buffers are added to the main and irq queues. Both operations are - * protected by the queue lock, and the later is protected by the irq - * spinlock as well. - * - * The completion handler fetches a buffer from the irq queue and fills it - * with video data. If no buffer is available (irq queue empty), the handler - * returns immediately. - * - * When the buffer is full, the completion handler removes it from the irq - * queue, marks it as done (UVC_BUF_STATE_DONE) and wakes its wait queue. - * At that point, any process waiting on the buffer will be woken up. If a - * process tries to dequeue a buffer after it has been marked done, the - * dequeing will succeed immediately. - * - * 2. Buffers are queued, user is waiting on a buffer and the device gets - * disconnected. - * - * When the device is disconnected, the kernel calls the completion handler - * with an appropriate status code. The handler marks all buffers in the - * irq queue as being erroneous (UVC_BUF_STATE_ERROR) and wakes them up so - * that any process waiting on a buffer gets woken up. - * - * Waking up up the first buffer on the irq list is not enough, as the - * process waiting on the buffer might restart the dequeue operation - * immediately. - * - */ - -void uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type, - int drop_corrupted) -{ - mutex_init(&queue->mutex); - spin_lock_init(&queue->irqlock); - INIT_LIST_HEAD(&queue->mainqueue); - INIT_LIST_HEAD(&queue->irqqueue); - queue->flags = drop_corrupted ? UVC_QUEUE_DROP_CORRUPTED : 0; - queue->type = type; -} - -/* - * Allocate the video buffers. - * - * Pages are reserved to make sure they will not be swapped, as they will be - * filled in the URB completion handler. - * - * Buffers will be individually mapped, so they must all be page aligned. - */ -int uvc_alloc_buffers(struct uvc_video_queue *queue, unsigned int nbuffers, - unsigned int buflength) -{ - unsigned int bufsize = PAGE_ALIGN(buflength); - unsigned int i; - void *mem = NULL; - int ret; - - if (nbuffers > UVC_MAX_VIDEO_BUFFERS) - nbuffers = UVC_MAX_VIDEO_BUFFERS; - - mutex_lock(&queue->mutex); - - if ((ret = uvc_free_buffers(queue)) < 0) - goto done; - - /* Bail out if no buffers should be allocated. */ - if (nbuffers == 0) - goto done; - - /* Decrement the number of buffers until allocation succeeds. */ - for (; nbuffers > 0; --nbuffers) { - mem = vmalloc_32(nbuffers * bufsize); - if (mem != NULL) - break; - } - - if (mem == NULL) { - ret = -ENOMEM; - goto done; - } - - for (i = 0; i < nbuffers; ++i) { - memset(&queue->buffer[i], 0, sizeof queue->buffer[i]); - queue->buffer[i].buf.index = i; - queue->buffer[i].buf.m.offset = i * bufsize; - queue->buffer[i].buf.length = buflength; - queue->buffer[i].buf.type = queue->type; - queue->buffer[i].buf.field = V4L2_FIELD_NONE; - queue->buffer[i].buf.memory = V4L2_MEMORY_MMAP; - queue->buffer[i].buf.flags = 0; - init_waitqueue_head(&queue->buffer[i].wait); - } - - queue->mem = mem; - queue->count = nbuffers; - queue->buf_size = bufsize; - ret = nbuffers; - -done: - mutex_unlock(&queue->mutex); - return ret; -} - -/* - * Free the video buffers. - * - * This function must be called with the queue lock held. - */ -int uvc_free_buffers(struct uvc_video_queue *queue) -{ - unsigned int i; - - for (i = 0; i < queue->count; ++i) { - if (queue->buffer[i].vma_use_count != 0) - return -EBUSY; - } - - if (queue->count) { - vfree(queue->mem); - queue->count = 0; - } - - return 0; -} - -/* - * Check if buffers have been allocated. - */ -int uvc_queue_allocated(struct uvc_video_queue *queue) -{ - int allocated; - - mutex_lock(&queue->mutex); - allocated = queue->count != 0; - mutex_unlock(&queue->mutex); - - return allocated; -} - -static void __uvc_query_buffer(struct uvc_buffer *buf, - struct v4l2_buffer *v4l2_buf) -{ - memcpy(v4l2_buf, &buf->buf, sizeof *v4l2_buf); - - if (buf->vma_use_count) - v4l2_buf->flags |= V4L2_BUF_FLAG_MAPPED; - - switch (buf->state) { - case UVC_BUF_STATE_ERROR: - case UVC_BUF_STATE_DONE: - v4l2_buf->flags |= V4L2_BUF_FLAG_DONE; - break; - case UVC_BUF_STATE_QUEUED: - case UVC_BUF_STATE_ACTIVE: - case UVC_BUF_STATE_READY: - v4l2_buf->flags |= V4L2_BUF_FLAG_QUEUED; - break; - case UVC_BUF_STATE_IDLE: - default: - break; - } -} - -int uvc_query_buffer(struct uvc_video_queue *queue, - struct v4l2_buffer *v4l2_buf) -{ - int ret = 0; - - mutex_lock(&queue->mutex); - if (v4l2_buf->index >= queue->count) { - ret = -EINVAL; - goto done; - } - - __uvc_query_buffer(&queue->buffer[v4l2_buf->index], v4l2_buf); - -done: - mutex_unlock(&queue->mutex); - return ret; -} - -/* - * Queue a video buffer. Attempting to queue a buffer that has already been - * queued will return -EINVAL. - */ -int uvc_queue_buffer(struct uvc_video_queue *queue, - struct v4l2_buffer *v4l2_buf) -{ - struct uvc_buffer *buf; - unsigned long flags; - int ret = 0; - - uvc_trace(UVC_TRACE_CAPTURE, "Queuing buffer %u.\n", v4l2_buf->index); - - if (v4l2_buf->type != queue->type || - v4l2_buf->memory != V4L2_MEMORY_MMAP) { - uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer type (%u) " - "and/or memory (%u).\n", v4l2_buf->type, - v4l2_buf->memory); - return -EINVAL; - } - - mutex_lock(&queue->mutex); - if (v4l2_buf->index >= queue->count) { - uvc_trace(UVC_TRACE_CAPTURE, "[E] Out of range index.\n"); - ret = -EINVAL; - goto done; - } - - buf = &queue->buffer[v4l2_buf->index]; - if (buf->state != UVC_BUF_STATE_IDLE) { - uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer state " - "(%u).\n", buf->state); - ret = -EINVAL; - goto done; - } - - if (v4l2_buf->type == V4L2_BUF_TYPE_VIDEO_OUTPUT && - v4l2_buf->bytesused > buf->buf.length) { - uvc_trace(UVC_TRACE_CAPTURE, "[E] Bytes used out of bounds.\n"); - ret = -EINVAL; - goto done; - } - - spin_lock_irqsave(&queue->irqlock, flags); - if (queue->flags & UVC_QUEUE_DISCONNECTED) { - spin_unlock_irqrestore(&queue->irqlock, flags); - ret = -ENODEV; - goto done; - } - buf->state = UVC_BUF_STATE_QUEUED; - if (v4l2_buf->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) - buf->buf.bytesused = 0; - else - buf->buf.bytesused = v4l2_buf->bytesused; - - list_add_tail(&buf->stream, &queue->mainqueue); - list_add_tail(&buf->queue, &queue->irqqueue); - spin_unlock_irqrestore(&queue->irqlock, flags); - -done: - mutex_unlock(&queue->mutex); - return ret; -} - -static int uvc_queue_waiton(struct uvc_buffer *buf, int nonblocking) -{ - if (nonblocking) { - return (buf->state != UVC_BUF_STATE_QUEUED && - buf->state != UVC_BUF_STATE_ACTIVE && - buf->state != UVC_BUF_STATE_READY) - ? 0 : -EAGAIN; - } - - return wait_event_interruptible(buf->wait, - buf->state != UVC_BUF_STATE_QUEUED && - buf->state != UVC_BUF_STATE_ACTIVE && - buf->state != UVC_BUF_STATE_READY); -} - -/* - * Dequeue a video buffer. If nonblocking is false, block until a buffer is - * available. - */ -int uvc_dequeue_buffer(struct uvc_video_queue *queue, - struct v4l2_buffer *v4l2_buf, int nonblocking) -{ - struct uvc_buffer *buf; - int ret = 0; - - if (v4l2_buf->type != queue->type || - v4l2_buf->memory != V4L2_MEMORY_MMAP) { - uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer type (%u) " - "and/or memory (%u).\n", v4l2_buf->type, - v4l2_buf->memory); - return -EINVAL; - } - - mutex_lock(&queue->mutex); - if (list_empty(&queue->mainqueue)) { - uvc_trace(UVC_TRACE_CAPTURE, "[E] Empty buffer queue.\n"); - ret = -EINVAL; - goto done; - } - - buf = list_first_entry(&queue->mainqueue, struct uvc_buffer, stream); - if ((ret = uvc_queue_waiton(buf, nonblocking)) < 0) - goto done; - - uvc_trace(UVC_TRACE_CAPTURE, "Dequeuing buffer %u (%u, %u bytes).\n", - buf->buf.index, buf->state, buf->buf.bytesused); - - switch (buf->state) { - case UVC_BUF_STATE_ERROR: - uvc_trace(UVC_TRACE_CAPTURE, "[W] Corrupted data " - "(transmission error).\n"); - ret = -EIO; - case UVC_BUF_STATE_DONE: - buf->state = UVC_BUF_STATE_IDLE; - break; - - case UVC_BUF_STATE_IDLE: - case UVC_BUF_STATE_QUEUED: - case UVC_BUF_STATE_ACTIVE: - case UVC_BUF_STATE_READY: - default: - uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer state %u " - "(driver bug?).\n", buf->state); - ret = -EINVAL; - goto done; - } - - list_del(&buf->stream); - __uvc_query_buffer(buf, v4l2_buf); - -done: - 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. - */ -unsigned int uvc_queue_poll(struct uvc_video_queue *queue, struct file *file, - poll_table *wait) -{ - struct uvc_buffer *buf; - unsigned int mask = 0; - - mutex_lock(&queue->mutex); - if (list_empty(&queue->mainqueue)) { - mask |= POLLERR; - goto done; - } - buf = list_first_entry(&queue->mainqueue, struct uvc_buffer, stream); - - poll_wait(file, &buf->wait, wait); - if (buf->state == UVC_BUF_STATE_DONE || - buf->state == UVC_BUF_STATE_ERROR) { - if (queue->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) - mask |= POLLIN | POLLRDNORM; - else - mask |= POLLOUT | POLLWRNORM; - } - -done: - mutex_unlock(&queue->mutex); - return mask; -} - -/* - * 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 returns -EBUSY if the queue is already enabled. - * - * 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. - */ -int uvc_queue_enable(struct uvc_video_queue *queue, int enable) -{ - unsigned int i; - int ret = 0; - - mutex_lock(&queue->mutex); - if (enable) { - if (uvc_queue_streaming(queue)) { - ret = -EBUSY; - goto done; - } - queue->flags |= UVC_QUEUE_STREAMING; - queue->buf_used = 0; - } else { - uvc_queue_cancel(queue, 0); - INIT_LIST_HEAD(&queue->mainqueue); - - for (i = 0; i < queue->count; ++i) { - queue->buffer[i].error = 0; - queue->buffer[i].state = UVC_BUF_STATE_IDLE; - } - - queue->flags &= ~UVC_QUEUE_STREAMING; - } - -done: - mutex_unlock(&queue->mutex); - return ret; -} - -/* - * 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) -{ - 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; - wake_up(&buf->wait); - } - /* 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); -} - -struct uvc_buffer *uvc_queue_next_buffer(struct uvc_video_queue *queue, - struct uvc_buffer *buf) -{ - struct uvc_buffer *nextbuf; - unsigned long flags; - - if ((queue->flags & UVC_QUEUE_DROP_CORRUPTED) && buf->error) { - buf->error = 0; - buf->state = UVC_BUF_STATE_QUEUED; - buf->buf.bytesused = 0; - return buf; - } - - spin_lock_irqsave(&queue->irqlock, flags); - list_del(&buf->queue); - buf->error = 0; - buf->state = UVC_BUF_STATE_DONE; - if (!list_empty(&queue->irqqueue)) - nextbuf = list_first_entry(&queue->irqqueue, struct uvc_buffer, - queue); - else - nextbuf = NULL; - spin_unlock_irqrestore(&queue->irqlock, flags); - - wake_up(&buf->wait); - return nextbuf; -} - |
