1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * STK1160 driver
4  *
5  * Copyright (C) 2012 Ezequiel Garcia
6  * <elezegarcia--a.t--gmail.com>
7  *
8  * Based on Easycap driver by R.M. Thomas
9  *	Copyright (C) 2010 R.M. Thomas
10  *	<rmthomas--a.t--sciolus.org>
11  */
12 
13 #include <linux/module.h>
14 #include <linux/usb.h>
15 #include <linux/slab.h>
16 #include <linux/ratelimit.h>
17 
18 #include "stk1160.h"
19 
20 static unsigned int debug;
21 module_param(debug, int, 0644);
22 MODULE_PARM_DESC(debug, "enable debug messages");
23 
24 static inline void print_err_status(struct stk1160 *dev,
25 				     int packet, int status)
26 {
27 	char *errmsg = "Unknown";
28 
29 	switch (status) {
30 	case -ENOENT:
31 		errmsg = "unlinked synchronously";
32 		break;
33 	case -ECONNRESET:
34 		errmsg = "unlinked asynchronously";
35 		break;
36 	case -ENOSR:
37 		errmsg = "Buffer error (overrun)";
38 		break;
39 	case -EPIPE:
40 		errmsg = "Stalled (device not responding)";
41 		break;
42 	case -EOVERFLOW:
43 		errmsg = "Babble (bad cable?)";
44 		break;
45 	case -EPROTO:
46 		errmsg = "Bit-stuff error (bad cable?)";
47 		break;
48 	case -EILSEQ:
49 		errmsg = "CRC/Timeout (could be anything)";
50 		break;
51 	case -ETIME:
52 		errmsg = "Device does not respond";
53 		break;
54 	}
55 
56 	if (packet < 0)
57 		printk_ratelimited(KERN_WARNING "URB status %d [%s].\n",
58 				status, errmsg);
59 	else
60 		printk_ratelimited(KERN_INFO "URB packet %d, status %d [%s].\n",
61 			       packet, status, errmsg);
62 }
63 
64 static inline
65 struct stk1160_buffer *stk1160_next_buffer(struct stk1160 *dev)
66 {
67 	struct stk1160_buffer *buf = NULL;
68 	unsigned long flags = 0;
69 
70 	/* Current buffer must be NULL when this functions gets called */
71 	WARN_ON(dev->isoc_ctl.buf);
72 
73 	spin_lock_irqsave(&dev->buf_lock, flags);
74 	if (!list_empty(&dev->avail_bufs)) {
75 		buf = list_first_entry(&dev->avail_bufs,
76 				struct stk1160_buffer, list);
77 		list_del(&buf->list);
78 	}
79 	spin_unlock_irqrestore(&dev->buf_lock, flags);
80 
81 	return buf;
82 }
83 
84 static inline
85 void stk1160_buffer_done(struct stk1160 *dev)
86 {
87 	struct stk1160_buffer *buf = dev->isoc_ctl.buf;
88 
89 	buf->vb.sequence = dev->sequence++;
90 	buf->vb.field = V4L2_FIELD_INTERLACED;
91 	buf->vb.vb2_buf.timestamp = ktime_get_ns();
92 
93 	vb2_set_plane_payload(&buf->vb.vb2_buf, 0, buf->bytesused);
94 	vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_DONE);
95 
96 	dev->isoc_ctl.buf = NULL;
97 }
98 
99 static inline
100 void stk1160_copy_video(struct stk1160 *dev, u8 *src, int len)
101 {
102 	int linesdone, lineoff, lencopy;
103 	int bytesperline = dev->width * 2;
104 	struct stk1160_buffer *buf = dev->isoc_ctl.buf;
105 	u8 *dst = buf->mem;
106 	int remain;
107 
108 	/*
109 	 * TODO: These stk1160_dbg are very spammy!
110 	 * We should check why we are getting them.
111 	 *
112 	 * UPDATE: One of the reasons (the only one?) for getting these
113 	 * is incorrect standard (mismatch between expected and configured).
114 	 * So perhaps, we could add a counter for errors. When the counter
115 	 * reaches some value, we simply stop streaming.
116 	 */
117 
118 	len -= 4;
119 	src += 4;
120 
121 	remain = len;
122 
123 	linesdone = buf->pos / bytesperline;
124 	lineoff = buf->pos % bytesperline; /* offset in current line */
125 
126 	if (!buf->odd)
127 		dst += bytesperline;
128 
129 	/* Multiply linesdone by two, to take account of the other field */
130 	dst += linesdone * bytesperline * 2 + lineoff;
131 
132 	/* Copy the remaining of current line */
133 	if (remain < (bytesperline - lineoff))
134 		lencopy = remain;
135 	else
136 		lencopy = bytesperline - lineoff;
137 
138 	/*
139 	 * Check if we have enough space left in the buffer.
140 	 * In that case, we force loop exit after copy.
141 	 */
142 	if (lencopy > buf->bytesused - buf->length) {
143 		lencopy = buf->bytesused - buf->length;
144 		remain = lencopy;
145 	}
146 
147 	/* Check if the copy is done */
148 	if (lencopy == 0 || remain == 0)
149 		return;
150 
151 	/* Let the bug hunt begin! sanity checks! */
152 	if (lencopy < 0) {
153 		printk_ratelimited(KERN_DEBUG "copy skipped: negative lencopy\n");
154 		return;
155 	}
156 
157 	if ((unsigned long)dst + lencopy >
158 		(unsigned long)buf->mem + buf->length) {
159 		printk_ratelimited(KERN_WARNING "stk1160: buffer overflow detected\n");
160 		return;
161 	}
162 
163 	memcpy(dst, src, lencopy);
164 
165 	buf->bytesused += lencopy;
166 	buf->pos += lencopy;
167 	remain -= lencopy;
168 
169 	/* Copy current field line by line, interlacing with the other field */
170 	while (remain > 0) {
171 
172 		dst += lencopy + bytesperline;
173 		src += lencopy;
174 
175 		/* Copy one line at a time */
176 		if (remain < bytesperline)
177 			lencopy = remain;
178 		else
179 			lencopy = bytesperline;
180 
181 		/*
182 		 * Check if we have enough space left in the buffer.
183 		 * In that case, we force loop exit after copy.
184 		 */
185 		if (lencopy > buf->bytesused - buf->length) {
186 			lencopy = buf->bytesused - buf->length;
187 			remain = lencopy;
188 		}
189 
190 		/* Check if the copy is done */
191 		if (lencopy == 0 || remain == 0)
192 			return;
193 
194 		if (lencopy < 0) {
195 			printk_ratelimited(KERN_WARNING "stk1160: negative lencopy detected\n");
196 			return;
197 		}
198 
199 		if ((unsigned long)dst + lencopy >
200 			(unsigned long)buf->mem + buf->length) {
201 			printk_ratelimited(KERN_WARNING "stk1160: buffer overflow detected\n");
202 			return;
203 		}
204 
205 		memcpy(dst, src, lencopy);
206 		remain -= lencopy;
207 
208 		buf->bytesused += lencopy;
209 		buf->pos += lencopy;
210 	}
211 }
212 
213 /*
214  * Controls the isoc copy of each urb packet
215  */
216 static void stk1160_process_isoc(struct stk1160 *dev, struct urb *urb)
217 {
218 	int i, len, status;
219 	u8 *p;
220 
221 	if (!dev) {
222 		stk1160_warn("%s called with null device\n", __func__);
223 		return;
224 	}
225 
226 	if (urb->status < 0) {
227 		/* Print status and drop current packet (or field?) */
228 		print_err_status(dev, -1, urb->status);
229 		return;
230 	}
231 
232 	for (i = 0; i < urb->number_of_packets; i++) {
233 		status = urb->iso_frame_desc[i].status;
234 		if (status < 0) {
235 			print_err_status(dev, i, status);
236 			continue;
237 		}
238 
239 		/* Get packet actual length and pointer to data */
240 		p = urb->transfer_buffer + urb->iso_frame_desc[i].offset;
241 		len = urb->iso_frame_desc[i].actual_length;
242 
243 		/* Empty packet */
244 		if (len <= 4)
245 			continue;
246 
247 		/*
248 		 * An 8-byte packet sequence means end of field.
249 		 * So if we don't have any packet, we start receiving one now
250 		 * and if we do have a packet, then we are done with it.
251 		 *
252 		 * These end of field packets are always 0xc0 or 0x80,
253 		 * but not always 8-byte long so we don't check packet length.
254 		 */
255 		if (p[0] == 0xc0) {
256 
257 			/*
258 			 * If first byte is 0xc0 then we received
259 			 * second field, and frame has ended.
260 			 */
261 			if (dev->isoc_ctl.buf != NULL)
262 				stk1160_buffer_done(dev);
263 
264 			dev->isoc_ctl.buf = stk1160_next_buffer(dev);
265 			if (dev->isoc_ctl.buf == NULL)
266 				return;
267 		}
268 
269 		/*
270 		 * If we don't have a buffer here, then it means we
271 		 * haven't found the start mark sequence.
272 		 */
273 		if (dev->isoc_ctl.buf == NULL)
274 			continue;
275 
276 		if (p[0] == 0xc0 || p[0] == 0x80) {
277 
278 			/* We set next packet parity and
279 			 * continue to get next one
280 			 */
281 			dev->isoc_ctl.buf->odd = *p & 0x40;
282 			dev->isoc_ctl.buf->pos = 0;
283 			continue;
284 		}
285 
286 		stk1160_copy_video(dev, p, len);
287 	}
288 }
289 
290 
291 /*
292  * IRQ callback, called by URB callback
293  */
294 static void stk1160_isoc_irq(struct urb *urb)
295 {
296 	int i, rc;
297 	struct stk1160_urb *stk_urb = urb->context;
298 	struct stk1160 *dev = stk_urb->dev;
299 	struct device *dma_dev = stk1160_get_dmadev(dev);
300 
301 	switch (urb->status) {
302 	case 0:
303 		break;
304 	case -ECONNRESET:   /* kill */
305 	case -ENOENT:
306 	case -ESHUTDOWN:
307 		/* TODO: check uvc driver: he frees the queue here */
308 		return;
309 	default:
310 		stk1160_err("urb error! status %d\n", urb->status);
311 		return;
312 	}
313 
314 	invalidate_kernel_vmap_range(stk_urb->transfer_buffer,
315 				     urb->transfer_buffer_length);
316 	dma_sync_sgtable_for_cpu(dma_dev, stk_urb->sgt, DMA_FROM_DEVICE);
317 
318 	stk1160_process_isoc(dev, urb);
319 
320 	/* Reset urb buffers */
321 	for (i = 0; i < urb->number_of_packets; i++) {
322 		urb->iso_frame_desc[i].status = 0;
323 		urb->iso_frame_desc[i].actual_length = 0;
324 	}
325 
326 	dma_sync_sgtable_for_device(dma_dev, stk_urb->sgt, DMA_FROM_DEVICE);
327 	rc = usb_submit_urb(urb, GFP_ATOMIC);
328 	if (rc)
329 		stk1160_err("urb re-submit failed (%d)\n", rc);
330 }
331 
332 /*
333  * Cancel urbs
334  * This function can't be called in atomic context
335  */
336 void stk1160_cancel_isoc(struct stk1160 *dev)
337 {
338 	int i, num_bufs = dev->isoc_ctl.num_bufs;
339 
340 	/*
341 	 * This check is not necessary, but we add it
342 	 * to avoid a spurious debug message
343 	 */
344 	if (!num_bufs)
345 		return;
346 
347 	stk1160_dbg("killing %d urbs...\n", num_bufs);
348 
349 	for (i = 0; i < num_bufs; i++) {
350 
351 		/*
352 		 * To kill urbs we can't be in atomic context.
353 		 * We don't care for NULL pointer since
354 		 * usb_kill_urb allows it.
355 		 */
356 		usb_kill_urb(dev->isoc_ctl.urb_ctl[i].urb);
357 	}
358 
359 	stk1160_dbg("all urbs killed\n");
360 }
361 
362 static void stk_free_urb(struct stk1160 *dev, struct stk1160_urb *stk_urb)
363 {
364 	struct device *dma_dev = stk1160_get_dmadev(dev);
365 
366 	dma_vunmap_noncontiguous(dma_dev, stk_urb->transfer_buffer);
367 	dma_free_noncontiguous(dma_dev, stk_urb->urb->transfer_buffer_length,
368 			       stk_urb->sgt, DMA_FROM_DEVICE);
369 	usb_free_urb(stk_urb->urb);
370 
371 	stk_urb->transfer_buffer = NULL;
372 	stk_urb->sgt = NULL;
373 	stk_urb->urb = NULL;
374 	stk_urb->dev = NULL;
375 	stk_urb->dma = 0;
376 }
377 
378 /*
379  * Releases urb and transfer buffers
380  * Obviusly, associated urb must be killed before releasing it.
381  */
382 void stk1160_free_isoc(struct stk1160 *dev)
383 {
384 	int i, num_bufs = dev->isoc_ctl.num_bufs;
385 
386 	stk1160_dbg("freeing %d urb buffers...\n", num_bufs);
387 
388 	for (i = 0; i < num_bufs; i++)
389 		stk_free_urb(dev, &dev->isoc_ctl.urb_ctl[i]);
390 
391 	dev->isoc_ctl.num_bufs = 0;
392 
393 	stk1160_dbg("all urb buffers freed\n");
394 }
395 
396 /*
397  * Helper for cancelling and freeing urbs
398  * This function can't be called in atomic context
399  */
400 void stk1160_uninit_isoc(struct stk1160 *dev)
401 {
402 	stk1160_cancel_isoc(dev);
403 	stk1160_free_isoc(dev);
404 }
405 
406 static int stk1160_fill_urb(struct stk1160 *dev, struct stk1160_urb *stk_urb,
407 			    int sb_size, int max_packets)
408 {
409 	struct device *dma_dev = stk1160_get_dmadev(dev);
410 
411 	stk_urb->urb = usb_alloc_urb(max_packets, GFP_KERNEL);
412 	if (!stk_urb->urb)
413 		return -ENOMEM;
414 	stk_urb->sgt = dma_alloc_noncontiguous(dma_dev, sb_size,
415 					       DMA_FROM_DEVICE, GFP_KERNEL, 0);
416 
417 	/*
418 	 * If the buffer allocation failed, we exit but return 0 since
419 	 * we allow the driver working with less buffers
420 	 */
421 	if (!stk_urb->sgt)
422 		goto free_urb;
423 
424 	stk_urb->transfer_buffer = dma_vmap_noncontiguous(dma_dev, sb_size,
425 							  stk_urb->sgt);
426 	if (!stk_urb->transfer_buffer)
427 		goto free_sgt;
428 
429 	stk_urb->dma = stk_urb->sgt->sgl->dma_address;
430 	stk_urb->dev = dev;
431 	return 0;
432 free_sgt:
433 	dma_free_noncontiguous(dma_dev, sb_size, stk_urb->sgt, DMA_FROM_DEVICE);
434 	stk_urb->sgt = NULL;
435 free_urb:
436 	usb_free_urb(stk_urb->urb);
437 	stk_urb->urb = NULL;
438 
439 	return 0;
440 }
441 /*
442  * Allocate URBs
443  */
444 int stk1160_alloc_isoc(struct stk1160 *dev)
445 {
446 	struct urb *urb;
447 	int i, j, k, sb_size, max_packets, num_bufs;
448 	int ret;
449 
450 	/*
451 	 * It may be necessary to release isoc here,
452 	 * since isoc are only released on disconnection.
453 	 * (see new_pkt_size flag)
454 	 */
455 	if (dev->isoc_ctl.num_bufs)
456 		stk1160_uninit_isoc(dev);
457 
458 	stk1160_dbg("allocating urbs...\n");
459 
460 	num_bufs = STK1160_NUM_BUFS;
461 	max_packets = STK1160_NUM_PACKETS;
462 	sb_size = max_packets * dev->max_pkt_size;
463 
464 	dev->isoc_ctl.buf = NULL;
465 	dev->isoc_ctl.max_pkt_size = dev->max_pkt_size;
466 
467 	/* allocate urbs and transfer buffers */
468 	for (i = 0; i < num_bufs; i++) {
469 
470 		ret = stk1160_fill_urb(dev, &dev->isoc_ctl.urb_ctl[i],
471 				       sb_size, max_packets);
472 		if (ret)
473 			goto free_i_bufs;
474 
475 		urb = dev->isoc_ctl.urb_ctl[i].urb;
476 
477 		if (!urb) {
478 			/* Not enough transfer buffers, so just give up */
479 			if (i < STK1160_MIN_BUFS)
480 				goto free_i_bufs;
481 			goto nomore_tx_bufs;
482 		}
483 		memset(dev->isoc_ctl.urb_ctl[i].transfer_buffer, 0, sb_size);
484 
485 		/*
486 		 * FIXME: Where can I get the endpoint?
487 		 */
488 		urb->dev = dev->udev;
489 		urb->pipe = usb_rcvisocpipe(dev->udev, STK1160_EP_VIDEO);
490 		urb->transfer_buffer = dev->isoc_ctl.urb_ctl[i].transfer_buffer;
491 		urb->transfer_buffer_length = sb_size;
492 		urb->complete = stk1160_isoc_irq;
493 		urb->context = &dev->isoc_ctl.urb_ctl[i];
494 		urb->interval = 1;
495 		urb->start_frame = 0;
496 		urb->number_of_packets = max_packets;
497 		urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
498 		urb->transfer_dma = dev->isoc_ctl.urb_ctl[i].dma;
499 
500 		k = 0;
501 		for (j = 0; j < max_packets; j++) {
502 			urb->iso_frame_desc[j].offset = k;
503 			urb->iso_frame_desc[j].length =
504 					dev->isoc_ctl.max_pkt_size;
505 			k += dev->isoc_ctl.max_pkt_size;
506 		}
507 	}
508 
509 	stk1160_dbg("%d urbs allocated\n", num_bufs);
510 
511 	/* At last we can say we have some buffers */
512 	dev->isoc_ctl.num_bufs = num_bufs;
513 
514 	return 0;
515 
516 nomore_tx_bufs:
517 	/*
518 	 * Failed to allocate desired buffer count. However, we may have
519 	 * enough to work fine, so we just free the extra urb,
520 	 * store the allocated count and keep going, fingers crossed!
521 	 */
522 
523 	stk1160_warn("%d urbs allocated. Trying to continue...\n", i);
524 
525 	dev->isoc_ctl.num_bufs = i;
526 
527 	return 0;
528 
529 free_i_bufs:
530 	/* Save the allocated buffers so far, so we can properly free them */
531 	dev->isoc_ctl.num_bufs = i;
532 	stk1160_free_isoc(dev);
533 	return -ENOMEM;
534 }
535 
536