sound/usb/line6/pcm.c - kernel/msm-4.9 - Gitiles

 /*
  * Line6 Linux USB driver - 0.9.1beta
  *
  * Copyright (C) 2004-2010 Markus Grabner (grabner@icg.tugraz.at)
  *
  *	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, version 2.
  *
  */

 #include <linux/slab.h>
 #include <linux/export.h>
 #include <sound/core.h>
 #include <sound/control.h>
 #include <sound/pcm.h>
 #include <sound/pcm_params.h>

 #include "audio.h"
 #include "capture.h"
 #include "driver.h"
 #include "playback.h"

 /* impulse response volume controls */
 static int snd_line6_impulse_volume_info(struct snd_kcontrol *kcontrol,
 					 struct snd_ctl_elem_info *uinfo)
 {
 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 	uinfo->count = 1;
 	uinfo->value.integer.min = 0;
 	uinfo->value.integer.max = 255;
 	return 0;
 }

 static int snd_line6_impulse_volume_get(struct snd_kcontrol *kcontrol,
 					struct snd_ctl_elem_value *ucontrol)
 {
 	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);

 	ucontrol->value.integer.value[0] = line6pcm->impulse_volume;
 	return 0;
 }

 static int snd_line6_impulse_volume_put(struct snd_kcontrol *kcontrol,
 					struct snd_ctl_elem_value *ucontrol)
 {
 	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);
 	int value = ucontrol->value.integer.value[0];

 	if (line6pcm->impulse_volume == value)
 		return 0;

 	line6pcm->impulse_volume = value;
 	if (value > 0)
 		line6_pcm_acquire(line6pcm, LINE6_BITS_PCM_IMPULSE);
 	else
 		line6_pcm_release(line6pcm, LINE6_BITS_PCM_IMPULSE);
 	return 1;
 }

 /* impulse response period controls */
 static int snd_line6_impulse_period_info(struct snd_kcontrol *kcontrol,
 					 struct snd_ctl_elem_info *uinfo)
 {
 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 	uinfo->count = 1;
 	uinfo->value.integer.min = 0;
 	uinfo->value.integer.max = 2000;
 	return 0;
 }

 static int snd_line6_impulse_period_get(struct snd_kcontrol *kcontrol,
 					struct snd_ctl_elem_value *ucontrol)
 {
 	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);

 	ucontrol->value.integer.value[0] = line6pcm->impulse_period;
 	return 0;
 }

 static int snd_line6_impulse_period_put(struct snd_kcontrol *kcontrol,
 					struct snd_ctl_elem_value *ucontrol)
 {
 	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);
 	int value = ucontrol->value.integer.value[0];

 	if (line6pcm->impulse_period == value)
 		return 0;

 	line6pcm->impulse_period = value;
 	return 1;
 }

 static bool test_flags(unsigned long flags0, unsigned long flags1,
 		       unsigned long mask)
 {
 	return ((flags0 & mask) == 0) && ((flags1 & mask) != 0);
 }

 int line6_pcm_acquire(struct snd_line6_pcm *line6pcm, int channels)
 {
 	unsigned long flags_old, flags_new, flags_final;
 	int err;

 	do {
 		flags_old = ACCESS_ONCE(line6pcm->flags);
 		flags_new = flags_old | channels;
 	} while (cmpxchg(&line6pcm->flags, flags_old, flags_new) != flags_old);

 	flags_final = flags_old;

 	line6pcm->prev_fbuf = NULL;

 	if (test_flags(flags_old, flags_new, LINE6_BITS_CAPTURE_BUFFER)) {
 		/* Invoked multiple times in a row so allocate once only */
 		if (!line6pcm->buffer_in) {
 			line6pcm->buffer_in =
 				kmalloc(LINE6_ISO_BUFFERS * LINE6_ISO_PACKETS *
 					line6pcm->max_packet_size, GFP_KERNEL);
 			if (!line6pcm->buffer_in) {
 				err = -ENOMEM;
 				goto pcm_acquire_error;
 			}

 			flags_final |= channels & LINE6_BITS_CAPTURE_BUFFER;
 		}
 	}

 	if (test_flags(flags_old, flags_new, LINE6_BITS_CAPTURE_STREAM)) {
 		/*
 		   Waiting for completion of active URBs in the stop handler is
 		   a bug, we therefore report an error if capturing is restarted
 		   too soon.
 		 */
 		if (line6pcm->active_urb_in | line6pcm->unlink_urb_in) {
 			dev_err(line6pcm->line6->ifcdev, "Device not yet ready\n");
 			return -EBUSY;
 		}

 		line6pcm->count_in = 0;
 		line6pcm->prev_fsize = 0;
 		err = line6_submit_audio_in_all_urbs(line6pcm);

 		if (err < 0)
 			goto pcm_acquire_error;

 		flags_final |= channels & LINE6_BITS_CAPTURE_STREAM;
 	}

 	if (test_flags(flags_old, flags_new, LINE6_BITS_PLAYBACK_BUFFER)) {
 		/* Invoked multiple times in a row so allocate once only */
 		if (!line6pcm->buffer_out) {
 			line6pcm->buffer_out =
 				kmalloc(LINE6_ISO_BUFFERS * LINE6_ISO_PACKETS *
 					line6pcm->max_packet_size, GFP_KERNEL);
 			if (!line6pcm->buffer_out) {
 				err = -ENOMEM;
 				goto pcm_acquire_error;
 			}

 			flags_final |= channels & LINE6_BITS_PLAYBACK_BUFFER;
 		}
 	}

 	if (test_flags(flags_old, flags_new, LINE6_BITS_PLAYBACK_STREAM)) {
 		/*
 		  See comment above regarding PCM restart.
 		*/
 		if (line6pcm->active_urb_out | line6pcm->unlink_urb_out) {
 			dev_err(line6pcm->line6->ifcdev, "Device not yet ready\n");
 			return -EBUSY;
 		}

 		line6pcm->count_out = 0;
 		err = line6_submit_audio_out_all_urbs(line6pcm);

 		if (err < 0)
 			goto pcm_acquire_error;

 		flags_final |= channels & LINE6_BITS_PLAYBACK_STREAM;
 	}

 	return 0;

 pcm_acquire_error:
 	/*
 	   If not all requested resources/streams could be obtained, release
 	   those which were successfully obtained (if any).
 	*/
 	line6_pcm_release(line6pcm, flags_final & channels);
 	return err;
 }
 EXPORT_SYMBOL_GPL(line6_pcm_acquire);

 int line6_pcm_release(struct snd_line6_pcm *line6pcm, int channels)
 {
 	unsigned long flags_old, flags_new;

 	do {
 		flags_old = ACCESS_ONCE(line6pcm->flags);
 		flags_new = flags_old & ~channels;
 	} while (cmpxchg(&line6pcm->flags, flags_old, flags_new) != flags_old);

 	if (test_flags(flags_new, flags_old, LINE6_BITS_CAPTURE_STREAM))
 		line6_unlink_audio_in_urbs(line6pcm);

 	if (test_flags(flags_new, flags_old, LINE6_BITS_CAPTURE_BUFFER)) {
 		line6_wait_clear_audio_in_urbs(line6pcm);
 		line6_free_capture_buffer(line6pcm);
 	}

 	if (test_flags(flags_new, flags_old, LINE6_BITS_PLAYBACK_STREAM))
 		line6_unlink_audio_out_urbs(line6pcm);

 	if (test_flags(flags_new, flags_old, LINE6_BITS_PLAYBACK_BUFFER)) {
 		line6_wait_clear_audio_out_urbs(line6pcm);
 		line6_free_playback_buffer(line6pcm);
 	}

 	return 0;
 }
 EXPORT_SYMBOL_GPL(line6_pcm_release);

 /* trigger callback */
 int snd_line6_trigger(struct snd_pcm_substream *substream, int cmd)
 {
 	struct snd_line6_pcm *line6pcm = snd_pcm_substream_chip(substream);
 	struct snd_pcm_substream *s;
 	int err;
 	unsigned long flags;

 	spin_lock_irqsave(&line6pcm->lock_trigger, flags);
 	clear_bit(LINE6_INDEX_PREPARED, &line6pcm->flags);

 	snd_pcm_group_for_each_entry(s, substream) {
 		if (s->pcm->card != substream->pcm->card)
 			continue;
 		switch (s->stream) {
 		case SNDRV_PCM_STREAM_PLAYBACK:
 			err = snd_line6_playback_trigger(line6pcm, cmd);

 			if (err < 0) {
 				spin_unlock_irqrestore(&line6pcm->lock_trigger,
 						       flags);
 				return err;
 			}

 			break;

 		case SNDRV_PCM_STREAM_CAPTURE:
 			err = snd_line6_capture_trigger(line6pcm, cmd);

 			if (err < 0) {
 				spin_unlock_irqrestore(&line6pcm->lock_trigger,
 						       flags);
 				return err;
 			}

 			break;

 		default:
 			dev_err(line6pcm->line6->ifcdev,
 				"Unknown stream direction %d\n", s->stream);
 		}
 	}

 	spin_unlock_irqrestore(&line6pcm->lock_trigger, flags);
 	return 0;
 }

 /* control info callback */
 static int snd_line6_control_playback_info(struct snd_kcontrol *kcontrol,
 					   struct snd_ctl_elem_info *uinfo)
 {
 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 	uinfo->count = 2;
 	uinfo->value.integer.min = 0;
 	uinfo->value.integer.max = 256;
 	return 0;
 }

 /* control get callback */
 static int snd_line6_control_playback_get(struct snd_kcontrol *kcontrol,
 					  struct snd_ctl_elem_value *ucontrol)
 {
 	int i;
 	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);

 	for (i = 2; i--;)
 		ucontrol->value.integer.value[i] = line6pcm->volume_playback[i];

 	return 0;
 }

 /* control put callback */
 static int snd_line6_control_playback_put(struct snd_kcontrol *kcontrol,
 					  struct snd_ctl_elem_value *ucontrol)
 {
 	int i, changed = 0;
 	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);

 	for (i = 2; i--;)
 		if (line6pcm->volume_playback[i] !=
 		    ucontrol->value.integer.value[i]) {
 			line6pcm->volume_playback[i] =
 			    ucontrol->value.integer.value[i];
 			changed = 1;
 		}

 	return changed;
 }

 /* control definition */
 static struct snd_kcontrol_new line6_controls[] = {
 	{
 		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
 		.name = "PCM Playback Volume",
 		.info = snd_line6_control_playback_info,
 		.get = snd_line6_control_playback_get,
 		.put = snd_line6_control_playback_put
 	},
 	{
 		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
 		.name = "Impulse Response Volume",
 		.info = snd_line6_impulse_volume_info,
 		.get = snd_line6_impulse_volume_get,
 		.put = snd_line6_impulse_volume_put
 	},
 	{
 		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
 		.name = "Impulse Response Period",
 		.info = snd_line6_impulse_period_info,
 		.get = snd_line6_impulse_period_get,
 		.put = snd_line6_impulse_period_put
 	},
 };

 /*
 	Cleanup the PCM device.
 */
 static void line6_cleanup_pcm(struct snd_pcm *pcm)
 {
 	int i;
 	struct snd_line6_pcm *line6pcm = snd_pcm_chip(pcm);

 	for (i = LINE6_ISO_BUFFERS; i--;) {
 		if (line6pcm->urb_audio_out[i]) {
 			usb_kill_urb(line6pcm->urb_audio_out[i]);
 			usb_free_urb(line6pcm->urb_audio_out[i]);
 		}
 		if (line6pcm->urb_audio_in[i]) {
 			usb_kill_urb(line6pcm->urb_audio_in[i]);
 			usb_free_urb(line6pcm->urb_audio_in[i]);
 		}
 	}
 	kfree(line6pcm);
 }

 /* create a PCM device */
 static int snd_line6_new_pcm(struct usb_line6 *line6, struct snd_pcm **pcm_ret)
 {
 	struct snd_pcm *pcm;
 	int err;

 	err = snd_pcm_new(line6->card, (char *)line6->properties->name,
 			  0, 1, 1, pcm_ret);
 	if (err < 0)
 		return err;
 	pcm = *pcm_ret;
 	strcpy(pcm->name, line6->properties->name);

 	/* set operators */
 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK,
 			&snd_line6_playback_ops);
 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &snd_line6_capture_ops);

 	/* pre-allocation of buffers */
 	snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
 					      snd_dma_continuous_data
 					      (GFP_KERNEL), 64 * 1024,
 					      128 * 1024);
 	return 0;
 }

 /*
 	Stop substream if still running.
 */
 static void pcm_disconnect_substream(struct snd_pcm_substream *substream)
 {
 	if (substream->runtime && snd_pcm_running(substream)) {
 		snd_pcm_stream_lock_irq(substream);
 		snd_pcm_stop(substream, SNDRV_PCM_STATE_DISCONNECTED);
 		snd_pcm_stream_unlock_irq(substream);
 	}
 }

 /*
 	Stop PCM stream.
 */
 void line6_pcm_disconnect(struct snd_line6_pcm *line6pcm)
 {
 	pcm_disconnect_substream(get_substream
 				 (line6pcm, SNDRV_PCM_STREAM_CAPTURE));
 	pcm_disconnect_substream(get_substream
 				 (line6pcm, SNDRV_PCM_STREAM_PLAYBACK));
 	line6_unlink_wait_clear_audio_out_urbs(line6pcm);
 	line6_unlink_wait_clear_audio_in_urbs(line6pcm);
 }
 EXPORT_SYMBOL_GPL(line6_pcm_disconnect);

 /*
 	Create and register the PCM device and mixer entries.
 	Create URBs for playback and capture.
 */
 int line6_init_pcm(struct usb_line6 *line6,
 		   struct line6_pcm_properties *properties)
 {
 	int i, err;
 	unsigned ep_read = line6->properties->ep_audio_r;
 	unsigned ep_write = line6->properties->ep_audio_w;
 	struct snd_pcm *pcm;
 	struct snd_line6_pcm *line6pcm;

 	if (!(line6->properties->capabilities & LINE6_CAP_PCM))
 		return 0;	/* skip PCM initialization and report success */

 	err = snd_line6_new_pcm(line6, &pcm);
 	if (err < 0)
 		return err;

 	line6pcm = kzalloc(sizeof(*line6pcm), GFP_KERNEL);
 	if (!line6pcm)
 		return -ENOMEM;

 	line6pcm->pcm = pcm;
 	line6pcm->properties = properties;
 	line6pcm->volume_playback[0] = line6pcm->volume_playback[1] = 255;
 	line6pcm->volume_monitor = 255;
 	line6pcm->line6 = line6;

 	/* Read and write buffers are sized identically, so choose minimum */
 	line6pcm->max_packet_size = min(
 			usb_maxpacket(line6->usbdev,
 				usb_rcvisocpipe(line6->usbdev, ep_read), 0),
 			usb_maxpacket(line6->usbdev,
 				usb_sndisocpipe(line6->usbdev, ep_write), 1));

 	spin_lock_init(&line6pcm->lock_audio_out);
 	spin_lock_init(&line6pcm->lock_audio_in);
 	spin_lock_init(&line6pcm->lock_trigger);
 	line6pcm->impulse_period = LINE6_IMPULSE_DEFAULT_PERIOD;

 	line6->line6pcm = line6pcm;

 	pcm->private_data = line6pcm;
 	pcm->private_free = line6_cleanup_pcm;

 	err = line6_create_audio_out_urbs(line6pcm);
 	if (err < 0)
 		return err;

 	err = line6_create_audio_in_urbs(line6pcm);
 	if (err < 0)
 		return err;

 	/* mixer: */
 	for (i = 0; i < ARRAY_SIZE(line6_controls); i++) {
 		err = snd_ctl_add(line6->card,
 				  snd_ctl_new1(&line6_controls[i], line6pcm));
 		if (err < 0)
 			return err;
 	}

 	return 0;
 }
 EXPORT_SYMBOL_GPL(line6_init_pcm);

 /* prepare pcm callback */
 int snd_line6_prepare(struct snd_pcm_substream *substream)
 {
 	struct snd_line6_pcm *line6pcm = snd_pcm_substream_chip(substream);

 	switch (substream->stream) {
 	case SNDRV_PCM_STREAM_PLAYBACK:
 		if ((line6pcm->flags & LINE6_BITS_PLAYBACK_STREAM) == 0)
 			line6_unlink_wait_clear_audio_out_urbs(line6pcm);

 		break;

 	case SNDRV_PCM_STREAM_CAPTURE:
 		if ((line6pcm->flags & LINE6_BITS_CAPTURE_STREAM) == 0)
 			line6_unlink_wait_clear_audio_in_urbs(line6pcm);

 		break;

 	default:
 		MISSING_CASE;
 	}

 	if (!test_and_set_bit(LINE6_INDEX_PREPARED, &line6pcm->flags)) {
 		line6pcm->count_out = 0;
 		line6pcm->pos_out = 0;
 		line6pcm->pos_out_done = 0;
 		line6pcm->bytes_out = 0;
 		line6pcm->count_in = 0;
 		line6pcm->pos_in_done = 0;
 		line6pcm->bytes_in = 0;
 	}

 	return 0;
 }
	/*
	* Line6 Linux USB driver - 0.9.1beta
	*
	* Copyright (C) 2004-2010 Markus Grabner (grabner@icg.tugraz.at)
	*
	* 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, version 2.
	*
	*/

	#include <linux/slab.h>
	#include <linux/export.h>
	#include <sound/core.h>
	#include <sound/control.h>
	#include <sound/pcm.h>
	#include <sound/pcm_params.h>

	#include "audio.h"
	#include "capture.h"
	#include "driver.h"
	#include "playback.h"

	/* impulse response volume controls */
	static int snd_line6_impulse_volume_info(struct snd_kcontrol *kcontrol,
	struct snd_ctl_elem_info *uinfo)
	{
	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
	uinfo->count = 1;
	uinfo->value.integer.min = 0;
	uinfo->value.integer.max = 255;
	return 0;
	}

	static int snd_line6_impulse_volume_get(struct snd_kcontrol *kcontrol,
	struct snd_ctl_elem_value *ucontrol)
	{
	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);

	ucontrol->value.integer.value[0] = line6pcm->impulse_volume;
	return 0;
	}

	static int snd_line6_impulse_volume_put(struct snd_kcontrol *kcontrol,
	struct snd_ctl_elem_value *ucontrol)
	{
	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);
	int value = ucontrol->value.integer.value[0];

	if (line6pcm->impulse_volume == value)
	return 0;

	line6pcm->impulse_volume = value;
	if (value > 0)
	line6_pcm_acquire(line6pcm, LINE6_BITS_PCM_IMPULSE);
	else
	line6_pcm_release(line6pcm, LINE6_BITS_PCM_IMPULSE);
	return 1;
	}

	/* impulse response period controls */
	static int snd_line6_impulse_period_info(struct snd_kcontrol *kcontrol,
	struct snd_ctl_elem_info *uinfo)
	{
	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
	uinfo->count = 1;
	uinfo->value.integer.min = 0;
	uinfo->value.integer.max = 2000;
	return 0;
	}

	static int snd_line6_impulse_period_get(struct snd_kcontrol *kcontrol,
	struct snd_ctl_elem_value *ucontrol)
	{
	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);

	ucontrol->value.integer.value[0] = line6pcm->impulse_period;
	return 0;
	}

	static int snd_line6_impulse_period_put(struct snd_kcontrol *kcontrol,
	struct snd_ctl_elem_value *ucontrol)
	{
	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);
	int value = ucontrol->value.integer.value[0];

	if (line6pcm->impulse_period == value)
	return 0;

	line6pcm->impulse_period = value;
	return 1;
	}

	static bool test_flags(unsigned long flags0, unsigned long flags1,
	unsigned long mask)
	{
	return ((flags0 & mask) == 0) && ((flags1 & mask) != 0);
	}

	int line6_pcm_acquire(struct snd_line6_pcm *line6pcm, int channels)
	{
	unsigned long flags_old, flags_new, flags_final;
	int err;

	do {
	flags_old = ACCESS_ONCE(line6pcm->flags);
	flags_new = flags_old \| channels;
	} while (cmpxchg(&line6pcm->flags, flags_old, flags_new) != flags_old);

	flags_final = flags_old;

	line6pcm->prev_fbuf = NULL;

	if (test_flags(flags_old, flags_new, LINE6_BITS_CAPTURE_BUFFER)) {
	/* Invoked multiple times in a row so allocate once only */
	if (!line6pcm->buffer_in) {
	line6pcm->buffer_in =
	kmalloc(LINE6_ISO_BUFFERS * LINE6_ISO_PACKETS *
	line6pcm->max_packet_size, GFP_KERNEL);
	if (!line6pcm->buffer_in) {
	err = -ENOMEM;
	goto pcm_acquire_error;
	}

	flags_final \|= channels & LINE6_BITS_CAPTURE_BUFFER;
	}
	}

	if (test_flags(flags_old, flags_new, LINE6_BITS_CAPTURE_STREAM)) {
	/*
	Waiting for completion of active URBs in the stop handler is
	a bug, we therefore report an error if capturing is restarted
	too soon.
	*/
	if (line6pcm->active_urb_in \| line6pcm->unlink_urb_in) {
	dev_err(line6pcm->line6->ifcdev, "Device not yet ready\n");
	return -EBUSY;
	}

	line6pcm->count_in = 0;
	line6pcm->prev_fsize = 0;
	err = line6_submit_audio_in_all_urbs(line6pcm);

	if (err < 0)
	goto pcm_acquire_error;

	flags_final \|= channels & LINE6_BITS_CAPTURE_STREAM;
	}

	if (test_flags(flags_old, flags_new, LINE6_BITS_PLAYBACK_BUFFER)) {
	/* Invoked multiple times in a row so allocate once only */
	if (!line6pcm->buffer_out) {
	line6pcm->buffer_out =
	kmalloc(LINE6_ISO_BUFFERS * LINE6_ISO_PACKETS *
	line6pcm->max_packet_size, GFP_KERNEL);
	if (!line6pcm->buffer_out) {
	err = -ENOMEM;
	goto pcm_acquire_error;
	}

	flags_final \|= channels & LINE6_BITS_PLAYBACK_BUFFER;
	}
	}

	if (test_flags(flags_old, flags_new, LINE6_BITS_PLAYBACK_STREAM)) {
	/*
	See comment above regarding PCM restart.
	*/
	if (line6pcm->active_urb_out \| line6pcm->unlink_urb_out) {
	dev_err(line6pcm->line6->ifcdev, "Device not yet ready\n");
	return -EBUSY;
	}

	line6pcm->count_out = 0;
	err = line6_submit_audio_out_all_urbs(line6pcm);

	if (err < 0)
	goto pcm_acquire_error;

	flags_final \|= channels & LINE6_BITS_PLAYBACK_STREAM;
	}

	return 0;

	pcm_acquire_error:
	/*
	If not all requested resources/streams could be obtained, release
	those which were successfully obtained (if any).
	*/
	line6_pcm_release(line6pcm, flags_final & channels);
	return err;
	}
	EXPORT_SYMBOL_GPL(line6_pcm_acquire);

	int line6_pcm_release(struct snd_line6_pcm *line6pcm, int channels)
	{
	unsigned long flags_old, flags_new;

	do {
	flags_old = ACCESS_ONCE(line6pcm->flags);
	flags_new = flags_old & ~channels;
	} while (cmpxchg(&line6pcm->flags, flags_old, flags_new) != flags_old);

	if (test_flags(flags_new, flags_old, LINE6_BITS_CAPTURE_STREAM))
	line6_unlink_audio_in_urbs(line6pcm);

	if (test_flags(flags_new, flags_old, LINE6_BITS_CAPTURE_BUFFER)) {
	line6_wait_clear_audio_in_urbs(line6pcm);
	line6_free_capture_buffer(line6pcm);
	}

	if (test_flags(flags_new, flags_old, LINE6_BITS_PLAYBACK_STREAM))
	line6_unlink_audio_out_urbs(line6pcm);

	if (test_flags(flags_new, flags_old, LINE6_BITS_PLAYBACK_BUFFER)) {
	line6_wait_clear_audio_out_urbs(line6pcm);
	line6_free_playback_buffer(line6pcm);
	}

	return 0;
	}
	EXPORT_SYMBOL_GPL(line6_pcm_release);

	/* trigger callback */
	int snd_line6_trigger(struct snd_pcm_substream *substream, int cmd)
	{
	struct snd_line6_pcm *line6pcm = snd_pcm_substream_chip(substream);
	struct snd_pcm_substream *s;
	int err;
	unsigned long flags;

	spin_lock_irqsave(&line6pcm->lock_trigger, flags);
	clear_bit(LINE6_INDEX_PREPARED, &line6pcm->flags);

	snd_pcm_group_for_each_entry(s, substream) {
	if (s->pcm->card != substream->pcm->card)
	continue;
	switch (s->stream) {
	case SNDRV_PCM_STREAM_PLAYBACK:
	err = snd_line6_playback_trigger(line6pcm, cmd);

	if (err < 0) {
	spin_unlock_irqrestore(&line6pcm->lock_trigger,
	flags);
	return err;
	}

	break;

	case SNDRV_PCM_STREAM_CAPTURE:
	err = snd_line6_capture_trigger(line6pcm, cmd);

	if (err < 0) {
	spin_unlock_irqrestore(&line6pcm->lock_trigger,
	flags);
	return err;
	}

	break;

	default:
	dev_err(line6pcm->line6->ifcdev,
	"Unknown stream direction %d\n", s->stream);
	}
	}

	spin_unlock_irqrestore(&line6pcm->lock_trigger, flags);
	return 0;
	}

	/* control info callback */
	static int snd_line6_control_playback_info(struct snd_kcontrol *kcontrol,
	struct snd_ctl_elem_info *uinfo)
	{
	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
	uinfo->count = 2;
	uinfo->value.integer.min = 0;
	uinfo->value.integer.max = 256;
	return 0;
	}

	/* control get callback */
	static int snd_line6_control_playback_get(struct snd_kcontrol *kcontrol,
	struct snd_ctl_elem_value *ucontrol)
	{
	int i;
	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);

	for (i = 2; i--;)
	ucontrol->value.integer.value[i] = line6pcm->volume_playback[i];

	return 0;
	}

	/* control put callback */
	static int snd_line6_control_playback_put(struct snd_kcontrol *kcontrol,
	struct snd_ctl_elem_value *ucontrol)
	{
	int i, changed = 0;
	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);

	for (i = 2; i--;)
	if (line6pcm->volume_playback[i] !=
	ucontrol->value.integer.value[i]) {
	line6pcm->volume_playback[i] =
	ucontrol->value.integer.value[i];
	changed = 1;
	}

	return changed;
	}

	/* control definition */
	static struct snd_kcontrol_new line6_controls[] = {
	{
	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
	.name = "PCM Playback Volume",
	.info = snd_line6_control_playback_info,
	.get = snd_line6_control_playback_get,
	.put = snd_line6_control_playback_put
	},
	{
	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
	.name = "Impulse Response Volume",
	.info = snd_line6_impulse_volume_info,
	.get = snd_line6_impulse_volume_get,
	.put = snd_line6_impulse_volume_put
	},
	{
	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
	.name = "Impulse Response Period",
	.info = snd_line6_impulse_period_info,
	.get = snd_line6_impulse_period_get,
	.put = snd_line6_impulse_period_put
	},
	};

	/*
	Cleanup the PCM device.
	*/
	static void line6_cleanup_pcm(struct snd_pcm *pcm)
	{
	int i;
	struct snd_line6_pcm *line6pcm = snd_pcm_chip(pcm);

	for (i = LINE6_ISO_BUFFERS; i--;) {
	if (line6pcm->urb_audio_out[i]) {
	usb_kill_urb(line6pcm->urb_audio_out[i]);
	usb_free_urb(line6pcm->urb_audio_out[i]);
	}
	if (line6pcm->urb_audio_in[i]) {
	usb_kill_urb(line6pcm->urb_audio_in[i]);
	usb_free_urb(line6pcm->urb_audio_in[i]);
	}
	}
	kfree(line6pcm);
	}

	/* create a PCM device */
	static int snd_line6_new_pcm(struct usb_line6 line6, struct snd_pcm *pcm_ret)
	{
	struct snd_pcm *pcm;
	int err;

	err = snd_pcm_new(line6->card, (char *)line6->properties->name,
	0, 1, 1, pcm_ret);
	if (err < 0)
	return err;
	pcm = *pcm_ret;
	strcpy(pcm->name, line6->properties->name);

	/* set operators */
	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK,
	&snd_line6_playback_ops);
	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &snd_line6_capture_ops);

	/* pre-allocation of buffers */
	snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
	snd_dma_continuous_data
	(GFP_KERNEL), 64 * 1024,
	128 * 1024);
	return 0;
	}

	/*
	Stop substream if still running.
	*/
	static void pcm_disconnect_substream(struct snd_pcm_substream *substream)
	{
	if (substream->runtime && snd_pcm_running(substream)) {
	snd_pcm_stream_lock_irq(substream);
	snd_pcm_stop(substream, SNDRV_PCM_STATE_DISCONNECTED);
	snd_pcm_stream_unlock_irq(substream);
	}
	}

	/*
	Stop PCM stream.
	*/
	void line6_pcm_disconnect(struct snd_line6_pcm *line6pcm)
	{
	pcm_disconnect_substream(get_substream
	(line6pcm, SNDRV_PCM_STREAM_CAPTURE));
	pcm_disconnect_substream(get_substream
	(line6pcm, SNDRV_PCM_STREAM_PLAYBACK));
	line6_unlink_wait_clear_audio_out_urbs(line6pcm);
	line6_unlink_wait_clear_audio_in_urbs(line6pcm);
	}
	EXPORT_SYMBOL_GPL(line6_pcm_disconnect);

	/*
	Create and register the PCM device and mixer entries.
	Create URBs for playback and capture.
	*/
	int line6_init_pcm(struct usb_line6 *line6,
	struct line6_pcm_properties *properties)
	{
	int i, err;
	unsigned ep_read = line6->properties->ep_audio_r;
	unsigned ep_write = line6->properties->ep_audio_w;
	struct snd_pcm *pcm;
	struct snd_line6_pcm *line6pcm;

	if (!(line6->properties->capabilities & LINE6_CAP_PCM))
	return 0; /* skip PCM initialization and report success */

	err = snd_line6_new_pcm(line6, &pcm);
	if (err < 0)
	return err;

	line6pcm = kzalloc(sizeof(*line6pcm), GFP_KERNEL);
	if (!line6pcm)
	return -ENOMEM;

	line6pcm->pcm = pcm;
	line6pcm->properties = properties;
	line6pcm->volume_playback[0] = line6pcm->volume_playback[1] = 255;
	line6pcm->volume_monitor = 255;
	line6pcm->line6 = line6;

	/* Read and write buffers are sized identically, so choose minimum */
	line6pcm->max_packet_size = min(
	usb_maxpacket(line6->usbdev,
	usb_rcvisocpipe(line6->usbdev, ep_read), 0),
	usb_maxpacket(line6->usbdev,
	usb_sndisocpipe(line6->usbdev, ep_write), 1));

	spin_lock_init(&line6pcm->lock_audio_out);
	spin_lock_init(&line6pcm->lock_audio_in);
	spin_lock_init(&line6pcm->lock_trigger);
	line6pcm->impulse_period = LINE6_IMPULSE_DEFAULT_PERIOD;

	line6->line6pcm = line6pcm;

	pcm->private_data = line6pcm;
	pcm->private_free = line6_cleanup_pcm;

	err = line6_create_audio_out_urbs(line6pcm);
	if (err < 0)
	return err;

	err = line6_create_audio_in_urbs(line6pcm);
	if (err < 0)
	return err;

	/* mixer: */
	for (i = 0; i < ARRAY_SIZE(line6_controls); i++) {
	err = snd_ctl_add(line6->card,
	snd_ctl_new1(&line6_controls[i], line6pcm));
	if (err < 0)
	return err;
	}

	return 0;
	}
	EXPORT_SYMBOL_GPL(line6_init_pcm);

	/* prepare pcm callback */
	int snd_line6_prepare(struct snd_pcm_substream *substream)
	{
	struct snd_line6_pcm *line6pcm = snd_pcm_substream_chip(substream);

	switch (substream->stream) {
	case SNDRV_PCM_STREAM_PLAYBACK:
	if ((line6pcm->flags & LINE6_BITS_PLAYBACK_STREAM) == 0)
	line6_unlink_wait_clear_audio_out_urbs(line6pcm);

	break;

	case SNDRV_PCM_STREAM_CAPTURE:
	if ((line6pcm->flags & LINE6_BITS_CAPTURE_STREAM) == 0)
	line6_unlink_wait_clear_audio_in_urbs(line6pcm);

	break;

	default:
	MISSING_CASE;
	}

	if (!test_and_set_bit(LINE6_INDEX_PREPARED, &line6pcm->flags)) {
	line6pcm->count_out = 0;
	line6pcm->pos_out = 0;
	line6pcm->pos_out_done = 0;
	line6pcm->bytes_out = 0;
	line6pcm->count_in = 0;
	line6pcm->pos_in_done = 0;
	line6pcm->bytes_in = 0;
	}

	return 0;
	}