endpoint.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 */
   4
   5#include <linux/gfp.h>
   6#include <linux/init.h>
   7#include <linux/ratelimit.h>
   8#include <linux/usb.h>
   9#include <linux/usb/audio.h>
  10#include <linux/slab.h>
  11
  12#include <sound/core.h>
  13#include <sound/pcm.h>
  14#include <sound/pcm_params.h>
  15
  16#include "usbaudio.h"
  17#include "helper.h"
  18#include "card.h"
  19#include "endpoint.h"
  20#include "pcm.h"
  21#include "clock.h"
  22#include "quirks.h"
  23
  24enum {
  25	EP_STATE_STOPPED,
  26	EP_STATE_RUNNING,
  27	EP_STATE_STOPPING,
  28};
  29
  30/* interface refcounting */
  31struct snd_usb_iface_ref {
  32	unsigned char iface;
  33	bool need_setup;
  34	int opened;
  35	int altset;
  36	struct list_head list;
  37};
  38
  39/* clock refcounting */
  40struct snd_usb_clock_ref {
  41	unsigned char clock;
  42	atomic_t locked;
  43	int opened;
  44	int rate;
  45	bool need_setup;
  46	struct list_head list;
  47};
  48
  49/*
  50 * snd_usb_endpoint is a model that abstracts everything related to an
  51 * USB endpoint and its streaming.
  52 *
  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.
  57 *
  58 * There are two different types of endpoints in audio applications.
  59 *
  60 * SND_USB_ENDPOINT_TYPE_DATA handles full audio data payload for both
  61 * inbound and outbound traffic.
  62 *
  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
  65 * (3 or 4 bytes).
  66 *
  67 * Each endpoint has to be configured prior to being used by calling
  68 * snd_usb_endpoint_set_params().
  69 *
  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.
  74 */
  75
  76/*
  77 * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
  78 * this will overflow at approx 524 kHz
  79 */
  80static inline unsigned get_usb_full_speed_rate(unsigned int rate)
  81{
  82	return ((rate << 13) + 62) / 125;
  83}
  84
  85/*
  86 * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
  87 * this will overflow at approx 4 MHz
  88 */
  89static inline unsigned get_usb_high_speed_rate(unsigned int rate)
  90{
  91	return ((rate << 10) + 62) / 125;
  92}
  93
  94/*
  95 * release a urb data
  96 */
  97static void release_urb_ctx(struct snd_urb_ctx *u)
  98{
  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);
 104	u->urb = NULL;
 105	u->buffer_size = 0;
 106}
 107
 108static const char *usb_error_string(int err)
 109{
 110	switch (err) {
 111	case -ENODEV:
 112		return "no device";
 113	case -ENOENT:
 114		return "endpoint not enabled";
 115	case -EPIPE:
 116		return "endpoint stalled";
 117	case -ENOSPC:
 118		return "not enough bandwidth";
 119	case -ESHUTDOWN:
 120		return "device disabled";
 121	case -EHOSTUNREACH:
 122		return "device suspended";
 123	case -EINVAL:
 124	case -EAGAIN:
 125	case -EFBIG:
 126	case -EMSGSIZE:
 127		return "internal error";
 128	default:
 129		return "unknown error";
 130	}
 131}
 132
 133static inline bool ep_state_running(struct snd_usb_endpoint *ep)
 134{
 135	return atomic_read(&ep->state) == EP_STATE_RUNNING;
 136}
 137
 138static inline bool ep_state_update(struct snd_usb_endpoint *ep, int old, int new)
 139{
 140	return atomic_try_cmpxchg(&ep->state, &old, new);
 141}
 142
 143/**
 144 * snd_usb_endpoint_implicit_feedback_sink: Report endpoint usage type
 145 *
 146 * @ep: The snd_usb_endpoint
 147 *
 148 * Determine whether an endpoint is driven by an implicit feedback
 149 * data endpoint source.
 150 */
 151int snd_usb_endpoint_implicit_feedback_sink(struct snd_usb_endpoint *ep)
 152{
 153	return  ep->implicit_fb_sync && usb_pipeout(ep->pipe);
 154}
 155
 156/*
 157 * Return the number of samples to be sent in the next packet
 158 * for streaming based on information derived from sync endpoints
 159 *
 160 * This won't be used for implicit feedback which takes the packet size
 161 * returned from the sync source
 162 */
 163static int synced_next_packet_size(struct snd_usb_endpoint *ep,
 164				   unsigned int avail)
 165{
 166	unsigned int phase;
 167	int ret;
 168
 169	if (ep->fill_max)
 170		return ep->maxframesize;
 171
 172	guard(spinlock_irqsave)(&ep->lock);
 173	phase = (ep->phase & 0xffff) + (ep->freqm << ep->datainterval);
 174	ret = min(phase >> 16, ep->maxframesize);
 175	if (avail && ret >= avail)
 176		ret = -EAGAIN;
 177	else
 178		ep->phase = phase;
 179	return ret;
 180}
 181
 182/*
 183 * Return the number of samples to be sent in the next packet
 184 * for adaptive and synchronous endpoints
 185 */
 186static int next_packet_size(struct snd_usb_endpoint *ep, unsigned int avail)
 187{
 188	unsigned int sample_accum;
 189	int ret;
 190
 191	if (ep->fill_max)
 192		return ep->maxframesize;
 193
 194	sample_accum = ep->sample_accum + ep->sample_rem;
 195	if (sample_accum >= ep->pps) {
 196		sample_accum -= ep->pps;
 197		ret = ep->packsize[1];
 198	} else {
 199		ret = ep->packsize[0];
 200	}
 201	if (avail && ret >= avail)
 202		ret = -EAGAIN;
 203	else
 204		ep->sample_accum = sample_accum;
 205
 206	return ret;
 207}
 208
 209/*
 210 * snd_usb_endpoint_next_packet_size: Return the number of samples to be sent
 211 * in the next packet
 212 *
 213 * If the size is equal or exceeds @avail, don't proceed but return -EAGAIN
 214 * Exception: @avail = 0 for skipping the check.
 215 */
 216int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep,
 217				      struct snd_urb_ctx *ctx, int idx,
 218				      unsigned int avail)
 219{
 220	unsigned int packet;
 221
 222	packet = ctx->packet_size[idx];
 223	if (packet) {
 224		packet = min(packet, ep->maxframesize);
 225		if (avail && packet >= avail)
 226			return -EAGAIN;
 227		return packet;
 228	}
 229
 230	if (ep->sync_source)
 231		return synced_next_packet_size(ep, avail);
 232	else
 233		return next_packet_size(ep, avail);
 234}
 235
 236static void call_retire_callback(struct snd_usb_endpoint *ep,
 237				 struct urb *urb)
 238{
 239	struct snd_usb_substream *data_subs;
 240
 241	data_subs = READ_ONCE(ep->data_subs);
 242	if (data_subs && ep->retire_data_urb)
 243		ep->retire_data_urb(data_subs, urb);
 244}
 245
 246static void retire_outbound_urb(struct snd_usb_endpoint *ep,
 247				struct snd_urb_ctx *urb_ctx)
 248{
 249	call_retire_callback(ep, urb_ctx->urb);
 250}
 251
 252static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
 253				    struct snd_usb_endpoint *sender,
 254				    const struct urb *urb);
 255
 256static void retire_inbound_urb(struct snd_usb_endpoint *ep,
 257			       struct snd_urb_ctx *urb_ctx)
 258{
 259	struct urb *urb = urb_ctx->urb;
 260	struct snd_usb_endpoint *sync_sink;
 261
 262	if (unlikely(ep->skip_packets > 0)) {
 263		ep->skip_packets--;
 264		return;
 265	}
 266
 267	sync_sink = READ_ONCE(ep->sync_sink);
 268	if (sync_sink)
 269		snd_usb_handle_sync_urb(sync_sink, ep, urb);
 270
 271	call_retire_callback(ep, urb);
 272}
 273
 274static inline bool has_tx_length_quirk(struct snd_usb_audio *chip)
 275{
 276	return chip->quirk_flags & QUIRK_FLAG_TX_LENGTH;
 277}
 278
 279static int prepare_silent_urb(struct snd_usb_endpoint *ep,
 280			      struct snd_urb_ctx *ctx)
 281{
 282	struct urb *urb = ctx->urb;
 283	unsigned int offs = 0;
 284	unsigned int extra = 0;
 285	__le32 packet_length;
 286	int i;
 287
 288	/* For tx_length_quirk, put packet length at start of packet */
 289	if (has_tx_length_quirk(ep->chip))
 290		extra = sizeof(packet_length);
 291
 292	for (i = 0; i < ctx->packets; ++i) {
 293		int length;
 294
 295		length = snd_usb_endpoint_next_packet_size(ep, ctx, i, 0);
 296		if (length < 0)
 297			return length;
 298		length *= ep->stride; /* number of silent bytes */
 299		if (offs + length + extra > ctx->buffer_size)
 300			break;
 301		urb->iso_frame_desc[i].offset = offs;
 302		urb->iso_frame_desc[i].length = length + extra;
 303		if (extra) {
 304			packet_length = cpu_to_le32(length);
 305			memcpy(urb->transfer_buffer + offs,
 306			       &packet_length, sizeof(packet_length));
 307			offs += extra;
 308		}
 309		memset(urb->transfer_buffer + offs,
 310		       ep->silence_value, length);
 311		offs += length;
 312	}
 313
 314	if (!offs)
 315		return -EPIPE;
 316
 317	urb->number_of_packets = i;
 318	urb->transfer_buffer_length = offs;
 319	ctx->queued = 0;
 320	return 0;
 321}
 322
 323/*
 324 * Prepare a PLAYBACK urb for submission to the bus.
 325 */
 326static int prepare_outbound_urb(struct snd_usb_endpoint *ep,
 327				struct snd_urb_ctx *ctx,
 328				bool in_stream_lock)
 329{
 330	struct urb *urb = ctx->urb;
 331	unsigned char *cp = urb->transfer_buffer;
 332	struct snd_usb_substream *data_subs;
 333
 334	urb->dev = ep->chip->dev; /* we need to set this at each time */
 335
 336	switch (ep->type) {
 337	case SND_USB_ENDPOINT_TYPE_DATA:
 338		data_subs = READ_ONCE(ep->data_subs);
 339		if (data_subs && ep->prepare_data_urb)
 340			return ep->prepare_data_urb(data_subs, urb, in_stream_lock);
 341		/* no data provider, so send silence */
 342		return prepare_silent_urb(ep, ctx);
 343
 344	case SND_USB_ENDPOINT_TYPE_SYNC:
 345		if (snd_usb_get_speed(ep->chip->dev) >= USB_SPEED_HIGH) {
 346			/*
 347			 * fill the length and offset of each urb descriptor.
 348			 * the fixed 12.13 frequency is passed as 16.16 through the pipe.
 349			 */
 350			urb->iso_frame_desc[0].length = 4;
 351			urb->iso_frame_desc[0].offset = 0;
 352			cp[0] = ep->freqn;
 353			cp[1] = ep->freqn >> 8;
 354			cp[2] = ep->freqn >> 16;
 355			cp[3] = ep->freqn >> 24;
 356		} else {
 357			/*
 358			 * fill the length and offset of each urb descriptor.
 359			 * the fixed 10.14 frequency is passed through the pipe.
 360			 */
 361			urb->iso_frame_desc[0].length = 3;
 362			urb->iso_frame_desc[0].offset = 0;
 363			cp[0] = ep->freqn >> 2;
 364			cp[1] = ep->freqn >> 10;
 365			cp[2] = ep->freqn >> 18;
 366		}
 367
 368		break;
 369	}
 370	return 0;
 371}
 372
 373/*
 374 * Prepare a CAPTURE or SYNC urb for submission to the bus.
 375 */
 376static int prepare_inbound_urb(struct snd_usb_endpoint *ep,
 377			       struct snd_urb_ctx *urb_ctx)
 378{
 379	int i, offs;
 380	struct urb *urb = urb_ctx->urb;
 381
 382	urb->dev = ep->chip->dev; /* we need to set this at each time */
 383
 384	switch (ep->type) {
 385	case SND_USB_ENDPOINT_TYPE_DATA:
 386		offs = 0;
 387		for (i = 0; i < urb_ctx->packets; i++) {
 388			urb->iso_frame_desc[i].offset = offs;
 389			urb->iso_frame_desc[i].length = ep->curpacksize;
 390			offs += ep->curpacksize;
 391		}
 392
 393		urb->transfer_buffer_length = offs;
 394		urb->number_of_packets = urb_ctx->packets;
 395		break;
 396
 397	case SND_USB_ENDPOINT_TYPE_SYNC:
 398		urb->iso_frame_desc[0].length = min(4u, ep->syncmaxsize);
 399		urb->iso_frame_desc[0].offset = 0;
 400		break;
 401	}
 402	return 0;
 403}
 404
 405/* notify an error as XRUN to the assigned PCM data substream */
 406static void notify_xrun(struct snd_usb_endpoint *ep)
 407{
 408	struct snd_usb_substream *data_subs;
 409	struct snd_pcm_substream *psubs;
 410
 411	data_subs = READ_ONCE(ep->data_subs);
 412	if (!data_subs)
 413		return;
 414	psubs = data_subs->pcm_substream;
 415	if (psubs && psubs->runtime &&
 416	    psubs->runtime->state == SNDRV_PCM_STATE_RUNNING)
 417		snd_pcm_stop_xrun(psubs);
 418}
 419
 420static struct snd_usb_packet_info *
 421next_packet_fifo_enqueue(struct snd_usb_endpoint *ep)
 422{
 423	struct snd_usb_packet_info *p;
 424
 425	p = ep->next_packet + (ep->next_packet_head + ep->next_packet_queued) %
 426		ARRAY_SIZE(ep->next_packet);
 427	ep->next_packet_queued++;
 428	return p;
 429}
 430
 431static struct snd_usb_packet_info *
 432next_packet_fifo_dequeue(struct snd_usb_endpoint *ep)
 433{
 434	struct snd_usb_packet_info *p;
 435
 436	p = ep->next_packet + ep->next_packet_head;
 437	ep->next_packet_head++;
 438	ep->next_packet_head %= ARRAY_SIZE(ep->next_packet);
 439	ep->next_packet_queued--;
 440	return p;
 441}
 442
 443static void push_back_to_ready_list(struct snd_usb_endpoint *ep,
 444				    struct snd_urb_ctx *ctx)
 445{
 446	guard(spinlock_irqsave)(&ep->lock);
 447	list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
 448}
 449
 450/*
 451 * Send output urbs that have been prepared previously. URBs are dequeued
 452 * from ep->ready_playback_urbs and in case there aren't any available
 453 * or there are no packets that have been prepared, this function does
 454 * nothing.
 455 *
 456 * The reason why the functionality of sending and preparing URBs is separated
 457 * is that host controllers don't guarantee the order in which they return
 458 * inbound and outbound packets to their submitters.
 459 *
 460 * This function is used both for implicit feedback endpoints and in low-
 461 * latency playback mode.
 462 */
 463int snd_usb_queue_pending_output_urbs(struct snd_usb_endpoint *ep,
 464				      bool in_stream_lock)
 465{
 466	bool implicit_fb = snd_usb_endpoint_implicit_feedback_sink(ep);
 467
 468	while (ep_state_running(ep)) {
 469		struct snd_usb_packet_info *packet;
 470		struct snd_urb_ctx *ctx = NULL;
 471		int err, i;
 472
 473		scoped_guard(spinlock_irqsave, &ep->lock) {
 474			if ((!implicit_fb || ep->next_packet_queued > 0) &&
 475			    !list_empty(&ep->ready_playback_urbs)) {
 476				/* take URB out of FIFO */
 477				ctx = list_first_entry(&ep->ready_playback_urbs,
 478						       struct snd_urb_ctx, ready_list);
 479				list_del_init(&ctx->ready_list);
 480				if (implicit_fb)
 481					packet = next_packet_fifo_dequeue(ep);
 482			}
 483		}
 484
 485		if (ctx == NULL)
 486			break;
 487
 488		/* copy over the length information */
 489		if (implicit_fb) {
 490			ctx->packets = packet->packets;
 491			for (i = 0; i < packet->packets; i++)
 492				ctx->packet_size[i] = packet->packet_size[i];
 493		}
 494
 495		/* call the data handler to fill in playback data */
 496		err = prepare_outbound_urb(ep, ctx, in_stream_lock);
 497		/* can be stopped during prepare callback */
 498		if (unlikely(!ep_state_running(ep)))
 499			break;
 500		if (err < 0) {
 501			/* push back to ready list again for -EAGAIN */
 502			if (err == -EAGAIN) {
 503				push_back_to_ready_list(ep, ctx);
 504				break;
 505			}
 506
 507			if (!in_stream_lock)
 508				notify_xrun(ep);
 509			return -EPIPE;
 510		}
 511
 512		if (!atomic_read(&ep->chip->shutdown))
 513			err = usb_submit_urb(ctx->urb, GFP_ATOMIC);
 514		else
 515			err = -ENODEV;
 516		if (err < 0) {
 517			if (!atomic_read(&ep->chip->shutdown)) {
 518				usb_audio_err(ep->chip,
 519					      "Unable to submit urb #%d: %d at %s\n",
 520					      ctx->index, err, __func__);
 521				if (!in_stream_lock)
 522					notify_xrun(ep);
 523			}
 524			return -EPIPE;
 525		}
 526
 527		set_bit(ctx->index, &ep->active_mask);
 528		atomic_inc(&ep->submitted_urbs);
 529	}
 530
 531	return 0;
 532}
 533
 534/*
 535 * complete callback for urbs
 536 */
 537static void snd_complete_urb(struct urb *urb)
 538{
 539	struct snd_urb_ctx *ctx = urb->context;
 540	struct snd_usb_endpoint *ep = ctx->ep;
 541	int err;
 542
 543	if (unlikely(urb->status == -ENOENT ||		/* unlinked */
 544		     urb->status == -ENODEV ||		/* device removed */
 545		     urb->status == -ECONNRESET ||	/* unlinked */
 546		     urb->status == -ESHUTDOWN))	/* device disabled */
 547		goto exit_clear;
 548	/* device disconnected */
 549	if (unlikely(atomic_read(&ep->chip->shutdown)))
 550		goto exit_clear;
 551
 552	if (unlikely(!ep_state_running(ep)))
 553		goto exit_clear;
 554
 555	if (usb_pipeout(ep->pipe)) {
 556		retire_outbound_urb(ep, ctx);
 557		/* can be stopped during retire callback */
 558		if (unlikely(!ep_state_running(ep)))
 559			goto exit_clear;
 560
 561		/* in low-latency and implicit-feedback modes, push back the
 562		 * URB to ready list at first, then process as much as possible
 563		 */
 564		if (ep->lowlatency_playback ||
 565		     snd_usb_endpoint_implicit_feedback_sink(ep)) {
 566			push_back_to_ready_list(ep, ctx);
 567			clear_bit(ctx->index, &ep->active_mask);
 568			snd_usb_queue_pending_output_urbs(ep, false);
 569			/* decrement at last, and check xrun */
 570			if (atomic_dec_and_test(&ep->submitted_urbs) &&
 571			    !snd_usb_endpoint_implicit_feedback_sink(ep))
 572				notify_xrun(ep);
 573			return;
 574		}
 575
 576		/* in non-lowlatency mode, no error handling for prepare */
 577		prepare_outbound_urb(ep, ctx, false);
 578		/* can be stopped during prepare callback */
 579		if (unlikely(!ep_state_running(ep)))
 580			goto exit_clear;
 581	} else {
 582		retire_inbound_urb(ep, ctx);
 583		/* can be stopped during retire callback */
 584		if (unlikely(!ep_state_running(ep)))
 585			goto exit_clear;
 586
 587		prepare_inbound_urb(ep, ctx);
 588	}
 589
 590	if (!atomic_read(&ep->chip->shutdown))
 591		err = usb_submit_urb(urb, GFP_ATOMIC);
 592	else
 593		err = -ENODEV;
 594	if (err == 0)
 595		return;
 596
 597	if (!atomic_read(&ep->chip->shutdown)) {
 598		usb_audio_err(ep->chip, "cannot submit urb (err = %d)\n", err);
 599		notify_xrun(ep);
 600	}
 601
 602exit_clear:
 603	clear_bit(ctx->index, &ep->active_mask);
 604	atomic_dec(&ep->submitted_urbs);
 605}
 606
 607/*
 608 * Find or create a refcount object for the given interface
 609 *
 610 * The objects are released altogether in snd_usb_endpoint_free_all()
 611 */
 612static struct snd_usb_iface_ref *
 613iface_ref_find(struct snd_usb_audio *chip, int iface)
 614{
 615	struct snd_usb_iface_ref *ip;
 616
 617	list_for_each_entry(ip, &chip->iface_ref_list, list)
 618		if (ip->iface == iface)
 619			return ip;
 620
 621	ip = kzalloc(sizeof(*ip), GFP_KERNEL);
 622	if (!ip)
 623		return NULL;
 624	ip->iface = iface;
 625	list_add_tail(&ip->list, &chip->iface_ref_list);
 626	return ip;
 627}
 628
 629/* Similarly, a refcount object for clock */
 630static struct snd_usb_clock_ref *
 631clock_ref_find(struct snd_usb_audio *chip, int clock)
 632{
 633	struct snd_usb_clock_ref *ref;
 634
 635	list_for_each_entry(ref, &chip->clock_ref_list, list)
 636		if (ref->clock == clock)
 637			return ref;
 638
 639	ref = kzalloc(sizeof(*ref), GFP_KERNEL);
 640	if (!ref)
 641		return NULL;
 642	ref->clock = clock;
 643	atomic_set(&ref->locked, 0);
 644	list_add_tail(&ref->list, &chip->clock_ref_list);
 645	return ref;
 646}
 647
 648/*
 649 * Get the existing endpoint object corresponding EP
 650 * Returns NULL if not present.
 651 */
 652struct snd_usb_endpoint *
 653snd_usb_get_endpoint(struct snd_usb_audio *chip, int ep_num)
 654{
 655	struct snd_usb_endpoint *ep;
 656
 657	list_for_each_entry(ep, &chip->ep_list, list) {
 658		if (ep->ep_num == ep_num)
 659			return ep;
 660	}
 661
 662	return NULL;
 663}
 664
 665#define ep_type_name(type) \
 666	(type == SND_USB_ENDPOINT_TYPE_DATA ? "data" : "sync")
 667
 668/**
 669 * snd_usb_add_endpoint: Add an endpoint to an USB audio chip
 670 *
 671 * @chip: The chip
 672 * @ep_num: The number of the endpoint to use
 673 * @type: SND_USB_ENDPOINT_TYPE_DATA or SND_USB_ENDPOINT_TYPE_SYNC
 674 *
 675 * If the requested endpoint has not been added to the given chip before,
 676 * a new instance is created.
 677 *
 678 * Returns zero on success or a negative error code.
 679 *
 680 * New endpoints will be added to chip->ep_list and freed by
 681 * calling snd_usb_endpoint_free_all().
 682 *
 683 * For SND_USB_ENDPOINT_TYPE_SYNC, the caller needs to guarantee that
 684 * bNumEndpoints > 1 beforehand.
 685 */
 686int snd_usb_add_endpoint(struct snd_usb_audio *chip, int ep_num, int type)
 687{
 688	struct snd_usb_endpoint *ep;
 689	bool is_playback;
 690
 691	ep = snd_usb_get_endpoint(chip, ep_num);
 692	if (ep)
 693		return 0;
 694
 695	usb_audio_dbg(chip, "Creating new %s endpoint #%x\n",
 696		      ep_type_name(type),
 697		      ep_num);
 698	ep = kzalloc(sizeof(*ep), GFP_KERNEL);
 699	if (!ep)
 700		return -ENOMEM;
 701
 702	ep->chip = chip;
 703	spin_lock_init(&ep->lock);
 704	ep->type = type;
 705	ep->ep_num = ep_num;
 706	INIT_LIST_HEAD(&ep->ready_playback_urbs);
 707	atomic_set(&ep->submitted_urbs, 0);
 708
 709	is_playback = ((ep_num & USB_ENDPOINT_DIR_MASK) == USB_DIR_OUT);
 710	ep_num &= USB_ENDPOINT_NUMBER_MASK;
 711	if (is_playback)
 712		ep->pipe = usb_sndisocpipe(chip->dev, ep_num);
 713	else
 714		ep->pipe = usb_rcvisocpipe(chip->dev, ep_num);
 715
 716	list_add_tail(&ep->list, &chip->ep_list);
 717	return 0;
 718}
 719
 720/* Set up syncinterval and maxsyncsize for a sync EP */
 721static void endpoint_set_syncinterval(struct snd_usb_audio *chip,
 722				      struct snd_usb_endpoint *ep)
 723{
 724	struct usb_host_interface *alts;
 725	struct usb_endpoint_descriptor *desc;
 726
 727	alts = snd_usb_get_host_interface(chip, ep->iface, ep->altsetting);
 728	if (!alts)
 729		return;
 730
 731	desc = get_endpoint(alts, ep->ep_idx);
 732	if (desc->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
 733	    desc->bRefresh >= 1 && desc->bRefresh <= 9)
 734		ep->syncinterval = desc->bRefresh;
 735	else if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL)
 736		ep->syncinterval = 1;
 737	else if (desc->bInterval >= 1 && desc->bInterval <= 16)
 738		ep->syncinterval = desc->bInterval - 1;
 739	else
 740		ep->syncinterval = 3;
 741
 742	ep->syncmaxsize = le16_to_cpu(desc->wMaxPacketSize);
 743}
 744
 745static bool endpoint_compatible(struct snd_usb_endpoint *ep,
 746				const struct audioformat *fp,
 747				const struct snd_pcm_hw_params *params)
 748{
 749	if (!ep->opened)
 750		return false;
 751	if (ep->cur_audiofmt != fp)
 752		return false;
 753	if (ep->cur_rate != params_rate(params) ||
 754	    ep->cur_format != params_format(params) ||
 755	    ep->cur_period_frames != params_period_size(params) ||
 756	    ep->cur_buffer_periods != params_periods(params))
 757		return false;
 758	return true;
 759}
 760
 761/*
 762 * Check whether the given fp and hw params are compatible with the current
 763 * setup of the target EP for implicit feedback sync
 764 */
 765bool snd_usb_endpoint_compatible(struct snd_usb_audio *chip,
 766				 struct snd_usb_endpoint *ep,
 767				 const struct audioformat *fp,
 768				 const struct snd_pcm_hw_params *params)
 769{
 770	guard(mutex)(&chip->mutex);
 771	return endpoint_compatible(ep, fp, params);
 772}
 773
 774/*
 775 * snd_usb_endpoint_open: Open the endpoint
 776 *
 777 * Called from hw_params to assign the endpoint to the substream.
 778 * It's reference-counted, and only the first opener is allowed to set up
 779 * arbitrary parameters.  The later opener must be compatible with the
 780 * former opened parameters.
 781 * The endpoint needs to be closed via snd_usb_endpoint_close() later.
 782 *
 783 * Note that this function doesn't configure the endpoint.  The substream
 784 * needs to set it up later via snd_usb_endpoint_set_params() and
 785 * snd_usb_endpoint_prepare().
 786 */
 787struct snd_usb_endpoint *
 788snd_usb_endpoint_open(struct snd_usb_audio *chip,
 789		      const struct audioformat *fp,
 790		      const struct snd_pcm_hw_params *params,
 791		      bool is_sync_ep,
 792		      bool fixed_rate)
 793{
 794	struct snd_usb_endpoint *ep;
 795	int ep_num = is_sync_ep ? fp->sync_ep : fp->endpoint;
 796
 797	guard(mutex)(&chip->mutex);
 798	ep = snd_usb_get_endpoint(chip, ep_num);
 799	if (!ep) {
 800		usb_audio_err(chip, "Cannot find EP 0x%x to open\n", ep_num);
 801		return NULL;
 802	}
 803
 804	if (!ep->opened) {
 805		if (is_sync_ep) {
 806			ep->iface = fp->sync_iface;
 807			ep->altsetting = fp->sync_altsetting;
 808			ep->ep_idx = fp->sync_ep_idx;
 809		} else {
 810			ep->iface = fp->iface;
 811			ep->altsetting = fp->altsetting;
 812			ep->ep_idx = fp->ep_idx;
 813		}
 814		usb_audio_dbg(chip, "Open EP 0x%x, iface=%d:%d, idx=%d\n",
 815			      ep_num, ep->iface, ep->altsetting, ep->ep_idx);
 816
 817		ep->iface_ref = iface_ref_find(chip, ep->iface);
 818		if (!ep->iface_ref)
 819			return NULL;
 820
 821		if (fp->protocol != UAC_VERSION_1) {
 822			ep->clock_ref = clock_ref_find(chip, fp->clock);
 823			if (!ep->clock_ref)
 824				return NULL;
 825			ep->clock_ref->opened++;
 826		}
 827
 828		ep->cur_audiofmt = fp;
 829		ep->cur_channels = fp->channels;
 830		ep->cur_rate = params_rate(params);
 831		ep->cur_format = params_format(params);
 832		ep->cur_frame_bytes = snd_pcm_format_physical_width(ep->cur_format) *
 833			ep->cur_channels / 8;
 834		ep->cur_period_frames = params_period_size(params);
 835		ep->cur_period_bytes = ep->cur_period_frames * ep->cur_frame_bytes;
 836		ep->cur_buffer_periods = params_periods(params);
 837
 838		if (ep->type == SND_USB_ENDPOINT_TYPE_SYNC)
 839			endpoint_set_syncinterval(chip, ep);
 840
 841		ep->implicit_fb_sync = fp->implicit_fb;
 842		ep->need_setup = true;
 843		ep->need_prepare = true;
 844		ep->fixed_rate = fixed_rate;
 845
 846		usb_audio_dbg(chip, "  channels=%d, rate=%d, format=%s, period_bytes=%d, periods=%d, implicit_fb=%d\n",
 847			      ep->cur_channels, ep->cur_rate,
 848			      snd_pcm_format_name(ep->cur_format),
 849			      ep->cur_period_bytes, ep->cur_buffer_periods,
 850			      ep->implicit_fb_sync);
 851
 852	} else {
 853		if (WARN_ON(!ep->iface_ref))
 854			return NULL;
 855
 856		if (!endpoint_compatible(ep, fp, params)) {
 857			usb_audio_err(chip, "Incompatible EP setup for 0x%x\n",
 858				      ep_num);
 859			return NULL;
 860		}
 861
 862		usb_audio_dbg(chip, "Reopened EP 0x%x (count %d)\n",
 863			      ep_num, ep->opened);
 864	}
 865
 866	if (!ep->iface_ref->opened++)
 867		ep->iface_ref->need_setup = true;
 868
 869	ep->opened++;
 870	return ep;
 871}
 872
 873/*
 874 * snd_usb_endpoint_set_sync: Link data and sync endpoints
 875 *
 876 * Pass NULL to sync_ep to unlink again
 877 */
 878void snd_usb_endpoint_set_sync(struct snd_usb_audio *chip,
 879			       struct snd_usb_endpoint *data_ep,
 880			       struct snd_usb_endpoint *sync_ep)
 881{
 882	data_ep->sync_source = sync_ep;
 883}
 884
 885/*
 886 * Set data endpoint callbacks and the assigned data stream
 887 *
 888 * Called at PCM trigger and cleanups.
 889 * Pass NULL to deactivate each callback.
 890 */
 891void snd_usb_endpoint_set_callback(struct snd_usb_endpoint *ep,
 892				   int (*prepare)(struct snd_usb_substream *subs,
 893						  struct urb *urb,
 894						  bool in_stream_lock),
 895				   void (*retire)(struct snd_usb_substream *subs,
 896						  struct urb *urb),
 897				   struct snd_usb_substream *data_subs)
 898{
 899	ep->prepare_data_urb = prepare;
 900	ep->retire_data_urb = retire;
 901	if (data_subs)
 902		ep->lowlatency_playback = data_subs->lowlatency_playback;
 903	else
 904		ep->lowlatency_playback = false;
 905	WRITE_ONCE(ep->data_subs, data_subs);
 906}
 907
 908static int endpoint_set_interface(struct snd_usb_audio *chip,
 909				  struct snd_usb_endpoint *ep,
 910				  bool set)
 911{
 912	int altset = set ? ep->altsetting : 0;
 913	int err;
 914	int retries = 0;
 915	const int max_retries = 5;
 916
 917	if (ep->iface_ref->altset == altset)
 918		return 0;
 919	/* already disconnected? */
 920	if (unlikely(atomic_read(&chip->shutdown)))
 921		return -ENODEV;
 922
 923	usb_audio_dbg(chip, "Setting usb interface %d:%d for EP 0x%x\n",
 924		      ep->iface, altset, ep->ep_num);
 925retry:
 926	err = usb_set_interface(chip->dev, ep->iface, altset);
 927	if (err < 0) {
 928		if (err == -EPROTO && ++retries <= max_retries) {
 929			msleep(5 * (1 << (retries - 1)));
 930			goto retry;
 931		}
 932		usb_audio_err_ratelimited(
 933			chip, "%d:%d: usb_set_interface failed (%d)\n",
 934			ep->iface, altset, err);
 935		return err;
 936	}
 937
 938	if (chip->quirk_flags & QUIRK_FLAG_IFACE_DELAY)
 939		msleep(50);
 940	ep->iface_ref->altset = altset;
 941	return 0;
 942}
 943
 944/*
 945 * snd_usb_endpoint_close: Close the endpoint
 946 *
 947 * Unreference the already opened endpoint via snd_usb_endpoint_open().
 948 */
 949void snd_usb_endpoint_close(struct snd_usb_audio *chip,
 950			    struct snd_usb_endpoint *ep)
 951{
 952	guard(mutex)(&chip->mutex);
 953	usb_audio_dbg(chip, "Closing EP 0x%x (count %d)\n",
 954		      ep->ep_num, ep->opened);
 955
 956	if (!--ep->iface_ref->opened &&
 957		!(chip->quirk_flags & QUIRK_FLAG_IFACE_SKIP_CLOSE))
 958		endpoint_set_interface(chip, ep, false);
 959
 960	if (!--ep->opened) {
 961		if (ep->clock_ref) {
 962			if (!--ep->clock_ref->opened)
 963				ep->clock_ref->rate = 0;
 964		}
 965		ep->iface = 0;
 966		ep->altsetting = 0;
 967		ep->cur_audiofmt = NULL;
 968		ep->cur_rate = 0;
 969		ep->iface_ref = NULL;
 970		ep->clock_ref = NULL;
 971		usb_audio_dbg(chip, "EP 0x%x closed\n", ep->ep_num);
 972	}
 973}
 974
 975/* Prepare for suspening EP, called from the main suspend handler */
 976void snd_usb_endpoint_suspend(struct snd_usb_endpoint *ep)
 977{
 978	ep->need_prepare = true;
 979	if (ep->iface_ref)
 980		ep->iface_ref->need_setup = true;
 981	if (ep->clock_ref)
 982		ep->clock_ref->rate = 0;
 983}
 984
 985/*
 986 *  wait until all urbs are processed.
 987 */
 988static int wait_clear_urbs(struct snd_usb_endpoint *ep)
 989{
 990	unsigned long end_time = jiffies + msecs_to_jiffies(1000);
 991	int alive;
 992
 993	if (atomic_read(&ep->state) != EP_STATE_STOPPING)
 994		return 0;
 995
 996	do {
 997		alive = atomic_read(&ep->submitted_urbs);
 998		if (!alive)
 999			break;
1000
1001		schedule_timeout_uninterruptible(1);
1002	} while (time_before(jiffies, end_time));
1003
1004	if (alive)
1005		usb_audio_err(ep->chip,
1006			"timeout: still %d active urbs on EP #%x\n",
1007			alive, ep->ep_num);
1008
1009	if (ep_state_update(ep, EP_STATE_STOPPING, EP_STATE_STOPPED)) {
1010		ep->sync_sink = NULL;
1011		snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
1012	}
1013
1014	return 0;
1015}
1016
1017/* sync the pending stop operation;
1018 * this function itself doesn't trigger the stop operation
1019 */
1020void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep)
1021{
1022	if (ep)
1023		wait_clear_urbs(ep);
1024}
1025
1026/*
1027 * Stop active urbs
1028 *
1029 * This function moves the EP to STOPPING state if it's being RUNNING.
1030 */
1031static int stop_urbs(struct snd_usb_endpoint *ep, bool force, bool keep_pending)
1032{
1033	unsigned int i;
1034
1035	if (!force && atomic_read(&ep->running))
1036		return -EBUSY;
1037
1038	if (!ep_state_update(ep, EP_STATE_RUNNING, EP_STATE_STOPPING))
1039		return 0;
1040
1041	scoped_guard(spinlock_irqsave, &ep->lock) {
1042		INIT_LIST_HEAD(&ep->ready_playback_urbs);
1043		ep->next_packet_head = 0;
1044		ep->next_packet_queued = 0;
1045	}
1046
1047	if (keep_pending)
1048		return 0;
1049
1050	for (i = 0; i < ep->nurbs; i++) {
1051		if (test_bit(i, &ep->active_mask)) {
1052			if (!test_and_set_bit(i, &ep->unlink_mask)) {
1053				struct urb *u = ep->urb[i].urb;
1054				usb_unlink_urb(u);
1055			}
1056		}
1057	}
1058
1059	return 0;
1060}
1061
1062/*
1063 * release an endpoint's urbs
1064 */
1065static int release_urbs(struct snd_usb_endpoint *ep, bool force)
1066{
1067	int i, err;
1068
1069	/* route incoming urbs to nirvana */
1070	snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
1071
1072	/* stop and unlink urbs */
1073	err = stop_urbs(ep, force, false);
1074	if (err)
1075		return err;
1076
1077	wait_clear_urbs(ep);
1078
1079	for (i = 0; i < ep->nurbs; i++)
1080		release_urb_ctx(&ep->urb[i]);
1081
1082	usb_free_coherent(ep->chip->dev, SYNC_URBS * 4,
1083			  ep->syncbuf, ep->sync_dma);
1084
1085	ep->syncbuf = NULL;
1086	ep->nurbs = 0;
1087	return 0;
1088}
1089
1090/*
1091 * configure a data endpoint
1092 */
1093static int data_ep_set_params(struct snd_usb_endpoint *ep)
1094{
1095	struct snd_usb_audio *chip = ep->chip;
1096	unsigned int maxsize, minsize, packs_per_ms, max_packs_per_urb;
1097	unsigned int max_packs_per_period, urbs_per_period, urb_packs;
1098	unsigned int max_urbs, i;
1099	const struct audioformat *fmt = ep->cur_audiofmt;
1100	int frame_bits = ep->cur_frame_bytes * 8;
1101	int tx_length_quirk = (has_tx_length_quirk(chip) &&
1102			       usb_pipeout(ep->pipe));
1103
1104	usb_audio_dbg(chip, "Setting params for data EP 0x%x, pipe 0x%x\n",
1105		      ep->ep_num, ep->pipe);
1106
1107	if (ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) {
1108		/*
1109		 * When operating in DSD DOP mode, the size of a sample frame
1110		 * in hardware differs from the actual physical format width
1111		 * because we need to make room for the DOP markers.
1112		 */
1113		frame_bits += ep->cur_channels << 3;
1114	}
1115
1116	ep->datainterval = fmt->datainterval;
1117	ep->stride = frame_bits >> 3;
1118
1119	switch (ep->cur_format) {
1120	case SNDRV_PCM_FORMAT_U8:
1121		ep->silence_value = 0x80;
1122		break;
1123	case SNDRV_PCM_FORMAT_DSD_U8:
1124	case SNDRV_PCM_FORMAT_DSD_U16_LE:
1125	case SNDRV_PCM_FORMAT_DSD_U32_LE:
1126	case SNDRV_PCM_FORMAT_DSD_U16_BE:
1127	case SNDRV_PCM_FORMAT_DSD_U32_BE:
1128		ep->silence_value = 0x69;
1129		break;
1130	default:
1131		ep->silence_value = 0;
1132	}
1133
1134	/* assume max. frequency is 50% higher than nominal */
1135	ep->freqmax = ep->freqn + (ep->freqn >> 1);
1136	/* Round up freqmax to nearest integer in order to calculate maximum
1137	 * packet size, which must represent a whole number of frames.
1138	 * This is accomplished by adding 0x0.ffff before converting the
1139	 * Q16.16 format into integer.
1140	 * In order to accurately calculate the maximum packet size when
1141	 * the data interval is more than 1 (i.e. ep->datainterval > 0),
1142	 * multiply by the data interval prior to rounding. For instance,
1143	 * a freqmax of 41 kHz will result in a max packet size of 6 (5.125)
1144	 * frames with a data interval of 1, but 11 (10.25) frames with a
1145	 * data interval of 2.
1146	 * (ep->freqmax << ep->datainterval overflows at 8.192 MHz for the
1147	 * maximum datainterval value of 3, at USB full speed, higher for
1148	 * USB high speed, noting that ep->freqmax is in units of
1149	 * frames per packet in Q16.16 format.)
1150	 */
1151	maxsize = (((ep->freqmax << ep->datainterval) + 0xffff) >> 16) *
1152			 (frame_bits >> 3);
1153	if (tx_length_quirk)
1154		maxsize += sizeof(__le32); /* Space for length descriptor */
1155	/* but wMaxPacketSize might reduce this */
1156	if (ep->maxpacksize && ep->maxpacksize < maxsize) {
1157		/* whatever fits into a max. size packet */
1158		unsigned int data_maxsize = maxsize = ep->maxpacksize;
1159
1160		if (tx_length_quirk)
1161			/* Need to remove the length descriptor to calc freq */
1162			data_maxsize -= sizeof(__le32);
1163		ep->freqmax = (data_maxsize / (frame_bits >> 3))
1164				<< (16 - ep->datainterval);
1165	}
1166
1167	if (ep->fill_max)
1168		ep->curpacksize = ep->maxpacksize;
1169	else
1170		ep->curpacksize = maxsize;
1171
1172	if (snd_usb_get_speed(chip->dev) != USB_SPEED_FULL) {
1173		packs_per_ms = 8 >> ep->datainterval;
1174		max_packs_per_urb = MAX_PACKS_HS;
1175	} else {
1176		packs_per_ms = 1;
1177		max_packs_per_urb = MAX_PACKS;
1178	}
1179	if (ep->sync_source && !ep->implicit_fb_sync)
1180		max_packs_per_urb = min(max_packs_per_urb,
1181					1U << ep->sync_source->syncinterval);
1182	max_packs_per_urb = max(1u, max_packs_per_urb >> ep->datainterval);
1183
1184	/*
1185	 * Capture endpoints need to use small URBs because there's no way
1186	 * to tell in advance where the next period will end, and we don't
1187	 * want the next URB to complete much after the period ends.
1188	 *
1189	 * Playback endpoints with implicit sync much use the same parameters
1190	 * as their corresponding capture endpoint.
1191	 */
1192	if (usb_pipein(ep->pipe) || ep->implicit_fb_sync) {
1193
1194		/* make capture URBs <= 1 ms and smaller than a period */
1195		urb_packs = min(max_packs_per_urb, packs_per_ms);
1196		while (urb_packs > 1 && urb_packs * maxsize >= ep->cur_period_bytes)
1197			urb_packs >>= 1;
1198		ep->nurbs = MAX_URBS;
1199
1200	/*
1201	 * Playback endpoints without implicit sync are adjusted so that
1202	 * a period fits as evenly as possible in the smallest number of
1203	 * URBs.  The total number of URBs is adjusted to the size of the
1204	 * ALSA buffer, subject to the MAX_URBS and MAX_QUEUE limits.
1205	 */
1206	} else {
1207		/* determine how small a packet can be */
1208		minsize = (ep->freqn >> (16 - ep->datainterval)) *
1209				(frame_bits >> 3);
1210		/* with sync from device, assume it can be 12% lower */
1211		if (ep->sync_source)
1212			minsize -= minsize >> 3;
1213		minsize = max(minsize, 1u);
1214
1215		/* how many packets will contain an entire ALSA period? */
1216		max_packs_per_period = DIV_ROUND_UP(ep->cur_period_bytes, minsize);
1217
1218		/* how many URBs will contain a period? */
1219		urbs_per_period = DIV_ROUND_UP(max_packs_per_period,
1220				max_packs_per_urb);
1221		/* how many packets are needed in each URB? */
1222		urb_packs = DIV_ROUND_UP(max_packs_per_period, urbs_per_period);
1223
1224		/* limit the number of frames in a single URB */
1225		ep->max_urb_frames = DIV_ROUND_UP(ep->cur_period_frames,
1226						  urbs_per_period);
1227
1228		/* try to use enough URBs to contain an entire ALSA buffer */
1229		max_urbs = min((unsigned) MAX_URBS,
1230				MAX_QUEUE * packs_per_ms / urb_packs);
1231		ep->nurbs = min(max_urbs, urbs_per_period * ep->cur_buffer_periods);
1232	}
1233
1234	/* allocate and initialize data urbs */
1235	for (i = 0; i < ep->nurbs; i++) {
1236		struct snd_urb_ctx *u = &ep->urb[i];
1237		u->index = i;
1238		u->ep = ep;
1239		u->packets = urb_packs;
1240		u->buffer_size = maxsize * u->packets;
1241
1242		if (fmt->fmt_type == UAC_FORMAT_TYPE_II)
1243			u->packets++; /* for transfer delimiter */
1244		u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
1245		if (!u->urb)
1246			goto out_of_memory;
1247
1248		u->urb->transfer_buffer =
1249			usb_alloc_coherent(chip->dev, u->buffer_size,
1250					   GFP_KERNEL, &u->urb->transfer_dma);
1251		if (!u->urb->transfer_buffer)
1252			goto out_of_memory;
1253		u->urb->pipe = ep->pipe;
1254		u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1255		u->urb->interval = 1 << ep->datainterval;
1256		u->urb->context = u;
1257		u->urb->complete = snd_complete_urb;
1258		INIT_LIST_HEAD(&u->ready_list);
1259	}
1260
1261	return 0;
1262
1263out_of_memory:
1264	release_urbs(ep, false);
1265	return -ENOMEM;
1266}
1267
1268/*
1269 * configure a sync endpoint
1270 */
1271static int sync_ep_set_params(struct snd_usb_endpoint *ep)
1272{
1273	struct snd_usb_audio *chip = ep->chip;
1274	int i;
1275
1276	usb_audio_dbg(chip, "Setting params for sync EP 0x%x, pipe 0x%x\n",
1277		      ep->ep_num, ep->pipe);
1278
1279	ep->syncbuf = usb_alloc_coherent(chip->dev, SYNC_URBS * 4,
1280					 GFP_KERNEL, &ep->sync_dma);
1281	if (!ep->syncbuf)
1282		return -ENOMEM;
1283
1284	ep->nurbs = SYNC_URBS;
1285	for (i = 0; i < SYNC_URBS; i++) {
1286		struct snd_urb_ctx *u = &ep->urb[i];
1287		u->index = i;
1288		u->ep = ep;
1289		u->packets = 1;
1290		u->urb = usb_alloc_urb(1, GFP_KERNEL);
1291		if (!u->urb)
1292			goto out_of_memory;
1293		u->urb->transfer_buffer = ep->syncbuf + i * 4;
1294		u->urb->transfer_dma = ep->sync_dma + i * 4;
1295		u->urb->transfer_buffer_length = 4;
1296		u->urb->pipe = ep->pipe;
1297		u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1298		u->urb->number_of_packets = 1;
1299		u->urb->interval = 1 << ep->syncinterval;
1300		u->urb->context = u;
1301		u->urb->complete = snd_complete_urb;
1302	}
1303
1304	return 0;
1305
1306out_of_memory:
1307	release_urbs(ep, false);
1308	return -ENOMEM;
1309}
1310
1311/* update the rate of the referred clock; return the actual rate */
1312static int update_clock_ref_rate(struct snd_usb_audio *chip,
1313				 struct snd_usb_endpoint *ep)
1314{
1315	struct snd_usb_clock_ref *clock = ep->clock_ref;
1316	int rate = ep->cur_rate;
1317
1318	if (!clock || clock->rate == rate)
1319		return rate;
1320	if (clock->rate) {
1321		if (atomic_read(&clock->locked))
1322			return clock->rate;
1323		if (clock->rate != rate) {
1324			usb_audio_err(chip, "Mismatched sample rate %d vs %d for EP 0x%x\n",
1325				      clock->rate, rate, ep->ep_num);
1326			return clock->rate;
1327		}
1328	}
1329	clock->rate = rate;
1330	clock->need_setup = true;
1331	return rate;
1332}
1333
1334/*
1335 * snd_usb_endpoint_set_params: configure an snd_usb_endpoint
1336 *
1337 * It's called either from hw_params callback.
1338 * Determine the number of URBs to be used on this endpoint.
1339 * An endpoint must be configured before it can be started.
1340 * An endpoint that is already running can not be reconfigured.
1341 */
1342int snd_usb_endpoint_set_params(struct snd_usb_audio *chip,
1343				struct snd_usb_endpoint *ep)
1344{
1345	const struct audioformat *fmt = ep->cur_audiofmt;
1346	int err;
1347
1348	guard(mutex)(&chip->mutex);
1349	if (!ep->need_setup)
1350		return 0;
1351
1352	/* release old buffers, if any */
1353	err = release_urbs(ep, false);
1354	if (err < 0)
1355		return err;
1356
1357	ep->datainterval = fmt->datainterval;
1358	ep->maxpacksize = fmt->maxpacksize;
1359	ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX);
1360
1361	if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL) {
1362		ep->freqn = get_usb_full_speed_rate(ep->cur_rate);
1363		ep->pps = 1000 >> ep->datainterval;
1364	} else {
1365		ep->freqn = get_usb_high_speed_rate(ep->cur_rate);
1366		ep->pps = 8000 >> ep->datainterval;
1367	}
1368
1369	ep->sample_rem = ep->cur_rate % ep->pps;
1370	ep->packsize[0] = ep->cur_rate / ep->pps;
1371	ep->packsize[1] = (ep->cur_rate + (ep->pps - 1)) / ep->pps;
1372	if (ep->packsize[1] > ep->maxpacksize) {
1373		usb_audio_dbg(chip, "Too small maxpacksize %u for rate %u / pps %u\n",
1374			      ep->maxpacksize, ep->cur_rate, ep->pps);
1375		return -EINVAL;
1376	}
1377
1378	ep->packsize[0] = min(ep->packsize[0], ep->maxframesize);
1379	ep->packsize[1] = min(ep->packsize[1], ep->maxframesize);
1380
1381	/* calculate the frequency in 16.16 format */
1382	ep->freqm = ep->freqn;
1383	ep->freqshift = INT_MIN;
1384
1385	ep->phase = 0;
1386
1387	switch (ep->type) {
1388	case  SND_USB_ENDPOINT_TYPE_DATA:
1389		err = data_ep_set_params(ep);
1390		break;
1391	case  SND_USB_ENDPOINT_TYPE_SYNC:
1392		err = sync_ep_set_params(ep);
1393		break;
1394	default:
1395		err = -EINVAL;
1396	}
1397
1398	usb_audio_dbg(chip, "Set up %d URBS, ret=%d\n", ep->nurbs, err);
1399
1400	if (err < 0)
1401		return err;
1402
1403	/* some unit conversions in runtime */
1404	ep->maxframesize = ep->maxpacksize / ep->cur_frame_bytes;
1405	ep->curframesize = ep->curpacksize / ep->cur_frame_bytes;
1406
1407	err = update_clock_ref_rate(chip, ep);
1408	if (err >= 0) {
1409		ep->need_setup = false;
1410		err = 0;
1411	}
1412
1413	return err;
1414}
1415
1416static int init_sample_rate(struct snd_usb_audio *chip,
1417			    struct snd_usb_endpoint *ep)
1418{
1419	struct snd_usb_clock_ref *clock = ep->clock_ref;
1420	int rate, err;
1421
1422	rate = update_clock_ref_rate(chip, ep);
1423	if (rate < 0)
1424		return rate;
1425	if (clock && !clock->need_setup)
1426		return 0;
1427
1428	if (!ep->fixed_rate) {
1429		err = snd_usb_init_sample_rate(chip, ep->cur_audiofmt, rate);
1430		if (err < 0) {
1431			if (clock)
1432				clock->rate = 0; /* reset rate */
1433			return err;
1434		}
1435	}
1436
1437	if (clock)
1438		clock->need_setup = false;
1439	return 0;
1440}
1441
1442/*
1443 * snd_usb_endpoint_prepare: Prepare the endpoint
1444 *
1445 * This function sets up the EP to be fully usable state.
1446 * It's called either from prepare callback.
1447 * The function checks need_setup flag, and performs nothing unless needed,
1448 * so it's safe to call this multiple times.
1449 *
1450 * This returns zero if unchanged, 1 if the configuration has changed,
1451 * or a negative error code.
1452 */
1453int snd_usb_endpoint_prepare(struct snd_usb_audio *chip,
1454			     struct snd_usb_endpoint *ep)
1455{
1456	bool iface_first;
1457	int err = 0;
1458
1459	guard(mutex)(&chip->mutex);
1460	if (WARN_ON(!ep->iface_ref))
1461		return 0;
1462	if (!ep->need_prepare)
1463		return 0;
1464
1465	/* If the interface has been already set up, just set EP parameters */
1466	if (!ep->iface_ref->need_setup) {
1467		/* sample rate setup of UAC1 is per endpoint, and we need
1468		 * to update at each EP configuration
1469		 */
1470		if (ep->cur_audiofmt->protocol == UAC_VERSION_1) {
1471			err = init_sample_rate(chip, ep);
1472			if (err < 0)
1473				return err;
1474		}
1475		goto done;
1476	}
1477
1478	/* Need to deselect altsetting at first */
1479	endpoint_set_interface(chip, ep, false);
1480
1481	/* Some UAC1 devices (e.g. Yamaha THR10) need the host interface
1482	 * to be set up before parameter setups
1483	 */
1484	iface_first = ep->cur_audiofmt->protocol == UAC_VERSION_1;
1485	/* Workaround for devices that require the interface setup at first like UAC1 */
1486	if (chip->quirk_flags & QUIRK_FLAG_SET_IFACE_FIRST)
1487		iface_first = true;
1488	if (iface_first) {
1489		err = endpoint_set_interface(chip, ep, true);
1490		if (err < 0)
1491			return err;
1492	}
1493
1494	err = snd_usb_select_mode_quirk(chip, ep->cur_audiofmt);
1495	if (err < 0)
1496		return err;
1497
1498	err = snd_usb_init_pitch(chip, ep->cur_audiofmt);
1499	if (err < 0)
1500		return err;
1501
1502	err = init_sample_rate(chip, ep);
1503	if (err < 0)
1504		return err;
1505
1506	/* for UAC2/3, enable the interface altset here at last */
1507	if (!iface_first) {
1508		err = endpoint_set_interface(chip, ep, true);
1509		if (err < 0)
1510			return err;
1511	}
1512
1513	ep->iface_ref->need_setup = false;
1514
1515 done:
1516	ep->need_prepare = false;
1517	return 1;
1518}
1519EXPORT_SYMBOL_GPL(snd_usb_endpoint_prepare);
1520
1521/* get the current rate set to the given clock by any endpoint */
1522int snd_usb_endpoint_get_clock_rate(struct snd_usb_audio *chip, int clock)
1523{
1524	struct snd_usb_clock_ref *ref;
1525	int rate = 0;
1526
1527	if (!clock)
1528		return 0;
1529	guard(mutex)(&chip->mutex);
1530	list_for_each_entry(ref, &chip->clock_ref_list, list) {
1531		if (ref->clock == clock) {
1532			rate = ref->rate;
1533			break;
1534		}
1535	}
1536	return rate;
1537}
1538
1539/**
1540 * snd_usb_endpoint_start: start an snd_usb_endpoint
1541 *
1542 * @ep: the endpoint to start
1543 *
1544 * A call to this function will increment the running count of the endpoint.
1545 * In case it is not already running, the URBs for this endpoint will be
1546 * submitted. Otherwise, this function does nothing.
1547 *
1548 * Must be balanced to calls of snd_usb_endpoint_stop().
1549 *
1550 * Returns an error if the URB submission failed, 0 in all other cases.
1551 */
1552int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
1553{
1554	bool is_playback = usb_pipeout(ep->pipe);
1555	int err;
1556	unsigned int i;
1557
1558	if (atomic_read(&ep->chip->shutdown))
1559		return -EBADFD;
1560
1561	if (ep->sync_source)
1562		WRITE_ONCE(ep->sync_source->sync_sink, ep);
1563
1564	usb_audio_dbg(ep->chip, "Starting %s EP 0x%x (running %d)\n",
1565		      ep_type_name(ep->type), ep->ep_num,
1566		      atomic_read(&ep->running));
1567
1568	/* already running? */
1569	if (atomic_inc_return(&ep->running) != 1)
1570		return 0;
1571
1572	if (ep->clock_ref)
1573		atomic_inc(&ep->clock_ref->locked);
1574
1575	ep->active_mask = 0;
1576	ep->unlink_mask = 0;
1577	ep->phase = 0;
1578	ep->sample_accum = 0;
1579
1580	snd_usb_endpoint_start_quirk(ep);
1581
1582	/*
1583	 * If this endpoint has a data endpoint as implicit feedback source,
1584	 * don't start the urbs here. Instead, mark them all as available,
1585	 * wait for the record urbs to return and queue the playback urbs
1586	 * from that context.
1587	 */
1588
1589	if (!ep_state_update(ep, EP_STATE_STOPPED, EP_STATE_RUNNING))
1590		goto __error;
1591
1592	if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1593	    !(ep->chip->quirk_flags & QUIRK_FLAG_PLAYBACK_FIRST)) {
1594		usb_audio_dbg(ep->chip, "No URB submission due to implicit fb sync\n");
1595		i = 0;
1596		goto fill_rest;
1597	}
1598
1599	for (i = 0; i < ep->nurbs; i++) {
1600		struct urb *urb = ep->urb[i].urb;
1601
1602		if (snd_BUG_ON(!urb))
1603			goto __error;
1604
1605		if (is_playback)
1606			err = prepare_outbound_urb(ep, urb->context, true);
1607		else
1608			err = prepare_inbound_urb(ep, urb->context);
1609		if (err < 0) {
1610			/* stop filling at applptr */
1611			if (err == -EAGAIN)
1612				break;
1613			usb_audio_dbg(ep->chip,
1614				      "EP 0x%x: failed to prepare urb: %d\n",
1615				      ep->ep_num, err);
1616			goto __error;
1617		}
1618
1619		if (!atomic_read(&ep->chip->shutdown))
1620			err = usb_submit_urb(urb, GFP_ATOMIC);
1621		else
1622			err = -ENODEV;
1623		if (err < 0) {
1624			if (!atomic_read(&ep->chip->shutdown))
1625				usb_audio_err(ep->chip,
1626					      "cannot submit urb %d, error %d: %s\n",
1627					      i, err, usb_error_string(err));
1628			goto __error;
1629		}
1630		set_bit(i, &ep->active_mask);
1631		atomic_inc(&ep->submitted_urbs);
1632	}
1633
1634	if (!i) {
1635		usb_audio_dbg(ep->chip, "XRUN at starting EP 0x%x\n",
1636			      ep->ep_num);
1637		goto __error;
1638	}
1639
1640	usb_audio_dbg(ep->chip, "%d URBs submitted for EP 0x%x\n",
1641		      i, ep->ep_num);
1642
1643 fill_rest:
1644	/* put the remaining URBs to ready list */
1645	if (is_playback) {
1646		for (; i < ep->nurbs; i++)
1647			push_back_to_ready_list(ep, ep->urb + i);
1648	}
1649
1650	return 0;
1651
1652__error:
1653	snd_usb_endpoint_stop(ep, false);
1654	return -EPIPE;
1655}
1656
1657/**
1658 * snd_usb_endpoint_stop: stop an snd_usb_endpoint
1659 *
1660 * @ep: the endpoint to stop (may be NULL)
1661 * @keep_pending: keep in-flight URBs
1662 *
1663 * A call to this function will decrement the running count of the endpoint.
1664 * In case the last user has requested the endpoint stop, the URBs will
1665 * actually be deactivated.
1666 *
1667 * Must be balanced to calls of snd_usb_endpoint_start().
1668 *
1669 * The caller needs to synchronize the pending stop operation via
1670 * snd_usb_endpoint_sync_pending_stop().
1671 */
1672void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep, bool keep_pending)
1673{
1674	if (!ep)
1675		return;
1676
1677	usb_audio_dbg(ep->chip, "Stopping %s EP 0x%x (running %d)\n",
1678		      ep_type_name(ep->type), ep->ep_num,
1679		      atomic_read(&ep->running));
1680
1681	if (snd_BUG_ON(!atomic_read(&ep->running)))
1682		return;
1683
1684	if (!atomic_dec_return(&ep->running)) {
1685		if (ep->sync_source)
1686			WRITE_ONCE(ep->sync_source->sync_sink, NULL);
1687		stop_urbs(ep, false, keep_pending);
1688		if (ep->clock_ref)
1689			atomic_dec(&ep->clock_ref->locked);
1690
1691		if (ep->chip->quirk_flags & QUIRK_FLAG_FORCE_IFACE_RESET &&
1692		    usb_pipeout(ep->pipe)) {
1693			ep->need_prepare = true;
1694			if (ep->iface_ref)
1695				ep->iface_ref->need_setup = true;
1696		}
1697	}
1698}
1699
1700/**
1701 * snd_usb_endpoint_release: Tear down an snd_usb_endpoint
1702 *
1703 * @ep: the endpoint to release
1704 *
1705 * This function does not care for the endpoint's running count but will tear
1706 * down all the streaming URBs immediately.
1707 */
1708void snd_usb_endpoint_release(struct snd_usb_endpoint *ep)
1709{
1710	release_urbs(ep, true);
1711}
1712
1713/**
1714 * snd_usb_endpoint_free_all: Free the resources of an snd_usb_endpoint
1715 * @chip: The chip
1716 *
1717 * This free all endpoints and those resources
1718 */
1719void snd_usb_endpoint_free_all(struct snd_usb_audio *chip)
1720{
1721	struct snd_usb_endpoint *ep, *en;
1722	struct snd_usb_iface_ref *ip, *in;
1723	struct snd_usb_clock_ref *cp, *cn;
1724
1725	list_for_each_entry_safe(ep, en, &chip->ep_list, list)
1726		kfree(ep);
1727
1728	list_for_each_entry_safe(ip, in, &chip->iface_ref_list, list)
1729		kfree(ip);
1730
1731	list_for_each_entry_safe(cp, cn, &chip->clock_ref_list, list)
1732		kfree(cp);
1733}
1734
1735/*
1736 * snd_usb_handle_sync_urb: parse an USB sync packet
1737 *
1738 * @ep: the endpoint to handle the packet
1739 * @sender: the sending endpoint
1740 * @urb: the received packet
1741 *
1742 * This function is called from the context of an endpoint that received
1743 * the packet and is used to let another endpoint object handle the payload.
1744 */
1745static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
1746				    struct snd_usb_endpoint *sender,
1747				    const struct urb *urb)
1748{
1749	int shift;
1750	unsigned int f;
1751	unsigned long flags;
1752
1753	snd_BUG_ON(ep == sender);
1754
1755	/*
1756	 * In case the endpoint is operating in implicit feedback mode, prepare
1757	 * a new outbound URB that has the same layout as the received packet
1758	 * and add it to the list of pending urbs. queue_pending_output_urbs()
1759	 * will take care of them later.
1760	 */
1761	if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1762	    atomic_read(&ep->running)) {
1763
1764		/* implicit feedback case */
1765		int i, bytes = 0;
1766		struct snd_urb_ctx *in_ctx;
1767		struct snd_usb_packet_info *out_packet;
1768
1769		in_ctx = urb->context;
1770
1771		/* Count overall packet size */
1772		for (i = 0; i < in_ctx->packets; i++)
1773			if (urb->iso_frame_desc[i].status == 0)
1774				bytes += urb->iso_frame_desc[i].actual_length;
1775
1776		/*
1777		 * skip empty packets. At least M-Audio's Fast Track Ultra stops
1778		 * streaming once it received a 0-byte OUT URB
1779		 */
1780		if (bytes == 0)
1781			return;
1782
1783		spin_lock_irqsave(&ep->lock, flags);
1784		if (ep->next_packet_queued >= ARRAY_SIZE(ep->next_packet)) {
1785			spin_unlock_irqrestore(&ep->lock, flags);
1786			usb_audio_err(ep->chip,
1787				      "next package FIFO overflow EP 0x%x\n",
1788				      ep->ep_num);
1789			notify_xrun(ep);
1790			return;
1791		}
1792
1793		out_packet = next_packet_fifo_enqueue(ep);
1794
1795		/*
1796		 * Iterate through the inbound packet and prepare the lengths
1797		 * for the output packet. The OUT packet we are about to send
1798		 * will have the same amount of payload bytes per stride as the
1799		 * IN packet we just received. Since the actual size is scaled
1800		 * by the stride, use the sender stride to calculate the length
1801		 * in case the number of channels differ between the implicitly
1802		 * fed-back endpoint and the synchronizing endpoint.
1803		 */
1804
1805		out_packet->packets = in_ctx->packets;
1806		for (i = 0; i < in_ctx->packets; i++) {
1807			if (urb->iso_frame_desc[i].status == 0)
1808				out_packet->packet_size[i] =
1809					urb->iso_frame_desc[i].actual_length / sender->stride;
1810			else
1811				out_packet->packet_size[i] = 0;
1812		}
1813
1814		spin_unlock_irqrestore(&ep->lock, flags);
1815		snd_usb_queue_pending_output_urbs(ep, false);
1816
1817		return;
1818	}
1819
1820	/*
1821	 * process after playback sync complete
1822	 *
1823	 * Full speed devices report feedback values in 10.14 format as samples
1824	 * per frame, high speed devices in 16.16 format as samples per
1825	 * microframe.
1826	 *
1827	 * Because the Audio Class 1 spec was written before USB 2.0, many high
1828	 * speed devices use a wrong interpretation, some others use an
1829	 * entirely different format.
1830	 *
1831	 * Therefore, we cannot predict what format any particular device uses
1832	 * and must detect it automatically.
1833	 */
1834
1835	if (urb->iso_frame_desc[0].status != 0 ||
1836	    urb->iso_frame_desc[0].actual_length < 3)
1837		return;
1838
1839	f = le32_to_cpup(urb->transfer_buffer);
1840	if (urb->iso_frame_desc[0].actual_length == 3)
1841		f &= 0x00ffffff;
1842	else
1843		f &= 0x0fffffff;
1844
1845	if (f == 0)
1846		return;
1847
1848	if (unlikely(sender->tenor_fb_quirk)) {
1849		/*
1850		 * Devices based on Tenor 8802 chipsets (TEAC UD-H01
1851		 * and others) sometimes change the feedback value
1852		 * by +/- 0x1.0000.
1853		 */
1854		if (f < ep->freqn - 0x8000)
1855			f += 0xf000;
1856		else if (f > ep->freqn + 0x8000)
1857			f -= 0xf000;
1858	} else if (unlikely(ep->freqshift == INT_MIN)) {
1859		/*
1860		 * The first time we see a feedback value, determine its format
1861		 * by shifting it left or right until it matches the nominal
1862		 * frequency value.  This assumes that the feedback does not
1863		 * differ from the nominal value more than +50% or -25%.
1864		 */
1865		shift = 0;
1866		while (f < ep->freqn - ep->freqn / 4) {
1867			f <<= 1;
1868			shift++;
1869		}
1870		while (f > ep->freqn + ep->freqn / 2) {
1871			f >>= 1;
1872			shift--;
1873		}
1874		ep->freqshift = shift;
1875	} else if (ep->freqshift >= 0)
1876		f <<= ep->freqshift;
1877	else
1878		f >>= -ep->freqshift;
1879
1880	if (likely(f >= ep->freqn - ep->freqn / 8 && f <= ep->freqmax)) {
1881		/*
1882		 * If the frequency looks valid, set it.
1883		 * This value is referred to in prepare_playback_urb().
1884		 */
1885		guard(spinlock_irqsave)(&ep->lock);
1886		ep->freqm = f;
1887	} else {
1888		/*
1889		 * Out of range; maybe the shift value is wrong.
1890		 * Reset it so that we autodetect again the next time.
1891		 */
1892		ep->freqshift = INT_MIN;
1893	}
1894}
1895