1 /*
2  * STK1160 driver
3  *
4  * Copyright (C) 2012 Ezequiel Garcia
5  * <elezegarcia--a.t--gmail.com>
6  *
7  * Based on Easycap driver by R.M. Thomas
8  *	Copyright (C) 2010 R.M. Thomas
9  *	<rmthomas--a.t--sciolus.org>
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation; either version 2 of the License, or
14  * (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU General Public License for more details.
20  *
21  */
22 
23 #include <linux/module.h>
24 #include <linux/usb.h>
25 #include <linux/slab.h>
26 #include <linux/ratelimit.h>
27 
28 #include "stk1160.h"
29 
30 static unsigned int debug;
31 module_param(debug, int, 0644);
32 MODULE_PARM_DESC(debug, "enable debug messages");
33 
34 static inline void print_err_status(struct stk1160 *dev,
35 				     int packet, int status)
36 {
37 	char *errmsg = "Unknown";
38 
39 	switch (status) {
40 	case -ENOENT:
41 		errmsg = "unlinked synchronuously";
42 		break;
43 	case -ECONNRESET:
44 		errmsg = "unlinked asynchronuously";
45 		break;
46 	case -ENOSR:
47 		errmsg = "Buffer error (overrun)";
48 		break;
49 	case -EPIPE:
50 		errmsg = "Stalled (device not responding)";
51 		break;
52 	case -EOVERFLOW:
53 		errmsg = "Babble (bad cable?)";
54 		break;
55 	case -EPROTO:
56 		errmsg = "Bit-stuff error (bad cable?)";
57 		break;
58 	case -EILSEQ:
59 		errmsg = "CRC/Timeout (could be anything)";
60 		break;
61 	case -ETIME:
62 		errmsg = "Device does not respond";
63 		break;
64 	}
65 
66 	if (packet < 0)
67 		printk_ratelimited(KERN_WARNING "URB status %d [%s].\n",
68 				status, errmsg);
69 	else
70 		printk_ratelimited(KERN_INFO "URB packet %d, status %d [%s].\n",
71 			       packet, status, errmsg);
72 }
73 
74 static inline
75 struct stk1160_buffer *stk1160_next_buffer(struct stk1160 *dev)
76 {
77 	struct stk1160_buffer *buf = NULL;
78 	unsigned long flags = 0;
79 
80 	/* Current buffer must be NULL when this functions gets called */
81 	WARN_ON(dev->isoc_ctl.buf);
82 
83 	spin_lock_irqsave(&dev->buf_lock, flags);
84 	if (!list_empty(&dev->avail_bufs)) {
85 		buf = list_first_entry(&dev->avail_bufs,
86 				struct stk1160_buffer, list);
87 		list_del(&buf->list);
88 	}
89 	spin_unlock_irqrestore(&dev->buf_lock, flags);
90 
91 	return buf;
92 }
93 
94 static inline
95 void stk1160_buffer_done(struct stk1160 *dev)
96 {
97 	struct stk1160_buffer *buf = dev->isoc_ctl.buf;
98 
99 	buf->vb.v4l2_buf.sequence = dev->sequence++;
100 	buf->vb.v4l2_buf.field = V4L2_FIELD_INTERLACED;
101 	buf->vb.v4l2_buf.bytesused = buf->bytesused;
102 	v4l2_get_timestamp(&buf->vb.v4l2_buf.timestamp);
103 
104 	vb2_set_plane_payload(&buf->vb, 0, buf->bytesused);
105 	vb2_buffer_done(&buf->vb, VB2_BUF_STATE_DONE);
106 
107 	dev->isoc_ctl.buf = NULL;
108 }
109 
110 static inline
111 void stk1160_copy_video(struct stk1160 *dev, u8 *src, int len)
112 {
113 	int linesdone, lineoff, lencopy;
114 	int bytesperline = dev->width * 2;
115 	struct stk1160_buffer *buf = dev->isoc_ctl.buf;
116 	u8 *dst = buf->mem;
117 	int remain;
118 
119 	/*
120 	 * TODO: These stk1160_dbg are very spammy!
121 	 * We should 1) check why we are getting them
122 	 * and 2) add ratelimit.
123 	 *
124 	 * UPDATE: One of the reasons (the only one?) for getting these
125 	 * is incorrect standard (mismatch between expected and configured).
126 	 * So perhaps, we could add a counter for errors. When the counter
127 	 * reaches some value, we simply stop streaming.
128 	 */
129 
130 	len -= 4;
131 	src += 4;
132 
133 	remain = len;
134 
135 	linesdone = buf->pos / bytesperline;
136 	lineoff = buf->pos % bytesperline; /* offset in current line */
137 
138 	if (!buf->odd)
139 		dst += bytesperline;
140 
141 	/* Multiply linesdone by two, to take account of the other field */
142 	dst += linesdone * bytesperline * 2 + lineoff;
143 
144 	/* Copy the remaining of current line */
145 	if (remain < (bytesperline - lineoff))
146 		lencopy = remain;
147 	else
148 		lencopy = bytesperline - lineoff;
149 
150 	/*
151 	 * Check if we have enough space left in the buffer.
152 	 * In that case, we force loop exit after copy.
153 	 */
154 	if (lencopy > buf->bytesused - buf->length) {
155 		lencopy = buf->bytesused - buf->length;
156 		remain = lencopy;
157 	}
158 
159 	/* Check if the copy is done */
160 	if (lencopy == 0 || remain == 0)
161 		return;
162 
163 	/* Let the bug hunt begin! sanity checks! */
164 	if (lencopy < 0) {
165 		stk1160_dbg("copy skipped: negative lencopy\n");
166 		return;
167 	}
168 
169 	if ((unsigned long)dst + lencopy >
170 		(unsigned long)buf->mem + buf->length) {
171 		printk_ratelimited(KERN_WARNING "stk1160: buffer overflow detected\n");
172 		return;
173 	}
174 
175 	memcpy(dst, src, lencopy);
176 
177 	buf->bytesused += lencopy;
178 	buf->pos += lencopy;
179 	remain -= lencopy;
180 
181 	/* Copy current field line by line, interlacing with the other field */
182 	while (remain > 0) {
183 
184 		dst += lencopy + bytesperline;
185 		src += lencopy;
186 
187 		/* Copy one line at a time */
188 		if (remain < bytesperline)
189 			lencopy = remain;
190 		else
191 			lencopy = bytesperline;
192 
193 		/*
194 		 * Check if we have enough space left in the buffer.
195 		 * In that case, we force loop exit after copy.
196 		 */
197 		if (lencopy > buf->bytesused - buf->length) {
198 			lencopy = buf->bytesused - buf->length;
199 			remain = lencopy;
200 		}
201 
202 		/* Check if the copy is done */
203 		if (lencopy == 0 || remain == 0)
204 			return;
205 
206 		if (lencopy < 0) {
207 			printk_ratelimited(KERN_WARNING "stk1160: negative lencopy detected\n");
208 			return;
209 		}
210 
211 		if ((unsigned long)dst + lencopy >
212 			(unsigned long)buf->mem + buf->length) {
213 			printk_ratelimited(KERN_WARNING "stk1160: buffer overflow detected\n");
214 			return;
215 		}
216 
217 		memcpy(dst, src, lencopy);
218 		remain -= lencopy;
219 
220 		buf->bytesused += lencopy;
221 		buf->pos += lencopy;
222 	}
223 }
224 
225 /*
226  * Controls the isoc copy of each urb packet
227  */
228 static void stk1160_process_isoc(struct stk1160 *dev, struct urb *urb)
229 {
230 	int i, len, status;
231 	u8 *p;
232 
233 	if (!dev) {
234 		stk1160_warn("%s called with null device\n", __func__);
235 		return;
236 	}
237 
238 	if (urb->status < 0) {
239 		/* Print status and drop current packet (or field?) */
240 		print_err_status(dev, -1, urb->status);
241 		return;
242 	}
243 
244 	for (i = 0; i < urb->number_of_packets; i++) {
245 		status = urb->iso_frame_desc[i].status;
246 		if (status < 0) {
247 			print_err_status(dev, i, status);
248 			continue;
249 		}
250 
251 		/* Get packet actual length and pointer to data */
252 		p = urb->transfer_buffer + urb->iso_frame_desc[i].offset;
253 		len = urb->iso_frame_desc[i].actual_length;
254 
255 		/* Empty packet */
256 		if (len <= 4)
257 			continue;
258 
259 		/*
260 		 * An 8-byte packet sequence means end of field.
261 		 * So if we don't have any packet, we start receiving one now
262 		 * and if we do have a packet, then we are done with it.
263 		 *
264 		 * These end of field packets are always 0xc0 or 0x80,
265 		 * but not always 8-byte long so we don't check packet length.
266 		 */
267 		if (p[0] == 0xc0) {
268 
269 			/*
270 			 * If first byte is 0xc0 then we received
271 			 * second field, and frame has ended.
272 			 */
273 			if (dev->isoc_ctl.buf != NULL)
274 				stk1160_buffer_done(dev);
275 
276 			dev->isoc_ctl.buf = stk1160_next_buffer(dev);
277 			if (dev->isoc_ctl.buf == NULL)
278 				return;
279 		}
280 
281 		/*
282 		 * If we don't have a buffer here, then it means we
283 		 * haven't found the start mark sequence.
284 		 */
285 		if (dev->isoc_ctl.buf == NULL)
286 			continue;
287 
288 		if (p[0] == 0xc0 || p[0] == 0x80) {
289 
290 			/* We set next packet parity and
291 			 * continue to get next one
292 			 */
293 			dev->isoc_ctl.buf->odd = *p & 0x40;
294 			dev->isoc_ctl.buf->pos = 0;
295 			continue;
296 		}
297 
298 		stk1160_copy_video(dev, p, len);
299 	}
300 }
301 
302 
303 /*
304  * IRQ callback, called by URB callback
305  */
306 static void stk1160_isoc_irq(struct urb *urb)
307 {
308 	int i, rc;
309 	struct stk1160 *dev = urb->context;
310 
311 	switch (urb->status) {
312 	case 0:
313 		break;
314 	case -ECONNRESET:   /* kill */
315 	case -ENOENT:
316 	case -ESHUTDOWN:
317 		/* TODO: check uvc driver: he frees the queue here */
318 		return;
319 	default:
320 		stk1160_err("urb error! status %d\n", urb->status);
321 		return;
322 	}
323 
324 	stk1160_process_isoc(dev, urb);
325 
326 	/* Reset urb buffers */
327 	for (i = 0; i < urb->number_of_packets; i++) {
328 		urb->iso_frame_desc[i].status = 0;
329 		urb->iso_frame_desc[i].actual_length = 0;
330 	}
331 
332 	rc = usb_submit_urb(urb, GFP_ATOMIC);
333 	if (rc)
334 		stk1160_err("urb re-submit failed (%d)\n", rc);
335 }
336 
337 /*
338  * Cancel urbs
339  * This function can't be called in atomic context
340  */
341 void stk1160_cancel_isoc(struct stk1160 *dev)
342 {
343 	int i, num_bufs = dev->isoc_ctl.num_bufs;
344 
345 	/*
346 	 * This check is not necessary, but we add it
347 	 * to avoid a spurious debug message
348 	 */
349 	if (!num_bufs)
350 		return;
351 
352 	stk1160_dbg("killing %d urbs...\n", num_bufs);
353 
354 	for (i = 0; i < num_bufs; i++) {
355 
356 		/*
357 		 * To kill urbs we can't be in atomic context.
358 		 * We don't care for NULL pointer since
359 		 * usb_kill_urb allows it.
360 		 */
361 		usb_kill_urb(dev->isoc_ctl.urb[i]);
362 	}
363 
364 	stk1160_dbg("all urbs killed\n");
365 }
366 
367 /*
368  * Releases urb and transfer buffers
369  * Obviusly, associated urb must be killed before releasing it.
370  */
371 void stk1160_free_isoc(struct stk1160 *dev)
372 {
373 	struct urb *urb;
374 	int i, num_bufs = dev->isoc_ctl.num_bufs;
375 
376 	stk1160_dbg("freeing %d urb buffers...\n", num_bufs);
377 
378 	for (i = 0; i < num_bufs; i++) {
379 
380 		urb = dev->isoc_ctl.urb[i];
381 		if (urb) {
382 
383 			if (dev->isoc_ctl.transfer_buffer[i]) {
384 #ifndef CONFIG_DMA_NONCOHERENT
385 				usb_free_coherent(dev->udev,
386 					urb->transfer_buffer_length,
387 					dev->isoc_ctl.transfer_buffer[i],
388 					urb->transfer_dma);
389 #else
390 				kfree(dev->isoc_ctl.transfer_buffer[i]);
391 #endif
392 			}
393 			usb_free_urb(urb);
394 			dev->isoc_ctl.urb[i] = NULL;
395 		}
396 		dev->isoc_ctl.transfer_buffer[i] = NULL;
397 	}
398 
399 	kfree(dev->isoc_ctl.urb);
400 	kfree(dev->isoc_ctl.transfer_buffer);
401 
402 	dev->isoc_ctl.urb = NULL;
403 	dev->isoc_ctl.transfer_buffer = NULL;
404 	dev->isoc_ctl.num_bufs = 0;
405 
406 	stk1160_dbg("all urb buffers freed\n");
407 }
408 
409 /*
410  * Helper for cancelling and freeing urbs
411  * This function can't be called in atomic context
412  */
413 void stk1160_uninit_isoc(struct stk1160 *dev)
414 {
415 	stk1160_cancel_isoc(dev);
416 	stk1160_free_isoc(dev);
417 }
418 
419 /*
420  * Allocate URBs
421  */
422 int stk1160_alloc_isoc(struct stk1160 *dev)
423 {
424 	struct urb *urb;
425 	int i, j, k, sb_size, max_packets, num_bufs;
426 
427 	/*
428 	 * It may be necessary to release isoc here,
429 	 * since isoc are only released on disconnection.
430 	 * (see new_pkt_size flag)
431 	 */
432 	if (dev->isoc_ctl.num_bufs)
433 		stk1160_uninit_isoc(dev);
434 
435 	stk1160_dbg("allocating urbs...\n");
436 
437 	num_bufs = STK1160_NUM_BUFS;
438 	max_packets = STK1160_NUM_PACKETS;
439 	sb_size = max_packets * dev->max_pkt_size;
440 
441 	dev->isoc_ctl.buf = NULL;
442 	dev->isoc_ctl.max_pkt_size = dev->max_pkt_size;
443 	dev->isoc_ctl.urb = kzalloc(sizeof(void *)*num_bufs, GFP_KERNEL);
444 	if (!dev->isoc_ctl.urb) {
445 		stk1160_err("out of memory for urb array\n");
446 		return -ENOMEM;
447 	}
448 
449 	dev->isoc_ctl.transfer_buffer = kzalloc(sizeof(void *)*num_bufs,
450 					      GFP_KERNEL);
451 	if (!dev->isoc_ctl.transfer_buffer) {
452 		stk1160_err("out of memory for usb transfers\n");
453 		kfree(dev->isoc_ctl.urb);
454 		return -ENOMEM;
455 	}
456 
457 	/* allocate urbs and transfer buffers */
458 	for (i = 0; i < num_bufs; i++) {
459 
460 		urb = usb_alloc_urb(max_packets, GFP_KERNEL);
461 		if (!urb) {
462 			stk1160_err("cannot alloc urb[%d]\n", i);
463 			goto free_i_bufs;
464 		}
465 		dev->isoc_ctl.urb[i] = urb;
466 
467 #ifndef CONFIG_DMA_NONCOHERENT
468 		dev->isoc_ctl.transfer_buffer[i] = usb_alloc_coherent(dev->udev,
469 			sb_size, GFP_KERNEL, &urb->transfer_dma);
470 #else
471 		dev->isoc_ctl.transfer_buffer[i] = kmalloc(sb_size, GFP_KERNEL);
472 #endif
473 		if (!dev->isoc_ctl.transfer_buffer[i]) {
474 			stk1160_err("cannot alloc %d bytes for tx[%d] buffer\n",
475 				sb_size, i);
476 
477 			/* Not enough transfer buffers, so just give up */
478 			if (i < STK1160_MIN_BUFS)
479 				goto free_i_bufs;
480 			goto nomore_tx_bufs;
481 		}
482 		memset(dev->isoc_ctl.transfer_buffer[i], 0, sb_size);
483 
484 		/*
485 		 * FIXME: Where can I get the endpoint?
486 		 */
487 		urb->dev = dev->udev;
488 		urb->pipe = usb_rcvisocpipe(dev->udev, STK1160_EP_VIDEO);
489 		urb->transfer_buffer = dev->isoc_ctl.transfer_buffer[i];
490 		urb->transfer_buffer_length = sb_size;
491 		urb->complete = stk1160_isoc_irq;
492 		urb->context = dev;
493 		urb->interval = 1;
494 		urb->start_frame = 0;
495 		urb->number_of_packets = max_packets;
496 #ifndef CONFIG_DMA_NONCOHERENT
497 		urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
498 #else
499 		urb->transfer_flags = URB_ISO_ASAP;
500 #endif
501 
502 		k = 0;
503 		for (j = 0; j < max_packets; j++) {
504 			urb->iso_frame_desc[j].offset = k;
505 			urb->iso_frame_desc[j].length =
506 					dev->isoc_ctl.max_pkt_size;
507 			k += dev->isoc_ctl.max_pkt_size;
508 		}
509 	}
510 
511 	stk1160_dbg("%d urbs allocated\n", num_bufs);
512 
513 	/* At last we can say we have some buffers */
514 	dev->isoc_ctl.num_bufs = num_bufs;
515 
516 	return 0;
517 
518 nomore_tx_bufs:
519 	/*
520 	 * Failed to allocate desired buffer count. However, we may have
521 	 * enough to work fine, so we just free the extra urb,
522 	 * store the allocated count and keep going, fingers crossed!
523 	 */
524 	usb_free_urb(dev->isoc_ctl.urb[i]);
525 	dev->isoc_ctl.urb[i] = NULL;
526 
527 	stk1160_warn("%d urbs allocated. Trying to continue...\n", i - 1);
528 
529 	dev->isoc_ctl.num_bufs = i - 1;
530 
531 	return 0;
532 
533 free_i_bufs:
534 	/* Save the allocated buffers so far, so we can properly free them */
535 	dev->isoc_ctl.num_bufs = i+1;
536 	stk1160_free_isoc(dev);
537 	return -ENOMEM;
538 }
539 
540