[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / usb / gadget / uvc_video.c

/*
 *	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.
 */
static 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.
 */
static 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.
 */
static 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;
}
Commit	Line	Data
cdda479f LP	1	/*
	2	* uvc_video.c -- USB Video Class Gadget driver
	3	*
	4	* Copyright (C) 2009-2010
	5	* Laurent Pinchart (laurent.pinchart@ideasonboard.com)
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License as published by
	9	* the Free Software Foundation; either version 2 of the License, or
	10	* (at your option) any later version.
cdda479f LP	11	*/
	12
	13	#include <linux/kernel.h>
	14	#include <linux/device.h>
	15	#include <linux/errno.h>
	16	#include <linux/usb/ch9.h>
	17	#include <linux/usb/gadget.h>
	18
	19	#include <media/v4l2-dev.h>
	20
	21	#include "uvc.h"
	22	#include "uvc_queue.h"
	23
	24	/* --------------------------------------------------------------------------
	25	* Video codecs
	26	*/
	27
	28	static int
	29	uvc_video_encode_header(struct uvc_video video, struct uvc_buffer buf,
	30	u8 *data, int len)
	31	{
	32	data[0] = 2;
	33	data[1] = UVC_STREAM_EOH \| video->fid;
	34
	35	if (buf->buf.bytesused - video->queue.buf_used <= len - 2)
	36	data[1] \|= UVC_STREAM_EOF;
	37
	38	return 2;
	39	}
	40
	41	static int
	42	uvc_video_encode_data(struct uvc_video video, struct uvc_buffer buf,
	43	u8 *data, int len)
	44	{
	45	struct uvc_video_queue *queue = &video->queue;
	46	unsigned int nbytes;
	47	void *mem;
	48
	49	/* Copy video data to the USB buffer. */
	50	mem = queue->mem + buf->buf.m.offset + queue->buf_used;
	51	nbytes = min((unsigned int)len, buf->buf.bytesused - queue->buf_used);
	52
	53	memcpy(data, mem, nbytes);
	54	queue->buf_used += nbytes;
	55
	56	return nbytes;
	57	}
	58
	59	static void
	60	uvc_video_encode_bulk(struct usb_request req, struct uvc_video video,
	61	struct uvc_buffer *buf)
	62	{
	63	void *mem = req->buf;
	64	int len = video->req_size;
	65	int ret;
	66
	67	/* Add a header at the beginning of the payload. */
	68	if (video->payload_size == 0) {
	69	ret = uvc_video_encode_header(video, buf, mem, len);
	70	video->payload_size += ret;
	71	mem += ret;
	72	len -= ret;
	73	}
	74
75	/* Process video data. */
76	len = min((int)(video->max_payload_size - video->payload_size), len);
77	ret = uvc_video_encode_data(video, buf, mem, len);
78
79	video->payload_size += ret;
80	len -= ret;
81
82	req->length = video->req_size - len;
83	req->zero = video->payload_size == video->max_payload_size;
84
85	if (buf->buf.bytesused == video->queue.buf_used) {
86	video->queue.buf_used = 0;
87	buf->state = UVC_BUF_STATE_DONE;
88	uvc_queue_next_buffer(&video->queue, buf);
89	video->fid ^= UVC_STREAM_FID;
90
91	video->payload_size = 0;
92	}
93
94	if (video->payload_size == video->max_payload_size \|\|
95	buf->buf.bytesused == video->queue.buf_used)
96	video->payload_size = 0;
97	}
98
99	static void
100	uvc_video_encode_isoc(struct usb_request req, struct uvc_video video,
101	struct uvc_buffer *buf)
102	{
103	void *mem = req->buf;
104	int len = video->req_size;
105	int ret;
106
107	/* Add the header. */
108	ret = uvc_video_encode_header(video, buf, mem, len);
109	mem += ret;
110	len -= ret;
111
112	/* Process video data. */
113	ret = uvc_video_encode_data(video, buf, mem, len);
114	len -= ret;
115
116	req->length = video->req_size - len;
117
118	if (buf->buf.bytesused == video->queue.buf_used) {
119	video->queue.buf_used = 0;
120	buf->state = UVC_BUF_STATE_DONE;
121	uvc_queue_next_buffer(&video->queue, buf);
122	video->fid ^= UVC_STREAM_FID;
123	}
124	}
125
126	/* --------------------------------------------------------------------------
127	* Request handling
128	*/
129
130	/*
131	* I somehow feel that synchronisation won't be easy to achieve here. We have
132	* three events that control USB requests submission:
133	*
134	* - USB request completion: the completion handler will resubmit the request
135	* if a video buffer is available.
136	*
137	* - USB interface setting selection: in response to a SET_INTERFACE request,
138	* the handler will start streaming if a video buffer is available and if
139	* video is not currently streaming.
140	*
141	* - V4L2 buffer queueing: the driver will start streaming if video is not
142	* currently streaming.
143	*
144	* Race conditions between those 3 events might lead to deadlocks or other
145	* nasty side effects.
146	*
147	* The "video currently streaming" condition can't be detected by the irqqueue
148	* being empty, as a request can still be in flight. A separate "queue paused"
149	* flag is thus needed.
150	*
151	* The paused flag will be set when we try to retrieve the irqqueue head if the
152	* queue is empty, and cleared when we queue a buffer.
153	*
154	* The USB request completion handler will get the buffer at the irqqueue head
155	* under protection of the queue spinlock. If the queue is empty, the streaming
156	* paused flag will be set. Right after releasing the spinlock a userspace
157	* application can queue a buffer. The flag will then cleared, and the ioctl
158	* handler will restart the video stream.
159	*/
160	static void
161	uvc_video_complete(struct usb_ep ep, struct usb_request req)
162	{
163	struct uvc_video *video = req->context;
164	struct uvc_buffer *buf;
165	unsigned long flags;
166	int ret;
167
168	switch (req->status) {
169	case 0:
170	break;
171
172	case -ESHUTDOWN:
173	printk(KERN_INFO "VS request cancelled.\n");
174	goto requeue;
175
176	default:
177	printk(KERN_INFO "VS request completed with status %d.\n",
178	req->status);
179	goto requeue;
180	}
181
182	spin_lock_irqsave(&video->queue.irqlock, flags);
183	buf = uvc_queue_head(&video->queue);
184	if (buf == NULL) {
185	spin_unlock_irqrestore(&video->queue.irqlock, flags);
186	goto requeue;
187	}
188
189	video->encode(req, video, buf);
190
191	if ((ret = usb_ep_queue(ep, req, GFP_ATOMIC)) < 0) {
192	printk(KERN_INFO "Failed to queue request (%d).\n", ret);
193	usb_ep_set_halt(ep);
194	spin_unlock_irqrestore(&video->queue.irqlock, flags);
195	goto requeue;
196	}
197	spin_unlock_irqrestore(&video->queue.irqlock, flags);
198
199	return;
200
201	requeue:
202	spin_lock_irqsave(&video->req_lock, flags);
203	list_add_tail(&req->list, &video->req_free);
204	spin_unlock_irqrestore(&video->req_lock, flags);
205	}
206
207	static int
208	uvc_video_free_requests(struct uvc_video *video)
209	{
210	unsigned int i;
211
212	for (i = 0; i < UVC_NUM_REQUESTS; ++i) {
213	if (video->req[i]) {
214	usb_ep_free_request(video->ep, video->req[i]);
215	video->req[i] = NULL;
216	}
217
218	if (video->req_buffer[i]) {
219	kfree(video->req_buffer[i]);
220	video->req_buffer[i] = NULL;
221	}
222	}
223
224	INIT_LIST_HEAD(&video->req_free);
225	video->req_size = 0;
226	return 0;
227	}
228
229	static int
230	uvc_video_alloc_requests(struct uvc_video *video)
231	{
232	unsigned int i;
233	int ret = -ENOMEM;
234
235	BUG_ON(video->req_size);
236
237	for (i = 0; i < UVC_NUM_REQUESTS; ++i) {
238	video->req_buffer[i] = kmalloc(video->ep->maxpacket, GFP_KERNEL);
239	if (video->req_buffer[i] == NULL)
240	goto error;
241
242	video->req[i] = usb_ep_alloc_request(video->ep, GFP_KERNEL);
243	if (video->req[i] == NULL)
244	goto error;
245
246	video->req[i]->buf = video->req_buffer[i];
247	video->req[i]->length = 0;
248	video->req[i]->dma = DMA_ADDR_INVALID;
249	video->req[i]->complete = uvc_video_complete;
250	video->req[i]->context = video;
251
252	list_add_tail(&video->req[i]->list, &video->req_free);
253	}
254
255	video->req_size = video->ep->maxpacket;
256	return 0;
257
258	error:
259	uvc_video_free_requests(video);
260	return ret;
261	}
262
263	/* --------------------------------------------------------------------------
264	* Video streaming
265	*/
266
267	/*
268	* uvc_video_pump - Pump video data into the USB requests
269	*
270	* This function fills the available USB requests (listed in req_free) with
271	* video data from the queued buffers.
272	*/
5d9955f8	273	static int
cdda479f LP	274	uvc_video_pump(struct uvc_video *video)
	275	{
	276	struct usb_request *req;
	277	struct uvc_buffer *buf;
	278	unsigned long flags;
	279	int ret;
	280
	281	/* FIXME TODO Race between uvc_video_pump and requests completion
	282	* handler ???
	283	*/
	284
	285	while (1) {
	286	/* Retrieve the first available USB request, protected by the
	287	* request lock.
	288	*/
	289	spin_lock_irqsave(&video->req_lock, flags);
	290	if (list_empty(&video->req_free)) {
	291	spin_unlock_irqrestore(&video->req_lock, flags);
	292	return 0;
	293	}
	294	req = list_first_entry(&video->req_free, struct usb_request,
	295	list);
	296	list_del(&req->list);
	297	spin_unlock_irqrestore(&video->req_lock, flags);
	298
	299	/* Retrieve the first available video buffer and fill the
	300	* request, protected by the video queue irqlock.
	301	*/
	302	spin_lock_irqsave(&video->queue.irqlock, flags);
	303	buf = uvc_queue_head(&video->queue);
	304	if (buf == NULL) {
	305	spin_unlock_irqrestore(&video->queue.irqlock, flags);
	306	break;
	307	}
	308
	309	video->encode(req, video, buf);
	310
	311	/* Queue the USB request */
	312	if ((ret = usb_ep_queue(video->ep, req, GFP_KERNEL)) < 0) {
	313	printk(KERN_INFO "Failed to queue request (%d)\n", ret);
	314	usb_ep_set_halt(video->ep);
	315	spin_unlock_irqrestore(&video->queue.irqlock, flags);
	316	break;
	317	}
	318	spin_unlock_irqrestore(&video->queue.irqlock, flags);
	319	}
	320
	321	spin_lock_irqsave(&video->req_lock, flags);
	322	list_add_tail(&req->list, &video->req_free);
	323	spin_unlock_irqrestore(&video->req_lock, flags);
	324	return 0;
	325	}
	326
	327	/*
	328	* Enable or disable the video stream.
	329	*/
5d9955f8	330	static int
cdda479f LP	331	uvc_video_enable(struct uvc_video *video, int enable)
	332	{
	333	unsigned int i;
	334	int ret;
	335
	336	if (video->ep == NULL) {
	337	printk(KERN_INFO "Video enable failed, device is "
	338	"uninitialized.\n");
	339	return -ENODEV;
	340	}
	341
	342	if (!enable) {
	343	for (i = 0; i < UVC_NUM_REQUESTS; ++i)
	344	usb_ep_dequeue(video->ep, video->req[i]);
	345
	346	uvc_video_free_requests(video);
	347	uvc_queue_enable(&video->queue, 0);
	348	return 0;
	349	}
	350
	351	if ((ret = uvc_queue_enable(&video->queue, 1)) < 0)
	352	return ret;
	353
	354	if ((ret = uvc_video_alloc_requests(video)) < 0)
	355	return ret;
	356
	357	if (video->max_payload_size) {
	358	video->encode = uvc_video_encode_bulk;
	359	video->payload_size = 0;
	360	} else
	361	video->encode = uvc_video_encode_isoc;
	362
	363	return uvc_video_pump(video);
	364	}
	365
	366	/*
	367	* Initialize the UVC video stream.
	368	*/
5d9955f8	369	static int
cdda479f LP	370	uvc_video_init(struct uvc_video *video)
	371	{
	372	INIT_LIST_HEAD(&video->req_free);
	373	spin_lock_init(&video->req_lock);
	374
	375	video->fcc = V4L2_PIX_FMT_YUYV;
	376	video->bpp = 16;
	377	video->width = 320;
	378	video->height = 240;
	379	video->imagesize = 320 * 240 * 2;
	380
	381	/* Initialize the video buffers queue. */
	382	uvc_queue_init(&video->queue, V4L2_BUF_TYPE_VIDEO_OUTPUT);
	383	return 0;
	384	}
	385