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0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  */
0004 
0005 #include <linux/gfp.h>
0006 #include <linux/init.h>
0007 #include <linux/ratelimit.h>
0008 #include <linux/usb.h>
0009 #include <linux/usb/audio.h>
0010 #include <linux/slab.h>
0011 
0012 #include <sound/core.h>
0013 #include <sound/pcm.h>
0014 #include <sound/pcm_params.h>
0015 
0016 #include "usbaudio.h"
0017 #include "helper.h"
0018 #include "card.h"
0019 #include "endpoint.h"
0020 #include "pcm.h"
0021 #include "clock.h"
0022 #include "quirks.h"
0023 
0024 enum {
0025     EP_STATE_STOPPED,
0026     EP_STATE_RUNNING,
0027     EP_STATE_STOPPING,
0028 };
0029 
0030 /* interface refcounting */
0031 struct snd_usb_iface_ref {
0032     unsigned char iface;
0033     bool need_setup;
0034     int opened;
0035     struct list_head list;
0036 };
0037 
0038 /* clock refcounting */
0039 struct snd_usb_clock_ref {
0040     unsigned char clock;
0041     atomic_t locked;
0042     int rate;
0043     struct list_head list;
0044 };
0045 
0046 /*
0047  * snd_usb_endpoint is a model that abstracts everything related to an
0048  * USB endpoint and its streaming.
0049  *
0050  * There are functions to activate and deactivate the streaming URBs and
0051  * optional callbacks to let the pcm logic handle the actual content of the
0052  * packets for playback and record. Thus, the bus streaming and the audio
0053  * handlers are fully decoupled.
0054  *
0055  * There are two different types of endpoints in audio applications.
0056  *
0057  * SND_USB_ENDPOINT_TYPE_DATA handles full audio data payload for both
0058  * inbound and outbound traffic.
0059  *
0060  * SND_USB_ENDPOINT_TYPE_SYNC endpoints are for inbound traffic only and
0061  * expect the payload to carry Q10.14 / Q16.16 formatted sync information
0062  * (3 or 4 bytes).
0063  *
0064  * Each endpoint has to be configured prior to being used by calling
0065  * snd_usb_endpoint_set_params().
0066  *
0067  * The model incorporates a reference counting, so that multiple users
0068  * can call snd_usb_endpoint_start() and snd_usb_endpoint_stop(), and
0069  * only the first user will effectively start the URBs, and only the last
0070  * one to stop it will tear the URBs down again.
0071  */
0072 
0073 /*
0074  * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
0075  * this will overflow at approx 524 kHz
0076  */
0077 static inline unsigned get_usb_full_speed_rate(unsigned int rate)
0078 {
0079     return ((rate << 13) + 62) / 125;
0080 }
0081 
0082 /*
0083  * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
0084  * this will overflow at approx 4 MHz
0085  */
0086 static inline unsigned get_usb_high_speed_rate(unsigned int rate)
0087 {
0088     return ((rate << 10) + 62) / 125;
0089 }
0090 
0091 /*
0092  * release a urb data
0093  */
0094 static void release_urb_ctx(struct snd_urb_ctx *u)
0095 {
0096     if (u->buffer_size)
0097         usb_free_coherent(u->ep->chip->dev, u->buffer_size,
0098                   u->urb->transfer_buffer,
0099                   u->urb->transfer_dma);
0100     usb_free_urb(u->urb);
0101     u->urb = NULL;
0102 }
0103 
0104 static const char *usb_error_string(int err)
0105 {
0106     switch (err) {
0107     case -ENODEV:
0108         return "no device";
0109     case -ENOENT:
0110         return "endpoint not enabled";
0111     case -EPIPE:
0112         return "endpoint stalled";
0113     case -ENOSPC:
0114         return "not enough bandwidth";
0115     case -ESHUTDOWN:
0116         return "device disabled";
0117     case -EHOSTUNREACH:
0118         return "device suspended";
0119     case -EINVAL:
0120     case -EAGAIN:
0121     case -EFBIG:
0122     case -EMSGSIZE:
0123         return "internal error";
0124     default:
0125         return "unknown error";
0126     }
0127 }
0128 
0129 static inline bool ep_state_running(struct snd_usb_endpoint *ep)
0130 {
0131     return atomic_read(&ep->state) == EP_STATE_RUNNING;
0132 }
0133 
0134 static inline bool ep_state_update(struct snd_usb_endpoint *ep, int old, int new)
0135 {
0136     return atomic_try_cmpxchg(&ep->state, &old, new);
0137 }
0138 
0139 /**
0140  * snd_usb_endpoint_implicit_feedback_sink: Report endpoint usage type
0141  *
0142  * @ep: The snd_usb_endpoint
0143  *
0144  * Determine whether an endpoint is driven by an implicit feedback
0145  * data endpoint source.
0146  */
0147 int snd_usb_endpoint_implicit_feedback_sink(struct snd_usb_endpoint *ep)
0148 {
0149     return  ep->implicit_fb_sync && usb_pipeout(ep->pipe);
0150 }
0151 
0152 /*
0153  * Return the number of samples to be sent in the next packet
0154  * for streaming based on information derived from sync endpoints
0155  *
0156  * This won't be used for implicit feedback which takes the packet size
0157  * returned from the sync source
0158  */
0159 static int slave_next_packet_size(struct snd_usb_endpoint *ep,
0160                   unsigned int avail)
0161 {
0162     unsigned long flags;
0163     unsigned int phase;
0164     int ret;
0165 
0166     if (ep->fill_max)
0167         return ep->maxframesize;
0168 
0169     spin_lock_irqsave(&ep->lock, flags);
0170     phase = (ep->phase & 0xffff) + (ep->freqm << ep->datainterval);
0171     ret = min(phase >> 16, ep->maxframesize);
0172     if (avail && ret >= avail)
0173         ret = -EAGAIN;
0174     else
0175         ep->phase = phase;
0176     spin_unlock_irqrestore(&ep->lock, flags);
0177 
0178     return ret;
0179 }
0180 
0181 /*
0182  * Return the number of samples to be sent in the next packet
0183  * for adaptive and synchronous endpoints
0184  */
0185 static int next_packet_size(struct snd_usb_endpoint *ep, unsigned int avail)
0186 {
0187     unsigned int sample_accum;
0188     int ret;
0189 
0190     if (ep->fill_max)
0191         return ep->maxframesize;
0192 
0193     sample_accum = ep->sample_accum + ep->sample_rem;
0194     if (sample_accum >= ep->pps) {
0195         sample_accum -= ep->pps;
0196         ret = ep->packsize[1];
0197     } else {
0198         ret = ep->packsize[0];
0199     }
0200     if (avail && ret >= avail)
0201         ret = -EAGAIN;
0202     else
0203         ep->sample_accum = sample_accum;
0204 
0205     return ret;
0206 }
0207 
0208 /*
0209  * snd_usb_endpoint_next_packet_size: Return the number of samples to be sent
0210  * in the next packet
0211  *
0212  * If the size is equal or exceeds @avail, don't proceed but return -EAGAIN
0213  * Exception: @avail = 0 for skipping the check.
0214  */
0215 int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep,
0216                       struct snd_urb_ctx *ctx, int idx,
0217                       unsigned int avail)
0218 {
0219     unsigned int packet;
0220 
0221     packet = ctx->packet_size[idx];
0222     if (packet) {
0223         if (avail && packet >= avail)
0224             return -EAGAIN;
0225         return packet;
0226     }
0227 
0228     if (ep->sync_source)
0229         return slave_next_packet_size(ep, avail);
0230     else
0231         return next_packet_size(ep, avail);
0232 }
0233 
0234 static void call_retire_callback(struct snd_usb_endpoint *ep,
0235                  struct urb *urb)
0236 {
0237     struct snd_usb_substream *data_subs;
0238 
0239     data_subs = READ_ONCE(ep->data_subs);
0240     if (data_subs && ep->retire_data_urb)
0241         ep->retire_data_urb(data_subs, urb);
0242 }
0243 
0244 static void retire_outbound_urb(struct snd_usb_endpoint *ep,
0245                 struct snd_urb_ctx *urb_ctx)
0246 {
0247     call_retire_callback(ep, urb_ctx->urb);
0248 }
0249 
0250 static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
0251                     struct snd_usb_endpoint *sender,
0252                     const struct urb *urb);
0253 
0254 static void retire_inbound_urb(struct snd_usb_endpoint *ep,
0255                    struct snd_urb_ctx *urb_ctx)
0256 {
0257     struct urb *urb = urb_ctx->urb;
0258     struct snd_usb_endpoint *sync_sink;
0259 
0260     if (unlikely(ep->skip_packets > 0)) {
0261         ep->skip_packets--;
0262         return;
0263     }
0264 
0265     sync_sink = READ_ONCE(ep->sync_sink);
0266     if (sync_sink)
0267         snd_usb_handle_sync_urb(sync_sink, ep, urb);
0268 
0269     call_retire_callback(ep, urb);
0270 }
0271 
0272 static inline bool has_tx_length_quirk(struct snd_usb_audio *chip)
0273 {
0274     return chip->quirk_flags & QUIRK_FLAG_TX_LENGTH;
0275 }
0276 
0277 static void prepare_silent_urb(struct snd_usb_endpoint *ep,
0278                    struct snd_urb_ctx *ctx)
0279 {
0280     struct urb *urb = ctx->urb;
0281     unsigned int offs = 0;
0282     unsigned int extra = 0;
0283     __le32 packet_length;
0284     int i;
0285 
0286     /* For tx_length_quirk, put packet length at start of packet */
0287     if (has_tx_length_quirk(ep->chip))
0288         extra = sizeof(packet_length);
0289 
0290     for (i = 0; i < ctx->packets; ++i) {
0291         unsigned int offset;
0292         unsigned int length;
0293         int counts;
0294 
0295         counts = snd_usb_endpoint_next_packet_size(ep, ctx, i, 0);
0296         length = counts * ep->stride; /* number of silent bytes */
0297         offset = offs * ep->stride + extra * i;
0298         urb->iso_frame_desc[i].offset = offset;
0299         urb->iso_frame_desc[i].length = length + extra;
0300         if (extra) {
0301             packet_length = cpu_to_le32(length);
0302             memcpy(urb->transfer_buffer + offset,
0303                    &packet_length, sizeof(packet_length));
0304         }
0305         memset(urb->transfer_buffer + offset + extra,
0306                ep->silence_value, length);
0307         offs += counts;
0308     }
0309 
0310     urb->number_of_packets = ctx->packets;
0311     urb->transfer_buffer_length = offs * ep->stride + ctx->packets * extra;
0312     ctx->queued = 0;
0313 }
0314 
0315 /*
0316  * Prepare a PLAYBACK urb for submission to the bus.
0317  */
0318 static int prepare_outbound_urb(struct snd_usb_endpoint *ep,
0319                 struct snd_urb_ctx *ctx,
0320                 bool in_stream_lock)
0321 {
0322     struct urb *urb = ctx->urb;
0323     unsigned char *cp = urb->transfer_buffer;
0324     struct snd_usb_substream *data_subs;
0325 
0326     urb->dev = ep->chip->dev; /* we need to set this at each time */
0327 
0328     switch (ep->type) {
0329     case SND_USB_ENDPOINT_TYPE_DATA:
0330         data_subs = READ_ONCE(ep->data_subs);
0331         if (data_subs && ep->prepare_data_urb)
0332             return ep->prepare_data_urb(data_subs, urb, in_stream_lock);
0333         /* no data provider, so send silence */
0334         prepare_silent_urb(ep, ctx);
0335         break;
0336 
0337     case SND_USB_ENDPOINT_TYPE_SYNC:
0338         if (snd_usb_get_speed(ep->chip->dev) >= USB_SPEED_HIGH) {
0339             /*
0340              * fill the length and offset of each urb descriptor.
0341              * the fixed 12.13 frequency is passed as 16.16 through the pipe.
0342              */
0343             urb->iso_frame_desc[0].length = 4;
0344             urb->iso_frame_desc[0].offset = 0;
0345             cp[0] = ep->freqn;
0346             cp[1] = ep->freqn >> 8;
0347             cp[2] = ep->freqn >> 16;
0348             cp[3] = ep->freqn >> 24;
0349         } else {
0350             /*
0351              * fill the length and offset of each urb descriptor.
0352              * the fixed 10.14 frequency is passed through the pipe.
0353              */
0354             urb->iso_frame_desc[0].length = 3;
0355             urb->iso_frame_desc[0].offset = 0;
0356             cp[0] = ep->freqn >> 2;
0357             cp[1] = ep->freqn >> 10;
0358             cp[2] = ep->freqn >> 18;
0359         }
0360 
0361         break;
0362     }
0363     return 0;
0364 }
0365 
0366 /*
0367  * Prepare a CAPTURE or SYNC urb for submission to the bus.
0368  */
0369 static int prepare_inbound_urb(struct snd_usb_endpoint *ep,
0370                    struct snd_urb_ctx *urb_ctx)
0371 {
0372     int i, offs;
0373     struct urb *urb = urb_ctx->urb;
0374 
0375     urb->dev = ep->chip->dev; /* we need to set this at each time */
0376 
0377     switch (ep->type) {
0378     case SND_USB_ENDPOINT_TYPE_DATA:
0379         offs = 0;
0380         for (i = 0; i < urb_ctx->packets; i++) {
0381             urb->iso_frame_desc[i].offset = offs;
0382             urb->iso_frame_desc[i].length = ep->curpacksize;
0383             offs += ep->curpacksize;
0384         }
0385 
0386         urb->transfer_buffer_length = offs;
0387         urb->number_of_packets = urb_ctx->packets;
0388         break;
0389 
0390     case SND_USB_ENDPOINT_TYPE_SYNC:
0391         urb->iso_frame_desc[0].length = min(4u, ep->syncmaxsize);
0392         urb->iso_frame_desc[0].offset = 0;
0393         break;
0394     }
0395     return 0;
0396 }
0397 
0398 /* notify an error as XRUN to the assigned PCM data substream */
0399 static void notify_xrun(struct snd_usb_endpoint *ep)
0400 {
0401     struct snd_usb_substream *data_subs;
0402 
0403     data_subs = READ_ONCE(ep->data_subs);
0404     if (data_subs && data_subs->pcm_substream)
0405         snd_pcm_stop_xrun(data_subs->pcm_substream);
0406 }
0407 
0408 static struct snd_usb_packet_info *
0409 next_packet_fifo_enqueue(struct snd_usb_endpoint *ep)
0410 {
0411     struct snd_usb_packet_info *p;
0412 
0413     p = ep->next_packet + (ep->next_packet_head + ep->next_packet_queued) %
0414         ARRAY_SIZE(ep->next_packet);
0415     ep->next_packet_queued++;
0416     return p;
0417 }
0418 
0419 static struct snd_usb_packet_info *
0420 next_packet_fifo_dequeue(struct snd_usb_endpoint *ep)
0421 {
0422     struct snd_usb_packet_info *p;
0423 
0424     p = ep->next_packet + ep->next_packet_head;
0425     ep->next_packet_head++;
0426     ep->next_packet_head %= ARRAY_SIZE(ep->next_packet);
0427     ep->next_packet_queued--;
0428     return p;
0429 }
0430 
0431 static void push_back_to_ready_list(struct snd_usb_endpoint *ep,
0432                     struct snd_urb_ctx *ctx)
0433 {
0434     unsigned long flags;
0435 
0436     spin_lock_irqsave(&ep->lock, flags);
0437     list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
0438     spin_unlock_irqrestore(&ep->lock, flags);
0439 }
0440 
0441 /*
0442  * Send output urbs that have been prepared previously. URBs are dequeued
0443  * from ep->ready_playback_urbs and in case there aren't any available
0444  * or there are no packets that have been prepared, this function does
0445  * nothing.
0446  *
0447  * The reason why the functionality of sending and preparing URBs is separated
0448  * is that host controllers don't guarantee the order in which they return
0449  * inbound and outbound packets to their submitters.
0450  *
0451  * This function is used both for implicit feedback endpoints and in low-
0452  * latency playback mode.
0453  */
0454 void snd_usb_queue_pending_output_urbs(struct snd_usb_endpoint *ep,
0455                        bool in_stream_lock)
0456 {
0457     bool implicit_fb = snd_usb_endpoint_implicit_feedback_sink(ep);
0458 
0459     while (ep_state_running(ep)) {
0460 
0461         unsigned long flags;
0462         struct snd_usb_packet_info *packet;
0463         struct snd_urb_ctx *ctx = NULL;
0464         int err, i;
0465 
0466         spin_lock_irqsave(&ep->lock, flags);
0467         if ((!implicit_fb || ep->next_packet_queued > 0) &&
0468             !list_empty(&ep->ready_playback_urbs)) {
0469             /* take URB out of FIFO */
0470             ctx = list_first_entry(&ep->ready_playback_urbs,
0471                            struct snd_urb_ctx, ready_list);
0472             list_del_init(&ctx->ready_list);
0473             if (implicit_fb)
0474                 packet = next_packet_fifo_dequeue(ep);
0475         }
0476         spin_unlock_irqrestore(&ep->lock, flags);
0477 
0478         if (ctx == NULL)
0479             return;
0480 
0481         /* copy over the length information */
0482         if (implicit_fb) {
0483             for (i = 0; i < packet->packets; i++)
0484                 ctx->packet_size[i] = packet->packet_size[i];
0485         }
0486 
0487         /* call the data handler to fill in playback data */
0488         err = prepare_outbound_urb(ep, ctx, in_stream_lock);
0489         /* can be stopped during prepare callback */
0490         if (unlikely(!ep_state_running(ep)))
0491             break;
0492         if (err < 0) {
0493             /* push back to ready list again for -EAGAIN */
0494             if (err == -EAGAIN)
0495                 push_back_to_ready_list(ep, ctx);
0496             else
0497                 notify_xrun(ep);
0498             return;
0499         }
0500 
0501         err = usb_submit_urb(ctx->urb, GFP_ATOMIC);
0502         if (err < 0) {
0503             usb_audio_err(ep->chip,
0504                       "Unable to submit urb #%d: %d at %s\n",
0505                       ctx->index, err, __func__);
0506             notify_xrun(ep);
0507             return;
0508         }
0509 
0510         set_bit(ctx->index, &ep->active_mask);
0511         atomic_inc(&ep->submitted_urbs);
0512     }
0513 }
0514 
0515 /*
0516  * complete callback for urbs
0517  */
0518 static void snd_complete_urb(struct urb *urb)
0519 {
0520     struct snd_urb_ctx *ctx = urb->context;
0521     struct snd_usb_endpoint *ep = ctx->ep;
0522     int err;
0523 
0524     if (unlikely(urb->status == -ENOENT ||      /* unlinked */
0525              urb->status == -ENODEV ||      /* device removed */
0526              urb->status == -ECONNRESET ||  /* unlinked */
0527              urb->status == -ESHUTDOWN))    /* device disabled */
0528         goto exit_clear;
0529     /* device disconnected */
0530     if (unlikely(atomic_read(&ep->chip->shutdown)))
0531         goto exit_clear;
0532 
0533     if (unlikely(!ep_state_running(ep)))
0534         goto exit_clear;
0535 
0536     if (usb_pipeout(ep->pipe)) {
0537         retire_outbound_urb(ep, ctx);
0538         /* can be stopped during retire callback */
0539         if (unlikely(!ep_state_running(ep)))
0540             goto exit_clear;
0541 
0542         /* in low-latency and implicit-feedback modes, push back the
0543          * URB to ready list at first, then process as much as possible
0544          */
0545         if (ep->lowlatency_playback ||
0546              snd_usb_endpoint_implicit_feedback_sink(ep)) {
0547             push_back_to_ready_list(ep, ctx);
0548             clear_bit(ctx->index, &ep->active_mask);
0549             snd_usb_queue_pending_output_urbs(ep, false);
0550             atomic_dec(&ep->submitted_urbs); /* decrement at last */
0551             return;
0552         }
0553 
0554         /* in non-lowlatency mode, no error handling for prepare */
0555         prepare_outbound_urb(ep, ctx, false);
0556         /* can be stopped during prepare callback */
0557         if (unlikely(!ep_state_running(ep)))
0558             goto exit_clear;
0559     } else {
0560         retire_inbound_urb(ep, ctx);
0561         /* can be stopped during retire callback */
0562         if (unlikely(!ep_state_running(ep)))
0563             goto exit_clear;
0564 
0565         prepare_inbound_urb(ep, ctx);
0566     }
0567 
0568     err = usb_submit_urb(urb, GFP_ATOMIC);
0569     if (err == 0)
0570         return;
0571 
0572     usb_audio_err(ep->chip, "cannot submit urb (err = %d)\n", err);
0573     notify_xrun(ep);
0574 
0575 exit_clear:
0576     clear_bit(ctx->index, &ep->active_mask);
0577     atomic_dec(&ep->submitted_urbs);
0578 }
0579 
0580 /*
0581  * Find or create a refcount object for the given interface
0582  *
0583  * The objects are released altogether in snd_usb_endpoint_free_all()
0584  */
0585 static struct snd_usb_iface_ref *
0586 iface_ref_find(struct snd_usb_audio *chip, int iface)
0587 {
0588     struct snd_usb_iface_ref *ip;
0589 
0590     list_for_each_entry(ip, &chip->iface_ref_list, list)
0591         if (ip->iface == iface)
0592             return ip;
0593 
0594     ip = kzalloc(sizeof(*ip), GFP_KERNEL);
0595     if (!ip)
0596         return NULL;
0597     ip->iface = iface;
0598     list_add_tail(&ip->list, &chip->iface_ref_list);
0599     return ip;
0600 }
0601 
0602 /* Similarly, a refcount object for clock */
0603 static struct snd_usb_clock_ref *
0604 clock_ref_find(struct snd_usb_audio *chip, int clock)
0605 {
0606     struct snd_usb_clock_ref *ref;
0607 
0608     list_for_each_entry(ref, &chip->clock_ref_list, list)
0609         if (ref->clock == clock)
0610             return ref;
0611 
0612     ref = kzalloc(sizeof(*ref), GFP_KERNEL);
0613     if (!ref)
0614         return NULL;
0615     ref->clock = clock;
0616     atomic_set(&ref->locked, 0);
0617     list_add_tail(&ref->list, &chip->clock_ref_list);
0618     return ref;
0619 }
0620 
0621 /*
0622  * Get the existing endpoint object corresponding EP
0623  * Returns NULL if not present.
0624  */
0625 struct snd_usb_endpoint *
0626 snd_usb_get_endpoint(struct snd_usb_audio *chip, int ep_num)
0627 {
0628     struct snd_usb_endpoint *ep;
0629 
0630     list_for_each_entry(ep, &chip->ep_list, list) {
0631         if (ep->ep_num == ep_num)
0632             return ep;
0633     }
0634 
0635     return NULL;
0636 }
0637 
0638 #define ep_type_name(type) \
0639     (type == SND_USB_ENDPOINT_TYPE_DATA ? "data" : "sync")
0640 
0641 /**
0642  * snd_usb_add_endpoint: Add an endpoint to an USB audio chip
0643  *
0644  * @chip: The chip
0645  * @ep_num: The number of the endpoint to use
0646  * @type: SND_USB_ENDPOINT_TYPE_DATA or SND_USB_ENDPOINT_TYPE_SYNC
0647  *
0648  * If the requested endpoint has not been added to the given chip before,
0649  * a new instance is created.
0650  *
0651  * Returns zero on success or a negative error code.
0652  *
0653  * New endpoints will be added to chip->ep_list and freed by
0654  * calling snd_usb_endpoint_free_all().
0655  *
0656  * For SND_USB_ENDPOINT_TYPE_SYNC, the caller needs to guarantee that
0657  * bNumEndpoints > 1 beforehand.
0658  */
0659 int snd_usb_add_endpoint(struct snd_usb_audio *chip, int ep_num, int type)
0660 {
0661     struct snd_usb_endpoint *ep;
0662     bool is_playback;
0663 
0664     ep = snd_usb_get_endpoint(chip, ep_num);
0665     if (ep)
0666         return 0;
0667 
0668     usb_audio_dbg(chip, "Creating new %s endpoint #%x\n",
0669               ep_type_name(type),
0670               ep_num);
0671     ep = kzalloc(sizeof(*ep), GFP_KERNEL);
0672     if (!ep)
0673         return -ENOMEM;
0674 
0675     ep->chip = chip;
0676     spin_lock_init(&ep->lock);
0677     ep->type = type;
0678     ep->ep_num = ep_num;
0679     INIT_LIST_HEAD(&ep->ready_playback_urbs);
0680     atomic_set(&ep->submitted_urbs, 0);
0681 
0682     is_playback = ((ep_num & USB_ENDPOINT_DIR_MASK) == USB_DIR_OUT);
0683     ep_num &= USB_ENDPOINT_NUMBER_MASK;
0684     if (is_playback)
0685         ep->pipe = usb_sndisocpipe(chip->dev, ep_num);
0686     else
0687         ep->pipe = usb_rcvisocpipe(chip->dev, ep_num);
0688 
0689     list_add_tail(&ep->list, &chip->ep_list);
0690     return 0;
0691 }
0692 
0693 /* Set up syncinterval and maxsyncsize for a sync EP */
0694 static void endpoint_set_syncinterval(struct snd_usb_audio *chip,
0695                       struct snd_usb_endpoint *ep)
0696 {
0697     struct usb_host_interface *alts;
0698     struct usb_endpoint_descriptor *desc;
0699 
0700     alts = snd_usb_get_host_interface(chip, ep->iface, ep->altsetting);
0701     if (!alts)
0702         return;
0703 
0704     desc = get_endpoint(alts, ep->ep_idx);
0705     if (desc->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
0706         desc->bRefresh >= 1 && desc->bRefresh <= 9)
0707         ep->syncinterval = desc->bRefresh;
0708     else if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL)
0709         ep->syncinterval = 1;
0710     else if (desc->bInterval >= 1 && desc->bInterval <= 16)
0711         ep->syncinterval = desc->bInterval - 1;
0712     else
0713         ep->syncinterval = 3;
0714 
0715     ep->syncmaxsize = le16_to_cpu(desc->wMaxPacketSize);
0716 }
0717 
0718 static bool endpoint_compatible(struct snd_usb_endpoint *ep,
0719                 const struct audioformat *fp,
0720                 const struct snd_pcm_hw_params *params)
0721 {
0722     if (!ep->opened)
0723         return false;
0724     if (ep->cur_audiofmt != fp)
0725         return false;
0726     if (ep->cur_rate != params_rate(params) ||
0727         ep->cur_format != params_format(params) ||
0728         ep->cur_period_frames != params_period_size(params) ||
0729         ep->cur_buffer_periods != params_periods(params))
0730         return false;
0731     return true;
0732 }
0733 
0734 /*
0735  * Check whether the given fp and hw params are compatible with the current
0736  * setup of the target EP for implicit feedback sync
0737  */
0738 bool snd_usb_endpoint_compatible(struct snd_usb_audio *chip,
0739                  struct snd_usb_endpoint *ep,
0740                  const struct audioformat *fp,
0741                  const struct snd_pcm_hw_params *params)
0742 {
0743     bool ret;
0744 
0745     mutex_lock(&chip->mutex);
0746     ret = endpoint_compatible(ep, fp, params);
0747     mutex_unlock(&chip->mutex);
0748     return ret;
0749 }
0750 
0751 /*
0752  * snd_usb_endpoint_open: Open the endpoint
0753  *
0754  * Called from hw_params to assign the endpoint to the substream.
0755  * It's reference-counted, and only the first opener is allowed to set up
0756  * arbitrary parameters.  The later opener must be compatible with the
0757  * former opened parameters.
0758  * The endpoint needs to be closed via snd_usb_endpoint_close() later.
0759  *
0760  * Note that this function doesn't configure the endpoint.  The substream
0761  * needs to set it up later via snd_usb_endpoint_configure().
0762  */
0763 struct snd_usb_endpoint *
0764 snd_usb_endpoint_open(struct snd_usb_audio *chip,
0765               const struct audioformat *fp,
0766               const struct snd_pcm_hw_params *params,
0767               bool is_sync_ep)
0768 {
0769     struct snd_usb_endpoint *ep;
0770     int ep_num = is_sync_ep ? fp->sync_ep : fp->endpoint;
0771 
0772     mutex_lock(&chip->mutex);
0773     ep = snd_usb_get_endpoint(chip, ep_num);
0774     if (!ep) {
0775         usb_audio_err(chip, "Cannot find EP 0x%x to open\n", ep_num);
0776         goto unlock;
0777     }
0778 
0779     if (!ep->opened) {
0780         if (is_sync_ep) {
0781             ep->iface = fp->sync_iface;
0782             ep->altsetting = fp->sync_altsetting;
0783             ep->ep_idx = fp->sync_ep_idx;
0784         } else {
0785             ep->iface = fp->iface;
0786             ep->altsetting = fp->altsetting;
0787             ep->ep_idx = fp->ep_idx;
0788         }
0789         usb_audio_dbg(chip, "Open EP 0x%x, iface=%d:%d, idx=%d\n",
0790                   ep_num, ep->iface, ep->altsetting, ep->ep_idx);
0791 
0792         ep->iface_ref = iface_ref_find(chip, ep->iface);
0793         if (!ep->iface_ref) {
0794             ep = NULL;
0795             goto unlock;
0796         }
0797 
0798         if (fp->protocol != UAC_VERSION_1) {
0799             ep->clock_ref = clock_ref_find(chip, fp->clock);
0800             if (!ep->clock_ref) {
0801                 ep = NULL;
0802                 goto unlock;
0803             }
0804         }
0805 
0806         ep->cur_audiofmt = fp;
0807         ep->cur_channels = fp->channels;
0808         ep->cur_rate = params_rate(params);
0809         ep->cur_format = params_format(params);
0810         ep->cur_frame_bytes = snd_pcm_format_physical_width(ep->cur_format) *
0811             ep->cur_channels / 8;
0812         ep->cur_period_frames = params_period_size(params);
0813         ep->cur_period_bytes = ep->cur_period_frames * ep->cur_frame_bytes;
0814         ep->cur_buffer_periods = params_periods(params);
0815 
0816         if (ep->type == SND_USB_ENDPOINT_TYPE_SYNC)
0817             endpoint_set_syncinterval(chip, ep);
0818 
0819         ep->implicit_fb_sync = fp->implicit_fb;
0820         ep->need_setup = true;
0821 
0822         usb_audio_dbg(chip, "  channels=%d, rate=%d, format=%s, period_bytes=%d, periods=%d, implicit_fb=%d\n",
0823                   ep->cur_channels, ep->cur_rate,
0824                   snd_pcm_format_name(ep->cur_format),
0825                   ep->cur_period_bytes, ep->cur_buffer_periods,
0826                   ep->implicit_fb_sync);
0827 
0828     } else {
0829         if (WARN_ON(!ep->iface_ref)) {
0830             ep = NULL;
0831             goto unlock;
0832         }
0833 
0834         if (!endpoint_compatible(ep, fp, params)) {
0835             usb_audio_err(chip, "Incompatible EP setup for 0x%x\n",
0836                       ep_num);
0837             ep = NULL;
0838             goto unlock;
0839         }
0840 
0841         usb_audio_dbg(chip, "Reopened EP 0x%x (count %d)\n",
0842                   ep_num, ep->opened);
0843     }
0844 
0845     if (!ep->iface_ref->opened++)
0846         ep->iface_ref->need_setup = true;
0847 
0848     ep->opened++;
0849 
0850  unlock:
0851     mutex_unlock(&chip->mutex);
0852     return ep;
0853 }
0854 
0855 /*
0856  * snd_usb_endpoint_set_sync: Link data and sync endpoints
0857  *
0858  * Pass NULL to sync_ep to unlink again
0859  */
0860 void snd_usb_endpoint_set_sync(struct snd_usb_audio *chip,
0861                    struct snd_usb_endpoint *data_ep,
0862                    struct snd_usb_endpoint *sync_ep)
0863 {
0864     data_ep->sync_source = sync_ep;
0865 }
0866 
0867 /*
0868  * Set data endpoint callbacks and the assigned data stream
0869  *
0870  * Called at PCM trigger and cleanups.
0871  * Pass NULL to deactivate each callback.
0872  */
0873 void snd_usb_endpoint_set_callback(struct snd_usb_endpoint *ep,
0874                    int (*prepare)(struct snd_usb_substream *subs,
0875                           struct urb *urb,
0876                           bool in_stream_lock),
0877                    void (*retire)(struct snd_usb_substream *subs,
0878                           struct urb *urb),
0879                    struct snd_usb_substream *data_subs)
0880 {
0881     ep->prepare_data_urb = prepare;
0882     ep->retire_data_urb = retire;
0883     if (data_subs)
0884         ep->lowlatency_playback = data_subs->lowlatency_playback;
0885     else
0886         ep->lowlatency_playback = false;
0887     WRITE_ONCE(ep->data_subs, data_subs);
0888 }
0889 
0890 static int endpoint_set_interface(struct snd_usb_audio *chip,
0891                   struct snd_usb_endpoint *ep,
0892                   bool set)
0893 {
0894     int altset = set ? ep->altsetting : 0;
0895     int err;
0896 
0897     usb_audio_dbg(chip, "Setting usb interface %d:%d for EP 0x%x\n",
0898               ep->iface, altset, ep->ep_num);
0899     err = usb_set_interface(chip->dev, ep->iface, altset);
0900     if (err < 0) {
0901         usb_audio_err(chip, "%d:%d: usb_set_interface failed (%d)\n",
0902                   ep->iface, altset, err);
0903         return err;
0904     }
0905 
0906     if (chip->quirk_flags & QUIRK_FLAG_IFACE_DELAY)
0907         msleep(50);
0908     return 0;
0909 }
0910 
0911 /*
0912  * snd_usb_endpoint_close: Close the endpoint
0913  *
0914  * Unreference the already opened endpoint via snd_usb_endpoint_open().
0915  */
0916 void snd_usb_endpoint_close(struct snd_usb_audio *chip,
0917                 struct snd_usb_endpoint *ep)
0918 {
0919     mutex_lock(&chip->mutex);
0920     usb_audio_dbg(chip, "Closing EP 0x%x (count %d)\n",
0921               ep->ep_num, ep->opened);
0922 
0923     if (!--ep->iface_ref->opened)
0924         endpoint_set_interface(chip, ep, false);
0925 
0926     if (!--ep->opened) {
0927         if (ep->clock_ref && !atomic_read(&ep->clock_ref->locked))
0928             ep->clock_ref->rate = 0;
0929         ep->iface = 0;
0930         ep->altsetting = 0;
0931         ep->cur_audiofmt = NULL;
0932         ep->cur_rate = 0;
0933         ep->iface_ref = NULL;
0934         ep->clock_ref = NULL;
0935         usb_audio_dbg(chip, "EP 0x%x closed\n", ep->ep_num);
0936     }
0937     mutex_unlock(&chip->mutex);
0938 }
0939 
0940 /* Prepare for suspening EP, called from the main suspend handler */
0941 void snd_usb_endpoint_suspend(struct snd_usb_endpoint *ep)
0942 {
0943     ep->need_setup = true;
0944     if (ep->iface_ref)
0945         ep->iface_ref->need_setup = true;
0946     if (ep->clock_ref)
0947         ep->clock_ref->rate = 0;
0948 }
0949 
0950 /*
0951  *  wait until all urbs are processed.
0952  */
0953 static int wait_clear_urbs(struct snd_usb_endpoint *ep)
0954 {
0955     unsigned long end_time = jiffies + msecs_to_jiffies(1000);
0956     int alive;
0957 
0958     if (atomic_read(&ep->state) != EP_STATE_STOPPING)
0959         return 0;
0960 
0961     do {
0962         alive = atomic_read(&ep->submitted_urbs);
0963         if (!alive)
0964             break;
0965 
0966         schedule_timeout_uninterruptible(1);
0967     } while (time_before(jiffies, end_time));
0968 
0969     if (alive)
0970         usb_audio_err(ep->chip,
0971             "timeout: still %d active urbs on EP #%x\n",
0972             alive, ep->ep_num);
0973 
0974     if (ep_state_update(ep, EP_STATE_STOPPING, EP_STATE_STOPPED)) {
0975         ep->sync_sink = NULL;
0976         snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
0977     }
0978 
0979     return 0;
0980 }
0981 
0982 /* sync the pending stop operation;
0983  * this function itself doesn't trigger the stop operation
0984  */
0985 void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep)
0986 {
0987     if (ep)
0988         wait_clear_urbs(ep);
0989 }
0990 
0991 /*
0992  * Stop active urbs
0993  *
0994  * This function moves the EP to STOPPING state if it's being RUNNING.
0995  */
0996 static int stop_urbs(struct snd_usb_endpoint *ep, bool force, bool keep_pending)
0997 {
0998     unsigned int i;
0999     unsigned long flags;
1000 
1001     if (!force && atomic_read(&ep->running))
1002         return -EBUSY;
1003 
1004     if (!ep_state_update(ep, EP_STATE_RUNNING, EP_STATE_STOPPING))
1005         return 0;
1006 
1007     spin_lock_irqsave(&ep->lock, flags);
1008     INIT_LIST_HEAD(&ep->ready_playback_urbs);
1009     ep->next_packet_head = 0;
1010     ep->next_packet_queued = 0;
1011     spin_unlock_irqrestore(&ep->lock, flags);
1012 
1013     if (keep_pending)
1014         return 0;
1015 
1016     for (i = 0; i < ep->nurbs; i++) {
1017         if (test_bit(i, &ep->active_mask)) {
1018             if (!test_and_set_bit(i, &ep->unlink_mask)) {
1019                 struct urb *u = ep->urb[i].urb;
1020                 usb_unlink_urb(u);
1021             }
1022         }
1023     }
1024 
1025     return 0;
1026 }
1027 
1028 /*
1029  * release an endpoint's urbs
1030  */
1031 static int release_urbs(struct snd_usb_endpoint *ep, bool force)
1032 {
1033     int i, err;
1034 
1035     /* route incoming urbs to nirvana */
1036     snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
1037 
1038     /* stop and unlink urbs */
1039     err = stop_urbs(ep, force, false);
1040     if (err)
1041         return err;
1042 
1043     wait_clear_urbs(ep);
1044 
1045     for (i = 0; i < ep->nurbs; i++)
1046         release_urb_ctx(&ep->urb[i]);
1047 
1048     usb_free_coherent(ep->chip->dev, SYNC_URBS * 4,
1049               ep->syncbuf, ep->sync_dma);
1050 
1051     ep->syncbuf = NULL;
1052     ep->nurbs = 0;
1053     return 0;
1054 }
1055 
1056 /*
1057  * configure a data endpoint
1058  */
1059 static int data_ep_set_params(struct snd_usb_endpoint *ep)
1060 {
1061     struct snd_usb_audio *chip = ep->chip;
1062     unsigned int maxsize, minsize, packs_per_ms, max_packs_per_urb;
1063     unsigned int max_packs_per_period, urbs_per_period, urb_packs;
1064     unsigned int max_urbs, i;
1065     const struct audioformat *fmt = ep->cur_audiofmt;
1066     int frame_bits = ep->cur_frame_bytes * 8;
1067     int tx_length_quirk = (has_tx_length_quirk(chip) &&
1068                    usb_pipeout(ep->pipe));
1069 
1070     usb_audio_dbg(chip, "Setting params for data EP 0x%x, pipe 0x%x\n",
1071               ep->ep_num, ep->pipe);
1072 
1073     if (ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) {
1074         /*
1075          * When operating in DSD DOP mode, the size of a sample frame
1076          * in hardware differs from the actual physical format width
1077          * because we need to make room for the DOP markers.
1078          */
1079         frame_bits += ep->cur_channels << 3;
1080     }
1081 
1082     ep->datainterval = fmt->datainterval;
1083     ep->stride = frame_bits >> 3;
1084 
1085     switch (ep->cur_format) {
1086     case SNDRV_PCM_FORMAT_U8:
1087         ep->silence_value = 0x80;
1088         break;
1089     case SNDRV_PCM_FORMAT_DSD_U8:
1090     case SNDRV_PCM_FORMAT_DSD_U16_LE:
1091     case SNDRV_PCM_FORMAT_DSD_U32_LE:
1092     case SNDRV_PCM_FORMAT_DSD_U16_BE:
1093     case SNDRV_PCM_FORMAT_DSD_U32_BE:
1094         ep->silence_value = 0x69;
1095         break;
1096     default:
1097         ep->silence_value = 0;
1098     }
1099 
1100     /* assume max. frequency is 50% higher than nominal */
1101     ep->freqmax = ep->freqn + (ep->freqn >> 1);
1102     /* Round up freqmax to nearest integer in order to calculate maximum
1103      * packet size, which must represent a whole number of frames.
1104      * This is accomplished by adding 0x0.ffff before converting the
1105      * Q16.16 format into integer.
1106      * In order to accurately calculate the maximum packet size when
1107      * the data interval is more than 1 (i.e. ep->datainterval > 0),
1108      * multiply by the data interval prior to rounding. For instance,
1109      * a freqmax of 41 kHz will result in a max packet size of 6 (5.125)
1110      * frames with a data interval of 1, but 11 (10.25) frames with a
1111      * data interval of 2.
1112      * (ep->freqmax << ep->datainterval overflows at 8.192 MHz for the
1113      * maximum datainterval value of 3, at USB full speed, higher for
1114      * USB high speed, noting that ep->freqmax is in units of
1115      * frames per packet in Q16.16 format.)
1116      */
1117     maxsize = (((ep->freqmax << ep->datainterval) + 0xffff) >> 16) *
1118              (frame_bits >> 3);
1119     if (tx_length_quirk)
1120         maxsize += sizeof(__le32); /* Space for length descriptor */
1121     /* but wMaxPacketSize might reduce this */
1122     if (ep->maxpacksize && ep->maxpacksize < maxsize) {
1123         /* whatever fits into a max. size packet */
1124         unsigned int data_maxsize = maxsize = ep->maxpacksize;
1125 
1126         if (tx_length_quirk)
1127             /* Need to remove the length descriptor to calc freq */
1128             data_maxsize -= sizeof(__le32);
1129         ep->freqmax = (data_maxsize / (frame_bits >> 3))
1130                 << (16 - ep->datainterval);
1131     }
1132 
1133     if (ep->fill_max)
1134         ep->curpacksize = ep->maxpacksize;
1135     else
1136         ep->curpacksize = maxsize;
1137 
1138     if (snd_usb_get_speed(chip->dev) != USB_SPEED_FULL) {
1139         packs_per_ms = 8 >> ep->datainterval;
1140         max_packs_per_urb = MAX_PACKS_HS;
1141     } else {
1142         packs_per_ms = 1;
1143         max_packs_per_urb = MAX_PACKS;
1144     }
1145     if (ep->sync_source && !ep->implicit_fb_sync)
1146         max_packs_per_urb = min(max_packs_per_urb,
1147                     1U << ep->sync_source->syncinterval);
1148     max_packs_per_urb = max(1u, max_packs_per_urb >> ep->datainterval);
1149 
1150     /*
1151      * Capture endpoints need to use small URBs because there's no way
1152      * to tell in advance where the next period will end, and we don't
1153      * want the next URB to complete much after the period ends.
1154      *
1155      * Playback endpoints with implicit sync much use the same parameters
1156      * as their corresponding capture endpoint.
1157      */
1158     if (usb_pipein(ep->pipe) || ep->implicit_fb_sync) {
1159 
1160         urb_packs = packs_per_ms;
1161         /*
1162          * Wireless devices can poll at a max rate of once per 4ms.
1163          * For dataintervals less than 5, increase the packet count to
1164          * allow the host controller to use bursting to fill in the
1165          * gaps.
1166          */
1167         if (snd_usb_get_speed(chip->dev) == USB_SPEED_WIRELESS) {
1168             int interval = ep->datainterval;
1169             while (interval < 5) {
1170                 urb_packs <<= 1;
1171                 ++interval;
1172             }
1173         }
1174         /* make capture URBs <= 1 ms and smaller than a period */
1175         urb_packs = min(max_packs_per_urb, urb_packs);
1176         while (urb_packs > 1 && urb_packs * maxsize >= ep->cur_period_bytes)
1177             urb_packs >>= 1;
1178         ep->nurbs = MAX_URBS;
1179 
1180     /*
1181      * Playback endpoints without implicit sync are adjusted so that
1182      * a period fits as evenly as possible in the smallest number of
1183      * URBs.  The total number of URBs is adjusted to the size of the
1184      * ALSA buffer, subject to the MAX_URBS and MAX_QUEUE limits.
1185      */
1186     } else {
1187         /* determine how small a packet can be */
1188         minsize = (ep->freqn >> (16 - ep->datainterval)) *
1189                 (frame_bits >> 3);
1190         /* with sync from device, assume it can be 12% lower */
1191         if (ep->sync_source)
1192             minsize -= minsize >> 3;
1193         minsize = max(minsize, 1u);
1194 
1195         /* how many packets will contain an entire ALSA period? */
1196         max_packs_per_period = DIV_ROUND_UP(ep->cur_period_bytes, minsize);
1197 
1198         /* how many URBs will contain a period? */
1199         urbs_per_period = DIV_ROUND_UP(max_packs_per_period,
1200                 max_packs_per_urb);
1201         /* how many packets are needed in each URB? */
1202         urb_packs = DIV_ROUND_UP(max_packs_per_period, urbs_per_period);
1203 
1204         /* limit the number of frames in a single URB */
1205         ep->max_urb_frames = DIV_ROUND_UP(ep->cur_period_frames,
1206                           urbs_per_period);
1207 
1208         /* try to use enough URBs to contain an entire ALSA buffer */
1209         max_urbs = min((unsigned) MAX_URBS,
1210                 MAX_QUEUE * packs_per_ms / urb_packs);
1211         ep->nurbs = min(max_urbs, urbs_per_period * ep->cur_buffer_periods);
1212     }
1213 
1214     /* allocate and initialize data urbs */
1215     for (i = 0; i < ep->nurbs; i++) {
1216         struct snd_urb_ctx *u = &ep->urb[i];
1217         u->index = i;
1218         u->ep = ep;
1219         u->packets = urb_packs;
1220         u->buffer_size = maxsize * u->packets;
1221 
1222         if (fmt->fmt_type == UAC_FORMAT_TYPE_II)
1223             u->packets++; /* for transfer delimiter */
1224         u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
1225         if (!u->urb)
1226             goto out_of_memory;
1227 
1228         u->urb->transfer_buffer =
1229             usb_alloc_coherent(chip->dev, u->buffer_size,
1230                        GFP_KERNEL, &u->urb->transfer_dma);
1231         if (!u->urb->transfer_buffer)
1232             goto out_of_memory;
1233         u->urb->pipe = ep->pipe;
1234         u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1235         u->urb->interval = 1 << ep->datainterval;
1236         u->urb->context = u;
1237         u->urb->complete = snd_complete_urb;
1238         INIT_LIST_HEAD(&u->ready_list);
1239     }
1240 
1241     return 0;
1242 
1243 out_of_memory:
1244     release_urbs(ep, false);
1245     return -ENOMEM;
1246 }
1247 
1248 /*
1249  * configure a sync endpoint
1250  */
1251 static int sync_ep_set_params(struct snd_usb_endpoint *ep)
1252 {
1253     struct snd_usb_audio *chip = ep->chip;
1254     int i;
1255 
1256     usb_audio_dbg(chip, "Setting params for sync EP 0x%x, pipe 0x%x\n",
1257               ep->ep_num, ep->pipe);
1258 
1259     ep->syncbuf = usb_alloc_coherent(chip->dev, SYNC_URBS * 4,
1260                      GFP_KERNEL, &ep->sync_dma);
1261     if (!ep->syncbuf)
1262         return -ENOMEM;
1263 
1264     for (i = 0; i < SYNC_URBS; i++) {
1265         struct snd_urb_ctx *u = &ep->urb[i];
1266         u->index = i;
1267         u->ep = ep;
1268         u->packets = 1;
1269         u->urb = usb_alloc_urb(1, GFP_KERNEL);
1270         if (!u->urb)
1271             goto out_of_memory;
1272         u->urb->transfer_buffer = ep->syncbuf + i * 4;
1273         u->urb->transfer_dma = ep->sync_dma + i * 4;
1274         u->urb->transfer_buffer_length = 4;
1275         u->urb->pipe = ep->pipe;
1276         u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1277         u->urb->number_of_packets = 1;
1278         u->urb->interval = 1 << ep->syncinterval;
1279         u->urb->context = u;
1280         u->urb->complete = snd_complete_urb;
1281     }
1282 
1283     ep->nurbs = SYNC_URBS;
1284 
1285     return 0;
1286 
1287 out_of_memory:
1288     release_urbs(ep, false);
1289     return -ENOMEM;
1290 }
1291 
1292 /*
1293  * snd_usb_endpoint_set_params: configure an snd_usb_endpoint
1294  *
1295  * Determine the number of URBs to be used on this endpoint.
1296  * An endpoint must be configured before it can be started.
1297  * An endpoint that is already running can not be reconfigured.
1298  */
1299 static int snd_usb_endpoint_set_params(struct snd_usb_audio *chip,
1300                        struct snd_usb_endpoint *ep)
1301 {
1302     const struct audioformat *fmt = ep->cur_audiofmt;
1303     int err;
1304 
1305     /* release old buffers, if any */
1306     err = release_urbs(ep, false);
1307     if (err < 0)
1308         return err;
1309 
1310     ep->datainterval = fmt->datainterval;
1311     ep->maxpacksize = fmt->maxpacksize;
1312     ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX);
1313 
1314     if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL) {
1315         ep->freqn = get_usb_full_speed_rate(ep->cur_rate);
1316         ep->pps = 1000 >> ep->datainterval;
1317     } else {
1318         ep->freqn = get_usb_high_speed_rate(ep->cur_rate);
1319         ep->pps = 8000 >> ep->datainterval;
1320     }
1321 
1322     ep->sample_rem = ep->cur_rate % ep->pps;
1323     ep->packsize[0] = ep->cur_rate / ep->pps;
1324     ep->packsize[1] = (ep->cur_rate + (ep->pps - 1)) / ep->pps;
1325 
1326     /* calculate the frequency in 16.16 format */
1327     ep->freqm = ep->freqn;
1328     ep->freqshift = INT_MIN;
1329 
1330     ep->phase = 0;
1331 
1332     switch (ep->type) {
1333     case  SND_USB_ENDPOINT_TYPE_DATA:
1334         err = data_ep_set_params(ep);
1335         break;
1336     case  SND_USB_ENDPOINT_TYPE_SYNC:
1337         err = sync_ep_set_params(ep);
1338         break;
1339     default:
1340         err = -EINVAL;
1341     }
1342 
1343     usb_audio_dbg(chip, "Set up %d URBS, ret=%d\n", ep->nurbs, err);
1344 
1345     if (err < 0)
1346         return err;
1347 
1348     /* some unit conversions in runtime */
1349     ep->maxframesize = ep->maxpacksize / ep->cur_frame_bytes;
1350     ep->curframesize = ep->curpacksize / ep->cur_frame_bytes;
1351 
1352     return 0;
1353 }
1354 
1355 static int init_sample_rate(struct snd_usb_audio *chip,
1356                 struct snd_usb_endpoint *ep)
1357 {
1358     struct snd_usb_clock_ref *clock = ep->clock_ref;
1359     int err;
1360 
1361     if (clock) {
1362         if (atomic_read(&clock->locked))
1363             return 0;
1364         if (clock->rate == ep->cur_rate)
1365             return 0;
1366         if (clock->rate && clock->rate != ep->cur_rate) {
1367             usb_audio_dbg(chip, "Mismatched sample rate %d vs %d for EP 0x%x\n",
1368                       clock->rate, ep->cur_rate, ep->ep_num);
1369             return -EINVAL;
1370         }
1371     }
1372 
1373     err = snd_usb_init_sample_rate(chip, ep->cur_audiofmt, ep->cur_rate);
1374     if (err < 0)
1375         return err;
1376 
1377     if (clock)
1378         clock->rate = ep->cur_rate;
1379     return 0;
1380 }
1381 
1382 /*
1383  * snd_usb_endpoint_configure: Configure the endpoint
1384  *
1385  * This function sets up the EP to be fully usable state.
1386  * It's called either from hw_params or prepare callback.
1387  * The function checks need_setup flag, and performs nothing unless needed,
1388  * so it's safe to call this multiple times.
1389  *
1390  * This returns zero if unchanged, 1 if the configuration has changed,
1391  * or a negative error code.
1392  */
1393 int snd_usb_endpoint_configure(struct snd_usb_audio *chip,
1394                    struct snd_usb_endpoint *ep)
1395 {
1396     bool iface_first;
1397     int err = 0;
1398 
1399     mutex_lock(&chip->mutex);
1400     if (WARN_ON(!ep->iface_ref))
1401         goto unlock;
1402     if (!ep->need_setup)
1403         goto unlock;
1404 
1405     /* If the interface has been already set up, just set EP parameters */
1406     if (!ep->iface_ref->need_setup) {
1407         /* sample rate setup of UAC1 is per endpoint, and we need
1408          * to update at each EP configuration
1409          */
1410         if (ep->cur_audiofmt->protocol == UAC_VERSION_1) {
1411             err = init_sample_rate(chip, ep);
1412             if (err < 0)
1413                 goto unlock;
1414         }
1415         err = snd_usb_endpoint_set_params(chip, ep);
1416         if (err < 0)
1417             goto unlock;
1418         goto done;
1419     }
1420 
1421     /* Need to deselect altsetting at first */
1422     endpoint_set_interface(chip, ep, false);
1423 
1424     /* Some UAC1 devices (e.g. Yamaha THR10) need the host interface
1425      * to be set up before parameter setups
1426      */
1427     iface_first = ep->cur_audiofmt->protocol == UAC_VERSION_1;
1428     /* Workaround for devices that require the interface setup at first like UAC1 */
1429     if (chip->quirk_flags & QUIRK_FLAG_SET_IFACE_FIRST)
1430         iface_first = true;
1431     if (iface_first) {
1432         err = endpoint_set_interface(chip, ep, true);
1433         if (err < 0)
1434             goto unlock;
1435     }
1436 
1437     err = snd_usb_init_pitch(chip, ep->cur_audiofmt);
1438     if (err < 0)
1439         goto unlock;
1440 
1441     err = init_sample_rate(chip, ep);
1442     if (err < 0)
1443         goto unlock;
1444 
1445     err = snd_usb_endpoint_set_params(chip, ep);
1446     if (err < 0)
1447         goto unlock;
1448 
1449     err = snd_usb_select_mode_quirk(chip, ep->cur_audiofmt);
1450     if (err < 0)
1451         goto unlock;
1452 
1453     /* for UAC2/3, enable the interface altset here at last */
1454     if (!iface_first) {
1455         err = endpoint_set_interface(chip, ep, true);
1456         if (err < 0)
1457             goto unlock;
1458     }
1459 
1460     ep->iface_ref->need_setup = false;
1461 
1462  done:
1463     ep->need_setup = false;
1464     err = 1;
1465 
1466 unlock:
1467     mutex_unlock(&chip->mutex);
1468     return err;
1469 }
1470 
1471 /* get the current rate set to the given clock by any endpoint */
1472 int snd_usb_endpoint_get_clock_rate(struct snd_usb_audio *chip, int clock)
1473 {
1474     struct snd_usb_clock_ref *ref;
1475     int rate = 0;
1476 
1477     if (!clock)
1478         return 0;
1479     mutex_lock(&chip->mutex);
1480     list_for_each_entry(ref, &chip->clock_ref_list, list) {
1481         if (ref->clock == clock) {
1482             rate = ref->rate;
1483             break;
1484         }
1485     }
1486     mutex_unlock(&chip->mutex);
1487     return rate;
1488 }
1489 
1490 /**
1491  * snd_usb_endpoint_start: start an snd_usb_endpoint
1492  *
1493  * @ep: the endpoint to start
1494  *
1495  * A call to this function will increment the running count of the endpoint.
1496  * In case it is not already running, the URBs for this endpoint will be
1497  * submitted. Otherwise, this function does nothing.
1498  *
1499  * Must be balanced to calls of snd_usb_endpoint_stop().
1500  *
1501  * Returns an error if the URB submission failed, 0 in all other cases.
1502  */
1503 int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
1504 {
1505     bool is_playback = usb_pipeout(ep->pipe);
1506     int err;
1507     unsigned int i;
1508 
1509     if (atomic_read(&ep->chip->shutdown))
1510         return -EBADFD;
1511 
1512     if (ep->sync_source)
1513         WRITE_ONCE(ep->sync_source->sync_sink, ep);
1514 
1515     usb_audio_dbg(ep->chip, "Starting %s EP 0x%x (running %d)\n",
1516               ep_type_name(ep->type), ep->ep_num,
1517               atomic_read(&ep->running));
1518 
1519     /* already running? */
1520     if (atomic_inc_return(&ep->running) != 1)
1521         return 0;
1522 
1523     if (ep->clock_ref)
1524         atomic_inc(&ep->clock_ref->locked);
1525 
1526     ep->active_mask = 0;
1527     ep->unlink_mask = 0;
1528     ep->phase = 0;
1529     ep->sample_accum = 0;
1530 
1531     snd_usb_endpoint_start_quirk(ep);
1532 
1533     /*
1534      * If this endpoint has a data endpoint as implicit feedback source,
1535      * don't start the urbs here. Instead, mark them all as available,
1536      * wait for the record urbs to return and queue the playback urbs
1537      * from that context.
1538      */
1539 
1540     if (!ep_state_update(ep, EP_STATE_STOPPED, EP_STATE_RUNNING))
1541         goto __error;
1542 
1543     if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1544         !(ep->chip->quirk_flags & QUIRK_FLAG_PLAYBACK_FIRST)) {
1545         usb_audio_dbg(ep->chip, "No URB submission due to implicit fb sync\n");
1546         i = 0;
1547         goto fill_rest;
1548     }
1549 
1550     for (i = 0; i < ep->nurbs; i++) {
1551         struct urb *urb = ep->urb[i].urb;
1552 
1553         if (snd_BUG_ON(!urb))
1554             goto __error;
1555 
1556         if (is_playback)
1557             err = prepare_outbound_urb(ep, urb->context, true);
1558         else
1559             err = prepare_inbound_urb(ep, urb->context);
1560         if (err < 0) {
1561             /* stop filling at applptr */
1562             if (err == -EAGAIN)
1563                 break;
1564             usb_audio_dbg(ep->chip,
1565                       "EP 0x%x: failed to prepare urb: %d\n",
1566                       ep->ep_num, err);
1567             goto __error;
1568         }
1569 
1570         err = usb_submit_urb(urb, GFP_ATOMIC);
1571         if (err < 0) {
1572             usb_audio_err(ep->chip,
1573                 "cannot submit urb %d, error %d: %s\n",
1574                 i, err, usb_error_string(err));
1575             goto __error;
1576         }
1577         set_bit(i, &ep->active_mask);
1578         atomic_inc(&ep->submitted_urbs);
1579     }
1580 
1581     if (!i) {
1582         usb_audio_dbg(ep->chip, "XRUN at starting EP 0x%x\n",
1583                   ep->ep_num);
1584         goto __error;
1585     }
1586 
1587     usb_audio_dbg(ep->chip, "%d URBs submitted for EP 0x%x\n",
1588               i, ep->ep_num);
1589 
1590  fill_rest:
1591     /* put the remaining URBs to ready list */
1592     if (is_playback) {
1593         for (; i < ep->nurbs; i++)
1594             push_back_to_ready_list(ep, ep->urb + i);
1595     }
1596 
1597     return 0;
1598 
1599 __error:
1600     snd_usb_endpoint_stop(ep, false);
1601     return -EPIPE;
1602 }
1603 
1604 /**
1605  * snd_usb_endpoint_stop: stop an snd_usb_endpoint
1606  *
1607  * @ep: the endpoint to stop (may be NULL)
1608  * @keep_pending: keep in-flight URBs
1609  *
1610  * A call to this function will decrement the running count of the endpoint.
1611  * In case the last user has requested the endpoint stop, the URBs will
1612  * actually be deactivated.
1613  *
1614  * Must be balanced to calls of snd_usb_endpoint_start().
1615  *
1616  * The caller needs to synchronize the pending stop operation via
1617  * snd_usb_endpoint_sync_pending_stop().
1618  */
1619 void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep, bool keep_pending)
1620 {
1621     if (!ep)
1622         return;
1623 
1624     usb_audio_dbg(ep->chip, "Stopping %s EP 0x%x (running %d)\n",
1625               ep_type_name(ep->type), ep->ep_num,
1626               atomic_read(&ep->running));
1627 
1628     if (snd_BUG_ON(!atomic_read(&ep->running)))
1629         return;
1630 
1631     if (!atomic_dec_return(&ep->running)) {
1632         if (ep->sync_source)
1633             WRITE_ONCE(ep->sync_source->sync_sink, NULL);
1634         stop_urbs(ep, false, keep_pending);
1635         if (ep->clock_ref)
1636             if (!atomic_dec_return(&ep->clock_ref->locked))
1637                 ep->clock_ref->rate = 0;
1638     }
1639 }
1640 
1641 /**
1642  * snd_usb_endpoint_release: Tear down an snd_usb_endpoint
1643  *
1644  * @ep: the endpoint to release
1645  *
1646  * This function does not care for the endpoint's running count but will tear
1647  * down all the streaming URBs immediately.
1648  */
1649 void snd_usb_endpoint_release(struct snd_usb_endpoint *ep)
1650 {
1651     release_urbs(ep, true);
1652 }
1653 
1654 /**
1655  * snd_usb_endpoint_free_all: Free the resources of an snd_usb_endpoint
1656  * @chip: The chip
1657  *
1658  * This free all endpoints and those resources
1659  */
1660 void snd_usb_endpoint_free_all(struct snd_usb_audio *chip)
1661 {
1662     struct snd_usb_endpoint *ep, *en;
1663     struct snd_usb_iface_ref *ip, *in;
1664     struct snd_usb_clock_ref *cp, *cn;
1665 
1666     list_for_each_entry_safe(ep, en, &chip->ep_list, list)
1667         kfree(ep);
1668 
1669     list_for_each_entry_safe(ip, in, &chip->iface_ref_list, list)
1670         kfree(ip);
1671 
1672     list_for_each_entry_safe(cp, cn, &chip->clock_ref_list, list)
1673         kfree(cp);
1674 }
1675 
1676 /*
1677  * snd_usb_handle_sync_urb: parse an USB sync packet
1678  *
1679  * @ep: the endpoint to handle the packet
1680  * @sender: the sending endpoint
1681  * @urb: the received packet
1682  *
1683  * This function is called from the context of an endpoint that received
1684  * the packet and is used to let another endpoint object handle the payload.
1685  */
1686 static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
1687                     struct snd_usb_endpoint *sender,
1688                     const struct urb *urb)
1689 {
1690     int shift;
1691     unsigned int f;
1692     unsigned long flags;
1693 
1694     snd_BUG_ON(ep == sender);
1695 
1696     /*
1697      * In case the endpoint is operating in implicit feedback mode, prepare
1698      * a new outbound URB that has the same layout as the received packet
1699      * and add it to the list of pending urbs. queue_pending_output_urbs()
1700      * will take care of them later.
1701      */
1702     if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1703         atomic_read(&ep->running)) {
1704 
1705         /* implicit feedback case */
1706         int i, bytes = 0;
1707         struct snd_urb_ctx *in_ctx;
1708         struct snd_usb_packet_info *out_packet;
1709 
1710         in_ctx = urb->context;
1711 
1712         /* Count overall packet size */
1713         for (i = 0; i < in_ctx->packets; i++)
1714             if (urb->iso_frame_desc[i].status == 0)
1715                 bytes += urb->iso_frame_desc[i].actual_length;
1716 
1717         /*
1718          * skip empty packets. At least M-Audio's Fast Track Ultra stops
1719          * streaming once it received a 0-byte OUT URB
1720          */
1721         if (bytes == 0)
1722             return;
1723 
1724         spin_lock_irqsave(&ep->lock, flags);
1725         if (ep->next_packet_queued >= ARRAY_SIZE(ep->next_packet)) {
1726             spin_unlock_irqrestore(&ep->lock, flags);
1727             usb_audio_err(ep->chip,
1728                       "next package FIFO overflow EP 0x%x\n",
1729                       ep->ep_num);
1730             notify_xrun(ep);
1731             return;
1732         }
1733 
1734         out_packet = next_packet_fifo_enqueue(ep);
1735 
1736         /*
1737          * Iterate through the inbound packet and prepare the lengths
1738          * for the output packet. The OUT packet we are about to send
1739          * will have the same amount of payload bytes per stride as the
1740          * IN packet we just received. Since the actual size is scaled
1741          * by the stride, use the sender stride to calculate the length
1742          * in case the number of channels differ between the implicitly
1743          * fed-back endpoint and the synchronizing endpoint.
1744          */
1745 
1746         out_packet->packets = in_ctx->packets;
1747         for (i = 0; i < in_ctx->packets; i++) {
1748             if (urb->iso_frame_desc[i].status == 0)
1749                 out_packet->packet_size[i] =
1750                     urb->iso_frame_desc[i].actual_length / sender->stride;
1751             else
1752                 out_packet->packet_size[i] = 0;
1753         }
1754 
1755         spin_unlock_irqrestore(&ep->lock, flags);
1756         snd_usb_queue_pending_output_urbs(ep, false);
1757 
1758         return;
1759     }
1760 
1761     /*
1762      * process after playback sync complete
1763      *
1764      * Full speed devices report feedback values in 10.14 format as samples
1765      * per frame, high speed devices in 16.16 format as samples per
1766      * microframe.
1767      *
1768      * Because the Audio Class 1 spec was written before USB 2.0, many high
1769      * speed devices use a wrong interpretation, some others use an
1770      * entirely different format.
1771      *
1772      * Therefore, we cannot predict what format any particular device uses
1773      * and must detect it automatically.
1774      */
1775 
1776     if (urb->iso_frame_desc[0].status != 0 ||
1777         urb->iso_frame_desc[0].actual_length < 3)
1778         return;
1779 
1780     f = le32_to_cpup(urb->transfer_buffer);
1781     if (urb->iso_frame_desc[0].actual_length == 3)
1782         f &= 0x00ffffff;
1783     else
1784         f &= 0x0fffffff;
1785 
1786     if (f == 0)
1787         return;
1788 
1789     if (unlikely(sender->tenor_fb_quirk)) {
1790         /*
1791          * Devices based on Tenor 8802 chipsets (TEAC UD-H01
1792          * and others) sometimes change the feedback value
1793          * by +/- 0x1.0000.
1794          */
1795         if (f < ep->freqn - 0x8000)
1796             f += 0xf000;
1797         else if (f > ep->freqn + 0x8000)
1798             f -= 0xf000;
1799     } else if (unlikely(ep->freqshift == INT_MIN)) {
1800         /*
1801          * The first time we see a feedback value, determine its format
1802          * by shifting it left or right until it matches the nominal
1803          * frequency value.  This assumes that the feedback does not
1804          * differ from the nominal value more than +50% or -25%.
1805          */
1806         shift = 0;
1807         while (f < ep->freqn - ep->freqn / 4) {
1808             f <<= 1;
1809             shift++;
1810         }
1811         while (f > ep->freqn + ep->freqn / 2) {
1812             f >>= 1;
1813             shift--;
1814         }
1815         ep->freqshift = shift;
1816     } else if (ep->freqshift >= 0)
1817         f <<= ep->freqshift;
1818     else
1819         f >>= -ep->freqshift;
1820 
1821     if (likely(f >= ep->freqn - ep->freqn / 8 && f <= ep->freqmax)) {
1822         /*
1823          * If the frequency looks valid, set it.
1824          * This value is referred to in prepare_playback_urb().
1825          */
1826         spin_lock_irqsave(&ep->lock, flags);
1827         ep->freqm = f;
1828         spin_unlock_irqrestore(&ep->lock, flags);
1829     } else {
1830         /*
1831          * Out of range; maybe the shift value is wrong.
1832          * Reset it so that we autodetect again the next time.
1833          */
1834         ep->freqshift = INT_MIN;
1835     }
1836 }
1837
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