// SPDX-License-Identifier: GPL-2.0-or-later /* */ #include #include #include #include #include #include #include #include #include #include "usbaudio.h" #include "helper.h" #include "card.h" #include "endpoint.h" #include "pcm.h" #include "clock.h" #include "quirks.h" enum { EP_STATE_STOPPED, EP_STATE_RUNNING, EP_STATE_STOPPING, }; /* interface refcounting */ struct snd_usb_iface_ref { unsigned char iface; bool need_setup; int opened; int altset; struct list_head list; }; /* clock refcounting */ struct snd_usb_clock_ref { unsigned char clock; atomic_t locked; int opened; int rate; bool need_setup; struct list_head list; }; /* * snd_usb_endpoint is a model that abstracts everything related to an * USB endpoint and its streaming. * * There are functions to activate and deactivate the streaming URBs and * optional callbacks to let the pcm logic handle the actual content of the * packets for playback and record. Thus, the bus streaming and the audio * handlers are fully decoupled. * * There are two different types of endpoints in audio applications. * * SND_USB_ENDPOINT_TYPE_DATA handles full audio data payload for both * inbound and outbound traffic. * * SND_USB_ENDPOINT_TYPE_SYNC endpoints are for inbound traffic only and * expect the payload to carry Q10.14 / Q16.16 formatted sync information * (3 or 4 bytes). * * Each endpoint has to be configured prior to being used by calling * snd_usb_endpoint_set_params(). * * The model incorporates a reference counting, so that multiple users * can call snd_usb_endpoint_start() and snd_usb_endpoint_stop(), and * only the first user will effectively start the URBs, and only the last * one to stop it will tear the URBs down again. */ /* * convert a sampling rate into our full speed format (fs/1000 in Q16.16) * this will overflow at approx 524 kHz */ static inline unsigned get_usb_full_speed_rate(unsigned int rate) { return ((rate << 13) + 62) / 125; } /* * convert a sampling rate into USB high speed format (fs/8000 in Q16.16) * this will overflow at approx 4 MHz */ static inline unsigned get_usb_high_speed_rate(unsigned int rate) { return ((rate << 10) + 62) / 125; } /* * release a urb data */ static void release_urb_ctx(struct snd_urb_ctx *u) { if (u->urb && u->buffer_size) usb_free_coherent(u->ep->chip->dev, u->buffer_size, u->urb->transfer_buffer, u->urb->transfer_dma); usb_free_urb(u->urb); u->urb = NULL; u->buffer_size = 0; } static const char *usb_error_string(int err) { switch (err) { case -ENODEV: return "no device"; case -ENOENT: return "endpoint not enabled"; case -EPIPE: return "endpoint stalled"; case -ENOSPC: return "not enough bandwidth"; case -ESHUTDOWN: return "device disabled"; case -EHOSTUNREACH: return "device suspended"; case -EINVAL: case -EAGAIN: case -EFBIG: case -EMSGSIZE: return "internal error"; default: return "unknown error"; } } static inline bool ep_state_running(struct snd_usb_endpoint *ep) { return atomic_read(&ep->state) == EP_STATE_RUNNING; } static inline bool ep_state_update(struct snd_usb_endpoint *ep, int old, int new) { return atomic_try_cmpxchg(&ep->state, &old, new); } /** * snd_usb_endpoint_implicit_feedback_sink: Report endpoint usage type * * @ep: The snd_usb_endpoint * * Determine whether an endpoint is driven by an implicit feedback * data endpoint source. */ int snd_usb_endpoint_implicit_feedback_sink(struct snd_usb_endpoint *ep) { return ep->implicit_fb_sync && usb_pipeout(ep->pipe); } /* * Return the number of samples to be sent in the next packet * for streaming based on information derived from sync endpoints * * This won't be used for implicit feedback which takes the packet size * returned from the sync source */ static int slave_next_packet_size(struct snd_usb_endpoint *ep, unsigned int avail) { unsigned long flags; unsigned int phase; int ret; if (ep->fill_max) return ep->maxframesize; spin_lock_irqsave(&ep->lock, flags); phase = (ep->phase & 0xffff) + (ep->freqm << ep->datainterval); ret = min(phase >> 16, ep->maxframesize); if (avail && ret >= avail) ret = -EAGAIN; else ep->phase = phase; spin_unlock_irqrestore(&ep->lock, flags); return ret; } /* * Return the number of samples to be sent in the next packet * for adaptive and synchronous endpoints */ static int next_packet_size(struct snd_usb_endpoint *ep, unsigned int avail) { unsigned int sample_accum; int ret; if (ep->fill_max) return ep->maxframesize; sample_accum = ep->sample_accum + ep->sample_rem; if (sample_accum >= ep->pps) { sample_accum -= ep->pps; ret = ep->packsize[1]; } else { ret = ep->packsize[0]; } if (avail && ret >= avail) ret = -EAGAIN; else ep->sample_accum = sample_accum; return ret; } /* * snd_usb_endpoint_next_packet_size: Return the number of samples to be sent * in the next packet * * If the size is equal or exceeds @avail, don't proceed but return -EAGAIN * Exception: @avail = 0 for skipping the check. */ int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep, struct snd_urb_ctx *ctx, int idx, unsigned int avail) { unsigned int packet; packet = ctx->packet_size[idx]; if (packet) { if (avail && packet >= avail) return -EAGAIN; return packet; } if (ep->sync_source) return slave_next_packet_size(ep, avail); else return next_packet_size(ep, avail); } static void call_retire_callback(struct snd_usb_endpoint *ep, struct urb *urb) { struct snd_usb_substream *data_subs; data_subs = READ_ONCE(ep->data_subs); if (data_subs && ep->retire_data_urb) ep->retire_data_urb(data_subs, urb); } static void retire_outbound_urb(struct snd_usb_endpoint *ep, struct snd_urb_ctx *urb_ctx) { call_retire_callback(ep, urb_ctx->urb); } static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep, struct snd_usb_endpoint *sender, const struct urb *urb); static void retire_inbound_urb(struct snd_usb_endpoint *ep, struct snd_urb_ctx *urb_ctx) { struct urb *urb = urb_ctx->urb; struct snd_usb_endpoint *sync_sink; if (unlikely(ep->skip_packets > 0)) { ep->skip_packets--; return; } sync_sink = READ_ONCE(ep->sync_sink); if (sync_sink) snd_usb_handle_sync_urb(sync_sink, ep, urb); call_retire_callback(ep, urb); } static inline bool has_tx_length_quirk(struct snd_usb_audio *chip) { return chip->quirk_flags & QUIRK_FLAG_TX_LENGTH; } static void prepare_silent_urb(struct snd_usb_endpoint *ep, struct snd_urb_ctx *ctx) { struct urb *urb = ctx->urb; unsigned int offs = 0; unsigned int extra = 0; __le32 packet_length; int i; /* For tx_length_quirk, put packet length at start of packet */ if (has_tx_length_quirk(ep->chip)) extra = sizeof(packet_length); for (i = 0; i < ctx->packets; ++i) { unsigned int offset; unsigned int length; int counts; counts = snd_usb_endpoint_next_packet_size(ep, ctx, i, 0); length = counts * ep->stride; /* number of silent bytes */ offset = offs * ep->stride + extra * i; urb->iso_frame_desc[i].offset = offset; urb->iso_frame_desc[i].length = length + extra; if (extra) { packet_length = cpu_to_le32(length); memcpy(urb->transfer_buffer + offset, &packet_length, sizeof(packet_length)); } memset(urb->transfer_buffer + offset + extra, ep->silence_value, length); offs += counts; } urb->number_of_packets = ctx->packets; urb->transfer_buffer_length = offs * ep->stride + ctx->packets * extra; ctx->queued = 0; } /* * Prepare a PLAYBACK urb for submission to the bus. */ static int prepare_outbound_urb(struct snd_usb_endpoint *ep, struct snd_urb_ctx *ctx, bool in_stream_lock) { struct urb *urb = ctx->urb; unsigned char *cp = urb->transfer_buffer; struct snd_usb_substream *data_subs; urb->dev = ep->chip->dev; /* we need to set this at each time */ switch (ep->type) { case SND_USB_ENDPOINT_TYPE_DATA: data_subs = READ_ONCE(ep->data_subs); if (data_subs && ep->prepare_data_urb) return ep->prepare_data_urb(data_subs, urb, in_stream_lock); /* no data provider, so send silence */ prepare_silent_urb(ep, ctx); break; case SND_USB_ENDPOINT_TYPE_SYNC: if (snd_usb_get_speed(ep->chip->dev) >= USB_SPEED_HIGH) { /* * fill the length and offset of each urb descriptor. * the fixed 12.13 frequency is passed as 16.16 through the pipe. */ urb->iso_frame_desc[0].length = 4; urb->iso_frame_desc[0].offset = 0; cp[0] = ep->freqn; cp[1] = ep->freqn >> 8; cp[2] = ep->freqn >> 16; cp[3] = ep->freqn >> 24; } else { /* * fill the length and offset of each urb descriptor. * the fixed 10.14 frequency is passed through the pipe. */ urb->iso_frame_desc[0].length = 3; urb->iso_frame_desc[0].offset = 0; cp[0] = ep->freqn >> 2; cp[1] = ep->freqn >> 10; cp[2] = ep->freqn >> 18; } break; } return 0; } /* * Prepare a CAPTURE or SYNC urb for submission to the bus. */ static int prepare_inbound_urb(struct snd_usb_endpoint *ep, struct snd_urb_ctx *urb_ctx) { int i, offs; struct urb *urb = urb_ctx->urb; urb->dev = ep->chip->dev; /* we need to set this at each time */ switch (ep->type) { case SND_USB_ENDPOINT_TYPE_DATA: offs = 0; for (i = 0; i < urb_ctx->packets; i++) { urb->iso_frame_desc[i].offset = offs; urb->iso_frame_desc[i].length = ep->curpacksize; offs += ep->curpacksize; } urb->transfer_buffer_length = offs; urb->number_of_packets = urb_ctx->packets; break; case SND_USB_ENDPOINT_TYPE_SYNC: urb->iso_frame_desc[0].length = min(4u, ep->syncmaxsize); urb->iso_frame_desc[0].offset = 0; break; } return 0; } /* notify an error as XRUN to the assigned PCM data substream */ static void notify_xrun(struct snd_usb_endpoint *ep) { struct snd_usb_substream *data_subs; data_subs = READ_ONCE(ep->data_subs); if (data_subs && data_subs->pcm_substream) snd_pcm_stop_xrun(data_subs->pcm_substream); } static struct snd_usb_packet_info * next_packet_fifo_enqueue(struct snd_usb_endpoint *ep) { struct snd_usb_packet_info *p; p = ep->next_packet + (ep->next_packet_head + ep->next_packet_queued) % ARRAY_SIZE(ep->next_packet); ep->next_packet_queued++; return p; } static struct snd_usb_packet_info * next_packet_fifo_dequeue(struct snd_usb_endpoint *ep) { struct snd_usb_packet_info *p; p = ep->next_packet + ep->next_packet_head; ep->next_packet_head++; ep->next_packet_head %= ARRAY_SIZE(ep->next_packet); ep->next_packet_queued--; return p; } static void push_back_to_ready_list(struct snd_usb_endpoint *ep, struct snd_urb_ctx *ctx) { unsigned long flags; spin_lock_irqsave(&ep->lock, flags); list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs); spin_unlock_irqrestore(&ep->lock, flags); } /* * Send output urbs that have been prepared previously. URBs are dequeued * from ep->ready_playback_urbs and in case there aren't any available * or there are no packets that have been prepared, this function does * nothing. * * The reason why the functionality of sending and preparing URBs is separated * is that host controllers don't guarantee the order in which they return * inbound and outbound packets to their submitters. * * This function is used both for implicit feedback endpoints and in low- * latency playback mode. */ int snd_usb_queue_pending_output_urbs(struct snd_usb_endpoint *ep, bool in_stream_lock) { bool implicit_fb = snd_usb_endpoint_implicit_feedback_sink(ep); while (ep_state_running(ep)) { unsigned long flags; struct snd_usb_packet_info *packet; struct snd_urb_ctx *ctx = NULL; int err, i; spin_lock_irqsave(&ep->lock, flags); if ((!implicit_fb || ep->next_packet_queued > 0) && !list_empty(&ep->ready_playback_urbs)) { /* take URB out of FIFO */ ctx = list_first_entry(&ep->ready_playback_urbs, struct snd_urb_ctx, ready_list); list_del_init(&ctx->ready_list); if (implicit_fb) packet = next_packet_fifo_dequeue(ep); } spin_unlock_irqrestore(&ep->lock, flags); if (ctx == NULL) break; /* copy over the length information */ if (implicit_fb) { for (i = 0; i < packet->packets; i++) ctx->packet_size[i] = packet->packet_size[i]; } /* call the data handler to fill in playback data */ err = prepare_outbound_urb(ep, ctx, in_stream_lock); /* can be stopped during prepare callback */ if (unlikely(!ep_state_running(ep))) break; if (err < 0) { /* push back to ready list again for -EAGAIN */ if (err == -EAGAIN) { push_back_to_ready_list(ep, ctx); break; } if (!in_stream_lock) notify_xrun(ep); return -EPIPE; } if (!atomic_read(&ep->chip->shutdown)) err = usb_submit_urb(ctx->urb, GFP_ATOMIC); else err = -ENODEV; if (err < 0) { if (!atomic_read(&ep->chip->shutdown)) { usb_audio_err(ep->chip, "Unable to submit urb #%d: %d at %s\n", ctx->index, err, __func__); if (!in_stream_lock) notify_xrun(ep); } return -EPIPE; } set_bit(ctx->index, &ep->active_mask); atomic_inc(&ep->submitted_urbs); } return 0; } /* * complete callback for urbs */ static void snd_complete_urb(struct urb *urb) { struct snd_urb_ctx *ctx = urb->context; struct snd_usb_endpoint *ep = ctx->ep; int err; if (unlikely(urb->status == -ENOENT || /* unlinked */ urb->status == -ENODEV || /* device removed */ urb->status == -ECONNRESET || /* unlinked */ urb->status == -ESHUTDOWN)) /* device disabled */ goto exit_clear; /* device disconnected */ if (unlikely(atomic_read(&ep->chip->shutdown))) goto exit_clear; if (unlikely(!ep_state_running(ep))) goto exit_clear; if (usb_pipeout(ep->pipe)) { retire_outbound_urb(ep, ctx); /* can be stopped during retire callback */ if (unlikely(!ep_state_running(ep))) goto exit_clear; /* in low-latency and implicit-feedback modes, push back the * URB to ready list at first, then process as much as possible */ if (ep->lowlatency_playback || snd_usb_endpoint_implicit_feedback_sink(ep)) { push_back_to_ready_list(ep, ctx); clear_bit(ctx->index, &ep->active_mask); snd_usb_queue_pending_output_urbs(ep, false); atomic_dec(&ep->submitted_urbs); /* decrement at last */ return; } /* in non-lowlatency mode, no error handling for prepare */ prepare_outbound_urb(ep, ctx, false); /* can be stopped during prepare callback */ if (unlikely(!ep_state_running(ep))) goto exit_clear; } else { retire_inbound_urb(ep, ctx); /* can be stopped during retire callback */ if (unlikely(!ep_state_running(ep))) goto exit_clear; prepare_inbound_urb(ep, ctx); } if (!atomic_read(&ep->chip->shutdown)) err = usb_submit_urb(urb, GFP_ATOMIC); else err = -ENODEV; if (err == 0) return; if (!atomic_read(&ep->chip->shutdown)) { usb_audio_err(ep->chip, "cannot submit urb (err = %d)\n", err); notify_xrun(ep); } exit_clear: clear_bit(ctx->index, &ep->active_mask); atomic_dec(&ep->submitted_urbs); } /* * Find or create a refcount object for the given interface * * The objects are released altogether in snd_usb_endpoint_free_all() */ static struct snd_usb_iface_ref * iface_ref_find(struct snd_usb_audio *chip, int iface) { struct snd_usb_iface_ref *ip; list_for_each_entry(ip, &chip->iface_ref_list, list) if (ip->iface == iface) return ip; ip = kzalloc(sizeof(*ip), GFP_KERNEL); if (!ip) return NULL; ip->iface = iface; list_add_tail(&ip->list, &chip->iface_ref_list); return ip; } /* Similarly, a refcount object for clock */ static struct snd_usb_clock_ref * clock_ref_find(struct snd_usb_audio *chip, int clock) { struct snd_usb_clock_ref *ref; list_for_each_entry(ref, &chip->clock_ref_list, list) if (ref->clock == clock) return ref; ref = kzalloc(sizeof(*ref), GFP_KERNEL); if (!ref) return NULL; ref->clock = clock; atomic_set(&ref->locked, 0); list_add_tail(&ref->list, &chip->clock_ref_list); return ref; } /* * Get the existing endpoint object corresponding EP * Returns NULL if not present. */ struct snd_usb_endpoint * snd_usb_get_endpoint(struct snd_usb_audio *chip, int ep_num) { struct snd_usb_endpoint *ep; list_for_each_entry(ep, &chip->ep_list, list) { if (ep->ep_num == ep_num) return ep; } return NULL; } #define ep_type_name(type) \ (type == SND_USB_ENDPOINT_TYPE_DATA ? "data" : "sync") /** * snd_usb_add_endpoint: Add an endpoint to an USB audio chip * * @chip: The chip * @ep_num: The number of the endpoint to use * @type: SND_USB_ENDPOINT_TYPE_DATA or SND_USB_ENDPOINT_TYPE_SYNC * * If the requested endpoint has not been added to the given chip before, * a new instance is created. * * Returns zero on success or a negative error code. * * New endpoints will be added to chip->ep_list and freed by * calling snd_usb_endpoint_free_all(). * * For SND_USB_ENDPOINT_TYPE_SYNC, the caller needs to guarantee that * bNumEndpoints > 1 beforehand. */ int snd_usb_add_endpoint(struct snd_usb_audio *chip, int ep_num, int type) { struct snd_usb_endpoint *ep; bool is_playback; ep = snd_usb_get_endpoint(chip, ep_num); if (ep) return 0; usb_audio_dbg(chip, "Creating new %s endpoint #%x\n", ep_type_name(type), ep_num); ep = kzalloc(sizeof(*ep), GFP_KERNEL); if (!ep) return -ENOMEM; ep->chip = chip; spin_lock_init(&ep->lock); ep->type = type; ep->ep_num = ep_num; INIT_LIST_HEAD(&ep->ready_playback_urbs); atomic_set(&ep->submitted_urbs, 0); is_playback = ((ep_num & USB_ENDPOINT_DIR_MASK) == USB_DIR_OUT); ep_num &= USB_ENDPOINT_NUMBER_MASK; if (is_playback) ep->pipe = usb_sndisocpipe(chip->dev, ep_num); else ep->pipe = usb_rcvisocpipe(chip->dev, ep_num); list_add_tail(&ep->list, &chip->ep_list); return 0; } /* Set up syncinterval and maxsyncsize for a sync EP */ static void endpoint_set_syncinterval(struct snd_usb_audio *chip, struct snd_usb_endpoint *ep) { struct usb_host_interface *alts; struct usb_endpoint_descriptor *desc; alts = snd_usb_get_host_interface(chip, ep->iface, ep->altsetting); if (!alts) return; desc = get_endpoint(alts, ep->ep_idx); if (desc->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE && desc->bRefresh >= 1 && desc->bRefresh <= 9) ep->syncinterval = desc->bRefresh; else if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL) ep->syncinterval = 1; else if (desc->bInterval >= 1 && desc->bInterval <= 16) ep->syncinterval = desc->bInterval - 1; else ep->syncinterval = 3; ep->syncmaxsize = le16_to_cpu(desc->wMaxPacketSize); } static bool endpoint_compatible(struct snd_usb_endpoint *ep, const struct audioformat *fp, const struct snd_pcm_hw_params *params) { if (!ep->opened) return false; if (ep->cur_audiofmt != fp) return false; if (ep->cur_rate != params_rate(params) || ep->cur_format != params_format(params) || ep->cur_period_frames != params_period_size(params) || ep->cur_buffer_periods != params_periods(params)) return false; return true; } /* * Check whether the given fp and hw params are compatible with the current * setup of the target EP for implicit feedback sync */ bool snd_usb_endpoint_compatible(struct snd_usb_audio *chip, struct snd_usb_endpoint *ep, const struct audioformat *fp, const struct snd_pcm_hw_params *params) { bool ret; mutex_lock(&chip->mutex); ret = endpoint_compatible(ep, fp, params); mutex_unlock(&chip->mutex); return ret; } /* * snd_usb_endpoint_open: Open the endpoint * * Called from hw_params to assign the endpoint to the substream. * It's reference-counted, and only the first opener is allowed to set up * arbitrary parameters. The later opener must be compatible with the * former opened parameters. * The endpoint needs to be closed via snd_usb_endpoint_close() later. * * Note that this function doesn't configure the endpoint. The substream * needs to set it up later via snd_usb_endpoint_set_params() and * snd_usb_endpoint_prepare(). */ struct snd_usb_endpoint * snd_usb_endpoint_open(struct snd_usb_audio *chip, const struct audioformat *fp, const struct snd_pcm_hw_params *params, bool is_sync_ep, bool fixed_rate) { struct snd_usb_endpoint *ep; int ep_num = is_sync_ep ? fp->sync_ep : fp->endpoint; mutex_lock(&chip->mutex); ep = snd_usb_get_endpoint(chip, ep_num); if (!ep) { usb_audio_err(chip, "Cannot find EP 0x%x to open\n", ep_num); goto unlock; } if (!ep->opened) { if (is_sync_ep) { ep->iface = fp->sync_iface; ep->altsetting = fp->sync_altsetting; ep->ep_idx = fp->sync_ep_idx; } else { ep->iface = fp->iface; ep->altsetting = fp->altsetting; ep->ep_idx = fp->ep_idx; } usb_audio_dbg(chip, "Open EP 0x%x, iface=%d:%d, idx=%d\n", ep_num, ep->iface, ep->altsetting, ep->ep_idx); ep->iface_ref = iface_ref_find(chip, ep->iface); if (!ep->iface_ref) { ep = NULL; goto unlock; } if (fp->protocol != UAC_VERSION_1) { ep->clock_ref = clock_ref_find(chip, fp->clock); if (!ep->clock_ref) { ep = NULL; goto unlock; } ep->clock_ref->opened++; } ep->cur_audiofmt = fp; ep->cur_channels = fp->channels; ep->cur_rate = params_rate(params); ep->cur_format = params_format(params); ep->cur_frame_bytes = snd_pcm_format_physical_width(ep->cur_format) * ep->cur_channels / 8; ep->cur_period_frames = params_period_size(params); ep->cur_period_bytes = ep->cur_period_frames * ep->cur_frame_bytes; ep->cur_buffer_periods = params_periods(params); if (ep->type == SND_USB_ENDPOINT_TYPE_SYNC) endpoint_set_syncinterval(chip, ep); ep->implicit_fb_sync = fp->implicit_fb; ep->need_setup = true; ep->need_prepare = true; ep->fixed_rate = fixed_rate; usb_audio_dbg(chip, " channels=%d, rate=%d, format=%s, period_bytes=%d, periods=%d, implicit_fb=%d\n", ep->cur_channels, ep->cur_rate, snd_pcm_format_name(ep->cur_format), ep->cur_period_bytes, ep->cur_buffer_periods, ep->implicit_fb_sync); } else { if (WARN_ON(!ep->iface_ref)) { ep = NULL; goto unlock; } if (!endpoint_compatible(ep, fp, params)) { usb_audio_err(chip, "Incompatible EP setup for 0x%x\n", ep_num); ep = NULL; goto unlock; } usb_audio_dbg(chip, "Reopened EP 0x%x (count %d)\n", ep_num, ep->opened); } if (!ep->iface_ref->opened++) ep->iface_ref->need_setup = true; ep->opened++; unlock: mutex_unlock(&chip->mutex); return ep; } /* * snd_usb_endpoint_set_sync: Link data and sync endpoints * * Pass NULL to sync_ep to unlink again */ void snd_usb_endpoint_set_sync(struct snd_usb_audio *chip, struct snd_usb_endpoint *data_ep, struct snd_usb_endpoint *sync_ep) { data_ep->sync_source = sync_ep; } /* * Set data endpoint callbacks and the assigned data stream * * Called at PCM trigger and cleanups. * Pass NULL to deactivate each callback. */ void snd_usb_endpoint_set_callback(struct snd_usb_endpoint *ep, int (*prepare)(struct snd_usb_substream *subs, struct urb *urb, bool in_stream_lock), void (*retire)(struct snd_usb_substream *subs, struct urb *urb), struct snd_usb_substream *data_subs) { ep->prepare_data_urb = prepare; ep->retire_data_urb = retire; if (data_subs) ep->lowlatency_playback = data_subs->lowlatency_playback; else ep->lowlatency_playback = false; WRITE_ONCE(ep->data_subs, data_subs); } static int endpoint_set_interface(struct snd_usb_audio *chip, struct snd_usb_endpoint *ep, bool set) { int altset = set ? ep->altsetting : 0; int err; if (ep->iface_ref->altset == altset) return 0; usb_audio_dbg(chip, "Setting usb interface %d:%d for EP 0x%x\n", ep->iface, altset, ep->ep_num); err = usb_set_interface(chip->dev, ep->iface, altset); if (err < 0) { usb_audio_err_ratelimited( chip, "%d:%d: usb_set_interface failed (%d)\n", ep->iface, altset, err); return err; } if (chip->quirk_flags & QUIRK_FLAG_IFACE_DELAY) msleep(50); ep->iface_ref->altset = altset; return 0; } /* * snd_usb_endpoint_close: Close the endpoint * * Unreference the already opened endpoint via snd_usb_endpoint_open(). */ void snd_usb_endpoint_close(struct snd_usb_audio *chip, struct snd_usb_endpoint *ep) { mutex_lock(&chip->mutex); usb_audio_dbg(chip, "Closing EP 0x%x (count %d)\n", ep->ep_num, ep->opened); if (!--ep->iface_ref->opened && !(chip->quirk_flags & QUIRK_FLAG_IFACE_SKIP_CLOSE)) endpoint_set_interface(chip, ep, false); if (!--ep->opened) { if (ep->clock_ref) { if (!--ep->clock_ref->opened) ep->clock_ref->rate = 0; } ep->iface = 0; ep->altsetting = 0; ep->cur_audiofmt = NULL; ep->cur_rate = 0; ep->iface_ref = NULL; ep->clock_ref = NULL; usb_audio_dbg(chip, "EP 0x%x closed\n", ep->ep_num); } mutex_unlock(&chip->mutex); } /* Prepare for suspening EP, called from the main suspend handler */ void snd_usb_endpoint_suspend(struct snd_usb_endpoint *ep) { ep->need_prepare = true; if (ep->iface_ref) ep->iface_ref->need_setup = true; if (ep->clock_ref) ep->clock_ref->rate = 0; } /* * wait until all urbs are processed. */ static int wait_clear_urbs(struct snd_usb_endpoint *ep) { unsigned long end_time = jiffies + msecs_to_jiffies(1000); int alive; if (atomic_read(&ep->state) != EP_STATE_STOPPING) return 0; do { alive = atomic_read(&ep->submitted_urbs); if (!alive) break; schedule_timeout_uninterruptible(1); } while (time_before(jiffies, end_time)); if (alive) usb_audio_err(ep->chip, "timeout: still %d active urbs on EP #%x\n", alive, ep->ep_num); if (ep_state_update(ep, EP_STATE_STOPPING, EP_STATE_STOPPED)) { ep->sync_sink = NULL; snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL); } return 0; } /* sync the pending stop operation; * this function itself doesn't trigger the stop operation */ void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep) { if (ep) wait_clear_urbs(ep); } /* * Stop active urbs * * This function moves the EP to STOPPING state if it's being RUNNING. */ static int stop_urbs(struct snd_usb_endpoint *ep, bool force, bool keep_pending) { unsigned int i; unsigned long flags; if (!force && atomic_read(&ep->running)) return -EBUSY; if (!ep_state_update(ep, EP_STATE_RUNNING, EP_STATE_STOPPING)) return 0; spin_lock_irqsave(&ep->lock, flags); INIT_LIST_HEAD(&ep->ready_playback_urbs); ep->next_packet_head = 0; ep->next_packet_queued = 0; spin_unlock_irqrestore(&ep->lock, flags); if (keep_pending) return 0; for (i = 0; i < ep->nurbs; i++) { if (test_bit(i, &ep->active_mask)) { if (!test_and_set_bit(i, &ep->unlink_mask)) { struct urb *u = ep->urb[i].urb; usb_unlink_urb(u); } } } return 0; } /* * release an endpoint's urbs */ static int release_urbs(struct snd_usb_endpoint *ep, bool force) { int i, err; /* route incoming urbs to nirvana */ snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL); /* stop and unlink urbs */ err = stop_urbs(ep, force, false); if (err) return err; wait_clear_urbs(ep); for (i = 0; i < ep->nurbs; i++) release_urb_ctx(&ep->urb[i]); usb_free_coherent(ep->chip->dev, SYNC_URBS * 4, ep->syncbuf, ep->sync_dma); ep->syncbuf = NULL; ep->nurbs = 0; return 0; } /* * configure a data endpoint */ static int data_ep_set_params(struct snd_usb_endpoint *ep) { struct snd_usb_audio *chip = ep->chip; unsigned int maxsize, minsize, packs_per_ms, max_packs_per_urb; unsigned int max_packs_per_period, urbs_per_period, urb_packs; unsigned int max_urbs, i; const struct audioformat *fmt = ep->cur_audiofmt; int frame_bits = ep->cur_frame_bytes * 8; int tx_length_quirk = (has_tx_length_quirk(chip) && usb_pipeout(ep->pipe)); usb_audio_dbg(chip, "Setting params for data EP 0x%x, pipe 0x%x\n", ep->ep_num, ep->pipe); if (ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) { /* * When operating in DSD DOP mode, the size of a sample frame * in hardware differs from the actual physical format width * because we need to make room for the DOP markers. */ frame_bits += ep->cur_channels << 3; } ep->datainterval = fmt->datainterval; ep->stride = frame_bits >> 3; switch (ep->cur_format) { case SNDRV_PCM_FORMAT_U8: ep->silence_value = 0x80; break; case SNDRV_PCM_FORMAT_DSD_U8: case SNDRV_PCM_FORMAT_DSD_U16_LE: case SNDRV_PCM_FORMAT_DSD_U32_LE: case SNDRV_PCM_FORMAT_DSD_U16_BE: case SNDRV_PCM_FORMAT_DSD_U32_BE: ep->silence_value = 0x69; break; default: ep->silence_value = 0; } /* assume max. frequency is 50% higher than nominal */ ep->freqmax = ep->freqn + (ep->freqn >> 1); /* Round up freqmax to nearest integer in order to calculate maximum * packet size, which must represent a whole number of frames. * This is accomplished by adding 0x0.ffff before converting the * Q16.16 format into integer. * In order to accurately calculate the maximum packet size when * the data interval is more than 1 (i.e. ep->datainterval > 0), * multiply by the data interval prior to rounding. For instance, * a freqmax of 41 kHz will result in a max packet size of 6 (5.125) * frames with a data interval of 1, but 11 (10.25) frames with a * data interval of 2. * (ep->freqmax << ep->datainterval overflows at 8.192 MHz for the * maximum datainterval value of 3, at USB full speed, higher for * USB high speed, noting that ep->freqmax is in units of * frames per packet in Q16.16 format.) */ maxsize = (((ep->freqmax << ep->datainterval) + 0xffff) >> 16) * (frame_bits >> 3); if (tx_length_quirk) maxsize += sizeof(__le32); /* Space for length descriptor */ /* but wMaxPacketSize might reduce this */ if (ep->maxpacksize && ep->maxpacksize < maxsize) { /* whatever fits into a max. size packet */ unsigned int data_maxsize = maxsize = ep->maxpacksize; if (tx_length_quirk) /* Need to remove the length descriptor to calc freq */ data_maxsize -= sizeof(__le32); ep->freqmax = (data_maxsize / (frame_bits >> 3)) << (16 - ep->datainterval); } if (ep->fill_max) ep->curpacksize = ep->maxpacksize; else ep->curpacksize = maxsize; if (snd_usb_get_speed(chip->dev) != USB_SPEED_FULL) { packs_per_ms = 8 >> ep->datainterval; max_packs_per_urb = MAX_PACKS_HS; } else { packs_per_ms = 1; max_packs_per_urb = MAX_PACKS; } if (ep->sync_source && !ep->implicit_fb_sync) max_packs_per_urb = min(max_packs_per_urb, 1U << ep->sync_source->syncinterval); max_packs_per_urb = max(1u, max_packs_per_urb >> ep->datainterval); /* * Capture endpoints need to use small URBs because there's no way * to tell in advance where the next period will end, and we don't * want the next URB to complete much after the period ends. * * Playback endpoints with implicit sync much use the same parameters * as their corresponding capture endpoint. */ if (usb_pipein(ep->pipe) || ep->implicit_fb_sync) { /* make capture URBs <= 1 ms and smaller than a period */ urb_packs = min(max_packs_per_urb, packs_per_ms); while (urb_packs > 1 && urb_packs * maxsize >= ep->cur_period_bytes) urb_packs >>= 1; ep->nurbs = MAX_URBS; /* * Playback endpoints without implicit sync are adjusted so that * a period fits as evenly as possible in the smallest number of * URBs. The total number of URBs is adjusted to the size of the * ALSA buffer, subject to the MAX_URBS and MAX_QUEUE limits. */ } else { /* determine how small a packet can be */ minsize = (ep->freqn >> (16 - ep->datainterval)) * (frame_bits >> 3); /* with sync from device, assume it can be 12% lower */ if (ep->sync_source) minsize -= minsize >> 3; minsize = max(minsize, 1u); /* how many packets will contain an entire ALSA period? */ max_packs_per_period = DIV_ROUND_UP(ep->cur_period_bytes, minsize); /* how many URBs will contain a period? */ urbs_per_period = DIV_ROUND_UP(max_packs_per_period, max_packs_per_urb); /* how many packets are needed in each URB? */ urb_packs = DIV_ROUND_UP(max_packs_per_period, urbs_per_period); /* limit the number of frames in a single URB */ ep->max_urb_frames = DIV_ROUND_UP(ep->cur_period_frames, urbs_per_period); /* try to use enough URBs to contain an entire ALSA buffer */ max_urbs = min((unsigned) MAX_URBS, MAX_QUEUE * packs_per_ms / urb_packs); ep->nurbs = min(max_urbs, urbs_per_period * ep->cur_buffer_periods); } /* allocate and initialize data urbs */ for (i = 0; i < ep->nurbs; i++) { struct snd_urb_ctx *u = &ep->urb[i]; u->index = i; u->ep = ep; u->packets = urb_packs; u->buffer_size = maxsize * u->packets; if (fmt->fmt_type == UAC_FORMAT_TYPE_II) u->packets++; /* for transfer delimiter */ u->urb = usb_alloc_urb(u->packets, GFP_KERNEL); if (!u->urb) goto out_of_memory; u->urb->transfer_buffer = usb_alloc_coherent(chip->dev, u->buffer_size, GFP_KERNEL, &u->urb->transfer_dma); if (!u->urb->transfer_buffer) goto out_of_memory; u->urb->pipe = ep->pipe; u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP; u->urb->interval = 1 << ep->datainterval; u->urb->context = u; u->urb->complete = snd_complete_urb; INIT_LIST_HEAD(&u->ready_list); } return 0; out_of_memory: release_urbs(ep, false); return -ENOMEM; } /* * configure a sync endpoint */ static int sync_ep_set_params(struct snd_usb_endpoint *ep) { struct snd_usb_audio *chip = ep->chip; int i; usb_audio_dbg(chip, "Setting params for sync EP 0x%x, pipe 0x%x\n", ep->ep_num, ep->pipe); ep->syncbuf = usb_alloc_coherent(chip->dev, SYNC_URBS * 4, GFP_KERNEL, &ep->sync_dma); if (!ep->syncbuf) return -ENOMEM; ep->nurbs = SYNC_URBS; for (i = 0; i < SYNC_URBS; i++) { struct snd_urb_ctx *u = &ep->urb[i]; u->index = i; u->ep = ep; u->packets = 1; u->urb = usb_alloc_urb(1, GFP_KERNEL); if (!u->urb) goto out_of_memory; u->urb->transfer_buffer = ep->syncbuf + i * 4; u->urb->transfer_dma = ep->sync_dma + i * 4; u->urb->transfer_buffer_length = 4; u->urb->pipe = ep->pipe; u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP; u->urb->number_of_packets = 1; u->urb->interval = 1 << ep->syncinterval; u->urb->context = u; u->urb->complete = snd_complete_urb; } return 0; out_of_memory: release_urbs(ep, false); return -ENOMEM; } /* update the rate of the referred clock; return the actual rate */ static int update_clock_ref_rate(struct snd_usb_audio *chip, struct snd_usb_endpoint *ep) { struct snd_usb_clock_ref *clock = ep->clock_ref; int rate = ep->cur_rate; if (!clock || clock->rate == rate) return rate; if (clock->rate) { if (atomic_read(&clock->locked)) return clock->rate; if (clock->rate != rate) { usb_audio_err(chip, "Mismatched sample rate %d vs %d for EP 0x%x\n", clock->rate, rate, ep->ep_num); return clock->rate; } } clock->rate = rate; clock->need_setup = true; return rate; } /* * snd_usb_endpoint_set_params: configure an snd_usb_endpoint * * It's called either from hw_params callback. * Determine the number of URBs to be used on this endpoint. * An endpoint must be configured before it can be started. * An endpoint that is already running can not be reconfigured. */ int snd_usb_endpoint_set_params(struct snd_usb_audio *chip, struct snd_usb_endpoint *ep) { const struct audioformat *fmt = ep->cur_audiofmt; int err = 0; mutex_lock(&chip->mutex); if (!ep->need_setup) goto unlock; /* release old buffers, if any */ err = release_urbs(ep, false); if (err < 0) goto unlock; ep->datainterval = fmt->datainterval; ep->maxpacksize = fmt->maxpacksize; ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX); if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL) { ep->freqn = get_usb_full_speed_rate(ep->cur_rate); ep->pps = 1000 >> ep->datainterval; } else { ep->freqn = get_usb_high_speed_rate(ep->cur_rate); ep->pps = 8000 >> ep->datainterval; } ep->sample_rem = ep->cur_rate % ep->pps; ep->packsize[0] = ep->cur_rate / ep->pps; ep->packsize[1] = (ep->cur_rate + (ep->pps - 1)) / ep->pps; /* calculate the frequency in 16.16 format */ ep->freqm = ep->freqn; ep->freqshift = INT_MIN; ep->phase = 0; switch (ep->type) { case SND_USB_ENDPOINT_TYPE_DATA: err = data_ep_set_params(ep); break; case SND_USB_ENDPOINT_TYPE_SYNC: err = sync_ep_set_params(ep); break; default: err = -EINVAL; } usb_audio_dbg(chip, "Set up %d URBS, ret=%d\n", ep->nurbs, err); if (err < 0) goto unlock; /* some unit conversions in runtime */ ep->maxframesize = ep->maxpacksize / ep->cur_frame_bytes; ep->curframesize = ep->curpacksize / ep->cur_frame_bytes; err = update_clock_ref_rate(chip, ep); if (err >= 0) { ep->need_setup = false; err = 0; } unlock: mutex_unlock(&chip->mutex); return err; } static int init_sample_rate(struct snd_usb_audio *chip, struct snd_usb_endpoint *ep) { struct snd_usb_clock_ref *clock = ep->clock_ref; int rate, err; rate = update_clock_ref_rate(chip, ep); if (rate < 0) return rate; if (clock && !clock->need_setup) return 0; if (!ep->fixed_rate) { err = snd_usb_init_sample_rate(chip, ep->cur_audiofmt, rate); if (err < 0) { if (clock) clock->rate = 0; /* reset rate */ return err; } } if (clock) clock->need_setup = false; return 0; } /* * snd_usb_endpoint_prepare: Prepare the endpoint * * This function sets up the EP to be fully usable state. * It's called either from prepare callback. * The function checks need_setup flag, and performs nothing unless needed, * so it's safe to call this multiple times. * * This returns zero if unchanged, 1 if the configuration has changed, * or a negative error code. */ int snd_usb_endpoint_prepare(struct snd_usb_audio *chip, struct snd_usb_endpoint *ep) { bool iface_first; int err = 0; mutex_lock(&chip->mutex); if (WARN_ON(!ep->iface_ref)) goto unlock; if (!ep->need_prepare) goto unlock; /* If the interface has been already set up, just set EP parameters */ if (!ep->iface_ref->need_setup) { /* sample rate setup of UAC1 is per endpoint, and we need * to update at each EP configuration */ if (ep->cur_audiofmt->protocol == UAC_VERSION_1) { err = init_sample_rate(chip, ep); if (err < 0) goto unlock; } goto done; } /* Need to deselect altsetting at first */ endpoint_set_interface(chip, ep, false); /* Some UAC1 devices (e.g. Yamaha THR10) need the host interface * to be set up before parameter setups */ iface_first = ep->cur_audiofmt->protocol == UAC_VERSION_1; /* Workaround for devices that require the interface setup at first like UAC1 */ if (chip->quirk_flags & QUIRK_FLAG_SET_IFACE_FIRST) iface_first = true; if (iface_first) { err = endpoint_set_interface(chip, ep, true); if (err < 0) goto unlock; } err = snd_usb_init_pitch(chip, ep->cur_audiofmt); if (err < 0) goto unlock; err = init_sample_rate(chip, ep); if (err < 0) goto unlock; err = snd_usb_select_mode_quirk(chip, ep->cur_audiofmt); if (err < 0) goto unlock; /* for UAC2/3, enable the interface altset here at last */ if (!iface_first) { err = endpoint_set_interface(chip, ep, true); if (err < 0) goto unlock; } ep->iface_ref->need_setup = false; done: ep->need_prepare = false; err = 1; unlock: mutex_unlock(&chip->mutex); return err; } /* get the current rate set to the given clock by any endpoint */ int snd_usb_endpoint_get_clock_rate(struct snd_usb_audio *chip, int clock) { struct snd_usb_clock_ref *ref; int rate = 0; if (!clock) return 0; mutex_lock(&chip->mutex); list_for_each_entry(ref, &chip->clock_ref_list, list) { if (ref->clock == clock) { rate = ref->rate; break; } } mutex_unlock(&chip->mutex); return rate; } /** * snd_usb_endpoint_start: start an snd_usb_endpoint * * @ep: the endpoint to start * * A call to this function will increment the running count of the endpoint. * In case it is not already running, the URBs for this endpoint will be * submitted. Otherwise, this function does nothing. * * Must be balanced to calls of snd_usb_endpoint_stop(). * * Returns an error if the URB submission failed, 0 in all other cases. */ int snd_usb_endpoint_start(struct snd_usb_endpoint *ep) { bool is_playback = usb_pipeout(ep->pipe); int err; unsigned int i; if (atomic_read(&ep->chip->shutdown)) return -EBADFD; if (ep->sync_source) WRITE_ONCE(ep->sync_source->sync_sink, ep); usb_audio_dbg(ep->chip, "Starting %s EP 0x%x (running %d)\n", ep_type_name(ep->type), ep->ep_num, atomic_read(&ep->running)); /* already running? */ if (atomic_inc_return(&ep->running) != 1) return 0; if (ep->clock_ref) atomic_inc(&ep->clock_ref->locked); ep->active_mask = 0; ep->unlink_mask = 0; ep->phase = 0; ep->sample_accum = 0; snd_usb_endpoint_start_quirk(ep); /* * If this endpoint has a data endpoint as implicit feedback source, * don't start the urbs here. Instead, mark them all as available, * wait for the record urbs to return and queue the playback urbs * from that context. */ if (!ep_state_update(ep, EP_STATE_STOPPED, EP_STATE_RUNNING)) goto __error; if (snd_usb_endpoint_implicit_feedback_sink(ep) && !(ep->chip->quirk_flags & QUIRK_FLAG_PLAYBACK_FIRST)) { usb_audio_dbg(ep->chip, "No URB submission due to implicit fb sync\n"); i = 0; goto fill_rest; } for (i = 0; i < ep->nurbs; i++) { struct urb *urb = ep->urb[i].urb; if (snd_BUG_ON(!urb)) goto __error; if (is_playback) err = prepare_outbound_urb(ep, urb->context, true); else err = prepare_inbound_urb(ep, urb->context); if (err < 0) { /* stop filling at applptr */ if (err == -EAGAIN) break; usb_audio_dbg(ep->chip, "EP 0x%x: failed to prepare urb: %d\n", ep->ep_num, err); goto __error; } if (!atomic_read(&ep->chip->shutdown)) err = usb_submit_urb(urb, GFP_ATOMIC); else err = -ENODEV; if (err < 0) { if (!atomic_read(&ep->chip->shutdown)) usb_audio_err(ep->chip, "cannot submit urb %d, error %d: %s\n", i, err, usb_error_string(err)); goto __error; } set_bit(i, &ep->active_mask); atomic_inc(&ep->submitted_urbs); } if (!i) { usb_audio_dbg(ep->chip, "XRUN at starting EP 0x%x\n", ep->ep_num); goto __error; } usb_audio_dbg(ep->chip, "%d URBs submitted for EP 0x%x\n", i, ep->ep_num); fill_rest: /* put the remaining URBs to ready list */ if (is_playback) { for (; i < ep->nurbs; i++) push_back_to_ready_list(ep, ep->urb + i); } return 0; __error: snd_usb_endpoint_stop(ep, false); return -EPIPE; } /** * snd_usb_endpoint_stop: stop an snd_usb_endpoint * * @ep: the endpoint to stop (may be NULL) * @keep_pending: keep in-flight URBs * * A call to this function will decrement the running count of the endpoint. * In case the last user has requested the endpoint stop, the URBs will * actually be deactivated. * * Must be balanced to calls of snd_usb_endpoint_start(). * * The caller needs to synchronize the pending stop operation via * snd_usb_endpoint_sync_pending_stop(). */ void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep, bool keep_pending) { if (!ep) return; usb_audio_dbg(ep->chip, "Stopping %s EP 0x%x (running %d)\n", ep_type_name(ep->type), ep->ep_num, atomic_read(&ep->running)); if (snd_BUG_ON(!atomic_read(&ep->running))) return; if (!atomic_dec_return(&ep->running)) { if (ep->sync_source) WRITE_ONCE(ep->sync_source->sync_sink, NULL); stop_urbs(ep, false, keep_pending); if (ep->clock_ref) atomic_dec(&ep->clock_ref->locked); if (ep->chip->quirk_flags & QUIRK_FLAG_FORCE_IFACE_RESET && usb_pipeout(ep->pipe)) { ep->need_prepare = true; if (ep->iface_ref) ep->iface_ref->need_setup = true; } } } /** * snd_usb_endpoint_release: Tear down an snd_usb_endpoint * * @ep: the endpoint to release * * This function does not care for the endpoint's running count but will tear * down all the streaming URBs immediately. */ void snd_usb_endpoint_release(struct snd_usb_endpoint *ep) { release_urbs(ep, true); } /** * snd_usb_endpoint_free_all: Free the resources of an snd_usb_endpoint * @chip: The chip * * This free all endpoints and those resources */ void snd_usb_endpoint_free_all(struct snd_usb_audio *chip) { struct snd_usb_endpoint *ep, *en; struct snd_usb_iface_ref *ip, *in; struct snd_usb_clock_ref *cp, *cn; list_for_each_entry_safe(ep, en, &chip->ep_list, list) kfree(ep); list_for_each_entry_safe(ip, in, &chip->iface_ref_list, list) kfree(ip); list_for_each_entry_safe(cp, cn, &chip->clock_ref_list, list) kfree(cp); } /* * snd_usb_handle_sync_urb: parse an USB sync packet * * @ep: the endpoint to handle the packet * @sender: the sending endpoint * @urb: the received packet * * This function is called from the context of an endpoint that received * the packet and is used to let another endpoint object handle the payload. */ static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep, struct snd_usb_endpoint *sender, const struct urb *urb) { int shift; unsigned int f; unsigned long flags; snd_BUG_ON(ep == sender); /* * In case the endpoint is operating in implicit feedback mode, prepare * a new outbound URB that has the same layout as the received packet * and add it to the list of pending urbs. queue_pending_output_urbs() * will take care of them later. */ if (snd_usb_endpoint_implicit_feedback_sink(ep) && atomic_read(&ep->running)) { /* implicit feedback case */ int i, bytes = 0; struct snd_urb_ctx *in_ctx; struct snd_usb_packet_info *out_packet; in_ctx = urb->context; /* Count overall packet size */ for (i = 0; i < in_ctx->packets; i++) if (urb->iso_frame_desc[i].status == 0) bytes += urb->iso_frame_desc[i].actual_length; /* * skip empty packets. At least M-Audio's Fast Track Ultra stops * streaming once it received a 0-byte OUT URB */ if (bytes == 0) return; spin_lock_irqsave(&ep->lock, flags); if (ep->next_packet_queued >= ARRAY_SIZE(ep->next_packet)) { spin_unlock_irqrestore(&ep->lock, flags); usb_audio_err(ep->chip, "next package FIFO overflow EP 0x%x\n", ep->ep_num); notify_xrun(ep); return; } out_packet = next_packet_fifo_enqueue(ep); /* * Iterate through the inbound packet and prepare the lengths * for the output packet. The OUT packet we are about to send * will have the same amount of payload bytes per stride as the * IN packet we just received. Since the actual size is scaled * by the stride, use the sender stride to calculate the length * in case the number of channels differ between the implicitly * fed-back endpoint and the synchronizing endpoint. */ out_packet->packets = in_ctx->packets; for (i = 0; i < in_ctx->packets; i++) { if (urb->iso_frame_desc[i].status == 0) out_packet->packet_size[i] = urb->iso_frame_desc[i].actual_length / sender->stride; else out_packet->packet_size[i] = 0; } spin_unlock_irqrestore(&ep->lock, flags); snd_usb_queue_pending_output_urbs(ep, false); return; } /* * process after playback sync complete * * Full speed devices report feedback values in 10.14 format as samples * per frame, high speed devices in 16.16 format as samples per * microframe. * * Because the Audio Class 1 spec was written before USB 2.0, many high * speed devices use a wrong interpretation, some others use an * entirely different format. * * Therefore, we cannot predict what format any particular device uses * and must detect it automatically. */ if (urb->iso_frame_desc[0].status != 0 || urb->iso_frame_desc[0].actual_length < 3) return; f = le32_to_cpup(urb->transfer_buffer); if (urb->iso_frame_desc[0].actual_length == 3) f &= 0x00ffffff; else f &= 0x0fffffff; if (f == 0) return; if (unlikely(sender->tenor_fb_quirk)) { /* * Devices based on Tenor 8802 chipsets (TEAC UD-H01 * and others) sometimes change the feedback value * by +/- 0x1.0000. */ if (f < ep->freqn - 0x8000) f += 0xf000; else if (f > ep->freqn + 0x8000) f -= 0xf000; } else if (unlikely(ep->freqshift == INT_MIN)) { /* * The first time we see a feedback value, determine its format * by shifting it left or right until it matches the nominal * frequency value. This assumes that the feedback does not * differ from the nominal value more than +50% or -25%. */ shift = 0; while (f < ep->freqn - ep->freqn / 4) { f <<= 1; shift++; } while (f > ep->freqn + ep->freqn / 2) { f >>= 1; shift--; } ep->freqshift = shift; } else if (ep->freqshift >= 0) f <<= ep->freqshift; else f >>= -ep->freqshift; if (likely(f >= ep->freqn - ep->freqn / 8 && f <= ep->freqmax)) { /* * If the frequency looks valid, set it. * This value is referred to in prepare_playback_urb(). */ spin_lock_irqsave(&ep->lock, flags); ep->freqm = f; spin_unlock_irqrestore(&ep->lock, flags); } else { /* * Out of range; maybe the shift value is wrong. * Reset it so that we autodetect again the next time. */ ep->freqshift = INT_MIN; } }