endpoint.c 29.3 KB
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/*
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

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#include <linux/gfp.h>
#include <linux/init.h>
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#include <linux/ratelimit.h>
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#include <linux/usb.h>
#include <linux/usb/audio.h>
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#include <linux/slab.h>
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#include <sound/core.h>
#include <sound/pcm.h>
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#include <sound/pcm_params.h>
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#include "usbaudio.h"
#include "helper.h"
#include "card.h"
#include "endpoint.h"
#include "pcm.h"
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#include "quirks.h"
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#define EP_FLAG_ACTIVATED	0
#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
 * USB endpoint and its streaming.
 *
 * 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
 * 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
 * inbound and outbound traffic.
 *
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 * 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).
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 *
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 * Each endpoint has to be configured prior to being used by calling
 * snd_usb_endpoint_set_params().
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 *
 * 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
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 * one to stop it will tear the URBs down again.
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 */

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/*
 * 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)
{
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	if (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;
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}

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";
	}
}

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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
 * 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 &&
		ep->sync_master->type == SND_USB_ENDPOINT_TYPE_DATA &&
		ep->type == SND_USB_ENDPOINT_TYPE_DATA &&
		usb_pipeout(ep->pipe);
}

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/*
 * For streaming based on information derived from sync endpoints,
 * prepare_outbound_urb_sizes() will call next_packet_size() to
 * determine the number of samples to be sent in the next packet.
 *
 * 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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{
	unsigned long flags;
	int ret;

	if (ep->fill_max)
		return ep->maxframesize;

	spin_lock_irqsave(&ep->lock, flags);
	ep->phase = (ep->phase & 0xffff)
		+ (ep->freqm << ep->datainterval);
	ret = min(ep->phase >> 16, ep->maxframesize);
	spin_unlock_irqrestore(&ep->lock, flags);

	return ret;
}

static void retire_outbound_urb(struct snd_usb_endpoint *ep,
				struct snd_urb_ctx *urb_ctx)
{
	if (ep->retire_data_urb)
		ep->retire_data_urb(ep->data_subs, urb_ctx->urb);
}

static void retire_inbound_urb(struct snd_usb_endpoint *ep,
			       struct snd_urb_ctx *urb_ctx)
{
	struct urb *urb = urb_ctx->urb;

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	if (unlikely(ep->skip_packets > 0)) {
		ep->skip_packets--;
		return;
	}

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	if (ep->sync_slave)
		snd_usb_handle_sync_urb(ep->sync_slave, ep, urb);

	if (ep->retire_data_urb)
		ep->retire_data_urb(ep->data_subs, urb);
}

/*
 * Prepare a PLAYBACK urb for submission to the bus.
 */
static void prepare_outbound_urb(struct snd_usb_endpoint *ep,
				 struct snd_urb_ctx *ctx)
{
	int i;
	struct urb *urb = ctx->urb;
	unsigned char *cp = urb->transfer_buffer;

	urb->dev = ep->chip->dev; /* we need to set this at each time */

	switch (ep->type) {
	case SND_USB_ENDPOINT_TYPE_DATA:
		if (ep->prepare_data_urb) {
			ep->prepare_data_urb(ep->data_subs, urb);
		} else {
			/* no data provider, so send silence */
			unsigned int offs = 0;
			for (i = 0; i < ctx->packets; ++i) {
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				int counts;

				if (ctx->packet_size[i])
					counts = ctx->packet_size[i];
				else
					counts = snd_usb_endpoint_next_packet_size(ep);

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				urb->iso_frame_desc[i].offset = offs * ep->stride;
				urb->iso_frame_desc[i].length = counts * ep->stride;
				offs += counts;
			}

			urb->number_of_packets = ctx->packets;
			urb->transfer_buffer_length = offs * ep->stride;
			memset(urb->transfer_buffer, ep->silence_value,
			       offs * ep->stride);
		}
		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;
	}
}

/*
 * Prepare a CAPTURE or SYNC urb for submission to the bus.
 */
static inline void 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;
	}
}

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/*
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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
 * or there are no packets that have been prepared, this function does
 * nothing.
 *
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 * 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.
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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
 * from their completion handler.
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 */
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static void queue_pending_output_urbs(struct snd_usb_endpoint *ep)
{
	while (test_bit(EP_FLAG_RUNNING, &ep->flags)) {

		unsigned long flags;
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		struct snd_usb_packet_info *uninitialized_var(packet);
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		struct snd_urb_ctx *ctx = NULL;
		struct urb *urb;
		int err, i;

		spin_lock_irqsave(&ep->lock, flags);
		if (ep->next_packet_read_pos != ep->next_packet_write_pos) {
			packet = ep->next_packet + ep->next_packet_read_pos;
			ep->next_packet_read_pos++;
			ep->next_packet_read_pos %= MAX_URBS;

			/* take URB out of FIFO */
			if (!list_empty(&ep->ready_playback_urbs))
				ctx = list_first_entry(&ep->ready_playback_urbs,
					       struct snd_urb_ctx, ready_list);
		}
		spin_unlock_irqrestore(&ep->lock, flags);

		if (ctx == NULL)
			return;

		list_del_init(&ctx->ready_list);
		urb = ctx->urb;

		/* copy over the length information */
		for (i = 0; i < packet->packets; i++)
			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);

		err = usb_submit_urb(ctx->urb, GFP_ATOMIC);
		if (err < 0)
			snd_printk(KERN_ERR "Unable to submit urb #%d: %d (urb %p)\n",
				   ctx->index, err, ctx->urb);
		else
			set_bit(ctx->index, &ep->active_mask);
	}
}

/*
 * 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 */
		     ep->chip->shutdown))		/* device disconnected */
		goto exit_clear;

	if (usb_pipeout(ep->pipe)) {
		retire_outbound_urb(ep, ctx);
		/* can be stopped during retire callback */
		if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
			goto exit_clear;

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		if (snd_usb_endpoint_implicit_feedback_sink(ep)) {
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			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);
			queue_pending_output_urbs(ep);

			goto exit_clear;
		}

		prepare_outbound_urb(ep, ctx);
	} else {
		retire_inbound_urb(ep, ctx);
		/* can be stopped during retire callback */
		if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
			goto exit_clear;

		prepare_inbound_urb(ep, ctx);
	}

	err = usb_submit_urb(urb, GFP_ATOMIC);
	if (err == 0)
		return;

	snd_printk(KERN_ERR "cannot submit urb (err = %d)\n", err);
	//snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);

exit_clear:
	clear_bit(ctx->index, &ep->active_mask);
}

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/**
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 * snd_usb_add_endpoint: Add an endpoint to an USB audio chip
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 *
 * @chip: The chip
 * @alts: The USB host interface
 * @ep_num: The number of the endpoint to use
 * @direction: SNDRV_PCM_STREAM_PLAYBACK or SNDRV_PCM_STREAM_CAPTURE
 * @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. Otherwise, a pointer to the previoulsy
 * created instance is returned. In case of any error, NULL is returned.
 *
 * New endpoints will be added to chip->ep_list and must be freed by
 * calling snd_usb_endpoint_free().
 */
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struct snd_usb_endpoint *snd_usb_add_endpoint(struct snd_usb_audio *chip,
					      struct usb_host_interface *alts,
					      int ep_num, int direction, int type)
{
	struct snd_usb_endpoint *ep;
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	int is_playback = direction == SNDRV_PCM_STREAM_PLAYBACK;
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	if (WARN_ON(!alts))
		return NULL;

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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 &&
		    ep->iface == alts->desc.bInterfaceNumber &&
		    ep->alt_idx == alts->desc.bAlternateSetting) {
			snd_printdd(KERN_DEBUG "Re-using EP %x in iface %d,%d @%p\n",
					ep_num, ep->iface, ep->alt_idx, ep);
			goto __exit_unlock;
		}
	}

	snd_printdd(KERN_DEBUG "Creating new %s %s endpoint #%x\n",
		    is_playback ? "playback" : "capture",
		    type == SND_USB_ENDPOINT_TYPE_DATA ? "data" : "sync",
		    ep_num);

	ep = kzalloc(sizeof(*ep), GFP_KERNEL);
	if (!ep)
		goto __exit_unlock;

	ep->chip = chip;
	spin_lock_init(&ep->lock);
	ep->type = type;
	ep->ep_num = ep_num;
	ep->iface = alts->desc.bInterfaceNumber;
	ep->alt_idx = alts->desc.bAlternateSetting;
	INIT_LIST_HEAD(&ep->ready_playback_urbs);
	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);

	if (type == SND_USB_ENDPOINT_TYPE_SYNC) {
		if (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
		    get_endpoint(alts, 1)->bRefresh >= 1 &&
		    get_endpoint(alts, 1)->bRefresh <= 9)
			ep->syncinterval = get_endpoint(alts, 1)->bRefresh;
		else if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL)
			ep->syncinterval = 1;
		else if (get_endpoint(alts, 1)->bInterval >= 1 &&
			 get_endpoint(alts, 1)->bInterval <= 16)
			ep->syncinterval = get_endpoint(alts, 1)->bInterval - 1;
		else
			ep->syncinterval = 3;

		ep->syncmaxsize = le16_to_cpu(get_endpoint(alts, 1)->wMaxPacketSize);
	}

	list_add_tail(&ep->list, &chip->ep_list);

__exit_unlock:
	mutex_unlock(&chip->mutex);

	return ep;
}

/*
 *  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;

	do {
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		alive = bitmap_weight(&ep->active_mask, ep->nurbs);
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		if (!alive)
			break;

		schedule_timeout_uninterruptible(1);
	} while (time_before(jiffies, end_time));

	if (alive)
		snd_printk(KERN_ERR "timeout: still %d active urbs on EP #%x\n",
					alive, ep->ep_num);
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	clear_bit(EP_FLAG_STOPPING, &ep->flags);
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	return 0;
}

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/* 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 && test_bit(EP_FLAG_STOPPING, &ep->flags))
		wait_clear_urbs(ep);
}

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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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{
	unsigned int i;

	if (!force && ep->chip->shutdown) /* to be sure... */
		return -EBADFD;

	clear_bit(EP_FLAG_RUNNING, &ep->flags);

	INIT_LIST_HEAD(&ep->ready_playback_urbs);
	ep->next_packet_read_pos = 0;
	ep->next_packet_write_pos = 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;
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				usb_unlink_urb(u);
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			}
		}
	}

	return 0;
}

/*
 * release an endpoint's urbs
 */
static void release_urbs(struct snd_usb_endpoint *ep, int force)
{
	int i;

	/* route incoming urbs to nirvana */
	ep->retire_data_urb = NULL;
	ep->prepare_data_urb = NULL;

	/* stop urbs */
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	deactivate_urbs(ep, force);
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	wait_clear_urbs(ep);

	for (i = 0; i < ep->nurbs; i++)
		release_urb_ctx(&ep->urb[i]);

	if (ep->syncbuf)
		usb_free_coherent(ep->chip->dev, SYNC_URBS * 4,
				  ep->syncbuf, ep->sync_dma);

	ep->syncbuf = NULL;
	ep->nurbs = 0;
}

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/*
 * configure a data endpoint
 */
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static int data_ep_set_params(struct snd_usb_endpoint *ep,
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			      snd_pcm_format_t pcm_format,
			      unsigned int channels,
			      unsigned int period_bytes,
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			      struct audioformat *fmt,
			      struct snd_usb_endpoint *sync_ep)
{
	unsigned int maxsize, i, urb_packs, total_packs, packs_per_ms;
	int is_playback = usb_pipeout(ep->pipe);
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	int frame_bits = snd_pcm_format_physical_width(pcm_format) * channels;
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	if (pcm_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 += channels << 3;
	}

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	ep->datainterval = fmt->datainterval;
	ep->stride = frame_bits >> 3;
595
	ep->silence_value = pcm_format == SNDRV_PCM_FORMAT_U8 ? 0x80 : 0;
596

597
598
599
600
601
602
	/* assume max. frequency is 25% higher than nominal */
	ep->freqmax = ep->freqn + (ep->freqn >> 2);
	maxsize = ((ep->freqmax + 0xffff) * (frame_bits >> 3))
				>> (16 - ep->datainterval);
	/* but wMaxPacketSize might reduce this */
	if (ep->maxpacksize && ep->maxpacksize < maxsize) {
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
		/* whatever fits into a max. size packet */
		maxsize = ep->maxpacksize;
		ep->freqmax = (maxsize / (frame_bits >> 3))
				<< (16 - ep->datainterval);
	}

	if (ep->fill_max)
		ep->curpacksize = ep->maxpacksize;
	else
		ep->curpacksize = maxsize;

	if (snd_usb_get_speed(ep->chip->dev) != USB_SPEED_FULL)
		packs_per_ms = 8 >> ep->datainterval;
	else
		packs_per_ms = 1;

619
	if (is_playback && !snd_usb_endpoint_implicit_feedback_sink(ep)) {
620
621
622
623
624
625
626
627
		urb_packs = max(ep->chip->nrpacks, 1);
		urb_packs = min(urb_packs, (unsigned int) MAX_PACKS);
	} else {
		urb_packs = 1;
	}

	urb_packs *= packs_per_ms;

628
	if (sync_ep && !snd_usb_endpoint_implicit_feedback_sink(ep))
629
630
631
		urb_packs = min(urb_packs, 1U << sync_ep->syncinterval);

	/* decide how many packets to be used */
632
	if (is_playback && !snd_usb_endpoint_implicit_feedback_sink(ep)) {
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
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673
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677
678
679
680
681
682
683
684
685
686
687
688
		unsigned int minsize, maxpacks;
		/* 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 (sync_ep)
			minsize -= minsize >> 3;
		minsize = max(minsize, 1u);
		total_packs = (period_bytes + minsize - 1) / minsize;
		/* we need at least two URBs for queueing */
		if (total_packs < 2) {
			total_packs = 2;
		} else {
			/* and we don't want too long a queue either */
			maxpacks = max(MAX_QUEUE * packs_per_ms, urb_packs * 2);
			total_packs = min(total_packs, maxpacks);
		}
	} else {
		while (urb_packs > 1 && urb_packs * maxsize >= period_bytes)
			urb_packs >>= 1;
		total_packs = MAX_URBS * urb_packs;
	}

	ep->nurbs = (total_packs + urb_packs - 1) / urb_packs;
	if (ep->nurbs > MAX_URBS) {
		/* too much... */
		ep->nurbs = MAX_URBS;
		total_packs = MAX_URBS * urb_packs;
	} else if (ep->nurbs < 2) {
		/* too little - we need at least two packets
		 * to ensure contiguous playback/capture
		 */
		ep->nurbs = 2;
	}

	/* 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 = (i + 1) * total_packs / ep->nurbs
			- i * total_packs / ep->nurbs;
		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(ep->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;
689
		u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
690
691
692
693
694
695
696
697
698
699
700
701
702
		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, 0);
	return -ENOMEM;
}

703
704
705
/*
 * configure a sync endpoint
 */
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
static int sync_ep_set_params(struct snd_usb_endpoint *ep,
			      struct audioformat *fmt)
{
	int i;

	ep->syncbuf = usb_alloc_coherent(ep->chip->dev, SYNC_URBS * 4,
					 GFP_KERNEL, &ep->sync_dma);
	if (!ep->syncbuf)
		return -ENOMEM;

	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;
728
		u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
		u->urb->number_of_packets = 1;
		u->urb->interval = 1 << ep->syncinterval;
		u->urb->context = u;
		u->urb->complete = snd_complete_urb;
	}

	ep->nurbs = SYNC_URBS;

	return 0;

out_of_memory:
	release_urbs(ep, 0);
	return -ENOMEM;
}

744
/**
745
 * snd_usb_endpoint_set_params: configure an snd_usb_endpoint
746
 *
747
 * @ep: the snd_usb_endpoint to configure
748
749
750
751
 * @pcm_format: the audio fomat.
 * @channels: the number of audio channels.
 * @period_bytes: the number of bytes in one alsa period.
 * @rate: the frame rate.
752
753
 * @fmt: the USB audio format information
 * @sync_ep: the sync endpoint to use, if any
754
 *
755
 * Determine the number of URBs to be used on this endpoint.
756
757
758
 * An endpoint must be configured before it can be started.
 * An endpoint that is already running can not be reconfigured.
 */
759
int snd_usb_endpoint_set_params(struct snd_usb_endpoint *ep,
760
761
762
763
				snd_pcm_format_t pcm_format,
				unsigned int channels,
				unsigned int period_bytes,
				unsigned int rate,
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
				struct audioformat *fmt,
				struct snd_usb_endpoint *sync_ep)
{
	int err;

	if (ep->use_count != 0) {
		snd_printk(KERN_WARNING "Unable to change format on ep #%x: already in use\n",
			   ep->ep_num);
		return -EBUSY;
	}

	/* release old buffers, if any */
	release_urbs(ep, 0);

	ep->datainterval = fmt->datainterval;
	ep->maxpacksize = fmt->maxpacksize;
780
	ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX);
781
782

	if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_FULL)
783
		ep->freqn = get_usb_full_speed_rate(rate);
784
	else
785
		ep->freqn = get_usb_high_speed_rate(rate);
786
787
788
789
790
791
792
793
794

	/* 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:
795
796
		err = data_ep_set_params(ep, pcm_format, channels,
					 period_bytes, fmt, sync_ep);
797
798
		break;
	case  SND_USB_ENDPOINT_TYPE_SYNC:
799
		err = sync_ep_set_params(ep, fmt);
800
801
802
803
804
805
806
807
808
809
810
		break;
	default:
		err = -EINVAL;
	}

	snd_printdd(KERN_DEBUG "Setting params for ep #%x (type %d, %d urbs), ret=%d\n",
		   ep->ep_num, ep->type, ep->nurbs, err);

	return err;
}

811
812
813
/**
 * snd_usb_endpoint_start: start an snd_usb_endpoint
 *
814
815
816
 * @ep:		the endpoint to start
 * @can_sleep:	flag indicating whether the operation is executed in
 * 		non-atomic context
817
818
 *
 * A call to this function will increment the use count of the endpoint.
819
 * In case it is not already running, the URBs for this endpoint will be
820
821
822
823
824
825
 * 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.
 */
826
int snd_usb_endpoint_start(struct snd_usb_endpoint *ep, bool can_sleep)
827
828
829
830
831
832
833
834
835
836
837
{
	int err;
	unsigned int i;

	if (ep->chip->shutdown)
		return -EBADFD;

	/* already running? */
	if (++ep->use_count != 1)
		return 0;

838
	/* just to be sure */
839
	deactivate_urbs(ep, false);
840
841
842
	if (can_sleep)
		wait_clear_urbs(ep);

843
844
845
846
	ep->active_mask = 0;
	ep->unlink_mask = 0;
	ep->phase = 0;

847
848
	snd_usb_endpoint_start_quirk(ep);

849
850
851
	/*
	 * If this endpoint has a data endpoint as implicit feedback source,
	 * don't start the urbs here. Instead, mark them all as available,
852
853
	 * wait for the record urbs to return and queue the playback urbs
	 * from that context.
854
855
856
857
	 */

	set_bit(EP_FLAG_RUNNING, &ep->flags);

858
	if (snd_usb_endpoint_implicit_feedback_sink(ep)) {
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
		for (i = 0; i < ep->nurbs; i++) {
			struct snd_urb_ctx *ctx = ep->urb + i;
			list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
		}

		return 0;
	}

	for (i = 0; i < ep->nurbs; i++) {
		struct urb *urb = ep->urb[i].urb;

		if (snd_BUG_ON(!urb))
			goto __error;

		if (usb_pipeout(ep->pipe)) {
			prepare_outbound_urb(ep, urb->context);
		} else {
			prepare_inbound_urb(ep, urb->context);
		}

		err = usb_submit_urb(urb, GFP_ATOMIC);
		if (err < 0) {
			snd_printk(KERN_ERR "cannot submit urb %d, error %d: %s\n",
				   i, err, usb_error_string(err));
			goto __error;
		}
		set_bit(i, &ep->active_mask);
	}

	return 0;

__error:
	clear_bit(EP_FLAG_RUNNING, &ep->flags);
	ep->use_count--;
893
	deactivate_urbs(ep, false);
894
895
896
	return -EPIPE;
}

897
898
899
900
901
902
903
/**
 * snd_usb_endpoint_stop: stop an snd_usb_endpoint
 *
 * @ep: the endpoint to stop (may be NULL)
 *
 * A call to this function will decrement the use count of the endpoint.
 * In case the last user has requested the endpoint stop, the URBs will
904
 * actually be deactivated.
905
906
 *
 * Must be balanced to calls of snd_usb_endpoint_start().
907
908
909
 *
 * The caller needs to synchronize the pending stop operation via
 * snd_usb_endpoint_sync_pending_stop().
910
 */
911
void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep)
912
913
914
915
916
917
918
919
{
	if (!ep)
		return;

	if (snd_BUG_ON(ep->use_count == 0))
		return;

	if (--ep->use_count == 0) {
920
		deactivate_urbs(ep, false);
921
922
923
924
		ep->data_subs = NULL;
		ep->sync_slave = NULL;
		ep->retire_data_urb = NULL;
		ep->prepare_data_urb = NULL;
925
		set_bit(EP_FLAG_STOPPING, &ep->flags);
926
927
928
	}
}

929
930
931
932
933
934
935
936
937
938
939
940
941
/**
 * snd_usb_endpoint_deactivate: deactivate an snd_usb_endpoint
 *
 * @ep: the endpoint to deactivate
 *
 * If the endpoint is not currently in use, this functions will select the
 * alternate interface setting 0 for the interface of this endpoint.
 *
 * In case of any active users, this functions does nothing.
 *
 * Returns an error if usb_set_interface() failed, 0 in all other
 * cases.
 */
942
943
944
945
946
int snd_usb_endpoint_deactivate(struct snd_usb_endpoint *ep)
{
	if (!ep)
		return -EINVAL;

947
	deactivate_urbs(ep, true);
948
949
	wait_clear_urbs(ep);

950
951
952
	if (ep->use_count != 0)
		return 0;

953
	clear_bit(EP_FLAG_ACTIVATED, &ep->flags);
954

955
	return 0;
956
957
}

958
959
/**
 * snd_usb_endpoint_free: Free the resources of an snd_usb_endpoint
960
961
962
963
964
965
 *
 * @ep: the list header of the endpoint to free
 *
 * This function does not care for the endpoint's use count but will tear
 * down all the streaming URBs immediately and free all resources.
 */
966
967
968
969
970
971
972
973
974
void snd_usb_endpoint_free(struct list_head *head)
{
	struct snd_usb_endpoint *ep;

	ep = list_entry(head, struct snd_usb_endpoint, list);
	release_urbs(ep, 1);
	kfree(ep);
}

975
976
977
978
979
980
981
982
983
/**
 * 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.
984
985
986
987
988
989
990
991
992
993
994
 */
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);

995
996
	/*
	 * In case the endpoint is operating in implicit feedback mode, prepare
997
998
999
	 * 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.
1000
	 */
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