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>
23 #define EP_FLAG_RUNNING 1
24 #define EP_FLAG_STOPPING 2
27 * snd_usb_endpoint is a model that abstracts everything related to an
28 * USB endpoint and its streaming.
30 * There are functions to activate and deactivate the streaming URBs and
31 * optional callbacks to let the pcm logic handle the actual content of the
32 * packets for playback and record. Thus, the bus streaming and the audio
33 * handlers are fully decoupled.
35 * There are two different types of endpoints in audio applications.
37 * SND_USB_ENDPOINT_TYPE_DATA handles full audio data payload for both
38 * inbound and outbound traffic.
40 * SND_USB_ENDPOINT_TYPE_SYNC endpoints are for inbound traffic only and
41 * expect the payload to carry Q10.14 / Q16.16 formatted sync information
44 * Each endpoint has to be configured prior to being used by calling
45 * snd_usb_endpoint_set_params().
47 * The model incorporates a reference counting, so that multiple users
48 * can call snd_usb_endpoint_start() and snd_usb_endpoint_stop(), and
49 * only the first user will effectively start the URBs, and only the last
50 * one to stop it will tear the URBs down again.
54 * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
55 * this will overflow at approx 524 kHz
57 static inline unsigned get_usb_full_speed_rate(unsigned int rate)
59 return ((rate << 13) + 62) / 125;
63 * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
64 * this will overflow at approx 4 MHz
66 static inline unsigned get_usb_high_speed_rate(unsigned int rate)
68 return ((rate << 10) + 62) / 125;
74 static void release_urb_ctx(struct snd_urb_ctx *u)
77 usb_free_coherent(u->ep->chip->dev, u->buffer_size,
78 u->urb->transfer_buffer,
79 u->urb->transfer_dma);
84 static const char *usb_error_string(int err)
90 return "endpoint not enabled";
92 return "endpoint stalled";
94 return "not enough bandwidth";
96 return "device disabled";
98 return "device suspended";
103 return "internal error";
105 return "unknown error";
110 * snd_usb_endpoint_implicit_feedback_sink: Report endpoint usage type
112 * @ep: The snd_usb_endpoint
114 * Determine whether an endpoint is driven by an implicit feedback
115 * data endpoint source.
117 int snd_usb_endpoint_implicit_feedback_sink(struct snd_usb_endpoint *ep)
119 return ep->sync_master &&
120 ep->sync_master->type == SND_USB_ENDPOINT_TYPE_DATA &&
121 ep->type == SND_USB_ENDPOINT_TYPE_DATA &&
122 usb_pipeout(ep->pipe);
126 * For streaming based on information derived from sync endpoints,
127 * prepare_outbound_urb_sizes() will call slave_next_packet_size() to
128 * determine the number of samples to be sent in the next packet.
130 * For implicit feedback, slave_next_packet_size() is unused.
132 int snd_usb_endpoint_slave_next_packet_size(struct snd_usb_endpoint *ep)
138 return ep->maxframesize;
140 spin_lock_irqsave(&ep->lock, flags);
141 ep->phase = (ep->phase & 0xffff)
142 + (ep->freqm << ep->datainterval);
143 ret = min(ep->phase >> 16, ep->maxframesize);
144 spin_unlock_irqrestore(&ep->lock, flags);
150 * For adaptive and synchronous endpoints, prepare_outbound_urb_sizes()
151 * will call next_packet_size() to determine the number of samples to be
152 * sent in the next packet.
154 int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep)
159 return ep->maxframesize;
161 ep->sample_accum += ep->sample_rem;
162 if (ep->sample_accum >= ep->pps) {
163 ep->sample_accum -= ep->pps;
164 ret = ep->packsize[1];
166 ret = ep->packsize[0];
172 static void retire_outbound_urb(struct snd_usb_endpoint *ep,
173 struct snd_urb_ctx *urb_ctx)
175 if (ep->retire_data_urb)
176 ep->retire_data_urb(ep->data_subs, urb_ctx->urb);
179 static void retire_inbound_urb(struct snd_usb_endpoint *ep,
180 struct snd_urb_ctx *urb_ctx)
182 struct urb *urb = urb_ctx->urb;
184 if (unlikely(ep->skip_packets > 0)) {
190 snd_usb_handle_sync_urb(ep->sync_slave, ep, urb);
192 if (ep->retire_data_urb)
193 ep->retire_data_urb(ep->data_subs, urb);
196 static void prepare_silent_urb(struct snd_usb_endpoint *ep,
197 struct snd_urb_ctx *ctx)
199 struct urb *urb = ctx->urb;
200 unsigned int offs = 0;
201 unsigned int extra = 0;
202 __le32 packet_length;
205 /* For tx_length_quirk, put packet length at start of packet */
206 if (ep->chip->tx_length_quirk)
207 extra = sizeof(packet_length);
209 for (i = 0; i < ctx->packets; ++i) {
214 if (ctx->packet_size[i])
215 counts = ctx->packet_size[i];
216 else if (ep->sync_master)
217 counts = snd_usb_endpoint_slave_next_packet_size(ep);
219 counts = snd_usb_endpoint_next_packet_size(ep);
221 length = counts * ep->stride; /* number of silent bytes */
222 offset = offs * ep->stride + extra * i;
223 urb->iso_frame_desc[i].offset = offset;
224 urb->iso_frame_desc[i].length = length + extra;
226 packet_length = cpu_to_le32(length);
227 memcpy(urb->transfer_buffer + offset,
228 &packet_length, sizeof(packet_length));
230 memset(urb->transfer_buffer + offset + extra,
231 ep->silence_value, length);
235 urb->number_of_packets = ctx->packets;
236 urb->transfer_buffer_length = offs * ep->stride + ctx->packets * extra;
240 * Prepare a PLAYBACK urb for submission to the bus.
242 static void prepare_outbound_urb(struct snd_usb_endpoint *ep,
243 struct snd_urb_ctx *ctx)
245 struct urb *urb = ctx->urb;
246 unsigned char *cp = urb->transfer_buffer;
248 urb->dev = ep->chip->dev; /* we need to set this at each time */
251 case SND_USB_ENDPOINT_TYPE_DATA:
252 if (ep->prepare_data_urb) {
253 ep->prepare_data_urb(ep->data_subs, urb);
255 /* no data provider, so send silence */
256 prepare_silent_urb(ep, ctx);
260 case SND_USB_ENDPOINT_TYPE_SYNC:
261 if (snd_usb_get_speed(ep->chip->dev) >= USB_SPEED_HIGH) {
263 * fill the length and offset of each urb descriptor.
264 * the fixed 12.13 frequency is passed as 16.16 through the pipe.
266 urb->iso_frame_desc[0].length = 4;
267 urb->iso_frame_desc[0].offset = 0;
269 cp[1] = ep->freqn >> 8;
270 cp[2] = ep->freqn >> 16;
271 cp[3] = ep->freqn >> 24;
274 * fill the length and offset of each urb descriptor.
275 * the fixed 10.14 frequency is passed through the pipe.
277 urb->iso_frame_desc[0].length = 3;
278 urb->iso_frame_desc[0].offset = 0;
279 cp[0] = ep->freqn >> 2;
280 cp[1] = ep->freqn >> 10;
281 cp[2] = ep->freqn >> 18;
289 * Prepare a CAPTURE or SYNC urb for submission to the bus.
291 static inline void prepare_inbound_urb(struct snd_usb_endpoint *ep,
292 struct snd_urb_ctx *urb_ctx)
295 struct urb *urb = urb_ctx->urb;
297 urb->dev = ep->chip->dev; /* we need to set this at each time */
300 case SND_USB_ENDPOINT_TYPE_DATA:
302 for (i = 0; i < urb_ctx->packets; i++) {
303 urb->iso_frame_desc[i].offset = offs;
304 urb->iso_frame_desc[i].length = ep->curpacksize;
305 offs += ep->curpacksize;
308 urb->transfer_buffer_length = offs;
309 urb->number_of_packets = urb_ctx->packets;
312 case SND_USB_ENDPOINT_TYPE_SYNC:
313 urb->iso_frame_desc[0].length = min(4u, ep->syncmaxsize);
314 urb->iso_frame_desc[0].offset = 0;
320 * Send output urbs that have been prepared previously. URBs are dequeued
321 * from ep->ready_playback_urbs and in case there aren't any available
322 * or there are no packets that have been prepared, this function does
325 * The reason why the functionality of sending and preparing URBs is separated
326 * is that host controllers don't guarantee the order in which they return
327 * inbound and outbound packets to their submitters.
329 * This function is only used for implicit feedback endpoints. For endpoints
330 * driven by dedicated sync endpoints, URBs are immediately re-submitted
331 * from their completion handler.
333 static void queue_pending_output_urbs(struct snd_usb_endpoint *ep)
335 while (test_bit(EP_FLAG_RUNNING, &ep->flags)) {
338 struct snd_usb_packet_info *packet;
339 struct snd_urb_ctx *ctx = NULL;
342 spin_lock_irqsave(&ep->lock, flags);
343 if (ep->next_packet_read_pos != ep->next_packet_write_pos) {
344 packet = ep->next_packet + ep->next_packet_read_pos;
345 ep->next_packet_read_pos++;
346 ep->next_packet_read_pos %= MAX_URBS;
348 /* take URB out of FIFO */
349 if (!list_empty(&ep->ready_playback_urbs)) {
350 ctx = list_first_entry(&ep->ready_playback_urbs,
351 struct snd_urb_ctx, ready_list);
352 list_del_init(&ctx->ready_list);
355 spin_unlock_irqrestore(&ep->lock, flags);
360 /* copy over the length information */
361 for (i = 0; i < packet->packets; i++)
362 ctx->packet_size[i] = packet->packet_size[i];
364 /* call the data handler to fill in playback data */
365 prepare_outbound_urb(ep, ctx);
367 err = usb_submit_urb(ctx->urb, GFP_ATOMIC);
369 usb_audio_err(ep->chip,
370 "Unable to submit urb #%d: %d (urb %p)\n",
371 ctx->index, err, ctx->urb);
373 set_bit(ctx->index, &ep->active_mask);
378 * complete callback for urbs
380 static void snd_complete_urb(struct urb *urb)
382 struct snd_urb_ctx *ctx = urb->context;
383 struct snd_usb_endpoint *ep = ctx->ep;
384 struct snd_pcm_substream *substream;
388 if (unlikely(urb->status == -ENOENT || /* unlinked */
389 urb->status == -ENODEV || /* device removed */
390 urb->status == -ECONNRESET || /* unlinked */
391 urb->status == -ESHUTDOWN)) /* device disabled */
393 /* device disconnected */
394 if (unlikely(atomic_read(&ep->chip->shutdown)))
397 if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
400 if (usb_pipeout(ep->pipe)) {
401 retire_outbound_urb(ep, ctx);
402 /* can be stopped during retire callback */
403 if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
406 if (snd_usb_endpoint_implicit_feedback_sink(ep)) {
407 spin_lock_irqsave(&ep->lock, flags);
408 list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
409 spin_unlock_irqrestore(&ep->lock, flags);
410 queue_pending_output_urbs(ep);
415 prepare_outbound_urb(ep, ctx);
416 /* can be stopped during prepare callback */
417 if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
420 retire_inbound_urb(ep, ctx);
421 /* can be stopped during retire callback */
422 if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
425 prepare_inbound_urb(ep, ctx);
428 err = usb_submit_urb(urb, GFP_ATOMIC);
432 usb_audio_err(ep->chip, "cannot submit urb (err = %d)\n", err);
433 if (ep->data_subs && ep->data_subs->pcm_substream) {
434 substream = ep->data_subs->pcm_substream;
435 snd_pcm_stop_xrun(substream);
439 clear_bit(ctx->index, &ep->active_mask);
443 * snd_usb_add_endpoint: Add an endpoint to an USB audio chip
446 * @alts: The USB host interface
447 * @ep_num: The number of the endpoint to use
448 * @direction: SNDRV_PCM_STREAM_PLAYBACK or SNDRV_PCM_STREAM_CAPTURE
449 * @type: SND_USB_ENDPOINT_TYPE_DATA or SND_USB_ENDPOINT_TYPE_SYNC
451 * If the requested endpoint has not been added to the given chip before,
452 * a new instance is created. Otherwise, a pointer to the previoulsy
453 * created instance is returned. In case of any error, NULL is returned.
455 * New endpoints will be added to chip->ep_list and must be freed by
456 * calling snd_usb_endpoint_free().
458 * For SND_USB_ENDPOINT_TYPE_SYNC, the caller needs to guarantee that
459 * bNumEndpoints > 1 beforehand.
461 struct snd_usb_endpoint *snd_usb_add_endpoint(struct snd_usb_audio *chip,
462 struct usb_host_interface *alts,
463 int ep_num, int direction, int type)
465 struct snd_usb_endpoint *ep;
466 int is_playback = direction == SNDRV_PCM_STREAM_PLAYBACK;
471 mutex_lock(&chip->mutex);
473 list_for_each_entry(ep, &chip->ep_list, list) {
474 if (ep->ep_num == ep_num &&
475 ep->iface == alts->desc.bInterfaceNumber &&
476 ep->altsetting == alts->desc.bAlternateSetting) {
477 usb_audio_dbg(ep->chip,
478 "Re-using EP %x in iface %d,%d @%p\n",
479 ep_num, ep->iface, ep->altsetting, ep);
484 usb_audio_dbg(chip, "Creating new %s %s endpoint #%x\n",
485 is_playback ? "playback" : "capture",
486 type == SND_USB_ENDPOINT_TYPE_DATA ? "data" : "sync",
489 ep = kzalloc(sizeof(*ep), GFP_KERNEL);
494 spin_lock_init(&ep->lock);
497 ep->iface = alts->desc.bInterfaceNumber;
498 ep->altsetting = alts->desc.bAlternateSetting;
499 INIT_LIST_HEAD(&ep->ready_playback_urbs);
500 ep_num &= USB_ENDPOINT_NUMBER_MASK;
503 ep->pipe = usb_sndisocpipe(chip->dev, ep_num);
505 ep->pipe = usb_rcvisocpipe(chip->dev, ep_num);
507 if (type == SND_USB_ENDPOINT_TYPE_SYNC) {
508 if (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
509 get_endpoint(alts, 1)->bRefresh >= 1 &&
510 get_endpoint(alts, 1)->bRefresh <= 9)
511 ep->syncinterval = get_endpoint(alts, 1)->bRefresh;
512 else if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL)
513 ep->syncinterval = 1;
514 else if (get_endpoint(alts, 1)->bInterval >= 1 &&
515 get_endpoint(alts, 1)->bInterval <= 16)
516 ep->syncinterval = get_endpoint(alts, 1)->bInterval - 1;
518 ep->syncinterval = 3;
520 ep->syncmaxsize = le16_to_cpu(get_endpoint(alts, 1)->wMaxPacketSize);
523 list_add_tail(&ep->list, &chip->ep_list);
525 ep->is_implicit_feedback = 0;
528 mutex_unlock(&chip->mutex);
534 * wait until all urbs are processed.
536 static int wait_clear_urbs(struct snd_usb_endpoint *ep)
538 unsigned long end_time = jiffies + msecs_to_jiffies(1000);
542 alive = bitmap_weight(&ep->active_mask, ep->nurbs);
546 schedule_timeout_uninterruptible(1);
547 } while (time_before(jiffies, end_time));
550 usb_audio_err(ep->chip,
551 "timeout: still %d active urbs on EP #%x\n",
553 clear_bit(EP_FLAG_STOPPING, &ep->flags);
555 ep->data_subs = NULL;
556 ep->sync_slave = NULL;
557 ep->retire_data_urb = NULL;
558 ep->prepare_data_urb = NULL;
563 /* sync the pending stop operation;
564 * this function itself doesn't trigger the stop operation
566 void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep)
568 if (ep && test_bit(EP_FLAG_STOPPING, &ep->flags))
573 * unlink active urbs.
575 static int deactivate_urbs(struct snd_usb_endpoint *ep, bool force)
579 clear_bit(EP_FLAG_RUNNING, &ep->flags);
581 INIT_LIST_HEAD(&ep->ready_playback_urbs);
582 ep->next_packet_read_pos = 0;
583 ep->next_packet_write_pos = 0;
585 for (i = 0; i < ep->nurbs; i++) {
586 if (test_bit(i, &ep->active_mask)) {
587 if (!test_and_set_bit(i, &ep->unlink_mask)) {
588 struct urb *u = ep->urb[i].urb;
598 * release an endpoint's urbs
600 static void release_urbs(struct snd_usb_endpoint *ep, int force)
604 /* route incoming urbs to nirvana */
605 ep->retire_data_urb = NULL;
606 ep->prepare_data_urb = NULL;
609 deactivate_urbs(ep, force);
612 for (i = 0; i < ep->nurbs; i++)
613 release_urb_ctx(&ep->urb[i]);
615 usb_free_coherent(ep->chip->dev, SYNC_URBS * 4,
616 ep->syncbuf, ep->sync_dma);
623 * Check data endpoint for format differences
625 static bool check_ep_params(struct snd_usb_endpoint *ep,
626 snd_pcm_format_t pcm_format,
627 unsigned int channels,
628 unsigned int period_bytes,
629 unsigned int frames_per_period,
630 unsigned int periods_per_buffer,
631 struct audioformat *fmt,
632 struct snd_usb_endpoint *sync_ep)
634 unsigned int maxsize, minsize, packs_per_ms, max_packs_per_urb;
635 unsigned int max_packs_per_period, urbs_per_period, urb_packs;
636 unsigned int max_urbs;
637 int frame_bits = snd_pcm_format_physical_width(pcm_format) * channels;
638 int tx_length_quirk = (ep->chip->tx_length_quirk &&
639 usb_pipeout(ep->pipe));
642 if (pcm_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) {
644 * When operating in DSD DOP mode, the size of a sample frame
645 * in hardware differs from the actual physical format width
646 * because we need to make room for the DOP markers.
648 frame_bits += channels << 3;
651 ret = ret && (ep->datainterval == fmt->datainterval);
652 ret = ret && (ep->stride == frame_bits >> 3);
654 switch (pcm_format) {
655 case SNDRV_PCM_FORMAT_U8:
656 ret = ret && (ep->silence_value == 0x80);
658 case SNDRV_PCM_FORMAT_DSD_U8:
659 case SNDRV_PCM_FORMAT_DSD_U16_LE:
660 case SNDRV_PCM_FORMAT_DSD_U32_LE:
661 case SNDRV_PCM_FORMAT_DSD_U16_BE:
662 case SNDRV_PCM_FORMAT_DSD_U32_BE:
663 ret = ret && (ep->silence_value == 0x69);
666 ret = ret && (ep->silence_value == 0);
669 /* assume max. frequency is 50% higher than nominal */
670 ret = ret && (ep->freqmax == ep->freqn + (ep->freqn >> 1));
671 /* Round up freqmax to nearest integer in order to calculate maximum
672 * packet size, which must represent a whole number of frames.
673 * This is accomplished by adding 0x0.ffff before converting the
674 * Q16.16 format into integer.
675 * In order to accurately calculate the maximum packet size when
676 * the data interval is more than 1 (i.e. ep->datainterval > 0),
677 * multiply by the data interval prior to rounding. For instance,
678 * a freqmax of 41 kHz will result in a max packet size of 6 (5.125)
679 * frames with a data interval of 1, but 11 (10.25) frames with a
680 * data interval of 2.
681 * (ep->freqmax << ep->datainterval overflows at 8.192 MHz for the
682 * maximum datainterval value of 3, at USB full speed, higher for
683 * USB high speed, noting that ep->freqmax is in units of
684 * frames per packet in Q16.16 format.)
686 maxsize = (((ep->freqmax << ep->datainterval) + 0xffff) >> 16) *
689 maxsize += sizeof(__le32); /* Space for length descriptor */
690 /* but wMaxPacketSize might reduce this */
691 if (ep->maxpacksize && ep->maxpacksize < maxsize) {
692 /* whatever fits into a max. size packet */
693 unsigned int data_maxsize = maxsize = ep->maxpacksize;
696 /* Need to remove the length descriptor to calc freq */
697 data_maxsize -= sizeof(__le32);
698 ret = ret && (ep->freqmax == (data_maxsize / (frame_bits >> 3))
699 << (16 - ep->datainterval));
703 ret = ret && (ep->curpacksize == ep->maxpacksize);
705 ret = ret && (ep->curpacksize == maxsize);
707 if (snd_usb_get_speed(ep->chip->dev) != USB_SPEED_FULL) {
708 packs_per_ms = 8 >> ep->datainterval;
709 max_packs_per_urb = MAX_PACKS_HS;
712 max_packs_per_urb = MAX_PACKS;
714 if (sync_ep && !snd_usb_endpoint_implicit_feedback_sink(ep))
715 max_packs_per_urb = min(max_packs_per_urb,
716 1U << sync_ep->syncinterval);
717 max_packs_per_urb = max(1u, max_packs_per_urb >> ep->datainterval);
720 * Capture endpoints need to use small URBs because there's no way
721 * to tell in advance where the next period will end, and we don't
722 * want the next URB to complete much after the period ends.
724 * Playback endpoints with implicit sync much use the same parameters
725 * as their corresponding capture endpoint.
727 if (usb_pipein(ep->pipe) ||
728 snd_usb_endpoint_implicit_feedback_sink(ep)) {
730 urb_packs = packs_per_ms;
732 * Wireless devices can poll at a max rate of once per 4ms.
733 * For dataintervals less than 5, increase the packet count to
734 * allow the host controller to use bursting to fill in the
737 if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_WIRELESS) {
738 int interval = ep->datainterval;
740 while (interval < 5) {
745 /* make capture URBs <= 1 ms and smaller than a period */
746 urb_packs = min(max_packs_per_urb, urb_packs);
747 while (urb_packs > 1 && urb_packs * maxsize >= period_bytes)
749 ret = ret && (ep->nurbs == MAX_URBS);
752 * Playback endpoints without implicit sync are adjusted so that
753 * a period fits as evenly as possible in the smallest number of
754 * URBs. The total number of URBs is adjusted to the size of the
755 * ALSA buffer, subject to the MAX_URBS and MAX_QUEUE limits.
758 /* determine how small a packet can be */
759 minsize = (ep->freqn >> (16 - ep->datainterval)) *
761 /* with sync from device, assume it can be 12% lower */
763 minsize -= minsize >> 3;
764 minsize = max(minsize, 1u);
766 /* how many packets will contain an entire ALSA period? */
767 max_packs_per_period = DIV_ROUND_UP(period_bytes, minsize);
769 /* how many URBs will contain a period? */
770 urbs_per_period = DIV_ROUND_UP(max_packs_per_period,
772 /* how many packets are needed in each URB? */
773 urb_packs = DIV_ROUND_UP(max_packs_per_period, urbs_per_period);
775 /* limit the number of frames in a single URB */
776 ret = ret && (ep->max_urb_frames ==
777 DIV_ROUND_UP(frames_per_period, urbs_per_period));
779 /* try to use enough URBs to contain an entire ALSA buffer */
780 max_urbs = min((unsigned) MAX_URBS,
781 MAX_QUEUE * packs_per_ms / urb_packs);
782 ret = ret && (ep->nurbs == min(max_urbs,
783 urbs_per_period * periods_per_buffer));
786 ret = ret && (ep->datainterval == fmt->datainterval);
787 ret = ret && (ep->maxpacksize == fmt->maxpacksize);
789 (ep->fill_max == !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX));
795 * configure a data endpoint
797 static int data_ep_set_params(struct snd_usb_endpoint *ep,
798 snd_pcm_format_t pcm_format,
799 unsigned int channels,
800 unsigned int period_bytes,
801 unsigned int frames_per_period,
802 unsigned int periods_per_buffer,
803 struct audioformat *fmt,
804 struct snd_usb_endpoint *sync_ep)
806 unsigned int maxsize, minsize, packs_per_ms, max_packs_per_urb;
807 unsigned int max_packs_per_period, urbs_per_period, urb_packs;
808 unsigned int max_urbs, i;
809 int frame_bits = snd_pcm_format_physical_width(pcm_format) * channels;
810 int tx_length_quirk = (ep->chip->tx_length_quirk &&
811 usb_pipeout(ep->pipe));
813 if (pcm_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) {
815 * When operating in DSD DOP mode, the size of a sample frame
816 * in hardware differs from the actual physical format width
817 * because we need to make room for the DOP markers.
819 frame_bits += channels << 3;
822 ep->datainterval = fmt->datainterval;
823 ep->stride = frame_bits >> 3;
825 switch (pcm_format) {
826 case SNDRV_PCM_FORMAT_U8:
827 ep->silence_value = 0x80;
829 case SNDRV_PCM_FORMAT_DSD_U8:
830 case SNDRV_PCM_FORMAT_DSD_U16_LE:
831 case SNDRV_PCM_FORMAT_DSD_U32_LE:
832 case SNDRV_PCM_FORMAT_DSD_U16_BE:
833 case SNDRV_PCM_FORMAT_DSD_U32_BE:
834 ep->silence_value = 0x69;
837 ep->silence_value = 0;
840 /* assume max. frequency is 50% higher than nominal */
841 ep->freqmax = ep->freqn + (ep->freqn >> 1);
842 /* Round up freqmax to nearest integer in order to calculate maximum
843 * packet size, which must represent a whole number of frames.
844 * This is accomplished by adding 0x0.ffff before converting the
845 * Q16.16 format into integer.
846 * In order to accurately calculate the maximum packet size when
847 * the data interval is more than 1 (i.e. ep->datainterval > 0),
848 * multiply by the data interval prior to rounding. For instance,
849 * a freqmax of 41 kHz will result in a max packet size of 6 (5.125)
850 * frames with a data interval of 1, but 11 (10.25) frames with a
851 * data interval of 2.
852 * (ep->freqmax << ep->datainterval overflows at 8.192 MHz for the
853 * maximum datainterval value of 3, at USB full speed, higher for
854 * USB high speed, noting that ep->freqmax is in units of
855 * frames per packet in Q16.16 format.)
857 maxsize = (((ep->freqmax << ep->datainterval) + 0xffff) >> 16) *
860 maxsize += sizeof(__le32); /* Space for length descriptor */
861 /* but wMaxPacketSize might reduce this */
862 if (ep->maxpacksize && ep->maxpacksize < maxsize) {
863 /* whatever fits into a max. size packet */
864 unsigned int data_maxsize = maxsize = ep->maxpacksize;
867 /* Need to remove the length descriptor to calc freq */
868 data_maxsize -= sizeof(__le32);
869 ep->freqmax = (data_maxsize / (frame_bits >> 3))
870 << (16 - ep->datainterval);
874 ep->curpacksize = ep->maxpacksize;
876 ep->curpacksize = maxsize;
878 if (snd_usb_get_speed(ep->chip->dev) != USB_SPEED_FULL) {
879 packs_per_ms = 8 >> ep->datainterval;
880 max_packs_per_urb = MAX_PACKS_HS;
883 max_packs_per_urb = MAX_PACKS;
885 if (sync_ep && !snd_usb_endpoint_implicit_feedback_sink(ep))
886 max_packs_per_urb = min(max_packs_per_urb,
887 1U << sync_ep->syncinterval);
888 max_packs_per_urb = max(1u, max_packs_per_urb >> ep->datainterval);
891 * Capture endpoints need to use small URBs because there's no way
892 * to tell in advance where the next period will end, and we don't
893 * want the next URB to complete much after the period ends.
895 * Playback endpoints with implicit sync much use the same parameters
896 * as their corresponding capture endpoint.
898 if (usb_pipein(ep->pipe) ||
899 snd_usb_endpoint_implicit_feedback_sink(ep)) {
901 urb_packs = packs_per_ms;
903 * Wireless devices can poll at a max rate of once per 4ms.
904 * For dataintervals less than 5, increase the packet count to
905 * allow the host controller to use bursting to fill in the
908 if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_WIRELESS) {
909 int interval = ep->datainterval;
910 while (interval < 5) {
915 /* make capture URBs <= 1 ms and smaller than a period */
916 urb_packs = min(max_packs_per_urb, urb_packs);
917 while (urb_packs > 1 && urb_packs * maxsize >= period_bytes)
919 ep->nurbs = MAX_URBS;
922 * Playback endpoints without implicit sync are adjusted so that
923 * a period fits as evenly as possible in the smallest number of
924 * URBs. The total number of URBs is adjusted to the size of the
925 * ALSA buffer, subject to the MAX_URBS and MAX_QUEUE limits.
928 /* determine how small a packet can be */
929 minsize = (ep->freqn >> (16 - ep->datainterval)) *
931 /* with sync from device, assume it can be 12% lower */
933 minsize -= minsize >> 3;
934 minsize = max(minsize, 1u);
936 /* how many packets will contain an entire ALSA period? */
937 max_packs_per_period = DIV_ROUND_UP(period_bytes, minsize);
939 /* how many URBs will contain a period? */
940 urbs_per_period = DIV_ROUND_UP(max_packs_per_period,
942 /* how many packets are needed in each URB? */
943 urb_packs = DIV_ROUND_UP(max_packs_per_period, urbs_per_period);
945 /* limit the number of frames in a single URB */
946 ep->max_urb_frames = DIV_ROUND_UP(frames_per_period,
949 /* try to use enough URBs to contain an entire ALSA buffer */
950 max_urbs = min((unsigned) MAX_URBS,
951 MAX_QUEUE * packs_per_ms / urb_packs);
952 ep->nurbs = min(max_urbs, urbs_per_period * periods_per_buffer);
955 /* allocate and initialize data urbs */
956 for (i = 0; i < ep->nurbs; i++) {
957 struct snd_urb_ctx *u = &ep->urb[i];
960 u->packets = urb_packs;
961 u->buffer_size = maxsize * u->packets;
963 if (fmt->fmt_type == UAC_FORMAT_TYPE_II)
964 u->packets++; /* for transfer delimiter */
965 u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
969 u->urb->transfer_buffer =
970 usb_alloc_coherent(ep->chip->dev, u->buffer_size,
971 GFP_KERNEL, &u->urb->transfer_dma);
972 if (!u->urb->transfer_buffer)
974 u->urb->pipe = ep->pipe;
975 u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
976 u->urb->interval = 1 << ep->datainterval;
978 u->urb->complete = snd_complete_urb;
979 INIT_LIST_HEAD(&u->ready_list);
990 * configure a sync endpoint
992 static int sync_ep_set_params(struct snd_usb_endpoint *ep)
996 ep->syncbuf = usb_alloc_coherent(ep->chip->dev, SYNC_URBS * 4,
997 GFP_KERNEL, &ep->sync_dma);
1001 for (i = 0; i < SYNC_URBS; i++) {
1002 struct snd_urb_ctx *u = &ep->urb[i];
1006 u->urb = usb_alloc_urb(1, GFP_KERNEL);
1009 u->urb->transfer_buffer = ep->syncbuf + i * 4;
1010 u->urb->transfer_dma = ep->sync_dma + i * 4;
1011 u->urb->transfer_buffer_length = 4;
1012 u->urb->pipe = ep->pipe;
1013 u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1014 u->urb->number_of_packets = 1;
1015 u->urb->interval = 1 << ep->syncinterval;
1016 u->urb->context = u;
1017 u->urb->complete = snd_complete_urb;
1020 ep->nurbs = SYNC_URBS;
1025 release_urbs(ep, 0);
1030 * snd_usb_endpoint_set_params: configure an snd_usb_endpoint
1032 * @ep: the snd_usb_endpoint to configure
1033 * @pcm_format: the audio fomat.
1034 * @channels: the number of audio channels.
1035 * @period_bytes: the number of bytes in one alsa period.
1036 * @period_frames: the number of frames in one alsa period.
1037 * @buffer_periods: the number of periods in one alsa buffer.
1038 * @rate: the frame rate.
1039 * @fmt: the USB audio format information
1040 * @sync_ep: the sync endpoint to use, if any
1042 * Determine the number of URBs to be used on this endpoint.
1043 * An endpoint must be configured before it can be started.
1044 * An endpoint that is already running can not be reconfigured.
1046 int snd_usb_endpoint_set_params(struct snd_usb_endpoint *ep,
1047 snd_pcm_format_t pcm_format,
1048 unsigned int channels,
1049 unsigned int period_bytes,
1050 unsigned int period_frames,
1051 unsigned int buffer_periods,
1053 struct audioformat *fmt,
1054 struct snd_usb_endpoint *sync_ep)
1058 if (ep->use_count != 0) {
1059 bool check = ep->is_implicit_feedback &&
1060 check_ep_params(ep, pcm_format,
1061 channels, period_bytes,
1062 period_frames, buffer_periods,
1066 usb_audio_warn(ep->chip,
1067 "Unable to change format on ep #%x: already in use\n",
1072 usb_audio_dbg(ep->chip,
1073 "Ep #%x already in use as implicit feedback but format not changed\n",
1078 /* release old buffers, if any */
1079 release_urbs(ep, 0);
1081 ep->datainterval = fmt->datainterval;
1082 ep->maxpacksize = fmt->maxpacksize;
1083 ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX);
1085 if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_FULL) {
1086 ep->freqn = get_usb_full_speed_rate(rate);
1087 ep->pps = 1000 >> ep->datainterval;
1089 ep->freqn = get_usb_high_speed_rate(rate);
1090 ep->pps = 8000 >> ep->datainterval;
1093 ep->sample_rem = rate % ep->pps;
1094 ep->packsize[0] = rate / ep->pps;
1095 ep->packsize[1] = (rate + (ep->pps - 1)) / ep->pps;
1097 /* calculate the frequency in 16.16 format */
1098 ep->freqm = ep->freqn;
1099 ep->freqshift = INT_MIN;
1104 case SND_USB_ENDPOINT_TYPE_DATA:
1105 err = data_ep_set_params(ep, pcm_format, channels,
1106 period_bytes, period_frames,
1107 buffer_periods, fmt, sync_ep);
1109 case SND_USB_ENDPOINT_TYPE_SYNC:
1110 err = sync_ep_set_params(ep);
1116 usb_audio_dbg(ep->chip,
1117 "Setting params for ep #%x (type %d, %d urbs), ret=%d\n",
1118 ep->ep_num, ep->type, ep->nurbs, err);
1124 * snd_usb_endpoint_start: start an snd_usb_endpoint
1126 * @ep: the endpoint to start
1128 * A call to this function will increment the use count of the endpoint.
1129 * In case it is not already running, the URBs for this endpoint will be
1130 * submitted. Otherwise, this function does nothing.
1132 * Must be balanced to calls of snd_usb_endpoint_stop().
1134 * Returns an error if the URB submission failed, 0 in all other cases.
1136 int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
1141 if (atomic_read(&ep->chip->shutdown))
1144 /* already running? */
1145 if (++ep->use_count != 1)
1148 /* just to be sure */
1149 deactivate_urbs(ep, false);
1151 ep->active_mask = 0;
1152 ep->unlink_mask = 0;
1154 ep->sample_accum = 0;
1156 snd_usb_endpoint_start_quirk(ep);
1159 * If this endpoint has a data endpoint as implicit feedback source,
1160 * don't start the urbs here. Instead, mark them all as available,
1161 * wait for the record urbs to return and queue the playback urbs
1162 * from that context.
1165 set_bit(EP_FLAG_RUNNING, &ep->flags);
1167 if (snd_usb_endpoint_implicit_feedback_sink(ep)) {
1168 for (i = 0; i < ep->nurbs; i++) {
1169 struct snd_urb_ctx *ctx = ep->urb + i;
1170 list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
1176 for (i = 0; i < ep->nurbs; i++) {
1177 struct urb *urb = ep->urb[i].urb;
1179 if (snd_BUG_ON(!urb))
1182 if (usb_pipeout(ep->pipe)) {
1183 prepare_outbound_urb(ep, urb->context);
1185 prepare_inbound_urb(ep, urb->context);
1188 err = usb_submit_urb(urb, GFP_ATOMIC);
1190 usb_audio_err(ep->chip,
1191 "cannot submit urb %d, error %d: %s\n",
1192 i, err, usb_error_string(err));
1195 set_bit(i, &ep->active_mask);
1201 clear_bit(EP_FLAG_RUNNING, &ep->flags);
1203 deactivate_urbs(ep, false);
1208 * snd_usb_endpoint_stop: stop an snd_usb_endpoint
1210 * @ep: the endpoint to stop (may be NULL)
1212 * A call to this function will decrement the use count of the endpoint.
1213 * In case the last user has requested the endpoint stop, the URBs will
1214 * actually be deactivated.
1216 * Must be balanced to calls of snd_usb_endpoint_start().
1218 * The caller needs to synchronize the pending stop operation via
1219 * snd_usb_endpoint_sync_pending_stop().
1221 void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep)
1226 if (snd_BUG_ON(ep->use_count == 0))
1229 if (--ep->use_count == 0) {
1230 deactivate_urbs(ep, false);
1231 set_bit(EP_FLAG_STOPPING, &ep->flags);
1236 * snd_usb_endpoint_deactivate: deactivate an snd_usb_endpoint
1238 * @ep: the endpoint to deactivate
1240 * If the endpoint is not currently in use, this functions will
1241 * deactivate its associated URBs.
1243 * In case of any active users, this functions does nothing.
1245 void snd_usb_endpoint_deactivate(struct snd_usb_endpoint *ep)
1250 if (ep->use_count != 0)
1253 deactivate_urbs(ep, true);
1254 wait_clear_urbs(ep);
1258 * snd_usb_endpoint_release: Tear down an snd_usb_endpoint
1260 * @ep: the endpoint to release
1262 * This function does not care for the endpoint's use count but will tear
1263 * down all the streaming URBs immediately.
1265 void snd_usb_endpoint_release(struct snd_usb_endpoint *ep)
1267 release_urbs(ep, 1);
1271 * snd_usb_endpoint_free: Free the resources of an snd_usb_endpoint
1273 * @ep: the endpoint to free
1275 * This free all resources of the given ep.
1277 void snd_usb_endpoint_free(struct snd_usb_endpoint *ep)
1283 * snd_usb_handle_sync_urb: parse an USB sync packet
1285 * @ep: the endpoint to handle the packet
1286 * @sender: the sending endpoint
1287 * @urb: the received packet
1289 * This function is called from the context of an endpoint that received
1290 * the packet and is used to let another endpoint object handle the payload.
1292 void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
1293 struct snd_usb_endpoint *sender,
1294 const struct urb *urb)
1298 unsigned long flags;
1300 snd_BUG_ON(ep == sender);
1303 * In case the endpoint is operating in implicit feedback mode, prepare
1304 * a new outbound URB that has the same layout as the received packet
1305 * and add it to the list of pending urbs. queue_pending_output_urbs()
1306 * will take care of them later.
1308 if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1309 ep->use_count != 0) {
1311 /* implicit feedback case */
1313 struct snd_urb_ctx *in_ctx;
1314 struct snd_usb_packet_info *out_packet;
1316 in_ctx = urb->context;
1318 /* Count overall packet size */
1319 for (i = 0; i < in_ctx->packets; i++)
1320 if (urb->iso_frame_desc[i].status == 0)
1321 bytes += urb->iso_frame_desc[i].actual_length;
1324 * skip empty packets. At least M-Audio's Fast Track Ultra stops
1325 * streaming once it received a 0-byte OUT URB
1330 spin_lock_irqsave(&ep->lock, flags);
1331 out_packet = ep->next_packet + ep->next_packet_write_pos;
1334 * Iterate through the inbound packet and prepare the lengths
1335 * for the output packet. The OUT packet we are about to send
1336 * will have the same amount of payload bytes per stride as the
1337 * IN packet we just received. Since the actual size is scaled
1338 * by the stride, use the sender stride to calculate the length
1339 * in case the number of channels differ between the implicitly
1340 * fed-back endpoint and the synchronizing endpoint.
1343 out_packet->packets = in_ctx->packets;
1344 for (i = 0; i < in_ctx->packets; i++) {
1345 if (urb->iso_frame_desc[i].status == 0)
1346 out_packet->packet_size[i] =
1347 urb->iso_frame_desc[i].actual_length / sender->stride;
1349 out_packet->packet_size[i] = 0;
1352 ep->next_packet_write_pos++;
1353 ep->next_packet_write_pos %= MAX_URBS;
1354 spin_unlock_irqrestore(&ep->lock, flags);
1355 queue_pending_output_urbs(ep);
1361 * process after playback sync complete
1363 * Full speed devices report feedback values in 10.14 format as samples
1364 * per frame, high speed devices in 16.16 format as samples per
1367 * Because the Audio Class 1 spec was written before USB 2.0, many high
1368 * speed devices use a wrong interpretation, some others use an
1369 * entirely different format.
1371 * Therefore, we cannot predict what format any particular device uses
1372 * and must detect it automatically.
1375 if (urb->iso_frame_desc[0].status != 0 ||
1376 urb->iso_frame_desc[0].actual_length < 3)
1379 f = le32_to_cpup(urb->transfer_buffer);
1380 if (urb->iso_frame_desc[0].actual_length == 3)
1388 if (unlikely(sender->tenor_fb_quirk)) {
1390 * Devices based on Tenor 8802 chipsets (TEAC UD-H01
1391 * and others) sometimes change the feedback value
1394 if (f < ep->freqn - 0x8000)
1396 else if (f > ep->freqn + 0x8000)
1398 } else if (unlikely(ep->freqshift == INT_MIN)) {
1400 * The first time we see a feedback value, determine its format
1401 * by shifting it left or right until it matches the nominal
1402 * frequency value. This assumes that the feedback does not
1403 * differ from the nominal value more than +50% or -25%.
1406 while (f < ep->freqn - ep->freqn / 4) {
1410 while (f > ep->freqn + ep->freqn / 2) {
1414 ep->freqshift = shift;
1415 } else if (ep->freqshift >= 0)
1416 f <<= ep->freqshift;
1418 f >>= -ep->freqshift;
1420 if (likely(f >= ep->freqn - ep->freqn / 8 && f <= ep->freqmax)) {
1422 * If the frequency looks valid, set it.
1423 * This value is referred to in prepare_playback_urb().
1425 spin_lock_irqsave(&ep->lock, flags);
1427 spin_unlock_irqrestore(&ep->lock, flags);
1430 * Out of range; maybe the shift value is wrong.
1431 * Reset it so that we autodetect again the next time.
1433 ep->freqshift = INT_MIN;