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.
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.
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
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>
25 #include <sound/core.h>
26 #include <sound/pcm.h>
27 #include <sound/pcm_params.h>
36 #define EP_FLAG_ACTIVATED 0
37 #define EP_FLAG_RUNNING 1
40 * snd_usb_endpoint is a model that abstracts everything related to an
41 * USB endpoint and its streaming.
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.
48 * There are two different types of endpoints in audio applications.
50 * SND_USB_ENDPOINT_TYPE_DATA handles full audio data payload for both
51 * inbound and outbound traffic.
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
57 * Each endpoint has to be configured prior to being used by calling
58 * snd_usb_endpoint_set_params().
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.
67 * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
68 * this will overflow at approx 524 kHz
70 static inline unsigned get_usb_full_speed_rate(unsigned int rate)
72 return ((rate << 13) + 62) / 125;
76 * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
77 * this will overflow at approx 4 MHz
79 static inline unsigned get_usb_high_speed_rate(unsigned int rate)
81 return ((rate << 10) + 62) / 125;
87 static void release_urb_ctx(struct snd_urb_ctx *u)
90 usb_free_coherent(u->ep->chip->dev, u->buffer_size,
91 u->urb->transfer_buffer,
92 u->urb->transfer_dma);
97 static const char *usb_error_string(int err)
103 return "endpoint not enabled";
105 return "endpoint stalled";
107 return "not enough bandwidth";
109 return "device disabled";
111 return "device suspended";
116 return "internal error";
118 return "unknown error";
123 * snd_usb_endpoint_implicit_feedback_sink: Report endpoint usage type
125 * @ep: The snd_usb_endpoint
127 * Determine whether an endpoint is driven by an implicit feedback
128 * data endpoint source.
130 int snd_usb_endpoint_implict_feedback_sink(struct snd_usb_endpoint *ep)
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);
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.
143 * For implicit feedback, next_packet_size() is unused.
145 int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep)
151 return ep->maxframesize;
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);
162 static void retire_outbound_urb(struct snd_usb_endpoint *ep,
163 struct snd_urb_ctx *urb_ctx)
165 if (ep->retire_data_urb)
166 ep->retire_data_urb(ep->data_subs, urb_ctx->urb);
169 static void retire_inbound_urb(struct snd_usb_endpoint *ep,
170 struct snd_urb_ctx *urb_ctx)
172 struct urb *urb = urb_ctx->urb;
174 if (unlikely(ep->skip_packets > 0)) {
180 snd_usb_handle_sync_urb(ep->sync_slave, ep, urb);
182 if (ep->retire_data_urb)
183 ep->retire_data_urb(ep->data_subs, urb);
187 * Prepare a PLAYBACK urb for submission to the bus.
189 static void prepare_outbound_urb(struct snd_usb_endpoint *ep,
190 struct snd_urb_ctx *ctx)
193 struct urb *urb = ctx->urb;
194 unsigned char *cp = urb->transfer_buffer;
196 urb->dev = ep->chip->dev; /* we need to set this at each time */
199 case SND_USB_ENDPOINT_TYPE_DATA:
200 if (ep->prepare_data_urb) {
201 ep->prepare_data_urb(ep->data_subs, urb);
203 /* no data provider, so send silence */
204 unsigned int offs = 0;
205 for (i = 0; i < ctx->packets; ++i) {
206 int counts = ctx->packet_size[i];
207 urb->iso_frame_desc[i].offset = offs * ep->stride;
208 urb->iso_frame_desc[i].length = counts * ep->stride;
212 urb->number_of_packets = ctx->packets;
213 urb->transfer_buffer_length = offs * ep->stride;
214 memset(urb->transfer_buffer, ep->silence_value,
219 case SND_USB_ENDPOINT_TYPE_SYNC:
220 if (snd_usb_get_speed(ep->chip->dev) >= USB_SPEED_HIGH) {
222 * fill the length and offset of each urb descriptor.
223 * the fixed 12.13 frequency is passed as 16.16 through the pipe.
225 urb->iso_frame_desc[0].length = 4;
226 urb->iso_frame_desc[0].offset = 0;
228 cp[1] = ep->freqn >> 8;
229 cp[2] = ep->freqn >> 16;
230 cp[3] = ep->freqn >> 24;
233 * fill the length and offset of each urb descriptor.
234 * the fixed 10.14 frequency is passed through the pipe.
236 urb->iso_frame_desc[0].length = 3;
237 urb->iso_frame_desc[0].offset = 0;
238 cp[0] = ep->freqn >> 2;
239 cp[1] = ep->freqn >> 10;
240 cp[2] = ep->freqn >> 18;
248 * Prepare a CAPTURE or SYNC urb for submission to the bus.
250 static inline void prepare_inbound_urb(struct snd_usb_endpoint *ep,
251 struct snd_urb_ctx *urb_ctx)
254 struct urb *urb = urb_ctx->urb;
256 urb->dev = ep->chip->dev; /* we need to set this at each time */
259 case SND_USB_ENDPOINT_TYPE_DATA:
261 for (i = 0; i < urb_ctx->packets; i++) {
262 urb->iso_frame_desc[i].offset = offs;
263 urb->iso_frame_desc[i].length = ep->curpacksize;
264 offs += ep->curpacksize;
267 urb->transfer_buffer_length = offs;
268 urb->number_of_packets = urb_ctx->packets;
271 case SND_USB_ENDPOINT_TYPE_SYNC:
272 urb->iso_frame_desc[0].length = min(4u, ep->syncmaxsize);
273 urb->iso_frame_desc[0].offset = 0;
279 * Send output urbs that have been prepared previously. URBs are dequeued
280 * from ep->ready_playback_urbs and in case there there aren't any available
281 * or there are no packets that have been prepared, this function does
284 * The reason why the functionality of sending and preparing URBs is separated
285 * is that host controllers don't guarantee the order in which they return
286 * inbound and outbound packets to their submitters.
288 * This function is only used for implicit feedback endpoints. For endpoints
289 * driven by dedicated sync endpoints, URBs are immediately re-submitted
290 * from their completion handler.
292 static void queue_pending_output_urbs(struct snd_usb_endpoint *ep)
294 while (test_bit(EP_FLAG_RUNNING, &ep->flags)) {
297 struct snd_usb_packet_info *uninitialized_var(packet);
298 struct snd_urb_ctx *ctx = NULL;
302 spin_lock_irqsave(&ep->lock, flags);
303 if (ep->next_packet_read_pos != ep->next_packet_write_pos) {
304 packet = ep->next_packet + ep->next_packet_read_pos;
305 ep->next_packet_read_pos++;
306 ep->next_packet_read_pos %= MAX_URBS;
308 /* take URB out of FIFO */
309 if (!list_empty(&ep->ready_playback_urbs))
310 ctx = list_first_entry(&ep->ready_playback_urbs,
311 struct snd_urb_ctx, ready_list);
313 spin_unlock_irqrestore(&ep->lock, flags);
318 list_del_init(&ctx->ready_list);
321 /* copy over the length information */
322 for (i = 0; i < packet->packets; i++)
323 ctx->packet_size[i] = packet->packet_size[i];
325 /* call the data handler to fill in playback data */
326 prepare_outbound_urb(ep, ctx);
328 err = usb_submit_urb(ctx->urb, GFP_ATOMIC);
330 snd_printk(KERN_ERR "Unable to submit urb #%d: %d (urb %p)\n",
331 ctx->index, err, ctx->urb);
333 set_bit(ctx->index, &ep->active_mask);
338 * complete callback for urbs
340 static void snd_complete_urb(struct urb *urb)
342 struct snd_urb_ctx *ctx = urb->context;
343 struct snd_usb_endpoint *ep = ctx->ep;
346 if (unlikely(urb->status == -ENOENT || /* unlinked */
347 urb->status == -ENODEV || /* device removed */
348 urb->status == -ECONNRESET || /* unlinked */
349 urb->status == -ESHUTDOWN || /* device disabled */
350 ep->chip->shutdown)) /* device disconnected */
353 if (usb_pipeout(ep->pipe)) {
354 retire_outbound_urb(ep, ctx);
355 /* can be stopped during retire callback */
356 if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
359 if (snd_usb_endpoint_implict_feedback_sink(ep)) {
362 spin_lock_irqsave(&ep->lock, flags);
363 list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
364 spin_unlock_irqrestore(&ep->lock, flags);
365 queue_pending_output_urbs(ep);
370 prepare_outbound_urb(ep, ctx);
372 retire_inbound_urb(ep, ctx);
373 /* can be stopped during retire callback */
374 if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
377 prepare_inbound_urb(ep, ctx);
380 err = usb_submit_urb(urb, GFP_ATOMIC);
384 snd_printk(KERN_ERR "cannot submit urb (err = %d)\n", err);
385 //snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
388 clear_bit(ctx->index, &ep->active_mask);
392 * snd_usb_add_endpoint: Add an endpoint to an USB audio chip
395 * @alts: The USB host interface
396 * @ep_num: The number of the endpoint to use
397 * @direction: SNDRV_PCM_STREAM_PLAYBACK or SNDRV_PCM_STREAM_CAPTURE
398 * @type: SND_USB_ENDPOINT_TYPE_DATA or SND_USB_ENDPOINT_TYPE_SYNC
400 * If the requested endpoint has not been added to the given chip before,
401 * a new instance is created. Otherwise, a pointer to the previoulsy
402 * created instance is returned. In case of any error, NULL is returned.
404 * New endpoints will be added to chip->ep_list and must be freed by
405 * calling snd_usb_endpoint_free().
407 struct snd_usb_endpoint *snd_usb_add_endpoint(struct snd_usb_audio *chip,
408 struct usb_host_interface *alts,
409 int ep_num, int direction, int type)
412 struct snd_usb_endpoint *ep;
413 int is_playback = direction == SNDRV_PCM_STREAM_PLAYBACK;
415 mutex_lock(&chip->mutex);
417 list_for_each(p, &chip->ep_list) {
418 ep = list_entry(p, struct snd_usb_endpoint, list);
419 if (ep->ep_num == ep_num &&
420 ep->iface == alts->desc.bInterfaceNumber &&
421 ep->alt_idx == alts->desc.bAlternateSetting) {
422 snd_printdd(KERN_DEBUG "Re-using EP %x in iface %d,%d @%p\n",
423 ep_num, ep->iface, ep->alt_idx, ep);
428 snd_printdd(KERN_DEBUG "Creating new %s %s endpoint #%x\n",
429 is_playback ? "playback" : "capture",
430 type == SND_USB_ENDPOINT_TYPE_DATA ? "data" : "sync",
433 ep = kzalloc(sizeof(*ep), GFP_KERNEL);
438 spin_lock_init(&ep->lock);
441 ep->iface = alts->desc.bInterfaceNumber;
442 ep->alt_idx = alts->desc.bAlternateSetting;
443 INIT_LIST_HEAD(&ep->ready_playback_urbs);
444 ep_num &= USB_ENDPOINT_NUMBER_MASK;
447 ep->pipe = usb_sndisocpipe(chip->dev, ep_num);
449 ep->pipe = usb_rcvisocpipe(chip->dev, ep_num);
451 if (type == SND_USB_ENDPOINT_TYPE_SYNC) {
452 if (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
453 get_endpoint(alts, 1)->bRefresh >= 1 &&
454 get_endpoint(alts, 1)->bRefresh <= 9)
455 ep->syncinterval = get_endpoint(alts, 1)->bRefresh;
456 else if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL)
457 ep->syncinterval = 1;
458 else if (get_endpoint(alts, 1)->bInterval >= 1 &&
459 get_endpoint(alts, 1)->bInterval <= 16)
460 ep->syncinterval = get_endpoint(alts, 1)->bInterval - 1;
462 ep->syncinterval = 3;
464 ep->syncmaxsize = le16_to_cpu(get_endpoint(alts, 1)->wMaxPacketSize);
467 list_add_tail(&ep->list, &chip->ep_list);
470 mutex_unlock(&chip->mutex);
476 * wait until all urbs are processed.
478 static int wait_clear_urbs(struct snd_usb_endpoint *ep)
480 unsigned long end_time = jiffies + msecs_to_jiffies(1000);
486 for (i = 0; i < ep->nurbs; i++)
487 if (test_bit(i, &ep->active_mask))
493 schedule_timeout_uninterruptible(1);
494 } while (time_before(jiffies, end_time));
497 snd_printk(KERN_ERR "timeout: still %d active urbs on EP #%x\n",
504 * unlink active urbs.
506 static int deactivate_urbs(struct snd_usb_endpoint *ep, int force, int can_sleep)
511 if (!force && ep->chip->shutdown) /* to be sure... */
514 async = !can_sleep && ep->chip->async_unlink;
516 clear_bit(EP_FLAG_RUNNING, &ep->flags);
518 INIT_LIST_HEAD(&ep->ready_playback_urbs);
519 ep->next_packet_read_pos = 0;
520 ep->next_packet_write_pos = 0;
522 if (!async && in_interrupt())
525 for (i = 0; i < ep->nurbs; i++) {
526 if (test_bit(i, &ep->active_mask)) {
527 if (!test_and_set_bit(i, &ep->unlink_mask)) {
528 struct urb *u = ep->urb[i].urb;
541 * release an endpoint's urbs
543 static void release_urbs(struct snd_usb_endpoint *ep, int force)
547 /* route incoming urbs to nirvana */
548 ep->retire_data_urb = NULL;
549 ep->prepare_data_urb = NULL;
552 deactivate_urbs(ep, force, 1);
555 for (i = 0; i < ep->nurbs; i++)
556 release_urb_ctx(&ep->urb[i]);
559 usb_free_coherent(ep->chip->dev, SYNC_URBS * 4,
560 ep->syncbuf, ep->sync_dma);
567 * configure a data endpoint
569 static int data_ep_set_params(struct snd_usb_endpoint *ep,
570 snd_pcm_format_t pcm_format,
571 unsigned int channels,
572 unsigned int period_bytes,
573 struct audioformat *fmt,
574 struct snd_usb_endpoint *sync_ep)
576 unsigned int maxsize, i, urb_packs, total_packs, packs_per_ms;
577 int is_playback = usb_pipeout(ep->pipe);
578 int frame_bits = snd_pcm_format_physical_width(pcm_format) * channels;
580 ep->datainterval = fmt->datainterval;
581 ep->stride = frame_bits >> 3;
582 ep->silence_value = pcm_format == SNDRV_PCM_FORMAT_U8 ? 0x80 : 0;
584 /* calculate max. frequency */
585 if (ep->maxpacksize) {
586 /* whatever fits into a max. size packet */
587 maxsize = ep->maxpacksize;
588 ep->freqmax = (maxsize / (frame_bits >> 3))
589 << (16 - ep->datainterval);
591 /* no max. packet size: just take 25% higher than nominal */
592 ep->freqmax = ep->freqn + (ep->freqn >> 2);
593 maxsize = ((ep->freqmax + 0xffff) * (frame_bits >> 3))
594 >> (16 - ep->datainterval);
598 ep->curpacksize = ep->maxpacksize;
600 ep->curpacksize = maxsize;
602 if (snd_usb_get_speed(ep->chip->dev) != USB_SPEED_FULL)
603 packs_per_ms = 8 >> ep->datainterval;
607 if (is_playback && !snd_usb_endpoint_implict_feedback_sink(ep)) {
608 urb_packs = max(ep->chip->nrpacks, 1);
609 urb_packs = min(urb_packs, (unsigned int) MAX_PACKS);
614 urb_packs *= packs_per_ms;
616 if (sync_ep && !snd_usb_endpoint_implict_feedback_sink(ep))
617 urb_packs = min(urb_packs, 1U << sync_ep->syncinterval);
619 /* decide how many packets to be used */
620 if (is_playback && !snd_usb_endpoint_implict_feedback_sink(ep)) {
621 unsigned int minsize, maxpacks;
622 /* determine how small a packet can be */
623 minsize = (ep->freqn >> (16 - ep->datainterval))
625 /* with sync from device, assume it can be 12% lower */
627 minsize -= minsize >> 3;
628 minsize = max(minsize, 1u);
629 total_packs = (period_bytes + minsize - 1) / minsize;
630 /* we need at least two URBs for queueing */
631 if (total_packs < 2) {
634 /* and we don't want too long a queue either */
635 maxpacks = max(MAX_QUEUE * packs_per_ms, urb_packs * 2);
636 total_packs = min(total_packs, maxpacks);
639 while (urb_packs > 1 && urb_packs * maxsize >= period_bytes)
641 total_packs = MAX_URBS * urb_packs;
644 ep->nurbs = (total_packs + urb_packs - 1) / urb_packs;
645 if (ep->nurbs > MAX_URBS) {
647 ep->nurbs = MAX_URBS;
648 total_packs = MAX_URBS * urb_packs;
649 } else if (ep->nurbs < 2) {
650 /* too little - we need at least two packets
651 * to ensure contiguous playback/capture
656 /* allocate and initialize data urbs */
657 for (i = 0; i < ep->nurbs; i++) {
658 struct snd_urb_ctx *u = &ep->urb[i];
661 u->packets = (i + 1) * total_packs / ep->nurbs
662 - i * total_packs / ep->nurbs;
663 u->buffer_size = maxsize * u->packets;
665 if (fmt->fmt_type == UAC_FORMAT_TYPE_II)
666 u->packets++; /* for transfer delimiter */
667 u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
671 u->urb->transfer_buffer =
672 usb_alloc_coherent(ep->chip->dev, u->buffer_size,
673 GFP_KERNEL, &u->urb->transfer_dma);
674 if (!u->urb->transfer_buffer)
676 u->urb->pipe = ep->pipe;
677 u->urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
678 u->urb->interval = 1 << ep->datainterval;
680 u->urb->complete = snd_complete_urb;
681 INIT_LIST_HEAD(&u->ready_list);
692 * configure a sync endpoint
694 static int sync_ep_set_params(struct snd_usb_endpoint *ep,
695 struct audioformat *fmt)
699 ep->syncbuf = usb_alloc_coherent(ep->chip->dev, SYNC_URBS * 4,
700 GFP_KERNEL, &ep->sync_dma);
704 for (i = 0; i < SYNC_URBS; i++) {
705 struct snd_urb_ctx *u = &ep->urb[i];
709 u->urb = usb_alloc_urb(1, GFP_KERNEL);
712 u->urb->transfer_buffer = ep->syncbuf + i * 4;
713 u->urb->transfer_dma = ep->sync_dma + i * 4;
714 u->urb->transfer_buffer_length = 4;
715 u->urb->pipe = ep->pipe;
716 u->urb->transfer_flags = URB_ISO_ASAP |
717 URB_NO_TRANSFER_DMA_MAP;
718 u->urb->number_of_packets = 1;
719 u->urb->interval = 1 << ep->syncinterval;
721 u->urb->complete = snd_complete_urb;
724 ep->nurbs = SYNC_URBS;
734 * snd_usb_endpoint_set_params: configure an snd_usb_endpoint
736 * @ep: the snd_usb_endpoint to configure
737 * @pcm_format: the audio fomat.
738 * @channels: the number of audio channels.
739 * @period_bytes: the number of bytes in one alsa period.
740 * @rate: the frame rate.
741 * @fmt: the USB audio format information
742 * @sync_ep: the sync endpoint to use, if any
744 * Determine the number of URBs to be used on this endpoint.
745 * An endpoint must be configured before it can be started.
746 * An endpoint that is already running can not be reconfigured.
748 int snd_usb_endpoint_set_params(struct snd_usb_endpoint *ep,
749 snd_pcm_format_t pcm_format,
750 unsigned int channels,
751 unsigned int period_bytes,
753 struct audioformat *fmt,
754 struct snd_usb_endpoint *sync_ep)
758 if (ep->use_count != 0) {
759 snd_printk(KERN_WARNING "Unable to change format on ep #%x: already in use\n",
764 /* release old buffers, if any */
767 ep->datainterval = fmt->datainterval;
768 ep->maxpacksize = fmt->maxpacksize;
769 ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX);
771 if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_FULL)
772 ep->freqn = get_usb_full_speed_rate(rate);
774 ep->freqn = get_usb_high_speed_rate(rate);
776 /* calculate the frequency in 16.16 format */
777 ep->freqm = ep->freqn;
778 ep->freqshift = INT_MIN;
783 case SND_USB_ENDPOINT_TYPE_DATA:
784 err = data_ep_set_params(ep, pcm_format, channels,
785 period_bytes, fmt, sync_ep);
787 case SND_USB_ENDPOINT_TYPE_SYNC:
788 err = sync_ep_set_params(ep, fmt);
794 snd_printdd(KERN_DEBUG "Setting params for ep #%x (type %d, %d urbs), ret=%d\n",
795 ep->ep_num, ep->type, ep->nurbs, err);
801 * snd_usb_endpoint_start: start an snd_usb_endpoint
803 * @ep: the endpoint to start
804 * @can_sleep: flag indicating whether the operation is executed in
807 * A call to this function will increment the use count of the endpoint.
808 * In case it is not already running, the URBs for this endpoint will be
809 * submitted. Otherwise, this function does nothing.
811 * Must be balanced to calls of snd_usb_endpoint_stop().
813 * Returns an error if the URB submission failed, 0 in all other cases.
815 int snd_usb_endpoint_start(struct snd_usb_endpoint *ep, int can_sleep)
820 if (ep->chip->shutdown)
823 /* already running? */
824 if (++ep->use_count != 1)
827 /* just to be sure */
828 deactivate_urbs(ep, 0, can_sleep);
836 snd_usb_endpoint_start_quirk(ep);
839 * If this endpoint has a data endpoint as implicit feedback source,
840 * don't start the urbs here. Instead, mark them all as available,
841 * wait for the record urbs to return and queue the playback urbs
845 set_bit(EP_FLAG_RUNNING, &ep->flags);
847 if (snd_usb_endpoint_implict_feedback_sink(ep)) {
848 for (i = 0; i < ep->nurbs; i++) {
849 struct snd_urb_ctx *ctx = ep->urb + i;
850 list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
856 for (i = 0; i < ep->nurbs; i++) {
857 struct urb *urb = ep->urb[i].urb;
859 if (snd_BUG_ON(!urb))
862 if (usb_pipeout(ep->pipe)) {
863 prepare_outbound_urb(ep, urb->context);
865 prepare_inbound_urb(ep, urb->context);
868 err = usb_submit_urb(urb, GFP_ATOMIC);
870 snd_printk(KERN_ERR "cannot submit urb %d, error %d: %s\n",
871 i, err, usb_error_string(err));
874 set_bit(i, &ep->active_mask);
880 clear_bit(EP_FLAG_RUNNING, &ep->flags);
882 deactivate_urbs(ep, 0, 0);
887 * snd_usb_endpoint_stop: stop an snd_usb_endpoint
889 * @ep: the endpoint to stop (may be NULL)
891 * A call to this function will decrement the use count of the endpoint.
892 * In case the last user has requested the endpoint stop, the URBs will
893 * actually be deactivated.
895 * Must be balanced to calls of snd_usb_endpoint_start().
897 void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep,
898 int force, int can_sleep, int wait)
903 if (snd_BUG_ON(ep->use_count == 0))
906 if (--ep->use_count == 0) {
907 deactivate_urbs(ep, force, can_sleep);
908 ep->data_subs = NULL;
909 ep->sync_slave = NULL;
910 ep->retire_data_urb = NULL;
911 ep->prepare_data_urb = NULL;
919 * snd_usb_endpoint_deactivate: deactivate an snd_usb_endpoint
921 * @ep: the endpoint to deactivate
923 * If the endpoint is not currently in use, this functions will select the
924 * alternate interface setting 0 for the interface of this endpoint.
926 * In case of any active users, this functions does nothing.
928 * Returns an error if usb_set_interface() failed, 0 in all other
931 int snd_usb_endpoint_deactivate(struct snd_usb_endpoint *ep)
936 deactivate_urbs(ep, 1, 1);
939 if (ep->use_count != 0)
942 clear_bit(EP_FLAG_ACTIVATED, &ep->flags);
948 * snd_usb_endpoint_free: Free the resources of an snd_usb_endpoint
950 * @ep: the list header of the endpoint to free
952 * This function does not care for the endpoint's use count but will tear
953 * down all the streaming URBs immediately and free all resources.
955 void snd_usb_endpoint_free(struct list_head *head)
957 struct snd_usb_endpoint *ep;
959 ep = list_entry(head, struct snd_usb_endpoint, list);
965 * snd_usb_handle_sync_urb: parse an USB sync packet
967 * @ep: the endpoint to handle the packet
968 * @sender: the sending endpoint
969 * @urb: the received packet
971 * This function is called from the context of an endpoint that received
972 * the packet and is used to let another endpoint object handle the payload.
974 void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
975 struct snd_usb_endpoint *sender,
976 const struct urb *urb)
982 snd_BUG_ON(ep == sender);
985 * In case the endpoint is operating in implicit feedback mode, prepare
986 * a new outbound URB that has the same layout as the received packet
987 * and add it to the list of pending urbs. queue_pending_output_urbs()
988 * will take care of them later.
990 if (snd_usb_endpoint_implict_feedback_sink(ep) &&
991 ep->use_count != 0) {
993 /* implicit feedback case */
995 struct snd_urb_ctx *in_ctx;
996 struct snd_usb_packet_info *out_packet;
998 in_ctx = urb->context;
1000 /* Count overall packet size */
1001 for (i = 0; i < in_ctx->packets; i++)
1002 if (urb->iso_frame_desc[i].status == 0)
1003 bytes += urb->iso_frame_desc[i].actual_length;
1006 * skip empty packets. At least M-Audio's Fast Track Ultra stops
1007 * streaming once it received a 0-byte OUT URB
1012 spin_lock_irqsave(&ep->lock, flags);
1013 out_packet = ep->next_packet + ep->next_packet_write_pos;
1016 * Iterate through the inbound packet and prepare the lengths
1017 * for the output packet. The OUT packet we are about to send
1018 * will have the same amount of payload bytes than the IN
1019 * packet we just received.
1022 out_packet->packets = in_ctx->packets;
1023 for (i = 0; i < in_ctx->packets; i++) {
1024 if (urb->iso_frame_desc[i].status == 0)
1025 out_packet->packet_size[i] =
1026 urb->iso_frame_desc[i].actual_length / ep->stride;
1028 out_packet->packet_size[i] = 0;
1031 ep->next_packet_write_pos++;
1032 ep->next_packet_write_pos %= MAX_URBS;
1033 spin_unlock_irqrestore(&ep->lock, flags);
1034 queue_pending_output_urbs(ep);
1040 * process after playback sync complete
1042 * Full speed devices report feedback values in 10.14 format as samples
1043 * per frame, high speed devices in 16.16 format as samples per
1046 * Because the Audio Class 1 spec was written before USB 2.0, many high
1047 * speed devices use a wrong interpretation, some others use an
1048 * entirely different format.
1050 * Therefore, we cannot predict what format any particular device uses
1051 * and must detect it automatically.
1054 if (urb->iso_frame_desc[0].status != 0 ||
1055 urb->iso_frame_desc[0].actual_length < 3)
1058 f = le32_to_cpup(urb->transfer_buffer);
1059 if (urb->iso_frame_desc[0].actual_length == 3)
1067 if (unlikely(ep->freqshift == INT_MIN)) {
1069 * The first time we see a feedback value, determine its format
1070 * by shifting it left or right until it matches the nominal
1071 * frequency value. This assumes that the feedback does not
1072 * differ from the nominal value more than +50% or -25%.
1075 while (f < ep->freqn - ep->freqn / 4) {
1079 while (f > ep->freqn + ep->freqn / 2) {
1083 ep->freqshift = shift;
1084 } else if (ep->freqshift >= 0)
1085 f <<= ep->freqshift;
1087 f >>= -ep->freqshift;
1089 if (likely(f >= ep->freqn - ep->freqn / 8 && f <= ep->freqmax)) {
1091 * If the frequency looks valid, set it.
1092 * This value is referred to in prepare_playback_urb().
1094 spin_lock_irqsave(&ep->lock, flags);
1096 spin_unlock_irqrestore(&ep->lock, flags);
1099 * Out of range; maybe the shift value is wrong.
1100 * Reset it so that we autodetect again the next time.
1102 ep->freqshift = INT_MIN;