diff options
Diffstat (limited to 'drivers/usb/gadget/uvc_video.c')
| -rw-r--r-- | drivers/usb/gadget/uvc_video.c | 386 |
1 files changed, 386 insertions, 0 deletions
diff --git a/drivers/usb/gadget/uvc_video.c b/drivers/usb/gadget/uvc_video.c new file mode 100644 index 00000000000..de8cbc46518 --- /dev/null +++ b/drivers/usb/gadget/uvc_video.c @@ -0,0 +1,386 @@ +/* + * uvc_video.c -- USB Video Class Gadget driver + * + * Copyright (C) 2009-2010 + * 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/device.h> +#include <linux/errno.h> +#include <linux/usb/ch9.h> +#include <linux/usb/gadget.h> + +#include <media/v4l2-dev.h> + +#include "uvc.h" +#include "uvc_queue.h" + +/* -------------------------------------------------------------------------- + * Video codecs + */ + +static int +uvc_video_encode_header(struct uvc_video *video, struct uvc_buffer *buf, + u8 *data, int len) +{ + data[0] = 2; + data[1] = UVC_STREAM_EOH | video->fid; + + if (buf->buf.bytesused - video->queue.buf_used <= len - 2) + data[1] |= UVC_STREAM_EOF; + + return 2; +} + +static int +uvc_video_encode_data(struct uvc_video *video, struct uvc_buffer *buf, + u8 *data, int len) +{ + struct uvc_video_queue *queue = &video->queue; + unsigned int nbytes; + void *mem; + + /* Copy video data to the USB buffer. */ + mem = queue->mem + buf->buf.m.offset + queue->buf_used; + nbytes = min((unsigned int)len, buf->buf.bytesused - queue->buf_used); + + memcpy(data, mem, nbytes); + queue->buf_used += nbytes; + + return nbytes; +} + +static void +uvc_video_encode_bulk(struct usb_request *req, struct uvc_video *video, + struct uvc_buffer *buf) +{ + void *mem = req->buf; + int len = video->req_size; + int ret; + + /* Add a header at the beginning of the payload. */ + if (video->payload_size == 0) { + ret = uvc_video_encode_header(video, buf, mem, len); + video->payload_size += ret; + mem += ret; + len -= ret; + } + + /* Process video data. */ + len = min((int)(video->max_payload_size - video->payload_size), len); + ret = uvc_video_encode_data(video, buf, mem, len); + + video->payload_size += ret; + len -= ret; + + req->length = video->req_size - len; + req->zero = video->payload_size == video->max_payload_size; + + if (buf->buf.bytesused == video->queue.buf_used) { + video->queue.buf_used = 0; + buf->state = UVC_BUF_STATE_DONE; + uvc_queue_next_buffer(&video->queue, buf); + video->fid ^= UVC_STREAM_FID; + + video->payload_size = 0; + } + + if (video->payload_size == video->max_payload_size || + buf->buf.bytesused == video->queue.buf_used) + video->payload_size = 0; +} + +static void +uvc_video_encode_isoc(struct usb_request *req, struct uvc_video *video, + struct uvc_buffer *buf) +{ + void *mem = req->buf; + int len = video->req_size; + int ret; + + /* Add the header. */ + ret = uvc_video_encode_header(video, buf, mem, len); + mem += ret; + len -= ret; + + /* Process video data. */ + ret = uvc_video_encode_data(video, buf, mem, len); + len -= ret; + + req->length = video->req_size - len; + + if (buf->buf.bytesused == video->queue.buf_used) { + video->queue.buf_used = 0; + buf->state = UVC_BUF_STATE_DONE; + uvc_queue_next_buffer(&video->queue, buf); + video->fid ^= UVC_STREAM_FID; + } +} + +/* -------------------------------------------------------------------------- + * Request handling + */ + +/* + * I somehow feel that synchronisation won't be easy to achieve here. We have + * three events that control USB requests submission: + * + * - USB request completion: the completion handler will resubmit the request + * if a video buffer is available. + * + * - USB interface setting selection: in response to a SET_INTERFACE request, + * the handler will start streaming if a video buffer is available and if + * video is not currently streaming. + * + * - V4L2 buffer queueing: the driver will start streaming if video is not + * currently streaming. + * + * Race conditions between those 3 events might lead to deadlocks or other + * nasty side effects. + * + * The "video currently streaming" condition can't be detected by the irqqueue + * being empty, as a request can still be in flight. A separate "queue paused" + * flag is thus needed. + * + * The paused flag will be set when we try to retrieve the irqqueue head if the + * queue is empty, and cleared when we queue a buffer. + * + * The USB request completion handler will get the buffer at the irqqueue head + * under protection of the queue spinlock. If the queue is empty, the streaming + * paused flag will be set. Right after releasing the spinlock a userspace + * application can queue a buffer. The flag will then cleared, and the ioctl + * handler will restart the video stream. + */ +static void +uvc_video_complete(struct usb_ep *ep, struct usb_request *req) +{ + struct uvc_video *video = req->context; + struct uvc_buffer *buf; + unsigned long flags; + int ret; + + switch (req->status) { + case 0: + break; + + case -ESHUTDOWN: + printk(KERN_INFO "VS request cancelled.\n"); + goto requeue; + + default: + printk(KERN_INFO "VS request completed with status %d.\n", + req->status); + goto requeue; + } + + spin_lock_irqsave(&video->queue.irqlock, flags); + buf = uvc_queue_head(&video->queue); + if (buf == NULL) { + spin_unlock_irqrestore(&video->queue.irqlock, flags); + goto requeue; + } + + video->encode(req, video, buf); + + if ((ret = usb_ep_queue(ep, req, GFP_ATOMIC)) < 0) { + printk(KERN_INFO "Failed to queue request (%d).\n", ret); + usb_ep_set_halt(ep); + spin_unlock_irqrestore(&video->queue.irqlock, flags); + goto requeue; + } + spin_unlock_irqrestore(&video->queue.irqlock, flags); + + return; + +requeue: + spin_lock_irqsave(&video->req_lock, flags); + list_add_tail(&req->list, &video->req_free); + spin_unlock_irqrestore(&video->req_lock, flags); +} + +static int +uvc_video_free_requests(struct uvc_video *video) +{ + unsigned int i; + + for (i = 0; i < UVC_NUM_REQUESTS; ++i) { + if (video->req[i]) { + usb_ep_free_request(video->ep, video->req[i]); + video->req[i] = NULL; + } + + if (video->req_buffer[i]) { + kfree(video->req_buffer[i]); + video->req_buffer[i] = NULL; + } + } + + INIT_LIST_HEAD(&video->req_free); + video->req_size = 0; + return 0; +} + +static int +uvc_video_alloc_requests(struct uvc_video *video) +{ + unsigned int i; + int ret = -ENOMEM; + + BUG_ON(video->req_size); + + for (i = 0; i < UVC_NUM_REQUESTS; ++i) { + video->req_buffer[i] = kmalloc(video->ep->maxpacket, GFP_KERNEL); + if (video->req_buffer[i] == NULL) + goto error; + + video->req[i] = usb_ep_alloc_request(video->ep, GFP_KERNEL); + if (video->req[i] == NULL) + goto error; + + video->req[i]->buf = video->req_buffer[i]; + video->req[i]->length = 0; + video->req[i]->dma = DMA_ADDR_INVALID; + video->req[i]->complete = uvc_video_complete; + video->req[i]->context = video; + + list_add_tail(&video->req[i]->list, &video->req_free); + } + + video->req_size = video->ep->maxpacket; + return 0; + +error: + uvc_video_free_requests(video); + return ret; +} + +/* -------------------------------------------------------------------------- + * Video streaming + */ + +/* + * uvc_video_pump - Pump video data into the USB requests + * + * This function fills the available USB requests (listed in req_free) with + * video data from the queued buffers. + */ +int +uvc_video_pump(struct uvc_video *video) +{ + struct usb_request *req; + struct uvc_buffer *buf; + unsigned long flags; + int ret; + + /* FIXME TODO Race between uvc_video_pump and requests completion + * handler ??? + */ + + while (1) { + /* Retrieve the first available USB request, protected by the + * request lock. + */ + spin_lock_irqsave(&video->req_lock, flags); + if (list_empty(&video->req_free)) { + spin_unlock_irqrestore(&video->req_lock, flags); + return 0; + } + req = list_first_entry(&video->req_free, struct usb_request, + list); + list_del(&req->list); + spin_unlock_irqrestore(&video->req_lock, flags); + + /* Retrieve the first available video buffer and fill the + * request, protected by the video queue irqlock. + */ + spin_lock_irqsave(&video->queue.irqlock, flags); + buf = uvc_queue_head(&video->queue); + if (buf == NULL) { + spin_unlock_irqrestore(&video->queue.irqlock, flags); + break; + } + + video->encode(req, video, buf); + + /* Queue the USB request */ + if ((ret = usb_ep_queue(video->ep, req, GFP_KERNEL)) < 0) { + printk(KERN_INFO "Failed to queue request (%d)\n", ret); + usb_ep_set_halt(video->ep); + spin_unlock_irqrestore(&video->queue.irqlock, flags); + break; + } + spin_unlock_irqrestore(&video->queue.irqlock, flags); + } + + spin_lock_irqsave(&video->req_lock, flags); + list_add_tail(&req->list, &video->req_free); + spin_unlock_irqrestore(&video->req_lock, flags); + return 0; +} + +/* + * Enable or disable the video stream. + */ +int +uvc_video_enable(struct uvc_video *video, int enable) +{ + unsigned int i; + int ret; + + if (video->ep == NULL) { + printk(KERN_INFO "Video enable failed, device is " + "uninitialized.\n"); + return -ENODEV; + } + + if (!enable) { + for (i = 0; i < UVC_NUM_REQUESTS; ++i) + usb_ep_dequeue(video->ep, video->req[i]); + + uvc_video_free_requests(video); + uvc_queue_enable(&video->queue, 0); + return 0; + } + + if ((ret = uvc_queue_enable(&video->queue, 1)) < 0) + return ret; + + if ((ret = uvc_video_alloc_requests(video)) < 0) + return ret; + + if (video->max_payload_size) { + video->encode = uvc_video_encode_bulk; + video->payload_size = 0; + } else + video->encode = uvc_video_encode_isoc; + + return uvc_video_pump(video); +} + +/* + * Initialize the UVC video stream. + */ +int +uvc_video_init(struct uvc_video *video) +{ + INIT_LIST_HEAD(&video->req_free); + spin_lock_init(&video->req_lock); + + video->fcc = V4L2_PIX_FMT_YUYV; + video->bpp = 16; + video->width = 320; + video->height = 240; + video->imagesize = 320 * 240 * 2; + + /* Initialize the video buffers queue. */ + uvc_queue_init(&video->queue, V4L2_BUF_TYPE_VIDEO_OUTPUT); + return 0; +} + |