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>
35 #define EP_FLAG_ACTIVATED 0
36 #define EP_FLAG_RUNNING 1
39 * snd_usb_endpoint is a model that abstracts everything related to an
40 * USB endpoint and its streaming.
42 * There are functions to activate and deactivate the streaming URBs and
43 * optinal callbacks to let the pcm logic handle the actual content of the
44 * packets for playback and record. Thus, the bus streaming and the audio
45 * handlers are fully decoupled.
47 * There are two different types of endpoints in for audio applications.
49 * SND_USB_ENDPOINT_TYPE_DATA handles full audio data payload for both
50 * inbound and outbound traffic.
52 * SND_USB_ENDPOINT_TYPE_SYNC are for inbound traffic only and expect the
53 * payload to carry Q16.16 formatted sync information (3 or 4 bytes).
55 * Each endpoint has to be configured (by calling
56 * snd_usb_endpoint_set_params()) before it can be used.
58 * The model incorporates a reference counting, so that multiple users
59 * can call snd_usb_endpoint_start() and snd_usb_endpoint_stop(), and
60 * only the first user will effectively start the URBs, and only the last
61 * one will tear them down again.
65 * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
66 * this will overflow at approx 524 kHz
68 static inline unsigned get_usb_full_speed_rate(unsigned int rate)
70 return ((rate << 13) + 62) / 125;
74 * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
75 * this will overflow at approx 4 MHz
77 static inline unsigned get_usb_high_speed_rate(unsigned int rate)
79 return ((rate << 10) + 62) / 125;
85 static void release_urb_ctx(struct snd_urb_ctx *u)
88 usb_free_coherent(u->ep->chip->dev, u->buffer_size,
89 u->urb->transfer_buffer,
90 u->urb->transfer_dma);
95 static const char *usb_error_string(int err)
101 return "endpoint not enabled";
103 return "endpoint stalled";
105 return "not enough bandwidth";
107 return "device disabled";
109 return "device suspended";
114 return "internal error";
116 return "unknown error";
121 * snd_usb_endpoint_implicit_feedback_sink: Report endpoint usage type
125 * Determine whether an endpoint is driven by an implicit feedback
126 * data endpoint source.
128 int snd_usb_endpoint_implict_feedback_sink(struct snd_usb_endpoint *ep)
130 return ep->sync_master &&
131 ep->sync_master->type == SND_USB_ENDPOINT_TYPE_DATA &&
132 ep->type == SND_USB_ENDPOINT_TYPE_DATA &&
133 usb_pipeout(ep->pipe);
137 * For streaming based on information derived from sync endpoints,
138 * prepare_outbound_urb_sizes() will call next_packet_size() to
139 * determine the number of samples to be sent in the next packet.
141 * For implicit feedback, next_packet_size() is unused.
143 static int next_packet_size(struct snd_usb_endpoint *ep)
149 return ep->maxframesize;
151 spin_lock_irqsave(&ep->lock, flags);
152 ep->phase = (ep->phase & 0xffff)
153 + (ep->freqm << ep->datainterval);
154 ret = min(ep->phase >> 16, ep->maxframesize);
155 spin_unlock_irqrestore(&ep->lock, flags);
160 static void retire_outbound_urb(struct snd_usb_endpoint *ep,
161 struct snd_urb_ctx *urb_ctx)
163 if (ep->retire_data_urb)
164 ep->retire_data_urb(ep->data_subs, urb_ctx->urb);
167 static void retire_inbound_urb(struct snd_usb_endpoint *ep,
168 struct snd_urb_ctx *urb_ctx)
170 struct urb *urb = urb_ctx->urb;
173 snd_usb_handle_sync_urb(ep->sync_slave, ep, urb);
175 if (ep->retire_data_urb)
176 ep->retire_data_urb(ep->data_subs, urb);
179 static void prepare_outbound_urb_sizes(struct snd_usb_endpoint *ep,
180 struct snd_urb_ctx *ctx)
184 for (i = 0; i < ctx->packets; ++i)
185 ctx->packet_size[i] = next_packet_size(ep);
189 * Prepare a PLAYBACK urb for submission to the bus.
191 static void prepare_outbound_urb(struct snd_usb_endpoint *ep,
192 struct snd_urb_ctx *ctx)
195 struct urb *urb = ctx->urb;
196 unsigned char *cp = urb->transfer_buffer;
198 urb->dev = ep->chip->dev; /* we need to set this at each time */
201 case SND_USB_ENDPOINT_TYPE_DATA:
202 if (ep->prepare_data_urb) {
203 ep->prepare_data_urb(ep->data_subs, urb);
205 /* no data provider, so send silence */
206 unsigned int offs = 0;
207 for (i = 0; i < ctx->packets; ++i) {
208 int counts = ctx->packet_size[i];
209 urb->iso_frame_desc[i].offset = offs * ep->stride;
210 urb->iso_frame_desc[i].length = counts * ep->stride;
214 urb->number_of_packets = ctx->packets;
215 urb->transfer_buffer_length = offs * ep->stride;
216 memset(urb->transfer_buffer, ep->silence_value,
221 case SND_USB_ENDPOINT_TYPE_SYNC:
222 if (snd_usb_get_speed(ep->chip->dev) >= USB_SPEED_HIGH) {
224 * fill the length and offset of each urb descriptor.
225 * the fixed 12.13 frequency is passed as 16.16 through the pipe.
227 urb->iso_frame_desc[0].length = 4;
228 urb->iso_frame_desc[0].offset = 0;
230 cp[1] = ep->freqn >> 8;
231 cp[2] = ep->freqn >> 16;
232 cp[3] = ep->freqn >> 24;
235 * fill the length and offset of each urb descriptor.
236 * the fixed 10.14 frequency is passed through the pipe.
238 urb->iso_frame_desc[0].length = 3;
239 urb->iso_frame_desc[0].offset = 0;
240 cp[0] = ep->freqn >> 2;
241 cp[1] = ep->freqn >> 10;
242 cp[2] = ep->freqn >> 18;
250 * Prepare a CAPTURE or SYNC urb for submission to the bus.
252 static inline void prepare_inbound_urb(struct snd_usb_endpoint *ep,
253 struct snd_urb_ctx *urb_ctx)
256 struct urb *urb = urb_ctx->urb;
258 urb->dev = ep->chip->dev; /* we need to set this at each time */
261 case SND_USB_ENDPOINT_TYPE_DATA:
263 for (i = 0; i < urb_ctx->packets; i++) {
264 urb->iso_frame_desc[i].offset = offs;
265 urb->iso_frame_desc[i].length = ep->curpacksize;
266 offs += ep->curpacksize;
269 urb->transfer_buffer_length = offs;
270 urb->number_of_packets = urb_ctx->packets;
273 case SND_USB_ENDPOINT_TYPE_SYNC:
274 urb->iso_frame_desc[0].length = min(4u, ep->syncmaxsize);
275 urb->iso_frame_desc[0].offset = 0;
281 * Send output urbs that have been prepared previously. Urbs are dequeued
282 * from ep->ready_playback_urbs and in case there there aren't any available
283 * or there are no packets that have been prepared, this function does
286 * The reason why the functionality of sending and preparing urbs is separated
287 * is that host controllers don't guarantee an ordering in returing inbound
288 * and outbound packets to their submitters.
290 * This function is only used for implicit feedback endpoints. For endpoints
291 * driven by sync endpoints, urbs are submitted from their completion handler.
293 static void queue_pending_output_urbs(struct snd_usb_endpoint *ep)
295 while (test_bit(EP_FLAG_RUNNING, &ep->flags)) {
298 struct snd_usb_packet_info *uninitialized_var(packet);
299 struct snd_urb_ctx *ctx = NULL;
303 spin_lock_irqsave(&ep->lock, flags);
304 if (ep->next_packet_read_pos != ep->next_packet_write_pos) {
305 packet = ep->next_packet + ep->next_packet_read_pos;
306 ep->next_packet_read_pos++;
307 ep->next_packet_read_pos %= MAX_URBS;
309 /* take URB out of FIFO */
310 if (!list_empty(&ep->ready_playback_urbs))
311 ctx = list_first_entry(&ep->ready_playback_urbs,
312 struct snd_urb_ctx, ready_list);
314 spin_unlock_irqrestore(&ep->lock, flags);
319 list_del_init(&ctx->ready_list);
322 /* copy over the length information */
323 for (i = 0; i < packet->packets; i++)
324 ctx->packet_size[i] = packet->packet_size[i];
326 /* call the data handler to fill in playback data */
327 prepare_outbound_urb(ep, ctx);
329 err = usb_submit_urb(ctx->urb, GFP_ATOMIC);
331 snd_printk(KERN_ERR "Unable to submit urb #%d: %d (urb %p)\n",
332 ctx->index, err, ctx->urb);
334 set_bit(ctx->index, &ep->active_mask);
339 * complete callback for urbs
341 static void snd_complete_urb(struct urb *urb)
343 struct snd_urb_ctx *ctx = urb->context;
344 struct snd_usb_endpoint *ep = ctx->ep;
347 if (unlikely(urb->status == -ENOENT || /* unlinked */
348 urb->status == -ENODEV || /* device removed */
349 urb->status == -ECONNRESET || /* unlinked */
350 urb->status == -ESHUTDOWN || /* device disabled */
351 ep->chip->shutdown)) /* device disconnected */
354 if (usb_pipeout(ep->pipe)) {
355 retire_outbound_urb(ep, ctx);
356 /* can be stopped during retire callback */
357 if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
360 if (snd_usb_endpoint_implict_feedback_sink(ep)) {
363 spin_lock_irqsave(&ep->lock, flags);
364 list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
365 spin_unlock_irqrestore(&ep->lock, flags);
366 queue_pending_output_urbs(ep);
371 prepare_outbound_urb_sizes(ep, ctx);
372 prepare_outbound_urb(ep, ctx);
374 retire_inbound_urb(ep, ctx);
375 /* can be stopped during retire callback */
376 if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
379 prepare_inbound_urb(ep, ctx);
382 err = usb_submit_urb(urb, GFP_ATOMIC);
386 snd_printk(KERN_ERR "cannot submit urb (err = %d)\n", err);
387 //snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
390 clear_bit(ctx->index, &ep->active_mask);
394 * snd_usb_add_endpoint: Add an endpoint to an audio chip
397 * @alts: The USB host interface
398 * @ep_num: The number of the endpoint to use
399 * @direction: SNDRV_PCM_STREAM_PLAYBACK or SNDRV_PCM_STREAM_CAPTURE
400 * @type: SND_USB_ENDPOINT_TYPE_DATA or SND_USB_ENDPOINT_TYPE_SYNC
402 * If the requested endpoint has not been added to the given chip before,
403 * a new instance is created. Otherwise, a pointer to the previoulsy
404 * created instance is returned. In case of any error, NULL is returned.
406 * New endpoints will be added to chip->ep_list and must be freed by
407 * calling snd_usb_endpoint_free().
409 struct snd_usb_endpoint *snd_usb_add_endpoint(struct snd_usb_audio *chip,
410 struct usb_host_interface *alts,
411 int ep_num, int direction, int type)
414 struct snd_usb_endpoint *ep;
415 int ret, is_playback = direction == SNDRV_PCM_STREAM_PLAYBACK;
417 mutex_lock(&chip->mutex);
419 list_for_each(p, &chip->ep_list) {
420 ep = list_entry(p, struct snd_usb_endpoint, list);
421 if (ep->ep_num == ep_num &&
422 ep->iface == alts->desc.bInterfaceNumber &&
423 ep->alt_idx == alts->desc.bAlternateSetting) {
424 snd_printdd(KERN_DEBUG "Re-using EP %x in iface %d,%d @%p\n",
425 ep_num, ep->iface, ep->alt_idx, ep);
430 snd_printdd(KERN_DEBUG "Creating new %s %s endpoint #%x\n",
431 is_playback ? "playback" : "capture",
432 type == SND_USB_ENDPOINT_TYPE_DATA ? "data" : "sync",
435 /* select the alt setting once so the endpoints become valid */
436 ret = usb_set_interface(chip->dev, alts->desc.bInterfaceNumber,
437 alts->desc.bAlternateSetting);
439 snd_printk(KERN_ERR "%s(): usb_set_interface() failed, ret = %d\n",
445 ep = kzalloc(sizeof(*ep), GFP_KERNEL);
450 spin_lock_init(&ep->lock);
453 ep->iface = alts->desc.bInterfaceNumber;
454 ep->alt_idx = alts->desc.bAlternateSetting;
455 INIT_LIST_HEAD(&ep->ready_playback_urbs);
456 ep_num &= USB_ENDPOINT_NUMBER_MASK;
459 ep->pipe = usb_sndisocpipe(chip->dev, ep_num);
461 ep->pipe = usb_rcvisocpipe(chip->dev, ep_num);
463 if (type == SND_USB_ENDPOINT_TYPE_SYNC) {
464 if (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
465 get_endpoint(alts, 1)->bRefresh >= 1 &&
466 get_endpoint(alts, 1)->bRefresh <= 9)
467 ep->syncinterval = get_endpoint(alts, 1)->bRefresh;
468 else if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL)
469 ep->syncinterval = 1;
470 else if (get_endpoint(alts, 1)->bInterval >= 1 &&
471 get_endpoint(alts, 1)->bInterval <= 16)
472 ep->syncinterval = get_endpoint(alts, 1)->bInterval - 1;
474 ep->syncinterval = 3;
476 ep->syncmaxsize = le16_to_cpu(get_endpoint(alts, 1)->wMaxPacketSize);
479 list_add_tail(&ep->list, &chip->ep_list);
482 mutex_unlock(&chip->mutex);
488 * wait until all urbs are processed.
490 static int wait_clear_urbs(struct snd_usb_endpoint *ep)
492 unsigned long end_time = jiffies + msecs_to_jiffies(1000);
498 for (i = 0; i < ep->nurbs; i++)
499 if (test_bit(i, &ep->active_mask))
505 schedule_timeout_uninterruptible(1);
506 } while (time_before(jiffies, end_time));
509 snd_printk(KERN_ERR "timeout: still %d active urbs on EP #%x\n",
516 * unlink active urbs.
518 static int deactivate_urbs(struct snd_usb_endpoint *ep, int force, int can_sleep)
523 if (!force && ep->chip->shutdown) /* to be sure... */
526 async = !can_sleep && ep->chip->async_unlink;
528 clear_bit(EP_FLAG_RUNNING, &ep->flags);
530 INIT_LIST_HEAD(&ep->ready_playback_urbs);
531 ep->next_packet_read_pos = 0;
532 ep->next_packet_write_pos = 0;
534 if (!async && in_interrupt())
537 for (i = 0; i < ep->nurbs; i++) {
538 if (test_bit(i, &ep->active_mask)) {
539 if (!test_and_set_bit(i, &ep->unlink_mask)) {
540 struct urb *u = ep->urb[i].urb;
553 * release an endpoint's urbs
555 static void release_urbs(struct snd_usb_endpoint *ep, int force)
559 /* route incoming urbs to nirvana */
560 ep->retire_data_urb = NULL;
561 ep->prepare_data_urb = NULL;
564 deactivate_urbs(ep, force, 1);
567 for (i = 0; i < ep->nurbs; i++)
568 release_urb_ctx(&ep->urb[i]);
571 usb_free_coherent(ep->chip->dev, SYNC_URBS * 4,
572 ep->syncbuf, ep->sync_dma);
579 * configure a data endpoint
581 static int data_ep_set_params(struct snd_usb_endpoint *ep,
582 struct snd_pcm_hw_params *hw_params,
583 struct audioformat *fmt,
584 struct snd_usb_endpoint *sync_ep)
586 unsigned int maxsize, i, urb_packs, total_packs, packs_per_ms;
587 int period_bytes = params_period_bytes(hw_params);
588 int format = params_format(hw_params);
589 int is_playback = usb_pipeout(ep->pipe);
590 int frame_bits = snd_pcm_format_physical_width(params_format(hw_params)) *
591 params_channels(hw_params);
593 ep->datainterval = fmt->datainterval;
594 ep->stride = frame_bits >> 3;
595 ep->silence_value = format == SNDRV_PCM_FORMAT_U8 ? 0x80 : 0;
597 /* calculate max. frequency */
598 if (ep->maxpacksize) {
599 /* whatever fits into a max. size packet */
600 maxsize = ep->maxpacksize;
601 ep->freqmax = (maxsize / (frame_bits >> 3))
602 << (16 - ep->datainterval);
604 /* no max. packet size: just take 25% higher than nominal */
605 ep->freqmax = ep->freqn + (ep->freqn >> 2);
606 maxsize = ((ep->freqmax + 0xffff) * (frame_bits >> 3))
607 >> (16 - ep->datainterval);
611 ep->curpacksize = ep->maxpacksize;
613 ep->curpacksize = maxsize;
615 if (snd_usb_get_speed(ep->chip->dev) != USB_SPEED_FULL)
616 packs_per_ms = 8 >> ep->datainterval;
620 if (is_playback && !snd_usb_endpoint_implict_feedback_sink(ep)) {
621 urb_packs = max(ep->chip->nrpacks, 1);
622 urb_packs = min(urb_packs, (unsigned int) MAX_PACKS);
627 urb_packs *= packs_per_ms;
629 if (sync_ep && !snd_usb_endpoint_implict_feedback_sink(ep))
630 urb_packs = min(urb_packs, 1U << sync_ep->syncinterval);
632 /* decide how many packets to be used */
633 if (is_playback && !snd_usb_endpoint_implict_feedback_sink(ep)) {
634 unsigned int minsize, maxpacks;
635 /* determine how small a packet can be */
636 minsize = (ep->freqn >> (16 - ep->datainterval))
638 /* with sync from device, assume it can be 12% lower */
640 minsize -= minsize >> 3;
641 minsize = max(minsize, 1u);
642 total_packs = (period_bytes + minsize - 1) / minsize;
643 /* we need at least two URBs for queueing */
644 if (total_packs < 2) {
647 /* and we don't want too long a queue either */
648 maxpacks = max(MAX_QUEUE * packs_per_ms, urb_packs * 2);
649 total_packs = min(total_packs, maxpacks);
652 while (urb_packs > 1 && urb_packs * maxsize >= period_bytes)
654 total_packs = MAX_URBS * urb_packs;
657 ep->nurbs = (total_packs + urb_packs - 1) / urb_packs;
658 if (ep->nurbs > MAX_URBS) {
660 ep->nurbs = MAX_URBS;
661 total_packs = MAX_URBS * urb_packs;
662 } else if (ep->nurbs < 2) {
663 /* too little - we need at least two packets
664 * to ensure contiguous playback/capture
669 /* allocate and initialize data urbs */
670 for (i = 0; i < ep->nurbs; i++) {
671 struct snd_urb_ctx *u = &ep->urb[i];
674 u->packets = (i + 1) * total_packs / ep->nurbs
675 - i * total_packs / ep->nurbs;
676 u->buffer_size = maxsize * u->packets;
678 if (fmt->fmt_type == UAC_FORMAT_TYPE_II)
679 u->packets++; /* for transfer delimiter */
680 u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
684 u->urb->transfer_buffer =
685 usb_alloc_coherent(ep->chip->dev, u->buffer_size,
686 GFP_KERNEL, &u->urb->transfer_dma);
687 if (!u->urb->transfer_buffer)
689 u->urb->pipe = ep->pipe;
690 u->urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
691 u->urb->interval = 1 << ep->datainterval;
693 u->urb->complete = snd_complete_urb;
694 INIT_LIST_HEAD(&u->ready_list);
705 * configure a sync endpoint
707 static int sync_ep_set_params(struct snd_usb_endpoint *ep,
708 struct snd_pcm_hw_params *hw_params,
709 struct audioformat *fmt)
713 ep->syncbuf = usb_alloc_coherent(ep->chip->dev, SYNC_URBS * 4,
714 GFP_KERNEL, &ep->sync_dma);
718 for (i = 0; i < SYNC_URBS; i++) {
719 struct snd_urb_ctx *u = &ep->urb[i];
723 u->urb = usb_alloc_urb(1, GFP_KERNEL);
726 u->urb->transfer_buffer = ep->syncbuf + i * 4;
727 u->urb->transfer_dma = ep->sync_dma + i * 4;
728 u->urb->transfer_buffer_length = 4;
729 u->urb->pipe = ep->pipe;
730 u->urb->transfer_flags = URB_ISO_ASAP |
731 URB_NO_TRANSFER_DMA_MAP;
732 u->urb->number_of_packets = 1;
733 u->urb->interval = 1 << ep->syncinterval;
735 u->urb->complete = snd_complete_urb;
738 ep->nurbs = SYNC_URBS;
748 * snd_usb_endpoint_set_params: configure an snd_endpoint
750 * @ep: the endpoint to configure
752 * Determine the number of of URBs to be used on this endpoint.
753 * An endpoint must be configured before it can be started.
754 * An endpoint that is already running can not be reconfigured.
756 int snd_usb_endpoint_set_params(struct snd_usb_endpoint *ep,
757 struct snd_pcm_hw_params *hw_params,
758 struct audioformat *fmt,
759 struct snd_usb_endpoint *sync_ep)
763 if (ep->use_count != 0) {
764 snd_printk(KERN_WARNING "Unable to change format on ep #%x: already in use\n",
769 /* release old buffers, if any */
772 ep->datainterval = fmt->datainterval;
773 ep->maxpacksize = fmt->maxpacksize;
774 ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX);
776 if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_FULL)
777 ep->freqn = get_usb_full_speed_rate(params_rate(hw_params));
779 ep->freqn = get_usb_high_speed_rate(params_rate(hw_params));
781 /* calculate the frequency in 16.16 format */
782 ep->freqm = ep->freqn;
783 ep->freqshift = INT_MIN;
788 case SND_USB_ENDPOINT_TYPE_DATA:
789 err = data_ep_set_params(ep, hw_params, fmt, sync_ep);
791 case SND_USB_ENDPOINT_TYPE_SYNC:
792 err = sync_ep_set_params(ep, hw_params, fmt);
798 snd_printdd(KERN_DEBUG "Setting params for ep #%x (type %d, %d urbs), ret=%d\n",
799 ep->ep_num, ep->type, ep->nurbs, err);
805 * snd_usb_endpoint_start: start an snd_usb_endpoint
807 * @ep: the endpoint to start
809 * A call to this function will increment the use count of the endpoint.
810 * In case this not already running, the URBs for this endpoint will be
811 * submitted. Otherwise, this function does nothing.
813 * Must be balanced to calls of snd_usb_endpoint_stop().
815 * Returns an error if the URB submission failed, 0 in all other cases.
817 int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
822 if (ep->chip->shutdown)
825 /* already running? */
826 if (++ep->use_count != 1)
829 if (snd_BUG_ON(!test_bit(EP_FLAG_ACTIVATED, &ep->flags)))
832 /* just to be sure */
833 deactivate_urbs(ep, 0, 1);
841 * If this endpoint has a data endpoint as implicit feedback source,
842 * don't start the urbs here. Instead, mark them all as available,
843 * wait for the record urbs to arrive and queue from that context.
846 set_bit(EP_FLAG_RUNNING, &ep->flags);
848 if (snd_usb_endpoint_implict_feedback_sink(ep)) {
849 for (i = 0; i < ep->nurbs; i++) {
850 struct snd_urb_ctx *ctx = ep->urb + i;
851 list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
857 for (i = 0; i < ep->nurbs; i++) {
858 struct urb *urb = ep->urb[i].urb;
860 if (snd_BUG_ON(!urb))
863 if (usb_pipeout(ep->pipe)) {
864 prepare_outbound_urb_sizes(ep, urb->context);
865 prepare_outbound_urb(ep, urb->context);
867 prepare_inbound_urb(ep, urb->context);
870 err = usb_submit_urb(urb, GFP_ATOMIC);
872 snd_printk(KERN_ERR "cannot submit urb %d, error %d: %s\n",
873 i, err, usb_error_string(err));
876 set_bit(i, &ep->active_mask);
882 clear_bit(EP_FLAG_RUNNING, &ep->flags);
884 deactivate_urbs(ep, 0, 0);
889 * snd_usb_endpoint_stop: stop an snd_usb_endpoint
891 * @ep: the endpoint to stop (may be NULL)
893 * A call to this function will decrement the use count of the endpoint.
894 * In case the last user has requested the endpoint stop, the URBs will
895 * actually deactivated.
897 * Must be balanced to calls of snd_usb_endpoint_start().
899 void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep,
900 int force, int can_sleep, int wait)
905 if (snd_BUG_ON(ep->use_count == 0))
908 if (snd_BUG_ON(!test_bit(EP_FLAG_ACTIVATED, &ep->flags)))
911 if (--ep->use_count == 0) {
912 deactivate_urbs(ep, force, can_sleep);
913 ep->data_subs = NULL;
914 ep->sync_slave = NULL;
915 ep->retire_data_urb = NULL;
916 ep->prepare_data_urb = NULL;
924 * snd_usb_endpoint_activate: activate an snd_usb_endpoint
926 * @ep: the endpoint to activate
928 * If the endpoint is not currently in use, this functions will select the
929 * correct alternate interface setting for the interface of this endpoint.
931 * In case of any active users, this functions does nothing.
933 * Returns an error if usb_set_interface() failed, 0 in all other
936 int snd_usb_endpoint_activate(struct snd_usb_endpoint *ep)
938 if (ep->use_count != 0)
941 if (!ep->chip->shutdown &&
942 !test_and_set_bit(EP_FLAG_ACTIVATED, &ep->flags)) {
945 ret = usb_set_interface(ep->chip->dev, ep->iface, ep->alt_idx);
947 snd_printk(KERN_ERR "%s() usb_set_interface() failed, ret = %d\n",
949 clear_bit(EP_FLAG_ACTIVATED, &ep->flags);
960 * snd_usb_endpoint_deactivate: deactivate an snd_usb_endpoint
962 * @ep: the endpoint to deactivate
964 * If the endpoint is not currently in use, this functions will select the
965 * alternate interface setting 0 for the interface of this endpoint.
967 * In case of any active users, this functions does nothing.
969 * Returns an error if usb_set_interface() failed, 0 in all other
972 int snd_usb_endpoint_deactivate(struct snd_usb_endpoint *ep)
977 if (ep->use_count != 0)
980 if (!ep->chip->shutdown &&
981 test_and_clear_bit(EP_FLAG_ACTIVATED, &ep->flags)) {
984 ret = usb_set_interface(ep->chip->dev, ep->iface, 0);
986 snd_printk(KERN_ERR "%s(): usb_set_interface() failed, ret = %d\n",
997 /** snd_usb_endpoint_free: Free the resources of an snd_usb_endpoint
999 * @ep: the list header of the endpoint to free
1001 * This function does not care for the endpoint's use count but will tear
1002 * down all the streaming URBs immediately and free all resources.
1004 void snd_usb_endpoint_free(struct list_head *head)
1006 struct snd_usb_endpoint *ep;
1008 ep = list_entry(head, struct snd_usb_endpoint, list);
1009 release_urbs(ep, 1);
1014 * snd_usb_handle_sync_urb: parse an USB sync packet
1016 * @ep: the endpoint to handle the packet
1017 * @sender: the sending endpoint
1018 * @urb: the received packet
1020 * This function is called from the context of an endpoint that received
1021 * the packet and is used to let another endpoint object handle the payload.
1023 void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
1024 struct snd_usb_endpoint *sender,
1025 const struct urb *urb)
1029 unsigned long flags;
1031 snd_BUG_ON(ep == sender);
1034 * In case the endpoint is operating in implicit feedback mode, prepare
1035 * and a new outbound URB that has the same layout as the received
1036 * packet and add it to the list of pending urbs.
1038 if (snd_usb_endpoint_implict_feedback_sink(ep) &&
1039 ep->use_count != 0) {
1041 /* implicit feedback case */
1043 struct snd_urb_ctx *in_ctx;
1044 struct snd_usb_packet_info *out_packet;
1046 in_ctx = urb->context;
1048 /* Count overall packet size */
1049 for (i = 0; i < in_ctx->packets; i++)
1050 if (urb->iso_frame_desc[i].status == 0)
1051 bytes += urb->iso_frame_desc[i].actual_length;
1054 * skip empty packets. At least M-Audio's Fast Track Ultra stops
1055 * streaming once it received a 0-byte OUT URB
1060 spin_lock_irqsave(&ep->lock, flags);
1061 out_packet = ep->next_packet + ep->next_packet_write_pos;
1064 * Iterate through the inbound packet and prepare the lengths
1065 * for the output packet. The OUT packet we are about to send
1066 * will have the same amount of payload than the IN packet we
1070 out_packet->packets = in_ctx->packets;
1071 for (i = 0; i < in_ctx->packets; i++) {
1072 if (urb->iso_frame_desc[i].status == 0)
1073 out_packet->packet_size[i] =
1074 urb->iso_frame_desc[i].actual_length / ep->stride;
1076 out_packet->packet_size[i] = 0;
1079 ep->next_packet_write_pos++;
1080 ep->next_packet_write_pos %= MAX_URBS;
1081 spin_unlock_irqrestore(&ep->lock, flags);
1082 queue_pending_output_urbs(ep);
1088 * process after playback sync complete
1090 * Full speed devices report feedback values in 10.14 format as samples
1091 * per frame, high speed devices in 16.16 format as samples per
1094 * Because the Audio Class 1 spec was written before USB 2.0, many high
1095 * speed devices use a wrong interpretation, some others use an
1096 * entirely different format.
1098 * Therefore, we cannot predict what format any particular device uses
1099 * and must detect it automatically.
1102 if (urb->iso_frame_desc[0].status != 0 ||
1103 urb->iso_frame_desc[0].actual_length < 3)
1106 f = le32_to_cpup(urb->transfer_buffer);
1107 if (urb->iso_frame_desc[0].actual_length == 3)
1115 if (unlikely(ep->freqshift == INT_MIN)) {
1117 * The first time we see a feedback value, determine its format
1118 * by shifting it left or right until it matches the nominal
1119 * frequency value. This assumes that the feedback does not
1120 * differ from the nominal value more than +50% or -25%.
1123 while (f < ep->freqn - ep->freqn / 4) {
1127 while (f > ep->freqn + ep->freqn / 2) {
1131 ep->freqshift = shift;
1132 } else if (ep->freqshift >= 0)
1133 f <<= ep->freqshift;
1135 f >>= -ep->freqshift;
1137 if (likely(f >= ep->freqn - ep->freqn / 8 && f <= ep->freqmax)) {
1139 * If the frequency looks valid, set it.
1140 * This value is referred to in prepare_playback_urb().
1142 spin_lock_irqsave(&ep->lock, flags);
1144 spin_unlock_irqrestore(&ep->lock, flags);
1147 * Out of range; maybe the shift value is wrong.
1148 * Reset it so that we autodetect again the next time.
1150 ep->freqshift = INT_MIN;