1 // SPDX-License-Identifier: GPL-2.0-or-later
6 #include <linux/init.h>
7 #include <linux/ratelimit.h>
9 #include <linux/usb/audio.h>
10 #include <linux/slab.h>
12 #include <sound/core.h>
13 #include <sound/pcm.h>
14 #include <sound/pcm_params.h>
30 /* interface refcounting */
31 struct snd_usb_iface_ref {
36 struct list_head list;
39 /* clock refcounting */
40 struct snd_usb_clock_ref {
46 struct list_head list;
50 * snd_usb_endpoint is a model that abstracts everything related to an
51 * USB endpoint and its streaming.
53 * There are functions to activate and deactivate the streaming URBs and
54 * optional callbacks to let the pcm logic handle the actual content of the
55 * packets for playback and record. Thus, the bus streaming and the audio
56 * handlers are fully decoupled.
58 * There are two different types of endpoints in audio applications.
60 * SND_USB_ENDPOINT_TYPE_DATA handles full audio data payload for both
61 * inbound and outbound traffic.
63 * SND_USB_ENDPOINT_TYPE_SYNC endpoints are for inbound traffic only and
64 * expect the payload to carry Q10.14 / Q16.16 formatted sync information
67 * Each endpoint has to be configured prior to being used by calling
68 * snd_usb_endpoint_set_params().
70 * The model incorporates a reference counting, so that multiple users
71 * can call snd_usb_endpoint_start() and snd_usb_endpoint_stop(), and
72 * only the first user will effectively start the URBs, and only the last
73 * one to stop it will tear the URBs down again.
77 * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
78 * this will overflow at approx 524 kHz
80 static inline unsigned get_usb_full_speed_rate(unsigned int rate)
82 return ((rate << 13) + 62) / 125;
86 * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
87 * this will overflow at approx 4 MHz
89 static inline unsigned get_usb_high_speed_rate(unsigned int rate)
91 return ((rate << 10) + 62) / 125;
97 static void release_urb_ctx(struct snd_urb_ctx *u)
99 if (u->urb && u->buffer_size)
100 usb_free_coherent(u->ep->chip->dev, u->buffer_size,
101 u->urb->transfer_buffer,
102 u->urb->transfer_dma);
103 usb_free_urb(u->urb);
108 static const char *usb_error_string(int err)
114 return "endpoint not enabled";
116 return "endpoint stalled";
118 return "not enough bandwidth";
120 return "device disabled";
122 return "device suspended";
127 return "internal error";
129 return "unknown error";
133 static inline bool ep_state_running(struct snd_usb_endpoint *ep)
135 return atomic_read(&ep->state) == EP_STATE_RUNNING;
138 static inline bool ep_state_update(struct snd_usb_endpoint *ep, int old, int new)
140 return atomic_try_cmpxchg(&ep->state, &old, new);
144 * snd_usb_endpoint_implicit_feedback_sink: Report endpoint usage type
146 * @ep: The snd_usb_endpoint
148 * Determine whether an endpoint is driven by an implicit feedback
149 * data endpoint source.
151 int snd_usb_endpoint_implicit_feedback_sink(struct snd_usb_endpoint *ep)
153 return ep->implicit_fb_sync && usb_pipeout(ep->pipe);
157 * Return the number of samples to be sent in the next packet
158 * for streaming based on information derived from sync endpoints
160 * This won't be used for implicit feedback which takes the packet size
161 * returned from the sync source
163 static int slave_next_packet_size(struct snd_usb_endpoint *ep,
171 return ep->maxframesize;
173 spin_lock_irqsave(&ep->lock, flags);
174 phase = (ep->phase & 0xffff) + (ep->freqm << ep->datainterval);
175 ret = min(phase >> 16, ep->maxframesize);
176 if (avail && ret >= avail)
180 spin_unlock_irqrestore(&ep->lock, flags);
186 * Return the number of samples to be sent in the next packet
187 * for adaptive and synchronous endpoints
189 static int next_packet_size(struct snd_usb_endpoint *ep, unsigned int avail)
191 unsigned int sample_accum;
195 return ep->maxframesize;
197 sample_accum = ep->sample_accum + ep->sample_rem;
198 if (sample_accum >= ep->pps) {
199 sample_accum -= ep->pps;
200 ret = ep->packsize[1];
202 ret = ep->packsize[0];
204 if (avail && ret >= avail)
207 ep->sample_accum = sample_accum;
213 * snd_usb_endpoint_next_packet_size: Return the number of samples to be sent
216 * If the size is equal or exceeds @avail, don't proceed but return -EAGAIN
217 * Exception: @avail = 0 for skipping the check.
219 int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep,
220 struct snd_urb_ctx *ctx, int idx,
225 packet = ctx->packet_size[idx];
227 if (avail && packet >= avail)
233 return slave_next_packet_size(ep, avail);
235 return next_packet_size(ep, avail);
238 static void call_retire_callback(struct snd_usb_endpoint *ep,
241 struct snd_usb_substream *data_subs;
243 data_subs = READ_ONCE(ep->data_subs);
244 if (data_subs && ep->retire_data_urb)
245 ep->retire_data_urb(data_subs, urb);
248 static void retire_outbound_urb(struct snd_usb_endpoint *ep,
249 struct snd_urb_ctx *urb_ctx)
251 call_retire_callback(ep, urb_ctx->urb);
254 static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
255 struct snd_usb_endpoint *sender,
256 const struct urb *urb);
258 static void retire_inbound_urb(struct snd_usb_endpoint *ep,
259 struct snd_urb_ctx *urb_ctx)
261 struct urb *urb = urb_ctx->urb;
262 struct snd_usb_endpoint *sync_sink;
264 if (unlikely(ep->skip_packets > 0)) {
269 sync_sink = READ_ONCE(ep->sync_sink);
271 snd_usb_handle_sync_urb(sync_sink, ep, urb);
273 call_retire_callback(ep, urb);
276 static inline bool has_tx_length_quirk(struct snd_usb_audio *chip)
278 return chip->quirk_flags & QUIRK_FLAG_TX_LENGTH;
281 static void prepare_silent_urb(struct snd_usb_endpoint *ep,
282 struct snd_urb_ctx *ctx)
284 struct urb *urb = ctx->urb;
285 unsigned int offs = 0;
286 unsigned int extra = 0;
287 __le32 packet_length;
290 /* For tx_length_quirk, put packet length at start of packet */
291 if (has_tx_length_quirk(ep->chip))
292 extra = sizeof(packet_length);
294 for (i = 0; i < ctx->packets; ++i) {
299 counts = snd_usb_endpoint_next_packet_size(ep, ctx, i, 0);
300 length = counts * ep->stride; /* number of silent bytes */
301 offset = offs * ep->stride + extra * i;
302 urb->iso_frame_desc[i].offset = offset;
303 urb->iso_frame_desc[i].length = length + extra;
305 packet_length = cpu_to_le32(length);
306 memcpy(urb->transfer_buffer + offset,
307 &packet_length, sizeof(packet_length));
309 memset(urb->transfer_buffer + offset + extra,
310 ep->silence_value, length);
314 urb->number_of_packets = ctx->packets;
315 urb->transfer_buffer_length = offs * ep->stride + ctx->packets * extra;
320 * Prepare a PLAYBACK urb for submission to the bus.
322 static int prepare_outbound_urb(struct snd_usb_endpoint *ep,
323 struct snd_urb_ctx *ctx,
326 struct urb *urb = ctx->urb;
327 unsigned char *cp = urb->transfer_buffer;
328 struct snd_usb_substream *data_subs;
330 urb->dev = ep->chip->dev; /* we need to set this at each time */
333 case SND_USB_ENDPOINT_TYPE_DATA:
334 data_subs = READ_ONCE(ep->data_subs);
335 if (data_subs && ep->prepare_data_urb)
336 return ep->prepare_data_urb(data_subs, urb, in_stream_lock);
337 /* no data provider, so send silence */
338 prepare_silent_urb(ep, ctx);
341 case SND_USB_ENDPOINT_TYPE_SYNC:
342 if (snd_usb_get_speed(ep->chip->dev) >= USB_SPEED_HIGH) {
344 * fill the length and offset of each urb descriptor.
345 * the fixed 12.13 frequency is passed as 16.16 through the pipe.
347 urb->iso_frame_desc[0].length = 4;
348 urb->iso_frame_desc[0].offset = 0;
350 cp[1] = ep->freqn >> 8;
351 cp[2] = ep->freqn >> 16;
352 cp[3] = ep->freqn >> 24;
355 * fill the length and offset of each urb descriptor.
356 * the fixed 10.14 frequency is passed through the pipe.
358 urb->iso_frame_desc[0].length = 3;
359 urb->iso_frame_desc[0].offset = 0;
360 cp[0] = ep->freqn >> 2;
361 cp[1] = ep->freqn >> 10;
362 cp[2] = ep->freqn >> 18;
371 * Prepare a CAPTURE or SYNC urb for submission to the bus.
373 static int prepare_inbound_urb(struct snd_usb_endpoint *ep,
374 struct snd_urb_ctx *urb_ctx)
377 struct urb *urb = urb_ctx->urb;
379 urb->dev = ep->chip->dev; /* we need to set this at each time */
382 case SND_USB_ENDPOINT_TYPE_DATA:
384 for (i = 0; i < urb_ctx->packets; i++) {
385 urb->iso_frame_desc[i].offset = offs;
386 urb->iso_frame_desc[i].length = ep->curpacksize;
387 offs += ep->curpacksize;
390 urb->transfer_buffer_length = offs;
391 urb->number_of_packets = urb_ctx->packets;
394 case SND_USB_ENDPOINT_TYPE_SYNC:
395 urb->iso_frame_desc[0].length = min(4u, ep->syncmaxsize);
396 urb->iso_frame_desc[0].offset = 0;
402 /* notify an error as XRUN to the assigned PCM data substream */
403 static void notify_xrun(struct snd_usb_endpoint *ep)
405 struct snd_usb_substream *data_subs;
407 data_subs = READ_ONCE(ep->data_subs);
408 if (data_subs && data_subs->pcm_substream)
409 snd_pcm_stop_xrun(data_subs->pcm_substream);
412 static struct snd_usb_packet_info *
413 next_packet_fifo_enqueue(struct snd_usb_endpoint *ep)
415 struct snd_usb_packet_info *p;
417 p = ep->next_packet + (ep->next_packet_head + ep->next_packet_queued) %
418 ARRAY_SIZE(ep->next_packet);
419 ep->next_packet_queued++;
423 static struct snd_usb_packet_info *
424 next_packet_fifo_dequeue(struct snd_usb_endpoint *ep)
426 struct snd_usb_packet_info *p;
428 p = ep->next_packet + ep->next_packet_head;
429 ep->next_packet_head++;
430 ep->next_packet_head %= ARRAY_SIZE(ep->next_packet);
431 ep->next_packet_queued--;
435 static void push_back_to_ready_list(struct snd_usb_endpoint *ep,
436 struct snd_urb_ctx *ctx)
440 spin_lock_irqsave(&ep->lock, flags);
441 list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
442 spin_unlock_irqrestore(&ep->lock, flags);
446 * Send output urbs that have been prepared previously. URBs are dequeued
447 * from ep->ready_playback_urbs and in case there aren't any available
448 * or there are no packets that have been prepared, this function does
451 * The reason why the functionality of sending and preparing URBs is separated
452 * is that host controllers don't guarantee the order in which they return
453 * inbound and outbound packets to their submitters.
455 * This function is used both for implicit feedback endpoints and in low-
456 * latency playback mode.
458 void snd_usb_queue_pending_output_urbs(struct snd_usb_endpoint *ep,
461 bool implicit_fb = snd_usb_endpoint_implicit_feedback_sink(ep);
463 while (ep_state_running(ep)) {
466 struct snd_usb_packet_info *packet;
467 struct snd_urb_ctx *ctx = NULL;
470 spin_lock_irqsave(&ep->lock, flags);
471 if ((!implicit_fb || ep->next_packet_queued > 0) &&
472 !list_empty(&ep->ready_playback_urbs)) {
473 /* take URB out of FIFO */
474 ctx = list_first_entry(&ep->ready_playback_urbs,
475 struct snd_urb_ctx, ready_list);
476 list_del_init(&ctx->ready_list);
478 packet = next_packet_fifo_dequeue(ep);
480 spin_unlock_irqrestore(&ep->lock, flags);
485 /* copy over the length information */
487 for (i = 0; i < packet->packets; i++)
488 ctx->packet_size[i] = packet->packet_size[i];
491 /* call the data handler to fill in playback data */
492 err = prepare_outbound_urb(ep, ctx, in_stream_lock);
493 /* can be stopped during prepare callback */
494 if (unlikely(!ep_state_running(ep)))
497 /* push back to ready list again for -EAGAIN */
499 push_back_to_ready_list(ep, ctx);
505 err = usb_submit_urb(ctx->urb, GFP_ATOMIC);
507 usb_audio_err(ep->chip,
508 "Unable to submit urb #%d: %d at %s\n",
509 ctx->index, err, __func__);
514 set_bit(ctx->index, &ep->active_mask);
515 atomic_inc(&ep->submitted_urbs);
520 * complete callback for urbs
522 static void snd_complete_urb(struct urb *urb)
524 struct snd_urb_ctx *ctx = urb->context;
525 struct snd_usb_endpoint *ep = ctx->ep;
528 if (unlikely(urb->status == -ENOENT || /* unlinked */
529 urb->status == -ENODEV || /* device removed */
530 urb->status == -ECONNRESET || /* unlinked */
531 urb->status == -ESHUTDOWN)) /* device disabled */
533 /* device disconnected */
534 if (unlikely(atomic_read(&ep->chip->shutdown)))
537 if (unlikely(!ep_state_running(ep)))
540 if (usb_pipeout(ep->pipe)) {
541 retire_outbound_urb(ep, ctx);
542 /* can be stopped during retire callback */
543 if (unlikely(!ep_state_running(ep)))
546 /* in low-latency and implicit-feedback modes, push back the
547 * URB to ready list at first, then process as much as possible
549 if (ep->lowlatency_playback ||
550 snd_usb_endpoint_implicit_feedback_sink(ep)) {
551 push_back_to_ready_list(ep, ctx);
552 clear_bit(ctx->index, &ep->active_mask);
553 snd_usb_queue_pending_output_urbs(ep, false);
554 atomic_dec(&ep->submitted_urbs); /* decrement at last */
558 /* in non-lowlatency mode, no error handling for prepare */
559 prepare_outbound_urb(ep, ctx, false);
560 /* can be stopped during prepare callback */
561 if (unlikely(!ep_state_running(ep)))
564 retire_inbound_urb(ep, ctx);
565 /* can be stopped during retire callback */
566 if (unlikely(!ep_state_running(ep)))
569 prepare_inbound_urb(ep, ctx);
572 err = usb_submit_urb(urb, GFP_ATOMIC);
576 usb_audio_err(ep->chip, "cannot submit urb (err = %d)\n", err);
580 clear_bit(ctx->index, &ep->active_mask);
581 atomic_dec(&ep->submitted_urbs);
585 * Find or create a refcount object for the given interface
587 * The objects are released altogether in snd_usb_endpoint_free_all()
589 static struct snd_usb_iface_ref *
590 iface_ref_find(struct snd_usb_audio *chip, int iface)
592 struct snd_usb_iface_ref *ip;
594 list_for_each_entry(ip, &chip->iface_ref_list, list)
595 if (ip->iface == iface)
598 ip = kzalloc(sizeof(*ip), GFP_KERNEL);
602 list_add_tail(&ip->list, &chip->iface_ref_list);
606 /* Similarly, a refcount object for clock */
607 static struct snd_usb_clock_ref *
608 clock_ref_find(struct snd_usb_audio *chip, int clock)
610 struct snd_usb_clock_ref *ref;
612 list_for_each_entry(ref, &chip->clock_ref_list, list)
613 if (ref->clock == clock)
616 ref = kzalloc(sizeof(*ref), GFP_KERNEL);
620 atomic_set(&ref->locked, 0);
621 list_add_tail(&ref->list, &chip->clock_ref_list);
626 * Get the existing endpoint object corresponding EP
627 * Returns NULL if not present.
629 struct snd_usb_endpoint *
630 snd_usb_get_endpoint(struct snd_usb_audio *chip, int ep_num)
632 struct snd_usb_endpoint *ep;
634 list_for_each_entry(ep, &chip->ep_list, list) {
635 if (ep->ep_num == ep_num)
642 #define ep_type_name(type) \
643 (type == SND_USB_ENDPOINT_TYPE_DATA ? "data" : "sync")
646 * snd_usb_add_endpoint: Add an endpoint to an USB audio chip
649 * @ep_num: The number of the endpoint to use
650 * @type: SND_USB_ENDPOINT_TYPE_DATA or SND_USB_ENDPOINT_TYPE_SYNC
652 * If the requested endpoint has not been added to the given chip before,
653 * a new instance is created.
655 * Returns zero on success or a negative error code.
657 * New endpoints will be added to chip->ep_list and freed by
658 * calling snd_usb_endpoint_free_all().
660 * For SND_USB_ENDPOINT_TYPE_SYNC, the caller needs to guarantee that
661 * bNumEndpoints > 1 beforehand.
663 int snd_usb_add_endpoint(struct snd_usb_audio *chip, int ep_num, int type)
665 struct snd_usb_endpoint *ep;
668 ep = snd_usb_get_endpoint(chip, ep_num);
672 usb_audio_dbg(chip, "Creating new %s endpoint #%x\n",
675 ep = kzalloc(sizeof(*ep), GFP_KERNEL);
680 spin_lock_init(&ep->lock);
683 INIT_LIST_HEAD(&ep->ready_playback_urbs);
684 atomic_set(&ep->submitted_urbs, 0);
686 is_playback = ((ep_num & USB_ENDPOINT_DIR_MASK) == USB_DIR_OUT);
687 ep_num &= USB_ENDPOINT_NUMBER_MASK;
689 ep->pipe = usb_sndisocpipe(chip->dev, ep_num);
691 ep->pipe = usb_rcvisocpipe(chip->dev, ep_num);
693 list_add_tail(&ep->list, &chip->ep_list);
697 /* Set up syncinterval and maxsyncsize for a sync EP */
698 static void endpoint_set_syncinterval(struct snd_usb_audio *chip,
699 struct snd_usb_endpoint *ep)
701 struct usb_host_interface *alts;
702 struct usb_endpoint_descriptor *desc;
704 alts = snd_usb_get_host_interface(chip, ep->iface, ep->altsetting);
708 desc = get_endpoint(alts, ep->ep_idx);
709 if (desc->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
710 desc->bRefresh >= 1 && desc->bRefresh <= 9)
711 ep->syncinterval = desc->bRefresh;
712 else if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL)
713 ep->syncinterval = 1;
714 else if (desc->bInterval >= 1 && desc->bInterval <= 16)
715 ep->syncinterval = desc->bInterval - 1;
717 ep->syncinterval = 3;
719 ep->syncmaxsize = le16_to_cpu(desc->wMaxPacketSize);
722 static bool endpoint_compatible(struct snd_usb_endpoint *ep,
723 const struct audioformat *fp,
724 const struct snd_pcm_hw_params *params)
728 if (ep->cur_audiofmt != fp)
730 if (ep->cur_rate != params_rate(params) ||
731 ep->cur_format != params_format(params) ||
732 ep->cur_period_frames != params_period_size(params) ||
733 ep->cur_buffer_periods != params_periods(params))
739 * Check whether the given fp and hw params are compatible with the current
740 * setup of the target EP for implicit feedback sync
742 bool snd_usb_endpoint_compatible(struct snd_usb_audio *chip,
743 struct snd_usb_endpoint *ep,
744 const struct audioformat *fp,
745 const struct snd_pcm_hw_params *params)
749 mutex_lock(&chip->mutex);
750 ret = endpoint_compatible(ep, fp, params);
751 mutex_unlock(&chip->mutex);
756 * snd_usb_endpoint_open: Open the endpoint
758 * Called from hw_params to assign the endpoint to the substream.
759 * It's reference-counted, and only the first opener is allowed to set up
760 * arbitrary parameters. The later opener must be compatible with the
761 * former opened parameters.
762 * The endpoint needs to be closed via snd_usb_endpoint_close() later.
764 * Note that this function doesn't configure the endpoint. The substream
765 * needs to set it up later via snd_usb_endpoint_set_params() and
766 * snd_usb_endpoint_prepare().
768 struct snd_usb_endpoint *
769 snd_usb_endpoint_open(struct snd_usb_audio *chip,
770 const struct audioformat *fp,
771 const struct snd_pcm_hw_params *params,
775 struct snd_usb_endpoint *ep;
776 int ep_num = is_sync_ep ? fp->sync_ep : fp->endpoint;
778 mutex_lock(&chip->mutex);
779 ep = snd_usb_get_endpoint(chip, ep_num);
781 usb_audio_err(chip, "Cannot find EP 0x%x to open\n", ep_num);
787 ep->iface = fp->sync_iface;
788 ep->altsetting = fp->sync_altsetting;
789 ep->ep_idx = fp->sync_ep_idx;
791 ep->iface = fp->iface;
792 ep->altsetting = fp->altsetting;
793 ep->ep_idx = fp->ep_idx;
795 usb_audio_dbg(chip, "Open EP 0x%x, iface=%d:%d, idx=%d\n",
796 ep_num, ep->iface, ep->altsetting, ep->ep_idx);
798 ep->iface_ref = iface_ref_find(chip, ep->iface);
799 if (!ep->iface_ref) {
804 if (fp->protocol != UAC_VERSION_1) {
805 ep->clock_ref = clock_ref_find(chip, fp->clock);
806 if (!ep->clock_ref) {
810 ep->clock_ref->opened++;
813 ep->cur_audiofmt = fp;
814 ep->cur_channels = fp->channels;
815 ep->cur_rate = params_rate(params);
816 ep->cur_format = params_format(params);
817 ep->cur_frame_bytes = snd_pcm_format_physical_width(ep->cur_format) *
818 ep->cur_channels / 8;
819 ep->cur_period_frames = params_period_size(params);
820 ep->cur_period_bytes = ep->cur_period_frames * ep->cur_frame_bytes;
821 ep->cur_buffer_periods = params_periods(params);
823 if (ep->type == SND_USB_ENDPOINT_TYPE_SYNC)
824 endpoint_set_syncinterval(chip, ep);
826 ep->implicit_fb_sync = fp->implicit_fb;
827 ep->need_setup = true;
828 ep->need_prepare = true;
829 ep->fixed_rate = fixed_rate;
831 usb_audio_dbg(chip, " channels=%d, rate=%d, format=%s, period_bytes=%d, periods=%d, implicit_fb=%d\n",
832 ep->cur_channels, ep->cur_rate,
833 snd_pcm_format_name(ep->cur_format),
834 ep->cur_period_bytes, ep->cur_buffer_periods,
835 ep->implicit_fb_sync);
838 if (WARN_ON(!ep->iface_ref)) {
843 if (!endpoint_compatible(ep, fp, params)) {
844 usb_audio_err(chip, "Incompatible EP setup for 0x%x\n",
850 usb_audio_dbg(chip, "Reopened EP 0x%x (count %d)\n",
854 if (!ep->iface_ref->opened++)
855 ep->iface_ref->need_setup = true;
860 mutex_unlock(&chip->mutex);
865 * snd_usb_endpoint_set_sync: Link data and sync endpoints
867 * Pass NULL to sync_ep to unlink again
869 void snd_usb_endpoint_set_sync(struct snd_usb_audio *chip,
870 struct snd_usb_endpoint *data_ep,
871 struct snd_usb_endpoint *sync_ep)
873 data_ep->sync_source = sync_ep;
877 * Set data endpoint callbacks and the assigned data stream
879 * Called at PCM trigger and cleanups.
880 * Pass NULL to deactivate each callback.
882 void snd_usb_endpoint_set_callback(struct snd_usb_endpoint *ep,
883 int (*prepare)(struct snd_usb_substream *subs,
885 bool in_stream_lock),
886 void (*retire)(struct snd_usb_substream *subs,
888 struct snd_usb_substream *data_subs)
890 ep->prepare_data_urb = prepare;
891 ep->retire_data_urb = retire;
893 ep->lowlatency_playback = data_subs->lowlatency_playback;
895 ep->lowlatency_playback = false;
896 WRITE_ONCE(ep->data_subs, data_subs);
899 static int endpoint_set_interface(struct snd_usb_audio *chip,
900 struct snd_usb_endpoint *ep,
903 int altset = set ? ep->altsetting : 0;
906 if (ep->iface_ref->altset == altset)
909 usb_audio_dbg(chip, "Setting usb interface %d:%d for EP 0x%x\n",
910 ep->iface, altset, ep->ep_num);
911 err = usb_set_interface(chip->dev, ep->iface, altset);
913 usb_audio_err(chip, "%d:%d: usb_set_interface failed (%d)\n",
914 ep->iface, altset, err);
918 if (chip->quirk_flags & QUIRK_FLAG_IFACE_DELAY)
920 ep->iface_ref->altset = altset;
925 * snd_usb_endpoint_close: Close the endpoint
927 * Unreference the already opened endpoint via snd_usb_endpoint_open().
929 void snd_usb_endpoint_close(struct snd_usb_audio *chip,
930 struct snd_usb_endpoint *ep)
932 mutex_lock(&chip->mutex);
933 usb_audio_dbg(chip, "Closing EP 0x%x (count %d)\n",
934 ep->ep_num, ep->opened);
936 if (!--ep->iface_ref->opened &&
937 !(chip->quirk_flags & QUIRK_FLAG_IFACE_SKIP_CLOSE))
938 endpoint_set_interface(chip, ep, false);
942 if (!--ep->clock_ref->opened)
943 ep->clock_ref->rate = 0;
947 ep->cur_audiofmt = NULL;
949 ep->iface_ref = NULL;
950 ep->clock_ref = NULL;
951 usb_audio_dbg(chip, "EP 0x%x closed\n", ep->ep_num);
953 mutex_unlock(&chip->mutex);
956 /* Prepare for suspening EP, called from the main suspend handler */
957 void snd_usb_endpoint_suspend(struct snd_usb_endpoint *ep)
959 ep->need_prepare = true;
961 ep->iface_ref->need_setup = true;
963 ep->clock_ref->rate = 0;
967 * wait until all urbs are processed.
969 static int wait_clear_urbs(struct snd_usb_endpoint *ep)
971 unsigned long end_time = jiffies + msecs_to_jiffies(1000);
974 if (atomic_read(&ep->state) != EP_STATE_STOPPING)
978 alive = atomic_read(&ep->submitted_urbs);
982 schedule_timeout_uninterruptible(1);
983 } while (time_before(jiffies, end_time));
986 usb_audio_err(ep->chip,
987 "timeout: still %d active urbs on EP #%x\n",
990 if (ep_state_update(ep, EP_STATE_STOPPING, EP_STATE_STOPPED)) {
991 ep->sync_sink = NULL;
992 snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
998 /* sync the pending stop operation;
999 * this function itself doesn't trigger the stop operation
1001 void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep)
1004 wait_clear_urbs(ep);
1010 * This function moves the EP to STOPPING state if it's being RUNNING.
1012 static int stop_urbs(struct snd_usb_endpoint *ep, bool force, bool keep_pending)
1015 unsigned long flags;
1017 if (!force && atomic_read(&ep->running))
1020 if (!ep_state_update(ep, EP_STATE_RUNNING, EP_STATE_STOPPING))
1023 spin_lock_irqsave(&ep->lock, flags);
1024 INIT_LIST_HEAD(&ep->ready_playback_urbs);
1025 ep->next_packet_head = 0;
1026 ep->next_packet_queued = 0;
1027 spin_unlock_irqrestore(&ep->lock, flags);
1032 for (i = 0; i < ep->nurbs; i++) {
1033 if (test_bit(i, &ep->active_mask)) {
1034 if (!test_and_set_bit(i, &ep->unlink_mask)) {
1035 struct urb *u = ep->urb[i].urb;
1045 * release an endpoint's urbs
1047 static int release_urbs(struct snd_usb_endpoint *ep, bool force)
1051 /* route incoming urbs to nirvana */
1052 snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
1054 /* stop and unlink urbs */
1055 err = stop_urbs(ep, force, false);
1059 wait_clear_urbs(ep);
1061 for (i = 0; i < ep->nurbs; i++)
1062 release_urb_ctx(&ep->urb[i]);
1064 usb_free_coherent(ep->chip->dev, SYNC_URBS * 4,
1065 ep->syncbuf, ep->sync_dma);
1073 * configure a data endpoint
1075 static int data_ep_set_params(struct snd_usb_endpoint *ep)
1077 struct snd_usb_audio *chip = ep->chip;
1078 unsigned int maxsize, minsize, packs_per_ms, max_packs_per_urb;
1079 unsigned int max_packs_per_period, urbs_per_period, urb_packs;
1080 unsigned int max_urbs, i;
1081 const struct audioformat *fmt = ep->cur_audiofmt;
1082 int frame_bits = ep->cur_frame_bytes * 8;
1083 int tx_length_quirk = (has_tx_length_quirk(chip) &&
1084 usb_pipeout(ep->pipe));
1086 usb_audio_dbg(chip, "Setting params for data EP 0x%x, pipe 0x%x\n",
1087 ep->ep_num, ep->pipe);
1089 if (ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) {
1091 * When operating in DSD DOP mode, the size of a sample frame
1092 * in hardware differs from the actual physical format width
1093 * because we need to make room for the DOP markers.
1095 frame_bits += ep->cur_channels << 3;
1098 ep->datainterval = fmt->datainterval;
1099 ep->stride = frame_bits >> 3;
1101 switch (ep->cur_format) {
1102 case SNDRV_PCM_FORMAT_U8:
1103 ep->silence_value = 0x80;
1105 case SNDRV_PCM_FORMAT_DSD_U8:
1106 case SNDRV_PCM_FORMAT_DSD_U16_LE:
1107 case SNDRV_PCM_FORMAT_DSD_U32_LE:
1108 case SNDRV_PCM_FORMAT_DSD_U16_BE:
1109 case SNDRV_PCM_FORMAT_DSD_U32_BE:
1110 ep->silence_value = 0x69;
1113 ep->silence_value = 0;
1116 /* assume max. frequency is 50% higher than nominal */
1117 ep->freqmax = ep->freqn + (ep->freqn >> 1);
1118 /* Round up freqmax to nearest integer in order to calculate maximum
1119 * packet size, which must represent a whole number of frames.
1120 * This is accomplished by adding 0x0.ffff before converting the
1121 * Q16.16 format into integer.
1122 * In order to accurately calculate the maximum packet size when
1123 * the data interval is more than 1 (i.e. ep->datainterval > 0),
1124 * multiply by the data interval prior to rounding. For instance,
1125 * a freqmax of 41 kHz will result in a max packet size of 6 (5.125)
1126 * frames with a data interval of 1, but 11 (10.25) frames with a
1127 * data interval of 2.
1128 * (ep->freqmax << ep->datainterval overflows at 8.192 MHz for the
1129 * maximum datainterval value of 3, at USB full speed, higher for
1130 * USB high speed, noting that ep->freqmax is in units of
1131 * frames per packet in Q16.16 format.)
1133 maxsize = (((ep->freqmax << ep->datainterval) + 0xffff) >> 16) *
1135 if (tx_length_quirk)
1136 maxsize += sizeof(__le32); /* Space for length descriptor */
1137 /* but wMaxPacketSize might reduce this */
1138 if (ep->maxpacksize && ep->maxpacksize < maxsize) {
1139 /* whatever fits into a max. size packet */
1140 unsigned int data_maxsize = maxsize = ep->maxpacksize;
1142 if (tx_length_quirk)
1143 /* Need to remove the length descriptor to calc freq */
1144 data_maxsize -= sizeof(__le32);
1145 ep->freqmax = (data_maxsize / (frame_bits >> 3))
1146 << (16 - ep->datainterval);
1150 ep->curpacksize = ep->maxpacksize;
1152 ep->curpacksize = maxsize;
1154 if (snd_usb_get_speed(chip->dev) != USB_SPEED_FULL) {
1155 packs_per_ms = 8 >> ep->datainterval;
1156 max_packs_per_urb = MAX_PACKS_HS;
1159 max_packs_per_urb = MAX_PACKS;
1161 if (ep->sync_source && !ep->implicit_fb_sync)
1162 max_packs_per_urb = min(max_packs_per_urb,
1163 1U << ep->sync_source->syncinterval);
1164 max_packs_per_urb = max(1u, max_packs_per_urb >> ep->datainterval);
1167 * Capture endpoints need to use small URBs because there's no way
1168 * to tell in advance where the next period will end, and we don't
1169 * want the next URB to complete much after the period ends.
1171 * Playback endpoints with implicit sync much use the same parameters
1172 * as their corresponding capture endpoint.
1174 if (usb_pipein(ep->pipe) || ep->implicit_fb_sync) {
1176 urb_packs = packs_per_ms;
1178 * Wireless devices can poll at a max rate of once per 4ms.
1179 * For dataintervals less than 5, increase the packet count to
1180 * allow the host controller to use bursting to fill in the
1183 if (snd_usb_get_speed(chip->dev) == USB_SPEED_WIRELESS) {
1184 int interval = ep->datainterval;
1185 while (interval < 5) {
1190 /* make capture URBs <= 1 ms and smaller than a period */
1191 urb_packs = min(max_packs_per_urb, urb_packs);
1192 while (urb_packs > 1 && urb_packs * maxsize >= ep->cur_period_bytes)
1194 ep->nurbs = MAX_URBS;
1197 * Playback endpoints without implicit sync are adjusted so that
1198 * a period fits as evenly as possible in the smallest number of
1199 * URBs. The total number of URBs is adjusted to the size of the
1200 * ALSA buffer, subject to the MAX_URBS and MAX_QUEUE limits.
1203 /* determine how small a packet can be */
1204 minsize = (ep->freqn >> (16 - ep->datainterval)) *
1206 /* with sync from device, assume it can be 12% lower */
1207 if (ep->sync_source)
1208 minsize -= minsize >> 3;
1209 minsize = max(minsize, 1u);
1211 /* how many packets will contain an entire ALSA period? */
1212 max_packs_per_period = DIV_ROUND_UP(ep->cur_period_bytes, minsize);
1214 /* how many URBs will contain a period? */
1215 urbs_per_period = DIV_ROUND_UP(max_packs_per_period,
1217 /* how many packets are needed in each URB? */
1218 urb_packs = DIV_ROUND_UP(max_packs_per_period, urbs_per_period);
1220 /* limit the number of frames in a single URB */
1221 ep->max_urb_frames = DIV_ROUND_UP(ep->cur_period_frames,
1224 /* try to use enough URBs to contain an entire ALSA buffer */
1225 max_urbs = min((unsigned) MAX_URBS,
1226 MAX_QUEUE * packs_per_ms / urb_packs);
1227 ep->nurbs = min(max_urbs, urbs_per_period * ep->cur_buffer_periods);
1230 /* allocate and initialize data urbs */
1231 for (i = 0; i < ep->nurbs; i++) {
1232 struct snd_urb_ctx *u = &ep->urb[i];
1235 u->packets = urb_packs;
1236 u->buffer_size = maxsize * u->packets;
1238 if (fmt->fmt_type == UAC_FORMAT_TYPE_II)
1239 u->packets++; /* for transfer delimiter */
1240 u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
1244 u->urb->transfer_buffer =
1245 usb_alloc_coherent(chip->dev, u->buffer_size,
1246 GFP_KERNEL, &u->urb->transfer_dma);
1247 if (!u->urb->transfer_buffer)
1249 u->urb->pipe = ep->pipe;
1250 u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1251 u->urb->interval = 1 << ep->datainterval;
1252 u->urb->context = u;
1253 u->urb->complete = snd_complete_urb;
1254 INIT_LIST_HEAD(&u->ready_list);
1260 release_urbs(ep, false);
1265 * configure a sync endpoint
1267 static int sync_ep_set_params(struct snd_usb_endpoint *ep)
1269 struct snd_usb_audio *chip = ep->chip;
1272 usb_audio_dbg(chip, "Setting params for sync EP 0x%x, pipe 0x%x\n",
1273 ep->ep_num, ep->pipe);
1275 ep->syncbuf = usb_alloc_coherent(chip->dev, SYNC_URBS * 4,
1276 GFP_KERNEL, &ep->sync_dma);
1280 ep->nurbs = SYNC_URBS;
1281 for (i = 0; i < SYNC_URBS; i++) {
1282 struct snd_urb_ctx *u = &ep->urb[i];
1286 u->urb = usb_alloc_urb(1, GFP_KERNEL);
1289 u->urb->transfer_buffer = ep->syncbuf + i * 4;
1290 u->urb->transfer_dma = ep->sync_dma + i * 4;
1291 u->urb->transfer_buffer_length = 4;
1292 u->urb->pipe = ep->pipe;
1293 u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1294 u->urb->number_of_packets = 1;
1295 u->urb->interval = 1 << ep->syncinterval;
1296 u->urb->context = u;
1297 u->urb->complete = snd_complete_urb;
1303 release_urbs(ep, false);
1307 /* update the rate of the referred clock; return the actual rate */
1308 static int update_clock_ref_rate(struct snd_usb_audio *chip,
1309 struct snd_usb_endpoint *ep)
1311 struct snd_usb_clock_ref *clock = ep->clock_ref;
1312 int rate = ep->cur_rate;
1314 if (!clock || clock->rate == rate)
1317 if (atomic_read(&clock->locked))
1319 if (clock->rate != rate) {
1320 usb_audio_err(chip, "Mismatched sample rate %d vs %d for EP 0x%x\n",
1321 clock->rate, rate, ep->ep_num);
1326 clock->need_setup = true;
1331 * snd_usb_endpoint_set_params: configure an snd_usb_endpoint
1333 * It's called either from hw_params callback.
1334 * Determine the number of URBs to be used on this endpoint.
1335 * An endpoint must be configured before it can be started.
1336 * An endpoint that is already running can not be reconfigured.
1338 int snd_usb_endpoint_set_params(struct snd_usb_audio *chip,
1339 struct snd_usb_endpoint *ep)
1341 const struct audioformat *fmt = ep->cur_audiofmt;
1344 mutex_lock(&chip->mutex);
1345 if (!ep->need_setup)
1348 /* release old buffers, if any */
1349 err = release_urbs(ep, false);
1353 ep->datainterval = fmt->datainterval;
1354 ep->maxpacksize = fmt->maxpacksize;
1355 ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX);
1357 if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL) {
1358 ep->freqn = get_usb_full_speed_rate(ep->cur_rate);
1359 ep->pps = 1000 >> ep->datainterval;
1361 ep->freqn = get_usb_high_speed_rate(ep->cur_rate);
1362 ep->pps = 8000 >> ep->datainterval;
1365 ep->sample_rem = ep->cur_rate % ep->pps;
1366 ep->packsize[0] = ep->cur_rate / ep->pps;
1367 ep->packsize[1] = (ep->cur_rate + (ep->pps - 1)) / ep->pps;
1369 /* calculate the frequency in 16.16 format */
1370 ep->freqm = ep->freqn;
1371 ep->freqshift = INT_MIN;
1376 case SND_USB_ENDPOINT_TYPE_DATA:
1377 err = data_ep_set_params(ep);
1379 case SND_USB_ENDPOINT_TYPE_SYNC:
1380 err = sync_ep_set_params(ep);
1386 usb_audio_dbg(chip, "Set up %d URBS, ret=%d\n", ep->nurbs, err);
1391 /* some unit conversions in runtime */
1392 ep->maxframesize = ep->maxpacksize / ep->cur_frame_bytes;
1393 ep->curframesize = ep->curpacksize / ep->cur_frame_bytes;
1395 err = update_clock_ref_rate(chip, ep);
1397 ep->need_setup = false;
1402 mutex_unlock(&chip->mutex);
1406 static int init_sample_rate(struct snd_usb_audio *chip,
1407 struct snd_usb_endpoint *ep)
1409 struct snd_usb_clock_ref *clock = ep->clock_ref;
1412 rate = update_clock_ref_rate(chip, ep);
1415 if (clock && !clock->need_setup)
1418 if (!ep->fixed_rate) {
1419 err = snd_usb_init_sample_rate(chip, ep->cur_audiofmt, rate);
1422 clock->rate = 0; /* reset rate */
1428 clock->need_setup = false;
1433 * snd_usb_endpoint_prepare: Prepare the endpoint
1435 * This function sets up the EP to be fully usable state.
1436 * It's called either from prepare callback.
1437 * The function checks need_setup flag, and performs nothing unless needed,
1438 * so it's safe to call this multiple times.
1440 * This returns zero if unchanged, 1 if the configuration has changed,
1441 * or a negative error code.
1443 int snd_usb_endpoint_prepare(struct snd_usb_audio *chip,
1444 struct snd_usb_endpoint *ep)
1449 mutex_lock(&chip->mutex);
1450 if (WARN_ON(!ep->iface_ref))
1452 if (!ep->need_prepare)
1455 /* If the interface has been already set up, just set EP parameters */
1456 if (!ep->iface_ref->need_setup) {
1457 /* sample rate setup of UAC1 is per endpoint, and we need
1458 * to update at each EP configuration
1460 if (ep->cur_audiofmt->protocol == UAC_VERSION_1) {
1461 err = init_sample_rate(chip, ep);
1468 /* Need to deselect altsetting at first */
1469 endpoint_set_interface(chip, ep, false);
1471 /* Some UAC1 devices (e.g. Yamaha THR10) need the host interface
1472 * to be set up before parameter setups
1474 iface_first = ep->cur_audiofmt->protocol == UAC_VERSION_1;
1475 /* Workaround for devices that require the interface setup at first like UAC1 */
1476 if (chip->quirk_flags & QUIRK_FLAG_SET_IFACE_FIRST)
1479 err = endpoint_set_interface(chip, ep, true);
1484 err = snd_usb_init_pitch(chip, ep->cur_audiofmt);
1488 err = init_sample_rate(chip, ep);
1492 err = snd_usb_select_mode_quirk(chip, ep->cur_audiofmt);
1496 /* for UAC2/3, enable the interface altset here at last */
1498 err = endpoint_set_interface(chip, ep, true);
1503 ep->iface_ref->need_setup = false;
1506 ep->need_prepare = false;
1510 mutex_unlock(&chip->mutex);
1514 /* get the current rate set to the given clock by any endpoint */
1515 int snd_usb_endpoint_get_clock_rate(struct snd_usb_audio *chip, int clock)
1517 struct snd_usb_clock_ref *ref;
1522 mutex_lock(&chip->mutex);
1523 list_for_each_entry(ref, &chip->clock_ref_list, list) {
1524 if (ref->clock == clock) {
1529 mutex_unlock(&chip->mutex);
1534 * snd_usb_endpoint_start: start an snd_usb_endpoint
1536 * @ep: the endpoint to start
1538 * A call to this function will increment the running count of the endpoint.
1539 * In case it is not already running, the URBs for this endpoint will be
1540 * submitted. Otherwise, this function does nothing.
1542 * Must be balanced to calls of snd_usb_endpoint_stop().
1544 * Returns an error if the URB submission failed, 0 in all other cases.
1546 int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
1548 bool is_playback = usb_pipeout(ep->pipe);
1552 if (atomic_read(&ep->chip->shutdown))
1555 if (ep->sync_source)
1556 WRITE_ONCE(ep->sync_source->sync_sink, ep);
1558 usb_audio_dbg(ep->chip, "Starting %s EP 0x%x (running %d)\n",
1559 ep_type_name(ep->type), ep->ep_num,
1560 atomic_read(&ep->running));
1562 /* already running? */
1563 if (atomic_inc_return(&ep->running) != 1)
1567 atomic_inc(&ep->clock_ref->locked);
1569 ep->active_mask = 0;
1570 ep->unlink_mask = 0;
1572 ep->sample_accum = 0;
1574 snd_usb_endpoint_start_quirk(ep);
1577 * If this endpoint has a data endpoint as implicit feedback source,
1578 * don't start the urbs here. Instead, mark them all as available,
1579 * wait for the record urbs to return and queue the playback urbs
1580 * from that context.
1583 if (!ep_state_update(ep, EP_STATE_STOPPED, EP_STATE_RUNNING))
1586 if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1587 !(ep->chip->quirk_flags & QUIRK_FLAG_PLAYBACK_FIRST)) {
1588 usb_audio_dbg(ep->chip, "No URB submission due to implicit fb sync\n");
1593 for (i = 0; i < ep->nurbs; i++) {
1594 struct urb *urb = ep->urb[i].urb;
1596 if (snd_BUG_ON(!urb))
1600 err = prepare_outbound_urb(ep, urb->context, true);
1602 err = prepare_inbound_urb(ep, urb->context);
1604 /* stop filling at applptr */
1607 usb_audio_dbg(ep->chip,
1608 "EP 0x%x: failed to prepare urb: %d\n",
1613 err = usb_submit_urb(urb, GFP_ATOMIC);
1615 usb_audio_err(ep->chip,
1616 "cannot submit urb %d, error %d: %s\n",
1617 i, err, usb_error_string(err));
1620 set_bit(i, &ep->active_mask);
1621 atomic_inc(&ep->submitted_urbs);
1625 usb_audio_dbg(ep->chip, "XRUN at starting EP 0x%x\n",
1630 usb_audio_dbg(ep->chip, "%d URBs submitted for EP 0x%x\n",
1634 /* put the remaining URBs to ready list */
1636 for (; i < ep->nurbs; i++)
1637 push_back_to_ready_list(ep, ep->urb + i);
1643 snd_usb_endpoint_stop(ep, false);
1648 * snd_usb_endpoint_stop: stop an snd_usb_endpoint
1650 * @ep: the endpoint to stop (may be NULL)
1651 * @keep_pending: keep in-flight URBs
1653 * A call to this function will decrement the running count of the endpoint.
1654 * In case the last user has requested the endpoint stop, the URBs will
1655 * actually be deactivated.
1657 * Must be balanced to calls of snd_usb_endpoint_start().
1659 * The caller needs to synchronize the pending stop operation via
1660 * snd_usb_endpoint_sync_pending_stop().
1662 void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep, bool keep_pending)
1667 usb_audio_dbg(ep->chip, "Stopping %s EP 0x%x (running %d)\n",
1668 ep_type_name(ep->type), ep->ep_num,
1669 atomic_read(&ep->running));
1671 if (snd_BUG_ON(!atomic_read(&ep->running)))
1674 if (!atomic_dec_return(&ep->running)) {
1675 if (ep->sync_source)
1676 WRITE_ONCE(ep->sync_source->sync_sink, NULL);
1677 stop_urbs(ep, false, keep_pending);
1679 atomic_dec(&ep->clock_ref->locked);
1681 if (ep->chip->quirk_flags & QUIRK_FLAG_FORCE_IFACE_RESET &&
1682 usb_pipeout(ep->pipe)) {
1683 ep->need_prepare = true;
1685 ep->iface_ref->need_setup = true;
1691 * snd_usb_endpoint_release: Tear down an snd_usb_endpoint
1693 * @ep: the endpoint to release
1695 * This function does not care for the endpoint's running count but will tear
1696 * down all the streaming URBs immediately.
1698 void snd_usb_endpoint_release(struct snd_usb_endpoint *ep)
1700 release_urbs(ep, true);
1704 * snd_usb_endpoint_free_all: Free the resources of an snd_usb_endpoint
1707 * This free all endpoints and those resources
1709 void snd_usb_endpoint_free_all(struct snd_usb_audio *chip)
1711 struct snd_usb_endpoint *ep, *en;
1712 struct snd_usb_iface_ref *ip, *in;
1713 struct snd_usb_clock_ref *cp, *cn;
1715 list_for_each_entry_safe(ep, en, &chip->ep_list, list)
1718 list_for_each_entry_safe(ip, in, &chip->iface_ref_list, list)
1721 list_for_each_entry_safe(cp, cn, &chip->clock_ref_list, list)
1726 * snd_usb_handle_sync_urb: parse an USB sync packet
1728 * @ep: the endpoint to handle the packet
1729 * @sender: the sending endpoint
1730 * @urb: the received packet
1732 * This function is called from the context of an endpoint that received
1733 * the packet and is used to let another endpoint object handle the payload.
1735 static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
1736 struct snd_usb_endpoint *sender,
1737 const struct urb *urb)
1741 unsigned long flags;
1743 snd_BUG_ON(ep == sender);
1746 * In case the endpoint is operating in implicit feedback mode, prepare
1747 * a new outbound URB that has the same layout as the received packet
1748 * and add it to the list of pending urbs. queue_pending_output_urbs()
1749 * will take care of them later.
1751 if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1752 atomic_read(&ep->running)) {
1754 /* implicit feedback case */
1756 struct snd_urb_ctx *in_ctx;
1757 struct snd_usb_packet_info *out_packet;
1759 in_ctx = urb->context;
1761 /* Count overall packet size */
1762 for (i = 0; i < in_ctx->packets; i++)
1763 if (urb->iso_frame_desc[i].status == 0)
1764 bytes += urb->iso_frame_desc[i].actual_length;
1767 * skip empty packets. At least M-Audio's Fast Track Ultra stops
1768 * streaming once it received a 0-byte OUT URB
1773 spin_lock_irqsave(&ep->lock, flags);
1774 if (ep->next_packet_queued >= ARRAY_SIZE(ep->next_packet)) {
1775 spin_unlock_irqrestore(&ep->lock, flags);
1776 usb_audio_err(ep->chip,
1777 "next package FIFO overflow EP 0x%x\n",
1783 out_packet = next_packet_fifo_enqueue(ep);
1786 * Iterate through the inbound packet and prepare the lengths
1787 * for the output packet. The OUT packet we are about to send
1788 * will have the same amount of payload bytes per stride as the
1789 * IN packet we just received. Since the actual size is scaled
1790 * by the stride, use the sender stride to calculate the length
1791 * in case the number of channels differ between the implicitly
1792 * fed-back endpoint and the synchronizing endpoint.
1795 out_packet->packets = in_ctx->packets;
1796 for (i = 0; i < in_ctx->packets; i++) {
1797 if (urb->iso_frame_desc[i].status == 0)
1798 out_packet->packet_size[i] =
1799 urb->iso_frame_desc[i].actual_length / sender->stride;
1801 out_packet->packet_size[i] = 0;
1804 spin_unlock_irqrestore(&ep->lock, flags);
1805 snd_usb_queue_pending_output_urbs(ep, false);
1811 * process after playback sync complete
1813 * Full speed devices report feedback values in 10.14 format as samples
1814 * per frame, high speed devices in 16.16 format as samples per
1817 * Because the Audio Class 1 spec was written before USB 2.0, many high
1818 * speed devices use a wrong interpretation, some others use an
1819 * entirely different format.
1821 * Therefore, we cannot predict what format any particular device uses
1822 * and must detect it automatically.
1825 if (urb->iso_frame_desc[0].status != 0 ||
1826 urb->iso_frame_desc[0].actual_length < 3)
1829 f = le32_to_cpup(urb->transfer_buffer);
1830 if (urb->iso_frame_desc[0].actual_length == 3)
1838 if (unlikely(sender->tenor_fb_quirk)) {
1840 * Devices based on Tenor 8802 chipsets (TEAC UD-H01
1841 * and others) sometimes change the feedback value
1844 if (f < ep->freqn - 0x8000)
1846 else if (f > ep->freqn + 0x8000)
1848 } else if (unlikely(ep->freqshift == INT_MIN)) {
1850 * The first time we see a feedback value, determine its format
1851 * by shifting it left or right until it matches the nominal
1852 * frequency value. This assumes that the feedback does not
1853 * differ from the nominal value more than +50% or -25%.
1856 while (f < ep->freqn - ep->freqn / 4) {
1860 while (f > ep->freqn + ep->freqn / 2) {
1864 ep->freqshift = shift;
1865 } else if (ep->freqshift >= 0)
1866 f <<= ep->freqshift;
1868 f >>= -ep->freqshift;
1870 if (likely(f >= ep->freqn - ep->freqn / 8 && f <= ep->freqmax)) {
1872 * If the frequency looks valid, set it.
1873 * This value is referred to in prepare_playback_urb().
1875 spin_lock_irqsave(&ep->lock, flags);
1877 spin_unlock_irqrestore(&ep->lock, flags);
1880 * Out of range; maybe the shift value is wrong.
1881 * Reset it so that we autodetect again the next time.
1883 ep->freqshift = INT_MIN;