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TOMOYO Linux Cross Reference
Linux/sound/usb/endpoint.c

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Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  *   This program is free software; you can redistribute it and/or modify
  3  *   it under the terms of the GNU General Public License as published by
  4  *   the Free Software Foundation; either version 2 of the License, or
  5  *   (at your option) any later version.
  6  *
  7  *   This program is distributed in the hope that it will be useful,
  8  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  9  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 10  *   GNU General Public License for more details.
 11  *
 12  *   You should have received a copy of the GNU General Public License
 13  *   along with this program; if not, write to the Free Software
 14  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 15  *
 16  */
 17 
 18 #include <linux/gfp.h>
 19 #include <linux/init.h>
 20 #include <linux/ratelimit.h>
 21 #include <linux/usb.h>
 22 #include <linux/usb/audio.h>
 23 #include <linux/slab.h>
 24 
 25 #include <sound/core.h>
 26 #include <sound/pcm.h>
 27 #include <sound/pcm_params.h>
 28 
 29 #include "usbaudio.h"
 30 #include "helper.h"
 31 #include "card.h"
 32 #include "endpoint.h"
 33 #include "pcm.h"
 34 #include "quirks.h"
 35 
 36 #define EP_FLAG_RUNNING         1
 37 #define EP_FLAG_STOPPING        2
 38 
 39 /*
 40  * snd_usb_endpoint is a model that abstracts everything related to an
 41  * USB endpoint and its streaming.
 42  *
 43  * There are functions to activate and deactivate the streaming URBs and
 44  * optional callbacks to let the pcm logic handle the actual content of the
 45  * packets for playback and record. Thus, the bus streaming and the audio
 46  * handlers are fully decoupled.
 47  *
 48  * There are two different types of endpoints in audio applications.
 49  *
 50  * SND_USB_ENDPOINT_TYPE_DATA handles full audio data payload for both
 51  * inbound and outbound traffic.
 52  *
 53  * SND_USB_ENDPOINT_TYPE_SYNC endpoints are for inbound traffic only and
 54  * expect the payload to carry Q10.14 / Q16.16 formatted sync information
 55  * (3 or 4 bytes).
 56  *
 57  * Each endpoint has to be configured prior to being used by calling
 58  * snd_usb_endpoint_set_params().
 59  *
 60  * The model incorporates a reference counting, so that multiple users
 61  * can call snd_usb_endpoint_start() and snd_usb_endpoint_stop(), and
 62  * only the first user will effectively start the URBs, and only the last
 63  * one to stop it will tear the URBs down again.
 64  */
 65 
 66 /*
 67  * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
 68  * this will overflow at approx 524 kHz
 69  */
 70 static inline unsigned get_usb_full_speed_rate(unsigned int rate)
 71 {
 72         return ((rate << 13) + 62) / 125;
 73 }
 74 
 75 /*
 76  * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
 77  * this will overflow at approx 4 MHz
 78  */
 79 static inline unsigned get_usb_high_speed_rate(unsigned int rate)
 80 {
 81         return ((rate << 10) + 62) / 125;
 82 }
 83 
 84 /*
 85  * release a urb data
 86  */
 87 static void release_urb_ctx(struct snd_urb_ctx *u)
 88 {
 89         if (u->buffer_size)
 90                 usb_free_coherent(u->ep->chip->dev, u->buffer_size,
 91                                   u->urb->transfer_buffer,
 92                                   u->urb->transfer_dma);
 93         usb_free_urb(u->urb);
 94         u->urb = NULL;
 95 }
 96 
 97 static const char *usb_error_string(int err)
 98 {
 99         switch (err) {
100         case -ENODEV:
101                 return "no device";
102         case -ENOENT:
103                 return "endpoint not enabled";
104         case -EPIPE:
105                 return "endpoint stalled";
106         case -ENOSPC:
107                 return "not enough bandwidth";
108         case -ESHUTDOWN:
109                 return "device disabled";
110         case -EHOSTUNREACH:
111                 return "device suspended";
112         case -EINVAL:
113         case -EAGAIN:
114         case -EFBIG:
115         case -EMSGSIZE:
116                 return "internal error";
117         default:
118                 return "unknown error";
119         }
120 }
121 
122 /**
123  * snd_usb_endpoint_implicit_feedback_sink: Report endpoint usage type
124  *
125  * @ep: The snd_usb_endpoint
126  *
127  * Determine whether an endpoint is driven by an implicit feedback
128  * data endpoint source.
129  */
130 int snd_usb_endpoint_implicit_feedback_sink(struct snd_usb_endpoint *ep)
131 {
132         return  ep->sync_master &&
133                 ep->sync_master->type == SND_USB_ENDPOINT_TYPE_DATA &&
134                 ep->type == SND_USB_ENDPOINT_TYPE_DATA &&
135                 usb_pipeout(ep->pipe);
136 }
137 
138 /*
139  * For streaming based on information derived from sync endpoints,
140  * prepare_outbound_urb_sizes() will call next_packet_size() to
141  * determine the number of samples to be sent in the next packet.
142  *
143  * For implicit feedback, next_packet_size() is unused.
144  */
145 int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep)
146 {
147         unsigned long flags;
148         int ret;
149 
150         if (ep->fill_max)
151                 return ep->maxframesize;
152 
153         spin_lock_irqsave(&ep->lock, flags);
154         ep->phase = (ep->phase & 0xffff)
155                 + (ep->freqm << ep->datainterval);
156         ret = min(ep->phase >> 16, ep->maxframesize);
157         spin_unlock_irqrestore(&ep->lock, flags);
158 
159         return ret;
160 }
161 
162 static void retire_outbound_urb(struct snd_usb_endpoint *ep,
163                                 struct snd_urb_ctx *urb_ctx)
164 {
165         if (ep->retire_data_urb)
166                 ep->retire_data_urb(ep->data_subs, urb_ctx->urb);
167 }
168 
169 static void retire_inbound_urb(struct snd_usb_endpoint *ep,
170                                struct snd_urb_ctx *urb_ctx)
171 {
172         struct urb *urb = urb_ctx->urb;
173 
174         if (unlikely(ep->skip_packets > 0)) {
175                 ep->skip_packets--;
176                 return;
177         }
178 
179         if (ep->sync_slave)
180                 snd_usb_handle_sync_urb(ep->sync_slave, ep, urb);
181 
182         if (ep->retire_data_urb)
183                 ep->retire_data_urb(ep->data_subs, urb);
184 }
185 
186 static void prepare_silent_urb(struct snd_usb_endpoint *ep,
187                                struct snd_urb_ctx *ctx)
188 {
189         struct urb *urb = ctx->urb;
190         unsigned int offs = 0;
191         unsigned int extra = 0;
192         __le32 packet_length;
193         int i;
194 
195         /* For tx_length_quirk, put packet length at start of packet */
196         if (ep->chip->tx_length_quirk)
197                 extra = sizeof(packet_length);
198 
199         for (i = 0; i < ctx->packets; ++i) {
200                 unsigned int offset;
201                 unsigned int length;
202                 int counts;
203 
204                 if (ctx->packet_size[i])
205                         counts = ctx->packet_size[i];
206                 else
207                         counts = snd_usb_endpoint_next_packet_size(ep);
208 
209                 length = counts * ep->stride; /* number of silent bytes */
210                 offset = offs * ep->stride + extra * i;
211                 urb->iso_frame_desc[i].offset = offset;
212                 urb->iso_frame_desc[i].length = length + extra;
213                 if (extra) {
214                         packet_length = cpu_to_le32(length);
215                         memcpy(urb->transfer_buffer + offset,
216                                &packet_length, sizeof(packet_length));
217                 }
218                 memset(urb->transfer_buffer + offset + extra,
219                        ep->silence_value, length);
220                 offs += counts;
221         }
222 
223         urb->number_of_packets = ctx->packets;
224         urb->transfer_buffer_length = offs * ep->stride + ctx->packets * extra;
225 }
226 
227 /*
228  * Prepare a PLAYBACK urb for submission to the bus.
229  */
230 static void prepare_outbound_urb(struct snd_usb_endpoint *ep,
231                                  struct snd_urb_ctx *ctx)
232 {
233         struct urb *urb = ctx->urb;
234         unsigned char *cp = urb->transfer_buffer;
235 
236         urb->dev = ep->chip->dev; /* we need to set this at each time */
237 
238         switch (ep->type) {
239         case SND_USB_ENDPOINT_TYPE_DATA:
240                 if (ep->prepare_data_urb) {
241                         ep->prepare_data_urb(ep->data_subs, urb);
242                 } else {
243                         /* no data provider, so send silence */
244                         prepare_silent_urb(ep, ctx);
245                 }
246                 break;
247 
248         case SND_USB_ENDPOINT_TYPE_SYNC:
249                 if (snd_usb_get_speed(ep->chip->dev) >= USB_SPEED_HIGH) {
250                         /*
251                          * fill the length and offset of each urb descriptor.
252                          * the fixed 12.13 frequency is passed as 16.16 through the pipe.
253                          */
254                         urb->iso_frame_desc[0].length = 4;
255                         urb->iso_frame_desc[0].offset = 0;
256                         cp[0] = ep->freqn;
257                         cp[1] = ep->freqn >> 8;
258                         cp[2] = ep->freqn >> 16;
259                         cp[3] = ep->freqn >> 24;
260                 } else {
261                         /*
262                          * fill the length and offset of each urb descriptor.
263                          * the fixed 10.14 frequency is passed through the pipe.
264                          */
265                         urb->iso_frame_desc[0].length = 3;
266                         urb->iso_frame_desc[0].offset = 0;
267                         cp[0] = ep->freqn >> 2;
268                         cp[1] = ep->freqn >> 10;
269                         cp[2] = ep->freqn >> 18;
270                 }
271 
272                 break;
273         }
274 }
275 
276 /*
277  * Prepare a CAPTURE or SYNC urb for submission to the bus.
278  */
279 static inline void prepare_inbound_urb(struct snd_usb_endpoint *ep,
280                                        struct snd_urb_ctx *urb_ctx)
281 {
282         int i, offs;
283         struct urb *urb = urb_ctx->urb;
284 
285         urb->dev = ep->chip->dev; /* we need to set this at each time */
286 
287         switch (ep->type) {
288         case SND_USB_ENDPOINT_TYPE_DATA:
289                 offs = 0;
290                 for (i = 0; i < urb_ctx->packets; i++) {
291                         urb->iso_frame_desc[i].offset = offs;
292                         urb->iso_frame_desc[i].length = ep->curpacksize;
293                         offs += ep->curpacksize;
294                 }
295 
296                 urb->transfer_buffer_length = offs;
297                 urb->number_of_packets = urb_ctx->packets;
298                 break;
299 
300         case SND_USB_ENDPOINT_TYPE_SYNC:
301                 urb->iso_frame_desc[0].length = min(4u, ep->syncmaxsize);
302                 urb->iso_frame_desc[0].offset = 0;
303                 break;
304         }
305 }
306 
307 /*
308  * Send output urbs that have been prepared previously. URBs are dequeued
309  * from ep->ready_playback_urbs and in case there there aren't any available
310  * or there are no packets that have been prepared, this function does
311  * nothing.
312  *
313  * The reason why the functionality of sending and preparing URBs is separated
314  * is that host controllers don't guarantee the order in which they return
315  * inbound and outbound packets to their submitters.
316  *
317  * This function is only used for implicit feedback endpoints. For endpoints
318  * driven by dedicated sync endpoints, URBs are immediately re-submitted
319  * from their completion handler.
320  */
321 static void queue_pending_output_urbs(struct snd_usb_endpoint *ep)
322 {
323         while (test_bit(EP_FLAG_RUNNING, &ep->flags)) {
324 
325                 unsigned long flags;
326                 struct snd_usb_packet_info *uninitialized_var(packet);
327                 struct snd_urb_ctx *ctx = NULL;
328                 struct urb *urb;
329                 int err, i;
330 
331                 spin_lock_irqsave(&ep->lock, flags);
332                 if (ep->next_packet_read_pos != ep->next_packet_write_pos) {
333                         packet = ep->next_packet + ep->next_packet_read_pos;
334                         ep->next_packet_read_pos++;
335                         ep->next_packet_read_pos %= MAX_URBS;
336 
337                         /* take URB out of FIFO */
338                         if (!list_empty(&ep->ready_playback_urbs))
339                                 ctx = list_first_entry(&ep->ready_playback_urbs,
340                                                struct snd_urb_ctx, ready_list);
341                 }
342                 spin_unlock_irqrestore(&ep->lock, flags);
343 
344                 if (ctx == NULL)
345                         return;
346 
347                 list_del_init(&ctx->ready_list);
348                 urb = ctx->urb;
349 
350                 /* copy over the length information */
351                 for (i = 0; i < packet->packets; i++)
352                         ctx->packet_size[i] = packet->packet_size[i];
353 
354                 /* call the data handler to fill in playback data */
355                 prepare_outbound_urb(ep, ctx);
356 
357                 err = usb_submit_urb(ctx->urb, GFP_ATOMIC);
358                 if (err < 0)
359                         usb_audio_err(ep->chip,
360                                 "Unable to submit urb #%d: %d (urb %p)\n",
361                                 ctx->index, err, ctx->urb);
362                 else
363                         set_bit(ctx->index, &ep->active_mask);
364         }
365 }
366 
367 /*
368  * complete callback for urbs
369  */
370 static void snd_complete_urb(struct urb *urb)
371 {
372         struct snd_urb_ctx *ctx = urb->context;
373         struct snd_usb_endpoint *ep = ctx->ep;
374         struct snd_pcm_substream *substream;
375         unsigned long flags;
376         int err;
377 
378         if (unlikely(urb->status == -ENOENT ||          /* unlinked */
379                      urb->status == -ENODEV ||          /* device removed */
380                      urb->status == -ECONNRESET ||      /* unlinked */
381                      urb->status == -ESHUTDOWN))        /* device disabled */
382                 goto exit_clear;
383         /* device disconnected */
384         if (unlikely(atomic_read(&ep->chip->shutdown)))
385                 goto exit_clear;
386 
387         if (usb_pipeout(ep->pipe)) {
388                 retire_outbound_urb(ep, ctx);
389                 /* can be stopped during retire callback */
390                 if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
391                         goto exit_clear;
392 
393                 if (snd_usb_endpoint_implicit_feedback_sink(ep)) {
394                         spin_lock_irqsave(&ep->lock, flags);
395                         list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
396                         spin_unlock_irqrestore(&ep->lock, flags);
397                         queue_pending_output_urbs(ep);
398 
399                         goto exit_clear;
400                 }
401 
402                 prepare_outbound_urb(ep, ctx);
403         } else {
404                 retire_inbound_urb(ep, ctx);
405                 /* can be stopped during retire callback */
406                 if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
407                         goto exit_clear;
408 
409                 prepare_inbound_urb(ep, ctx);
410         }
411 
412         err = usb_submit_urb(urb, GFP_ATOMIC);
413         if (err == 0)
414                 return;
415 
416         usb_audio_err(ep->chip, "cannot submit urb (err = %d)\n", err);
417         if (ep->data_subs && ep->data_subs->pcm_substream) {
418                 substream = ep->data_subs->pcm_substream;
419                 snd_pcm_stop_xrun(substream);
420         }
421 
422 exit_clear:
423         clear_bit(ctx->index, &ep->active_mask);
424 }
425 
426 /**
427  * snd_usb_add_endpoint: Add an endpoint to an USB audio chip
428  *
429  * @chip: The chip
430  * @alts: The USB host interface
431  * @ep_num: The number of the endpoint to use
432  * @direction: SNDRV_PCM_STREAM_PLAYBACK or SNDRV_PCM_STREAM_CAPTURE
433  * @type: SND_USB_ENDPOINT_TYPE_DATA or SND_USB_ENDPOINT_TYPE_SYNC
434  *
435  * If the requested endpoint has not been added to the given chip before,
436  * a new instance is created. Otherwise, a pointer to the previoulsy
437  * created instance is returned. In case of any error, NULL is returned.
438  *
439  * New endpoints will be added to chip->ep_list and must be freed by
440  * calling snd_usb_endpoint_free().
441  *
442  * For SND_USB_ENDPOINT_TYPE_SYNC, the caller needs to guarantee that
443  * bNumEndpoints > 1 beforehand.
444  */
445 struct snd_usb_endpoint *snd_usb_add_endpoint(struct snd_usb_audio *chip,
446                                               struct usb_host_interface *alts,
447                                               int ep_num, int direction, int type)
448 {
449         struct snd_usb_endpoint *ep;
450         int is_playback = direction == SNDRV_PCM_STREAM_PLAYBACK;
451 
452         if (WARN_ON(!alts))
453                 return NULL;
454 
455         mutex_lock(&chip->mutex);
456 
457         list_for_each_entry(ep, &chip->ep_list, list) {
458                 if (ep->ep_num == ep_num &&
459                     ep->iface == alts->desc.bInterfaceNumber &&
460                     ep->altsetting == alts->desc.bAlternateSetting) {
461                         usb_audio_dbg(ep->chip,
462                                       "Re-using EP %x in iface %d,%d @%p\n",
463                                         ep_num, ep->iface, ep->altsetting, ep);
464                         goto __exit_unlock;
465                 }
466         }
467 
468         usb_audio_dbg(chip, "Creating new %s %s endpoint #%x\n",
469                     is_playback ? "playback" : "capture",
470                     type == SND_USB_ENDPOINT_TYPE_DATA ? "data" : "sync",
471                     ep_num);
472 
473         ep = kzalloc(sizeof(*ep), GFP_KERNEL);
474         if (!ep)
475                 goto __exit_unlock;
476 
477         ep->chip = chip;
478         spin_lock_init(&ep->lock);
479         ep->type = type;
480         ep->ep_num = ep_num;
481         ep->iface = alts->desc.bInterfaceNumber;
482         ep->altsetting = alts->desc.bAlternateSetting;
483         INIT_LIST_HEAD(&ep->ready_playback_urbs);
484         ep_num &= USB_ENDPOINT_NUMBER_MASK;
485 
486         if (is_playback)
487                 ep->pipe = usb_sndisocpipe(chip->dev, ep_num);
488         else
489                 ep->pipe = usb_rcvisocpipe(chip->dev, ep_num);
490 
491         if (type == SND_USB_ENDPOINT_TYPE_SYNC) {
492                 if (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
493                     get_endpoint(alts, 1)->bRefresh >= 1 &&
494                     get_endpoint(alts, 1)->bRefresh <= 9)
495                         ep->syncinterval = get_endpoint(alts, 1)->bRefresh;
496                 else if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL)
497                         ep->syncinterval = 1;
498                 else if (get_endpoint(alts, 1)->bInterval >= 1 &&
499                          get_endpoint(alts, 1)->bInterval <= 16)
500                         ep->syncinterval = get_endpoint(alts, 1)->bInterval - 1;
501                 else
502                         ep->syncinterval = 3;
503 
504                 ep->syncmaxsize = le16_to_cpu(get_endpoint(alts, 1)->wMaxPacketSize);
505 
506                 if (chip->usb_id == USB_ID(0x0644, 0x8038) /* TEAC UD-H01 */ &&
507                     ep->syncmaxsize == 4)
508                         ep->udh01_fb_quirk = 1;
509         }
510 
511         list_add_tail(&ep->list, &chip->ep_list);
512 
513 __exit_unlock:
514         mutex_unlock(&chip->mutex);
515 
516         return ep;
517 }
518 
519 /*
520  *  wait until all urbs are processed.
521  */
522 static int wait_clear_urbs(struct snd_usb_endpoint *ep)
523 {
524         unsigned long end_time = jiffies + msecs_to_jiffies(1000);
525         int alive;
526 
527         do {
528                 alive = bitmap_weight(&ep->active_mask, ep->nurbs);
529                 if (!alive)
530                         break;
531 
532                 schedule_timeout_uninterruptible(1);
533         } while (time_before(jiffies, end_time));
534 
535         if (alive)
536                 usb_audio_err(ep->chip,
537                         "timeout: still %d active urbs on EP #%x\n",
538                         alive, ep->ep_num);
539         clear_bit(EP_FLAG_STOPPING, &ep->flags);
540 
541         return 0;
542 }
543 
544 /* sync the pending stop operation;
545  * this function itself doesn't trigger the stop operation
546  */
547 void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep)
548 {
549         if (ep && test_bit(EP_FLAG_STOPPING, &ep->flags))
550                 wait_clear_urbs(ep);
551 }
552 
553 /*
554  * unlink active urbs.
555  */
556 static int deactivate_urbs(struct snd_usb_endpoint *ep, bool force)
557 {
558         unsigned int i;
559 
560         if (!force && atomic_read(&ep->chip->shutdown)) /* to be sure... */
561                 return -EBADFD;
562 
563         clear_bit(EP_FLAG_RUNNING, &ep->flags);
564 
565         INIT_LIST_HEAD(&ep->ready_playback_urbs);
566         ep->next_packet_read_pos = 0;
567         ep->next_packet_write_pos = 0;
568 
569         for (i = 0; i < ep->nurbs; i++) {
570                 if (test_bit(i, &ep->active_mask)) {
571                         if (!test_and_set_bit(i, &ep->unlink_mask)) {
572                                 struct urb *u = ep->urb[i].urb;
573                                 usb_unlink_urb(u);
574                         }
575                 }
576         }
577 
578         return 0;
579 }
580 
581 /*
582  * release an endpoint's urbs
583  */
584 static void release_urbs(struct snd_usb_endpoint *ep, int force)
585 {
586         int i;
587 
588         /* route incoming urbs to nirvana */
589         ep->retire_data_urb = NULL;
590         ep->prepare_data_urb = NULL;
591 
592         /* stop urbs */
593         deactivate_urbs(ep, force);
594         wait_clear_urbs(ep);
595 
596         for (i = 0; i < ep->nurbs; i++)
597                 release_urb_ctx(&ep->urb[i]);
598 
599         if (ep->syncbuf)
600                 usb_free_coherent(ep->chip->dev, SYNC_URBS * 4,
601                                   ep->syncbuf, ep->sync_dma);
602 
603         ep->syncbuf = NULL;
604         ep->nurbs = 0;
605 }
606 
607 /*
608  * configure a data endpoint
609  */
610 static int data_ep_set_params(struct snd_usb_endpoint *ep,
611                               snd_pcm_format_t pcm_format,
612                               unsigned int channels,
613                               unsigned int period_bytes,
614                               unsigned int frames_per_period,
615                               unsigned int periods_per_buffer,
616                               struct audioformat *fmt,
617                               struct snd_usb_endpoint *sync_ep)
618 {
619         unsigned int maxsize, minsize, packs_per_ms, max_packs_per_urb;
620         unsigned int max_packs_per_period, urbs_per_period, urb_packs;
621         unsigned int max_urbs, i;
622         int frame_bits = snd_pcm_format_physical_width(pcm_format) * channels;
623         int tx_length_quirk = (ep->chip->tx_length_quirk &&
624                                usb_pipeout(ep->pipe));
625 
626         if (pcm_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) {
627                 /*
628                  * When operating in DSD DOP mode, the size of a sample frame
629                  * in hardware differs from the actual physical format width
630                  * because we need to make room for the DOP markers.
631                  */
632                 frame_bits += channels << 3;
633         }
634 
635         ep->datainterval = fmt->datainterval;
636         ep->stride = frame_bits >> 3;
637         ep->silence_value = pcm_format == SNDRV_PCM_FORMAT_U8 ? 0x80 : 0;
638 
639         /* assume max. frequency is 25% higher than nominal */
640         ep->freqmax = ep->freqn + (ep->freqn >> 2);
641         /* Round up freqmax to nearest integer in order to calculate maximum
642          * packet size, which must represent a whole number of frames.
643          * This is accomplished by adding 0x0.ffff before converting the
644          * Q16.16 format into integer.
645          * In order to accurately calculate the maximum packet size when
646          * the data interval is more than 1 (i.e. ep->datainterval > 0),
647          * multiply by the data interval prior to rounding. For instance,
648          * a freqmax of 41 kHz will result in a max packet size of 6 (5.125)
649          * frames with a data interval of 1, but 11 (10.25) frames with a
650          * data interval of 2.
651          * (ep->freqmax << ep->datainterval overflows at 8.192 MHz for the
652          * maximum datainterval value of 3, at USB full speed, higher for
653          * USB high speed, noting that ep->freqmax is in units of
654          * frames per packet in Q16.16 format.)
655          */
656         maxsize = (((ep->freqmax << ep->datainterval) + 0xffff) >> 16) *
657                          (frame_bits >> 3);
658         if (tx_length_quirk)
659                 maxsize += sizeof(__le32); /* Space for length descriptor */
660         /* but wMaxPacketSize might reduce this */
661         if (ep->maxpacksize && ep->maxpacksize < maxsize) {
662                 /* whatever fits into a max. size packet */
663                 unsigned int data_maxsize = maxsize = ep->maxpacksize;
664 
665                 if (tx_length_quirk)
666                         /* Need to remove the length descriptor to calc freq */
667                         data_maxsize -= sizeof(__le32);
668                 ep->freqmax = (data_maxsize / (frame_bits >> 3))
669                                 << (16 - ep->datainterval);
670         }
671 
672         if (ep->fill_max)
673                 ep->curpacksize = ep->maxpacksize;
674         else
675                 ep->curpacksize = maxsize;
676 
677         if (snd_usb_get_speed(ep->chip->dev) != USB_SPEED_FULL) {
678                 packs_per_ms = 8 >> ep->datainterval;
679                 max_packs_per_urb = MAX_PACKS_HS;
680         } else {
681                 packs_per_ms = 1;
682                 max_packs_per_urb = MAX_PACKS;
683         }
684         if (sync_ep && !snd_usb_endpoint_implicit_feedback_sink(ep))
685                 max_packs_per_urb = min(max_packs_per_urb,
686                                         1U << sync_ep->syncinterval);
687         max_packs_per_urb = max(1u, max_packs_per_urb >> ep->datainterval);
688 
689         /*
690          * Capture endpoints need to use small URBs because there's no way
691          * to tell in advance where the next period will end, and we don't
692          * want the next URB to complete much after the period ends.
693          *
694          * Playback endpoints with implicit sync much use the same parameters
695          * as their corresponding capture endpoint.
696          */
697         if (usb_pipein(ep->pipe) ||
698                         snd_usb_endpoint_implicit_feedback_sink(ep)) {
699 
700                 urb_packs = packs_per_ms;
701                 /*
702                  * Wireless devices can poll at a max rate of once per 4ms.
703                  * For dataintervals less than 5, increase the packet count to
704                  * allow the host controller to use bursting to fill in the
705                  * gaps.
706                  */
707                 if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_WIRELESS) {
708                         int interval = ep->datainterval;
709                         while (interval < 5) {
710                                 urb_packs <<= 1;
711                                 ++interval;
712                         }
713                 }
714                 /* make capture URBs <= 1 ms and smaller than a period */
715                 urb_packs = min(max_packs_per_urb, urb_packs);
716                 while (urb_packs > 1 && urb_packs * maxsize >= period_bytes)
717                         urb_packs >>= 1;
718                 ep->nurbs = MAX_URBS;
719 
720         /*
721          * Playback endpoints without implicit sync are adjusted so that
722          * a period fits as evenly as possible in the smallest number of
723          * URBs.  The total number of URBs is adjusted to the size of the
724          * ALSA buffer, subject to the MAX_URBS and MAX_QUEUE limits.
725          */
726         } else {
727                 /* determine how small a packet can be */
728                 minsize = (ep->freqn >> (16 - ep->datainterval)) *
729                                 (frame_bits >> 3);
730                 /* with sync from device, assume it can be 12% lower */
731                 if (sync_ep)
732                         minsize -= minsize >> 3;
733                 minsize = max(minsize, 1u);
734 
735                 /* how many packets will contain an entire ALSA period? */
736                 max_packs_per_period = DIV_ROUND_UP(period_bytes, minsize);
737 
738                 /* how many URBs will contain a period? */
739                 urbs_per_period = DIV_ROUND_UP(max_packs_per_period,
740                                 max_packs_per_urb);
741                 /* how many packets are needed in each URB? */
742                 urb_packs = DIV_ROUND_UP(max_packs_per_period, urbs_per_period);
743 
744                 /* limit the number of frames in a single URB */
745                 ep->max_urb_frames = DIV_ROUND_UP(frames_per_period,
746                                         urbs_per_period);
747 
748                 /* try to use enough URBs to contain an entire ALSA buffer */
749                 max_urbs = min((unsigned) MAX_URBS,
750                                 MAX_QUEUE * packs_per_ms / urb_packs);
751                 ep->nurbs = min(max_urbs, urbs_per_period * periods_per_buffer);
752         }
753 
754         /* allocate and initialize data urbs */
755         for (i = 0; i < ep->nurbs; i++) {
756                 struct snd_urb_ctx *u = &ep->urb[i];
757                 u->index = i;
758                 u->ep = ep;
759                 u->packets = urb_packs;
760                 u->buffer_size = maxsize * u->packets;
761 
762                 if (fmt->fmt_type == UAC_FORMAT_TYPE_II)
763                         u->packets++; /* for transfer delimiter */
764                 u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
765                 if (!u->urb)
766                         goto out_of_memory;
767 
768                 u->urb->transfer_buffer =
769                         usb_alloc_coherent(ep->chip->dev, u->buffer_size,
770                                            GFP_KERNEL, &u->urb->transfer_dma);
771                 if (!u->urb->transfer_buffer)
772                         goto out_of_memory;
773                 u->urb->pipe = ep->pipe;
774                 u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
775                 u->urb->interval = 1 << ep->datainterval;
776                 u->urb->context = u;
777                 u->urb->complete = snd_complete_urb;
778                 INIT_LIST_HEAD(&u->ready_list);
779         }
780 
781         return 0;
782 
783 out_of_memory:
784         release_urbs(ep, 0);
785         return -ENOMEM;
786 }
787 
788 /*
789  * configure a sync endpoint
790  */
791 static int sync_ep_set_params(struct snd_usb_endpoint *ep)
792 {
793         int i;
794 
795         ep->syncbuf = usb_alloc_coherent(ep->chip->dev, SYNC_URBS * 4,
796                                          GFP_KERNEL, &ep->sync_dma);
797         if (!ep->syncbuf)
798                 return -ENOMEM;
799 
800         for (i = 0; i < SYNC_URBS; i++) {
801                 struct snd_urb_ctx *u = &ep->urb[i];
802                 u->index = i;
803                 u->ep = ep;
804                 u->packets = 1;
805                 u->urb = usb_alloc_urb(1, GFP_KERNEL);
806                 if (!u->urb)
807                         goto out_of_memory;
808                 u->urb->transfer_buffer = ep->syncbuf + i * 4;
809                 u->urb->transfer_dma = ep->sync_dma + i * 4;
810                 u->urb->transfer_buffer_length = 4;
811                 u->urb->pipe = ep->pipe;
812                 u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
813                 u->urb->number_of_packets = 1;
814                 u->urb->interval = 1 << ep->syncinterval;
815                 u->urb->context = u;
816                 u->urb->complete = snd_complete_urb;
817         }
818 
819         ep->nurbs = SYNC_URBS;
820 
821         return 0;
822 
823 out_of_memory:
824         release_urbs(ep, 0);
825         return -ENOMEM;
826 }
827 
828 /**
829  * snd_usb_endpoint_set_params: configure an snd_usb_endpoint
830  *
831  * @ep: the snd_usb_endpoint to configure
832  * @pcm_format: the audio fomat.
833  * @channels: the number of audio channels.
834  * @period_bytes: the number of bytes in one alsa period.
835  * @period_frames: the number of frames in one alsa period.
836  * @buffer_periods: the number of periods in one alsa buffer.
837  * @rate: the frame rate.
838  * @fmt: the USB audio format information
839  * @sync_ep: the sync endpoint to use, if any
840  *
841  * Determine the number of URBs to be used on this endpoint.
842  * An endpoint must be configured before it can be started.
843  * An endpoint that is already running can not be reconfigured.
844  */
845 int snd_usb_endpoint_set_params(struct snd_usb_endpoint *ep,
846                                 snd_pcm_format_t pcm_format,
847                                 unsigned int channels,
848                                 unsigned int period_bytes,
849                                 unsigned int period_frames,
850                                 unsigned int buffer_periods,
851                                 unsigned int rate,
852                                 struct audioformat *fmt,
853                                 struct snd_usb_endpoint *sync_ep)
854 {
855         int err;
856 
857         if (ep->use_count != 0) {
858                 usb_audio_warn(ep->chip,
859                          "Unable to change format on ep #%x: already in use\n",
860                          ep->ep_num);
861                 return -EBUSY;
862         }
863 
864         /* release old buffers, if any */
865         release_urbs(ep, 0);
866 
867         ep->datainterval = fmt->datainterval;
868         ep->maxpacksize = fmt->maxpacksize;
869         ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX);
870 
871         if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_FULL)
872                 ep->freqn = get_usb_full_speed_rate(rate);
873         else
874                 ep->freqn = get_usb_high_speed_rate(rate);
875 
876         /* calculate the frequency in 16.16 format */
877         ep->freqm = ep->freqn;
878         ep->freqshift = INT_MIN;
879 
880         ep->phase = 0;
881 
882         switch (ep->type) {
883         case  SND_USB_ENDPOINT_TYPE_DATA:
884                 err = data_ep_set_params(ep, pcm_format, channels,
885                                          period_bytes, period_frames,
886                                          buffer_periods, fmt, sync_ep);
887                 break;
888         case  SND_USB_ENDPOINT_TYPE_SYNC:
889                 err = sync_ep_set_params(ep);
890                 break;
891         default:
892                 err = -EINVAL;
893         }
894 
895         usb_audio_dbg(ep->chip,
896                 "Setting params for ep #%x (type %d, %d urbs), ret=%d\n",
897                 ep->ep_num, ep->type, ep->nurbs, err);
898 
899         return err;
900 }
901 
902 /**
903  * snd_usb_endpoint_start: start an snd_usb_endpoint
904  *
905  * @ep:         the endpoint to start
906  * @can_sleep:  flag indicating whether the operation is executed in
907  *              non-atomic context
908  *
909  * A call to this function will increment the use count of the endpoint.
910  * In case it is not already running, the URBs for this endpoint will be
911  * submitted. Otherwise, this function does nothing.
912  *
913  * Must be balanced to calls of snd_usb_endpoint_stop().
914  *
915  * Returns an error if the URB submission failed, 0 in all other cases.
916  */
917 int snd_usb_endpoint_start(struct snd_usb_endpoint *ep, bool can_sleep)
918 {
919         int err;
920         unsigned int i;
921 
922         if (atomic_read(&ep->chip->shutdown))
923                 return -EBADFD;
924 
925         /* already running? */
926         if (++ep->use_count != 1)
927                 return 0;
928 
929         /* just to be sure */
930         deactivate_urbs(ep, false);
931         if (can_sleep)
932                 wait_clear_urbs(ep);
933 
934         ep->active_mask = 0;
935         ep->unlink_mask = 0;
936         ep->phase = 0;
937 
938         snd_usb_endpoint_start_quirk(ep);
939 
940         /*
941          * If this endpoint has a data endpoint as implicit feedback source,
942          * don't start the urbs here. Instead, mark them all as available,
943          * wait for the record urbs to return and queue the playback urbs
944          * from that context.
945          */
946 
947         set_bit(EP_FLAG_RUNNING, &ep->flags);
948 
949         if (snd_usb_endpoint_implicit_feedback_sink(ep)) {
950                 for (i = 0; i < ep->nurbs; i++) {
951                         struct snd_urb_ctx *ctx = ep->urb + i;
952                         list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
953                 }
954 
955                 return 0;
956         }
957 
958         for (i = 0; i < ep->nurbs; i++) {
959                 struct urb *urb = ep->urb[i].urb;
960 
961                 if (snd_BUG_ON(!urb))
962                         goto __error;
963 
964                 if (usb_pipeout(ep->pipe)) {
965                         prepare_outbound_urb(ep, urb->context);
966                 } else {
967                         prepare_inbound_urb(ep, urb->context);
968                 }
969 
970                 err = usb_submit_urb(urb, GFP_ATOMIC);
971                 if (err < 0) {
972                         usb_audio_err(ep->chip,
973                                 "cannot submit urb %d, error %d: %s\n",
974                                 i, err, usb_error_string(err));
975                         goto __error;
976                 }
977                 set_bit(i, &ep->active_mask);
978         }
979 
980         return 0;
981 
982 __error:
983         clear_bit(EP_FLAG_RUNNING, &ep->flags);
984         ep->use_count--;
985         deactivate_urbs(ep, false);
986         return -EPIPE;
987 }
988 
989 /**
990  * snd_usb_endpoint_stop: stop an snd_usb_endpoint
991  *
992  * @ep: the endpoint to stop (may be NULL)
993  *
994  * A call to this function will decrement the use count of the endpoint.
995  * In case the last user has requested the endpoint stop, the URBs will
996  * actually be deactivated.
997  *
998  * Must be balanced to calls of snd_usb_endpoint_start().
999  *
1000  * The caller needs to synchronize the pending stop operation via
1001  * snd_usb_endpoint_sync_pending_stop().
1002  */
1003 void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep)
1004 {
1005         if (!ep)
1006                 return;
1007 
1008         if (snd_BUG_ON(ep->use_count == 0))
1009                 return;
1010 
1011         if (--ep->use_count == 0) {
1012                 deactivate_urbs(ep, false);
1013                 ep->data_subs = NULL;
1014                 ep->sync_slave = NULL;
1015                 ep->retire_data_urb = NULL;
1016                 ep->prepare_data_urb = NULL;
1017                 set_bit(EP_FLAG_STOPPING, &ep->flags);
1018         }
1019 }
1020 
1021 /**
1022  * snd_usb_endpoint_deactivate: deactivate an snd_usb_endpoint
1023  *
1024  * @ep: the endpoint to deactivate
1025  *
1026  * If the endpoint is not currently in use, this functions will
1027  * deactivate its associated URBs.
1028  *
1029  * In case of any active users, this functions does nothing.
1030  */
1031 void snd_usb_endpoint_deactivate(struct snd_usb_endpoint *ep)
1032 {
1033         if (!ep)
1034                 return;
1035 
1036         if (ep->use_count != 0)
1037                 return;
1038 
1039         deactivate_urbs(ep, true);
1040         wait_clear_urbs(ep);
1041 }
1042 
1043 /**
1044  * snd_usb_endpoint_release: Tear down an snd_usb_endpoint
1045  *
1046  * @ep: the endpoint to release
1047  *
1048  * This function does not care for the endpoint's use count but will tear
1049  * down all the streaming URBs immediately.
1050  */
1051 void snd_usb_endpoint_release(struct snd_usb_endpoint *ep)
1052 {
1053         release_urbs(ep, 1);
1054 }
1055 
1056 /**
1057  * snd_usb_endpoint_free: Free the resources of an snd_usb_endpoint
1058  *
1059  * @ep: the endpoint to free
1060  *
1061  * This free all resources of the given ep.
1062  */
1063 void snd_usb_endpoint_free(struct snd_usb_endpoint *ep)
1064 {
1065         kfree(ep);
1066 }
1067 
1068 /**
1069  * snd_usb_handle_sync_urb: parse an USB sync packet
1070  *
1071  * @ep: the endpoint to handle the packet
1072  * @sender: the sending endpoint
1073  * @urb: the received packet
1074  *
1075  * This function is called from the context of an endpoint that received
1076  * the packet and is used to let another endpoint object handle the payload.
1077  */
1078 void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
1079                              struct snd_usb_endpoint *sender,
1080                              const struct urb *urb)
1081 {
1082         int shift;
1083         unsigned int f;
1084         unsigned long flags;
1085 
1086         snd_BUG_ON(ep == sender);
1087 
1088         /*
1089          * In case the endpoint is operating in implicit feedback mode, prepare
1090          * a new outbound URB that has the same layout as the received packet
1091          * and add it to the list of pending urbs. queue_pending_output_urbs()
1092          * will take care of them later.
1093          */
1094         if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1095             ep->use_count != 0) {
1096 
1097                 /* implicit feedback case */
1098                 int i, bytes = 0;
1099                 struct snd_urb_ctx *in_ctx;
1100                 struct snd_usb_packet_info *out_packet;
1101 
1102                 in_ctx = urb->context;
1103 
1104                 /* Count overall packet size */
1105                 for (i = 0; i < in_ctx->packets; i++)
1106                         if (urb->iso_frame_desc[i].status == 0)
1107                                 bytes += urb->iso_frame_desc[i].actual_length;
1108 
1109                 /*
1110                  * skip empty packets. At least M-Audio's Fast Track Ultra stops
1111                  * streaming once it received a 0-byte OUT URB
1112                  */
1113                 if (bytes == 0)
1114                         return;
1115 
1116                 spin_lock_irqsave(&ep->lock, flags);
1117                 out_packet = ep->next_packet + ep->next_packet_write_pos;
1118 
1119                 /*
1120                  * Iterate through the inbound packet and prepare the lengths
1121                  * for the output packet. The OUT packet we are about to send
1122                  * will have the same amount of payload bytes per stride as the
1123                  * IN packet we just received. Since the actual size is scaled
1124                  * by the stride, use the sender stride to calculate the length
1125                  * in case the number of channels differ between the implicitly
1126                  * fed-back endpoint and the synchronizing endpoint.
1127                  */
1128 
1129                 out_packet->packets = in_ctx->packets;
1130                 for (i = 0; i < in_ctx->packets; i++) {
1131                         if (urb->iso_frame_desc[i].status == 0)
1132                                 out_packet->packet_size[i] =
1133                                         urb->iso_frame_desc[i].actual_length / sender->stride;
1134                         else
1135                                 out_packet->packet_size[i] = 0;
1136                 }
1137 
1138                 ep->next_packet_write_pos++;
1139                 ep->next_packet_write_pos %= MAX_URBS;
1140                 spin_unlock_irqrestore(&ep->lock, flags);
1141                 queue_pending_output_urbs(ep);
1142 
1143                 return;
1144         }
1145 
1146         /*
1147          * process after playback sync complete
1148          *
1149          * Full speed devices report feedback values in 10.14 format as samples
1150          * per frame, high speed devices in 16.16 format as samples per
1151          * microframe.
1152          *
1153          * Because the Audio Class 1 spec was written before USB 2.0, many high
1154          * speed devices use a wrong interpretation, some others use an
1155          * entirely different format.
1156          *
1157          * Therefore, we cannot predict what format any particular device uses
1158          * and must detect it automatically.
1159          */
1160 
1161         if (urb->iso_frame_desc[0].status != 0 ||
1162             urb->iso_frame_desc[0].actual_length < 3)
1163                 return;
1164 
1165         f = le32_to_cpup(urb->transfer_buffer);
1166         if (urb->iso_frame_desc[0].actual_length == 3)
1167                 f &= 0x00ffffff;
1168         else
1169                 f &= 0x0fffffff;
1170 
1171         if (f == 0)
1172                 return;
1173 
1174         if (unlikely(sender->udh01_fb_quirk)) {
1175                 /*
1176                  * The TEAC UD-H01 firmware sometimes changes the feedback value
1177                  * by +/- 0x1.0000.
1178                  */
1179                 if (f < ep->freqn - 0x8000)
1180                         f += 0x10000;
1181                 else if (f > ep->freqn + 0x8000)
1182                         f -= 0x10000;
1183         } else if (unlikely(ep->freqshift == INT_MIN)) {
1184                 /*
1185                  * The first time we see a feedback value, determine its format
1186                  * by shifting it left or right until it matches the nominal
1187                  * frequency value.  This assumes that the feedback does not
1188                  * differ from the nominal value more than +50% or -25%.
1189                  */
1190                 shift = 0;
1191                 while (f < ep->freqn - ep->freqn / 4) {
1192                         f <<= 1;
1193                         shift++;
1194                 }
1195                 while (f > ep->freqn + ep->freqn / 2) {
1196                         f >>= 1;
1197                         shift--;
1198                 }
1199                 ep->freqshift = shift;
1200         } else if (ep->freqshift >= 0)
1201                 f <<= ep->freqshift;
1202         else
1203                 f >>= -ep->freqshift;
1204 
1205         if (likely(f >= ep->freqn - ep->freqn / 8 && f <= ep->freqmax)) {
1206                 /*
1207                  * If the frequency looks valid, set it.
1208                  * This value is referred to in prepare_playback_urb().
1209                  */
1210                 spin_lock_irqsave(&ep->lock, flags);
1211                 ep->freqm = f;
1212                 spin_unlock_irqrestore(&ep->lock, flags);
1213         } else {
1214                 /*
1215                  * Out of range; maybe the shift value is wrong.
1216                  * Reset it so that we autodetect again the next time.
1217                  */
1218                 ep->freqshift = INT_MIN;
1219         }
1220 }
1221 
1222 

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