![Klaus Schwarzkopf](/assets/img/avatar_default.png)
remove the following two paragraphs as they are not needed: This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc.,59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. Signed-off-by: Klaus Schwarzkopf <schwarzkopf@sensortherm.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
386 lines
9.4 KiB
C
386 lines
9.4 KiB
C
/*
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* uvc_video.c -- USB Video Class Gadget driver
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*
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* Copyright (C) 2009-2010
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* Laurent Pinchart (laurent.pinchart@ideasonboard.com)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <linux/kernel.h>
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#include <linux/device.h>
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#include <linux/errno.h>
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#include <linux/usb/ch9.h>
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#include <linux/usb/gadget.h>
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#include <media/v4l2-dev.h>
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#include "uvc.h"
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#include "uvc_queue.h"
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/* --------------------------------------------------------------------------
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* Video codecs
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*/
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static int
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uvc_video_encode_header(struct uvc_video *video, struct uvc_buffer *buf,
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u8 *data, int len)
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{
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data[0] = 2;
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data[1] = UVC_STREAM_EOH | video->fid;
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if (buf->buf.bytesused - video->queue.buf_used <= len - 2)
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data[1] |= UVC_STREAM_EOF;
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return 2;
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}
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static int
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uvc_video_encode_data(struct uvc_video *video, struct uvc_buffer *buf,
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u8 *data, int len)
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{
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struct uvc_video_queue *queue = &video->queue;
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unsigned int nbytes;
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void *mem;
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/* Copy video data to the USB buffer. */
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mem = queue->mem + buf->buf.m.offset + queue->buf_used;
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nbytes = min((unsigned int)len, buf->buf.bytesused - queue->buf_used);
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memcpy(data, mem, nbytes);
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queue->buf_used += nbytes;
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return nbytes;
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}
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static void
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uvc_video_encode_bulk(struct usb_request *req, struct uvc_video *video,
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struct uvc_buffer *buf)
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{
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void *mem = req->buf;
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int len = video->req_size;
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int ret;
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/* Add a header at the beginning of the payload. */
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if (video->payload_size == 0) {
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ret = uvc_video_encode_header(video, buf, mem, len);
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video->payload_size += ret;
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mem += ret;
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len -= ret;
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}
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/* Process video data. */
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len = min((int)(video->max_payload_size - video->payload_size), len);
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ret = uvc_video_encode_data(video, buf, mem, len);
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video->payload_size += ret;
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len -= ret;
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req->length = video->req_size - len;
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req->zero = video->payload_size == video->max_payload_size;
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if (buf->buf.bytesused == video->queue.buf_used) {
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video->queue.buf_used = 0;
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buf->state = UVC_BUF_STATE_DONE;
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uvc_queue_next_buffer(&video->queue, buf);
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video->fid ^= UVC_STREAM_FID;
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video->payload_size = 0;
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}
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if (video->payload_size == video->max_payload_size ||
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buf->buf.bytesused == video->queue.buf_used)
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video->payload_size = 0;
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}
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static void
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uvc_video_encode_isoc(struct usb_request *req, struct uvc_video *video,
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struct uvc_buffer *buf)
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{
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void *mem = req->buf;
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int len = video->req_size;
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int ret;
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/* Add the header. */
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ret = uvc_video_encode_header(video, buf, mem, len);
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mem += ret;
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len -= ret;
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/* Process video data. */
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ret = uvc_video_encode_data(video, buf, mem, len);
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len -= ret;
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req->length = video->req_size - len;
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if (buf->buf.bytesused == video->queue.buf_used) {
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video->queue.buf_used = 0;
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buf->state = UVC_BUF_STATE_DONE;
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uvc_queue_next_buffer(&video->queue, buf);
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video->fid ^= UVC_STREAM_FID;
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}
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}
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/* --------------------------------------------------------------------------
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* Request handling
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*/
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/*
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* I somehow feel that synchronisation won't be easy to achieve here. We have
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* three events that control USB requests submission:
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*
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* - USB request completion: the completion handler will resubmit the request
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* if a video buffer is available.
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*
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* - USB interface setting selection: in response to a SET_INTERFACE request,
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* the handler will start streaming if a video buffer is available and if
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* video is not currently streaming.
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*
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* - V4L2 buffer queueing: the driver will start streaming if video is not
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* currently streaming.
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*
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* Race conditions between those 3 events might lead to deadlocks or other
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* nasty side effects.
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*
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* The "video currently streaming" condition can't be detected by the irqqueue
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* being empty, as a request can still be in flight. A separate "queue paused"
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* flag is thus needed.
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*
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* The paused flag will be set when we try to retrieve the irqqueue head if the
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* queue is empty, and cleared when we queue a buffer.
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*
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* The USB request completion handler will get the buffer at the irqqueue head
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* under protection of the queue spinlock. If the queue is empty, the streaming
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* paused flag will be set. Right after releasing the spinlock a userspace
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* application can queue a buffer. The flag will then cleared, and the ioctl
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* handler will restart the video stream.
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*/
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static void
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uvc_video_complete(struct usb_ep *ep, struct usb_request *req)
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{
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struct uvc_video *video = req->context;
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struct uvc_buffer *buf;
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unsigned long flags;
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int ret;
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switch (req->status) {
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case 0:
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break;
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case -ESHUTDOWN:
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printk(KERN_INFO "VS request cancelled.\n");
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goto requeue;
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default:
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printk(KERN_INFO "VS request completed with status %d.\n",
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req->status);
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goto requeue;
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}
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spin_lock_irqsave(&video->queue.irqlock, flags);
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buf = uvc_queue_head(&video->queue);
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if (buf == NULL) {
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spin_unlock_irqrestore(&video->queue.irqlock, flags);
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goto requeue;
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}
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video->encode(req, video, buf);
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if ((ret = usb_ep_queue(ep, req, GFP_ATOMIC)) < 0) {
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printk(KERN_INFO "Failed to queue request (%d).\n", ret);
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usb_ep_set_halt(ep);
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spin_unlock_irqrestore(&video->queue.irqlock, flags);
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goto requeue;
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}
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spin_unlock_irqrestore(&video->queue.irqlock, flags);
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return;
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requeue:
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spin_lock_irqsave(&video->req_lock, flags);
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list_add_tail(&req->list, &video->req_free);
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spin_unlock_irqrestore(&video->req_lock, flags);
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}
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static int
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uvc_video_free_requests(struct uvc_video *video)
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{
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unsigned int i;
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for (i = 0; i < UVC_NUM_REQUESTS; ++i) {
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if (video->req[i]) {
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usb_ep_free_request(video->ep, video->req[i]);
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video->req[i] = NULL;
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}
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if (video->req_buffer[i]) {
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kfree(video->req_buffer[i]);
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video->req_buffer[i] = NULL;
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}
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}
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INIT_LIST_HEAD(&video->req_free);
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video->req_size = 0;
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return 0;
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}
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static int
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uvc_video_alloc_requests(struct uvc_video *video)
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{
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unsigned int i;
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int ret = -ENOMEM;
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BUG_ON(video->req_size);
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for (i = 0; i < UVC_NUM_REQUESTS; ++i) {
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video->req_buffer[i] = kmalloc(video->ep->maxpacket, GFP_KERNEL);
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if (video->req_buffer[i] == NULL)
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goto error;
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video->req[i] = usb_ep_alloc_request(video->ep, GFP_KERNEL);
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if (video->req[i] == NULL)
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goto error;
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video->req[i]->buf = video->req_buffer[i];
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video->req[i]->length = 0;
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video->req[i]->dma = DMA_ADDR_INVALID;
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video->req[i]->complete = uvc_video_complete;
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video->req[i]->context = video;
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list_add_tail(&video->req[i]->list, &video->req_free);
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}
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video->req_size = video->ep->maxpacket;
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return 0;
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error:
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uvc_video_free_requests(video);
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return ret;
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}
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/* --------------------------------------------------------------------------
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* Video streaming
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*/
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/*
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* uvc_video_pump - Pump video data into the USB requests
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*
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* This function fills the available USB requests (listed in req_free) with
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* video data from the queued buffers.
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*/
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static int
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uvc_video_pump(struct uvc_video *video)
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{
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struct usb_request *req;
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struct uvc_buffer *buf;
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unsigned long flags;
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int ret;
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/* FIXME TODO Race between uvc_video_pump and requests completion
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* handler ???
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*/
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while (1) {
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/* Retrieve the first available USB request, protected by the
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* request lock.
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*/
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spin_lock_irqsave(&video->req_lock, flags);
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if (list_empty(&video->req_free)) {
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spin_unlock_irqrestore(&video->req_lock, flags);
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return 0;
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}
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req = list_first_entry(&video->req_free, struct usb_request,
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list);
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list_del(&req->list);
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spin_unlock_irqrestore(&video->req_lock, flags);
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/* Retrieve the first available video buffer and fill the
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* request, protected by the video queue irqlock.
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*/
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spin_lock_irqsave(&video->queue.irqlock, flags);
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buf = uvc_queue_head(&video->queue);
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if (buf == NULL) {
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spin_unlock_irqrestore(&video->queue.irqlock, flags);
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break;
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}
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video->encode(req, video, buf);
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/* Queue the USB request */
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if ((ret = usb_ep_queue(video->ep, req, GFP_KERNEL)) < 0) {
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printk(KERN_INFO "Failed to queue request (%d)\n", ret);
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usb_ep_set_halt(video->ep);
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spin_unlock_irqrestore(&video->queue.irqlock, flags);
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break;
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}
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spin_unlock_irqrestore(&video->queue.irqlock, flags);
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}
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spin_lock_irqsave(&video->req_lock, flags);
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list_add_tail(&req->list, &video->req_free);
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spin_unlock_irqrestore(&video->req_lock, flags);
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return 0;
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}
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/*
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* Enable or disable the video stream.
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*/
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static int
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uvc_video_enable(struct uvc_video *video, int enable)
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{
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unsigned int i;
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int ret;
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if (video->ep == NULL) {
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printk(KERN_INFO "Video enable failed, device is "
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"uninitialized.\n");
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return -ENODEV;
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}
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if (!enable) {
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for (i = 0; i < UVC_NUM_REQUESTS; ++i)
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usb_ep_dequeue(video->ep, video->req[i]);
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uvc_video_free_requests(video);
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uvc_queue_enable(&video->queue, 0);
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return 0;
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}
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if ((ret = uvc_queue_enable(&video->queue, 1)) < 0)
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return ret;
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if ((ret = uvc_video_alloc_requests(video)) < 0)
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return ret;
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if (video->max_payload_size) {
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video->encode = uvc_video_encode_bulk;
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video->payload_size = 0;
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} else
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video->encode = uvc_video_encode_isoc;
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return uvc_video_pump(video);
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}
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/*
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* Initialize the UVC video stream.
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*/
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static int
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uvc_video_init(struct uvc_video *video)
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{
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INIT_LIST_HEAD(&video->req_free);
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spin_lock_init(&video->req_lock);
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video->fcc = V4L2_PIX_FMT_YUYV;
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video->bpp = 16;
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video->width = 320;
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video->height = 240;
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video->imagesize = 320 * 240 * 2;
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/* Initialize the video buffers queue. */
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uvc_queue_init(&video->queue, V4L2_BUF_TYPE_VIDEO_OUTPUT);
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return 0;
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}
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