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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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#include <linux/gfp.h>
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#include <linux/init.h>
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#include <linux/ratelimit.h>
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#include <linux/usb.h>
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#include <linux/usb/audio.h>
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#include <linux/slab.h>
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#include <sound/core.h>
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#include <sound/pcm.h>
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#include <sound/pcm_params.h>
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#define EP_FLAG_RUNNING 1
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#define EP_FLAG_STOPPING 2
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* snd_usb_endpoint is a model that abstracts everything related to an
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* USB endpoint and its streaming.
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* There are functions to activate and deactivate the streaming URBs and
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* optional callbacks to let the pcm logic handle the actual content of the
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* packets for playback and record. Thus, the bus streaming and the audio
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* handlers are fully decoupled.
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* There are two different types of endpoints in audio applications.
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* SND_USB_ENDPOINT_TYPE_DATA handles full audio data payload for both
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* inbound and outbound traffic.
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* SND_USB_ENDPOINT_TYPE_SYNC endpoints are for inbound traffic only and
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* expect the payload to carry Q10.14 / Q16.16 formatted sync information
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* Each endpoint has to be configured prior to being used by calling
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* snd_usb_endpoint_set_params().
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* The model incorporates a reference counting, so that multiple users
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* can call snd_usb_endpoint_start() and snd_usb_endpoint_stop(), and
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* only the first user will effectively start the URBs, and only the last
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* one to stop it will tear the URBs down again.
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* convert a sampling rate into our full speed format (fs/1000 in Q16.16)
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* this will overflow at approx 524 kHz
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static inline unsigned get_usb_full_speed_rate(unsigned int rate)
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return ((rate << 13) + 62) / 125;
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* convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
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* this will overflow at approx 4 MHz
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static inline unsigned get_usb_high_speed_rate(unsigned int rate)
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return ((rate << 10) + 62) / 125;
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static void release_urb_ctx(struct snd_urb_ctx *u)
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usb_free_coherent(u->ep->chip->dev, u->buffer_size,
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u->urb->transfer_buffer,
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u->urb->transfer_dma);
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static const char *usb_error_string(int err)
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return "endpoint not enabled";
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return "endpoint stalled";
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return "not enough bandwidth";
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return "device disabled";
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return "device suspended";
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return "internal error";
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return "unknown error";
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* snd_usb_endpoint_implicit_feedback_sink: Report endpoint usage type
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* @ep: The snd_usb_endpoint
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* Determine whether an endpoint is driven by an implicit feedback
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* data endpoint source.
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int snd_usb_endpoint_implicit_feedback_sink(struct snd_usb_endpoint *ep)
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return ep->sync_master &&
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ep->sync_master->type == SND_USB_ENDPOINT_TYPE_DATA &&
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ep->type == SND_USB_ENDPOINT_TYPE_DATA &&
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usb_pipeout(ep->pipe);
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* For streaming based on information derived from sync endpoints,
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* prepare_outbound_urb_sizes() will call next_packet_size() to
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* determine the number of samples to be sent in the next packet.
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* For implicit feedback, next_packet_size() is unused.
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int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep)
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return ep->maxframesize;
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spin_lock_irqsave(&ep->lock, flags);
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ep->phase = (ep->phase & 0xffff)
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+ (ep->freqm << ep->datainterval);
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ret = min(ep->phase >> 16, ep->maxframesize);
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spin_unlock_irqrestore(&ep->lock, flags);
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static void retire_outbound_urb(struct snd_usb_endpoint *ep,
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struct snd_urb_ctx *urb_ctx)
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if (ep->retire_data_urb)
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ep->retire_data_urb(ep->data_subs, urb_ctx->urb);
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static void retire_inbound_urb(struct snd_usb_endpoint *ep,
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struct snd_urb_ctx *urb_ctx)
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struct urb *urb = urb_ctx->urb;
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if (unlikely(ep->skip_packets > 0)) {
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snd_usb_handle_sync_urb(ep->sync_slave, ep, urb);
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if (ep->retire_data_urb)
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ep->retire_data_urb(ep->data_subs, urb);
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static void prepare_silent_urb(struct snd_usb_endpoint *ep,
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struct snd_urb_ctx *ctx)
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struct urb *urb = ctx->urb;
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unsigned int offs = 0;
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unsigned int extra = 0;
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__le32 packet_length;
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/* For tx_length_quirk, put packet length at start of packet */
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if (ep->chip->tx_length_quirk)
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extra = sizeof(packet_length);
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for (i = 0; i < ctx->packets; ++i) {
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if (ctx->packet_size[i])
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counts = ctx->packet_size[i];
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counts = snd_usb_endpoint_next_packet_size(ep);
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length = counts * ep->stride; /* number of silent bytes */
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offset = offs * ep->stride + extra * i;
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urb->iso_frame_desc[i].offset = offset;
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urb->iso_frame_desc[i].length = length + extra;
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packet_length = cpu_to_le32(length);
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memcpy(urb->transfer_buffer + offset,
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&packet_length, sizeof(packet_length));
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memset(urb->transfer_buffer + offset + extra,
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ep->silence_value, length);
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urb->number_of_packets = ctx->packets;
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urb->transfer_buffer_length = offs * ep->stride + ctx->packets * extra;
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* Prepare a PLAYBACK urb for submission to the bus.
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static void prepare_outbound_urb(struct snd_usb_endpoint *ep,
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struct snd_urb_ctx *ctx)
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struct urb *urb = ctx->urb;
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unsigned char *cp = urb->transfer_buffer;
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urb->dev = ep->chip->dev; /* we need to set this at each time */
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case SND_USB_ENDPOINT_TYPE_DATA:
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if (ep->prepare_data_urb) {
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ep->prepare_data_urb(ep->data_subs, urb);
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/* no data provider, so send silence */
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prepare_silent_urb(ep, ctx);
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case SND_USB_ENDPOINT_TYPE_SYNC:
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if (snd_usb_get_speed(ep->chip->dev) >= USB_SPEED_HIGH) {
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* fill the length and offset of each urb descriptor.
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* the fixed 12.13 frequency is passed as 16.16 through the pipe.
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urb->iso_frame_desc[0].length = 4;
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urb->iso_frame_desc[0].offset = 0;
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cp[1] = ep->freqn >> 8;
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cp[2] = ep->freqn >> 16;
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cp[3] = ep->freqn >> 24;
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* fill the length and offset of each urb descriptor.
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* the fixed 10.14 frequency is passed through the pipe.
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urb->iso_frame_desc[0].length = 3;
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urb->iso_frame_desc[0].offset = 0;
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cp[0] = ep->freqn >> 2;
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cp[1] = ep->freqn >> 10;
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cp[2] = ep->freqn >> 18;
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* Prepare a CAPTURE or SYNC urb for submission to the bus.
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static inline void prepare_inbound_urb(struct snd_usb_endpoint *ep,
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struct snd_urb_ctx *urb_ctx)
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struct urb *urb = urb_ctx->urb;
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urb->dev = ep->chip->dev; /* we need to set this at each time */
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case SND_USB_ENDPOINT_TYPE_DATA:
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for (i = 0; i < urb_ctx->packets; i++) {
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urb->iso_frame_desc[i].offset = offs;
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urb->iso_frame_desc[i].length = ep->curpacksize;
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offs += ep->curpacksize;
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urb->transfer_buffer_length = offs;
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urb->number_of_packets = urb_ctx->packets;
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case SND_USB_ENDPOINT_TYPE_SYNC:
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urb->iso_frame_desc[0].length = min(4u, ep->syncmaxsize);
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urb->iso_frame_desc[0].offset = 0;
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* Send output urbs that have been prepared previously. URBs are dequeued
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* from ep->ready_playback_urbs and in case there there aren't any available
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* or there are no packets that have been prepared, this function does
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* The reason why the functionality of sending and preparing URBs is separated
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* is that host controllers don't guarantee the order in which they return
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* inbound and outbound packets to their submitters.
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* This function is only used for implicit feedback endpoints. For endpoints
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* driven by dedicated sync endpoints, URBs are immediately re-submitted
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* from their completion handler.
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static void queue_pending_output_urbs(struct snd_usb_endpoint *ep)
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while (test_bit(EP_FLAG_RUNNING, &ep->flags)) {
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struct snd_usb_packet_info *uninitialized_var(packet);
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struct snd_urb_ctx *ctx = NULL;
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spin_lock_irqsave(&ep->lock, flags);
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if (ep->next_packet_read_pos != ep->next_packet_write_pos) {
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packet = ep->next_packet + ep->next_packet_read_pos;
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ep->next_packet_read_pos++;
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ep->next_packet_read_pos %= MAX_URBS;
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/* take URB out of FIFO */
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if (!list_empty(&ep->ready_playback_urbs))
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ctx = list_first_entry(&ep->ready_playback_urbs,
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struct snd_urb_ctx, ready_list);
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spin_unlock_irqrestore(&ep->lock, flags);
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list_del_init(&ctx->ready_list);
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/* copy over the length information */
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for (i = 0; i < packet->packets; i++)
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ctx->packet_size[i] = packet->packet_size[i];
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/* call the data handler to fill in playback data */
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prepare_outbound_urb(ep, ctx);
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err = usb_submit_urb(ctx->urb, GFP_ATOMIC);
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usb_audio_err(ep->chip,
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"Unable to submit urb #%d: %d (urb %p)\n",
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ctx->index, err, ctx->urb);
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set_bit(ctx->index, &ep->active_mask);
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* complete callback for urbs
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static void snd_complete_urb(struct urb *urb)
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struct snd_urb_ctx *ctx = urb->context;
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struct snd_usb_endpoint *ep = ctx->ep;
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struct snd_pcm_substream *substream;
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if (unlikely(urb->status == -ENOENT || /* unlinked */
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urb->status == -ENODEV || /* device removed */
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urb->status == -ECONNRESET || /* unlinked */
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urb->status == -ESHUTDOWN)) /* device disabled */
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/* device disconnected */
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if (unlikely(atomic_read(&ep->chip->shutdown)))
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if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
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if (usb_pipeout(ep->pipe)) {
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retire_outbound_urb(ep, ctx);
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/* can be stopped during retire callback */
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if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
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if (snd_usb_endpoint_implicit_feedback_sink(ep)) {
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spin_lock_irqsave(&ep->lock, flags);
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list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
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spin_unlock_irqrestore(&ep->lock, flags);
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queue_pending_output_urbs(ep);
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prepare_outbound_urb(ep, ctx);
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retire_inbound_urb(ep, ctx);
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/* can be stopped during retire callback */
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if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
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prepare_inbound_urb(ep, ctx);
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err = usb_submit_urb(urb, GFP_ATOMIC);
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usb_audio_err(ep->chip, "cannot submit urb (err = %d)\n", err);
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if (ep->data_subs && ep->data_subs->pcm_substream) {
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substream = ep->data_subs->pcm_substream;
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snd_pcm_stop_xrun(substream);
426
clear_bit(ctx->index, &ep->active_mask);
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* snd_usb_add_endpoint: Add an endpoint to an USB audio chip
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* @alts: The USB host interface
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* @ep_num: The number of the endpoint to use
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* @direction: SNDRV_PCM_STREAM_PLAYBACK or SNDRV_PCM_STREAM_CAPTURE
436
* @type: SND_USB_ENDPOINT_TYPE_DATA or SND_USB_ENDPOINT_TYPE_SYNC
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* If the requested endpoint has not been added to the given chip before,
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* a new instance is created. Otherwise, a pointer to the previoulsy
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* created instance is returned. In case of any error, NULL is returned.
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* New endpoints will be added to chip->ep_list and must be freed by
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* calling snd_usb_endpoint_free().
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* For SND_USB_ENDPOINT_TYPE_SYNC, the caller needs to guarantee that
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* bNumEndpoints > 1 beforehand.
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struct snd_usb_endpoint *snd_usb_add_endpoint(struct snd_usb_audio *chip,
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struct usb_host_interface *alts,
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int ep_num, int direction, int type)
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struct snd_usb_endpoint *ep;
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int is_playback = direction == SNDRV_PCM_STREAM_PLAYBACK;
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mutex_lock(&chip->mutex);
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list_for_each_entry(ep, &chip->ep_list, list) {
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if (ep->ep_num == ep_num &&
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ep->iface == alts->desc.bInterfaceNumber &&
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ep->altsetting == alts->desc.bAlternateSetting) {
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usb_audio_dbg(ep->chip,
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"Re-using EP %x in iface %d,%d @%p\n",
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ep_num, ep->iface, ep->altsetting, ep);
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usb_audio_dbg(chip, "Creating new %s %s endpoint #%x\n",
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is_playback ? "playback" : "capture",
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type == SND_USB_ENDPOINT_TYPE_DATA ? "data" : "sync",
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ep = kzalloc(sizeof(*ep), GFP_KERNEL);
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spin_lock_init(&ep->lock);
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ep->iface = alts->desc.bInterfaceNumber;
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ep->altsetting = alts->desc.bAlternateSetting;
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INIT_LIST_HEAD(&ep->ready_playback_urbs);
487
ep_num &= USB_ENDPOINT_NUMBER_MASK;
490
ep->pipe = usb_sndisocpipe(chip->dev, ep_num);
492
ep->pipe = usb_rcvisocpipe(chip->dev, ep_num);
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if (type == SND_USB_ENDPOINT_TYPE_SYNC) {
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if (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
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get_endpoint(alts, 1)->bRefresh >= 1 &&
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get_endpoint(alts, 1)->bRefresh <= 9)
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ep->syncinterval = get_endpoint(alts, 1)->bRefresh;
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else if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL)
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ep->syncinterval = 1;
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else if (get_endpoint(alts, 1)->bInterval >= 1 &&
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get_endpoint(alts, 1)->bInterval <= 16)
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ep->syncinterval = get_endpoint(alts, 1)->bInterval - 1;
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ep->syncinterval = 3;
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ep->syncmaxsize = le16_to_cpu(get_endpoint(alts, 1)->wMaxPacketSize);
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list_add_tail(&ep->list, &chip->ep_list);
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mutex_unlock(&chip->mutex);
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* wait until all urbs are processed.
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static int wait_clear_urbs(struct snd_usb_endpoint *ep)
523
unsigned long end_time = jiffies + msecs_to_jiffies(1000);
527
alive = bitmap_weight(&ep->active_mask, ep->nurbs);
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schedule_timeout_uninterruptible(1);
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} while (time_before(jiffies, end_time));
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usb_audio_err(ep->chip,
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"timeout: still %d active urbs on EP #%x\n",
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clear_bit(EP_FLAG_STOPPING, &ep->flags);
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ep->data_subs = NULL;
541
ep->sync_slave = NULL;
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ep->retire_data_urb = NULL;
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ep->prepare_data_urb = NULL;
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/* sync the pending stop operation;
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* this function itself doesn't trigger the stop operation
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void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep)
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if (ep && test_bit(EP_FLAG_STOPPING, &ep->flags))
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* unlink active urbs.
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static int deactivate_urbs(struct snd_usb_endpoint *ep, bool force)
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if (!force && atomic_read(&ep->chip->shutdown)) /* to be sure... */
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clear_bit(EP_FLAG_RUNNING, &ep->flags);
569
INIT_LIST_HEAD(&ep->ready_playback_urbs);
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ep->next_packet_read_pos = 0;
571
ep->next_packet_write_pos = 0;
573
for (i = 0; i < ep->nurbs; i++) {
574
if (test_bit(i, &ep->active_mask)) {
575
if (!test_and_set_bit(i, &ep->unlink_mask)) {
576
struct urb *u = ep->urb[i].urb;
586
* release an endpoint's urbs
588
static void release_urbs(struct snd_usb_endpoint *ep, int force)
592
/* route incoming urbs to nirvana */
593
ep->retire_data_urb = NULL;
594
ep->prepare_data_urb = NULL;
597
deactivate_urbs(ep, force);
600
for (i = 0; i < ep->nurbs; i++)
601
release_urb_ctx(&ep->urb[i]);
604
usb_free_coherent(ep->chip->dev, SYNC_URBS * 4,
605
ep->syncbuf, ep->sync_dma);
612
* configure a data endpoint
614
static int data_ep_set_params(struct snd_usb_endpoint *ep,
615
snd_pcm_format_t pcm_format,
616
unsigned int channels,
617
unsigned int period_bytes,
618
unsigned int frames_per_period,
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unsigned int periods_per_buffer,
620
struct audioformat *fmt,
621
struct snd_usb_endpoint *sync_ep)
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unsigned int maxsize, minsize, packs_per_ms, max_packs_per_urb;
624
unsigned int max_packs_per_period, urbs_per_period, urb_packs;
625
unsigned int max_urbs, i;
626
int frame_bits = snd_pcm_format_physical_width(pcm_format) * channels;
627
int tx_length_quirk = (ep->chip->tx_length_quirk &&
628
usb_pipeout(ep->pipe));
630
if (pcm_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) {
632
* When operating in DSD DOP mode, the size of a sample frame
633
* in hardware differs from the actual physical format width
634
* because we need to make room for the DOP markers.
636
frame_bits += channels << 3;
639
ep->datainterval = fmt->datainterval;
640
ep->stride = frame_bits >> 3;
642
switch (pcm_format) {
643
case SNDRV_PCM_FORMAT_U8:
644
ep->silence_value = 0x80;
646
case SNDRV_PCM_FORMAT_DSD_U8:
647
case SNDRV_PCM_FORMAT_DSD_U16_LE:
648
case SNDRV_PCM_FORMAT_DSD_U32_LE:
649
case SNDRV_PCM_FORMAT_DSD_U16_BE:
650
case SNDRV_PCM_FORMAT_DSD_U32_BE:
651
ep->silence_value = 0x69;
654
ep->silence_value = 0;
657
/* assume max. frequency is 50% higher than nominal */
658
ep->freqmax = ep->freqn + (ep->freqn >> 1);
659
/* Round up freqmax to nearest integer in order to calculate maximum
660
* packet size, which must represent a whole number of frames.
661
* This is accomplished by adding 0x0.ffff before converting the
662
* Q16.16 format into integer.
663
* In order to accurately calculate the maximum packet size when
664
* the data interval is more than 1 (i.e. ep->datainterval > 0),
665
* multiply by the data interval prior to rounding. For instance,
666
* a freqmax of 41 kHz will result in a max packet size of 6 (5.125)
667
* frames with a data interval of 1, but 11 (10.25) frames with a
668
* data interval of 2.
669
* (ep->freqmax << ep->datainterval overflows at 8.192 MHz for the
670
* maximum datainterval value of 3, at USB full speed, higher for
671
* USB high speed, noting that ep->freqmax is in units of
672
* frames per packet in Q16.16 format.)
674
maxsize = (((ep->freqmax << ep->datainterval) + 0xffff) >> 16) *
677
maxsize += sizeof(__le32); /* Space for length descriptor */
678
/* but wMaxPacketSize might reduce this */
679
if (ep->maxpacksize && ep->maxpacksize < maxsize) {
680
/* whatever fits into a max. size packet */
681
unsigned int data_maxsize = maxsize = ep->maxpacksize;
684
/* Need to remove the length descriptor to calc freq */
685
data_maxsize -= sizeof(__le32);
686
ep->freqmax = (data_maxsize / (frame_bits >> 3))
687
<< (16 - ep->datainterval);
691
ep->curpacksize = ep->maxpacksize;
693
ep->curpacksize = maxsize;
695
if (snd_usb_get_speed(ep->chip->dev) != USB_SPEED_FULL) {
696
packs_per_ms = 8 >> ep->datainterval;
697
max_packs_per_urb = MAX_PACKS_HS;
700
max_packs_per_urb = MAX_PACKS;
702
if (sync_ep && !snd_usb_endpoint_implicit_feedback_sink(ep))
703
max_packs_per_urb = min(max_packs_per_urb,
704
1U << sync_ep->syncinterval);
705
max_packs_per_urb = max(1u, max_packs_per_urb >> ep->datainterval);
708
* Capture endpoints need to use small URBs because there's no way
709
* to tell in advance where the next period will end, and we don't
710
* want the next URB to complete much after the period ends.
712
* Playback endpoints with implicit sync much use the same parameters
713
* as their corresponding capture endpoint.
715
if (usb_pipein(ep->pipe) ||
716
snd_usb_endpoint_implicit_feedback_sink(ep)) {
718
urb_packs = packs_per_ms;
720
* Wireless devices can poll at a max rate of once per 4ms.
721
* For dataintervals less than 5, increase the packet count to
722
* allow the host controller to use bursting to fill in the
725
if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_WIRELESS) {
726
int interval = ep->datainterval;
727
while (interval < 5) {
732
/* make capture URBs <= 1 ms and smaller than a period */
733
urb_packs = min(max_packs_per_urb, urb_packs);
734
while (urb_packs > 1 && urb_packs * maxsize >= period_bytes)
736
ep->nurbs = MAX_URBS;
739
* Playback endpoints without implicit sync are adjusted so that
740
* a period fits as evenly as possible in the smallest number of
741
* URBs. The total number of URBs is adjusted to the size of the
742
* ALSA buffer, subject to the MAX_URBS and MAX_QUEUE limits.
745
/* determine how small a packet can be */
746
minsize = (ep->freqn >> (16 - ep->datainterval)) *
748
/* with sync from device, assume it can be 12% lower */
750
minsize -= minsize >> 3;
751
minsize = max(minsize, 1u);
753
/* how many packets will contain an entire ALSA period? */
754
max_packs_per_period = DIV_ROUND_UP(period_bytes, minsize);
756
/* how many URBs will contain a period? */
757
urbs_per_period = DIV_ROUND_UP(max_packs_per_period,
759
/* how many packets are needed in each URB? */
760
urb_packs = DIV_ROUND_UP(max_packs_per_period, urbs_per_period);
762
/* limit the number of frames in a single URB */
763
ep->max_urb_frames = DIV_ROUND_UP(frames_per_period,
766
/* try to use enough URBs to contain an entire ALSA buffer */
767
max_urbs = min((unsigned) MAX_URBS,
768
MAX_QUEUE * packs_per_ms / urb_packs);
769
ep->nurbs = min(max_urbs, urbs_per_period * periods_per_buffer);
772
/* allocate and initialize data urbs */
773
for (i = 0; i < ep->nurbs; i++) {
774
struct snd_urb_ctx *u = &ep->urb[i];
777
u->packets = urb_packs;
778
u->buffer_size = maxsize * u->packets;
780
if (fmt->fmt_type == UAC_FORMAT_TYPE_II)
781
u->packets++; /* for transfer delimiter */
782
u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
786
u->urb->transfer_buffer =
787
usb_alloc_coherent(ep->chip->dev, u->buffer_size,
788
GFP_KERNEL, &u->urb->transfer_dma);
789
if (!u->urb->transfer_buffer)
791
u->urb->pipe = ep->pipe;
792
u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
793
u->urb->interval = 1 << ep->datainterval;
795
u->urb->complete = snd_complete_urb;
796
INIT_LIST_HEAD(&u->ready_list);
807
* configure a sync endpoint
809
static int sync_ep_set_params(struct snd_usb_endpoint *ep)
813
ep->syncbuf = usb_alloc_coherent(ep->chip->dev, SYNC_URBS * 4,
814
GFP_KERNEL, &ep->sync_dma);
818
for (i = 0; i < SYNC_URBS; i++) {
819
struct snd_urb_ctx *u = &ep->urb[i];
823
u->urb = usb_alloc_urb(1, GFP_KERNEL);
826
u->urb->transfer_buffer = ep->syncbuf + i * 4;
827
u->urb->transfer_dma = ep->sync_dma + i * 4;
828
u->urb->transfer_buffer_length = 4;
829
u->urb->pipe = ep->pipe;
830
u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
831
u->urb->number_of_packets = 1;
832
u->urb->interval = 1 << ep->syncinterval;
834
u->urb->complete = snd_complete_urb;
837
ep->nurbs = SYNC_URBS;
847
* snd_usb_endpoint_set_params: configure an snd_usb_endpoint
849
* @ep: the snd_usb_endpoint to configure
850
* @pcm_format: the audio fomat.
851
* @channels: the number of audio channels.
852
* @period_bytes: the number of bytes in one alsa period.
853
* @period_frames: the number of frames in one alsa period.
854
* @buffer_periods: the number of periods in one alsa buffer.
855
* @rate: the frame rate.
856
* @fmt: the USB audio format information
857
* @sync_ep: the sync endpoint to use, if any
859
* Determine the number of URBs to be used on this endpoint.
860
* An endpoint must be configured before it can be started.
861
* An endpoint that is already running can not be reconfigured.
863
int snd_usb_endpoint_set_params(struct snd_usb_endpoint *ep,
864
snd_pcm_format_t pcm_format,
865
unsigned int channels,
866
unsigned int period_bytes,
867
unsigned int period_frames,
868
unsigned int buffer_periods,
870
struct audioformat *fmt,
871
struct snd_usb_endpoint *sync_ep)
875
if (ep->use_count != 0) {
876
usb_audio_warn(ep->chip,
877
"Unable to change format on ep #%x: already in use\n",
882
/* release old buffers, if any */
885
ep->datainterval = fmt->datainterval;
886
ep->maxpacksize = fmt->maxpacksize;
887
ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX);
889
if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_FULL)
890
ep->freqn = get_usb_full_speed_rate(rate);
892
ep->freqn = get_usb_high_speed_rate(rate);
894
/* calculate the frequency in 16.16 format */
895
ep->freqm = ep->freqn;
896
ep->freqshift = INT_MIN;
901
case SND_USB_ENDPOINT_TYPE_DATA:
902
err = data_ep_set_params(ep, pcm_format, channels,
903
period_bytes, period_frames,
904
buffer_periods, fmt, sync_ep);
906
case SND_USB_ENDPOINT_TYPE_SYNC:
907
err = sync_ep_set_params(ep);
913
usb_audio_dbg(ep->chip,
914
"Setting params for ep #%x (type %d, %d urbs), ret=%d\n",
915
ep->ep_num, ep->type, ep->nurbs, err);
921
* snd_usb_endpoint_start: start an snd_usb_endpoint
923
* @ep: the endpoint to start
925
* A call to this function will increment the use count of the endpoint.
926
* In case it is not already running, the URBs for this endpoint will be
927
* submitted. Otherwise, this function does nothing.
929
* Must be balanced to calls of snd_usb_endpoint_stop().
931
* Returns an error if the URB submission failed, 0 in all other cases.
933
int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
938
if (atomic_read(&ep->chip->shutdown))
941
/* already running? */
942
if (++ep->use_count != 1)
945
/* just to be sure */
946
deactivate_urbs(ep, false);
952
snd_usb_endpoint_start_quirk(ep);
955
* If this endpoint has a data endpoint as implicit feedback source,
956
* don't start the urbs here. Instead, mark them all as available,
957
* wait for the record urbs to return and queue the playback urbs
961
set_bit(EP_FLAG_RUNNING, &ep->flags);
963
if (snd_usb_endpoint_implicit_feedback_sink(ep)) {
964
for (i = 0; i < ep->nurbs; i++) {
965
struct snd_urb_ctx *ctx = ep->urb + i;
966
list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
972
for (i = 0; i < ep->nurbs; i++) {
973
struct urb *urb = ep->urb[i].urb;
975
if (snd_BUG_ON(!urb))
978
if (usb_pipeout(ep->pipe)) {
979
prepare_outbound_urb(ep, urb->context);
981
prepare_inbound_urb(ep, urb->context);
984
err = usb_submit_urb(urb, GFP_ATOMIC);
986
usb_audio_err(ep->chip,
987
"cannot submit urb %d, error %d: %s\n",
988
i, err, usb_error_string(err));
991
set_bit(i, &ep->active_mask);
997
clear_bit(EP_FLAG_RUNNING, &ep->flags);
999
deactivate_urbs(ep, false);
1004
* snd_usb_endpoint_stop: stop an snd_usb_endpoint
1006
* @ep: the endpoint to stop (may be NULL)
1008
* A call to this function will decrement the use count of the endpoint.
1009
* In case the last user has requested the endpoint stop, the URBs will
1010
* actually be deactivated.
1012
* Must be balanced to calls of snd_usb_endpoint_start().
1014
* The caller needs to synchronize the pending stop operation via
1015
* snd_usb_endpoint_sync_pending_stop().
1017
void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep)
1022
if (snd_BUG_ON(ep->use_count == 0))
1025
if (--ep->use_count == 0) {
1026
deactivate_urbs(ep, false);
1027
set_bit(EP_FLAG_STOPPING, &ep->flags);
1032
* snd_usb_endpoint_deactivate: deactivate an snd_usb_endpoint
1034
* @ep: the endpoint to deactivate
1036
* If the endpoint is not currently in use, this functions will
1037
* deactivate its associated URBs.
1039
* In case of any active users, this functions does nothing.
1041
void snd_usb_endpoint_deactivate(struct snd_usb_endpoint *ep)
1046
if (ep->use_count != 0)
1049
deactivate_urbs(ep, true);
1050
wait_clear_urbs(ep);
1054
* snd_usb_endpoint_release: Tear down an snd_usb_endpoint
1056
* @ep: the endpoint to release
1058
* This function does not care for the endpoint's use count but will tear
1059
* down all the streaming URBs immediately.
1061
void snd_usb_endpoint_release(struct snd_usb_endpoint *ep)
1063
release_urbs(ep, 1);
1067
* snd_usb_endpoint_free: Free the resources of an snd_usb_endpoint
1069
* @ep: the endpoint to free
1071
* This free all resources of the given ep.
1073
void snd_usb_endpoint_free(struct snd_usb_endpoint *ep)
1079
* snd_usb_handle_sync_urb: parse an USB sync packet
1081
* @ep: the endpoint to handle the packet
1082
* @sender: the sending endpoint
1083
* @urb: the received packet
1085
* This function is called from the context of an endpoint that received
1086
* the packet and is used to let another endpoint object handle the payload.
1088
void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
1089
struct snd_usb_endpoint *sender,
1090
const struct urb *urb)
1094
unsigned long flags;
1096
snd_BUG_ON(ep == sender);
1099
* In case the endpoint is operating in implicit feedback mode, prepare
1100
* a new outbound URB that has the same layout as the received packet
1101
* and add it to the list of pending urbs. queue_pending_output_urbs()
1102
* will take care of them later.
1104
if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1105
ep->use_count != 0) {
1107
/* implicit feedback case */
1109
struct snd_urb_ctx *in_ctx;
1110
struct snd_usb_packet_info *out_packet;
1112
in_ctx = urb->context;
1114
/* Count overall packet size */
1115
for (i = 0; i < in_ctx->packets; i++)
1116
if (urb->iso_frame_desc[i].status == 0)
1117
bytes += urb->iso_frame_desc[i].actual_length;
1120
* skip empty packets. At least M-Audio's Fast Track Ultra stops
1121
* streaming once it received a 0-byte OUT URB
1126
spin_lock_irqsave(&ep->lock, flags);
1127
out_packet = ep->next_packet + ep->next_packet_write_pos;
1130
* Iterate through the inbound packet and prepare the lengths
1131
* for the output packet. The OUT packet we are about to send
1132
* will have the same amount of payload bytes per stride as the
1133
* IN packet we just received. Since the actual size is scaled
1134
* by the stride, use the sender stride to calculate the length
1135
* in case the number of channels differ between the implicitly
1136
* fed-back endpoint and the synchronizing endpoint.
1139
out_packet->packets = in_ctx->packets;
1140
for (i = 0; i < in_ctx->packets; i++) {
1141
if (urb->iso_frame_desc[i].status == 0)
1142
out_packet->packet_size[i] =
1143
urb->iso_frame_desc[i].actual_length / sender->stride;
1145
out_packet->packet_size[i] = 0;
1148
ep->next_packet_write_pos++;
1149
ep->next_packet_write_pos %= MAX_URBS;
1150
spin_unlock_irqrestore(&ep->lock, flags);
1151
queue_pending_output_urbs(ep);
1157
* process after playback sync complete
1159
* Full speed devices report feedback values in 10.14 format as samples
1160
* per frame, high speed devices in 16.16 format as samples per
1163
* Because the Audio Class 1 spec was written before USB 2.0, many high
1164
* speed devices use a wrong interpretation, some others use an
1165
* entirely different format.
1167
* Therefore, we cannot predict what format any particular device uses
1168
* and must detect it automatically.
1171
if (urb->iso_frame_desc[0].status != 0 ||
1172
urb->iso_frame_desc[0].actual_length < 3)
1175
f = le32_to_cpup(urb->transfer_buffer);
1176
if (urb->iso_frame_desc[0].actual_length == 3)
1184
if (unlikely(sender->tenor_fb_quirk)) {
1186
* Devices based on Tenor 8802 chipsets (TEAC UD-H01
1187
* and others) sometimes change the feedback value
1190
if (f < ep->freqn - 0x8000)
1192
else if (f > ep->freqn + 0x8000)
1194
} else if (unlikely(ep->freqshift == INT_MIN)) {
1196
* The first time we see a feedback value, determine its format
1197
* by shifting it left or right until it matches the nominal
1198
* frequency value. This assumes that the feedback does not
1199
* differ from the nominal value more than +50% or -25%.
1202
while (f < ep->freqn - ep->freqn / 4) {
1206
while (f > ep->freqn + ep->freqn / 2) {
1210
ep->freqshift = shift;
1211
} else if (ep->freqshift >= 0)
1212
f <<= ep->freqshift;
1214
f >>= -ep->freqshift;
1216
if (likely(f >= ep->freqn - ep->freqn / 8 && f <= ep->freqmax)) {
1218
* If the frequency looks valid, set it.
1219
* This value is referred to in prepare_playback_urb().
1221
spin_lock_irqsave(&ep->lock, flags);
1223
spin_unlock_irqrestore(&ep->lock, flags);
1226
* Out of range; maybe the shift value is wrong.
1227
* Reset it so that we autodetect again the next time.
1229
ep->freqshift = INT_MIN;