drivers/staging/line6/pcm.c - linux - Git at Google

 /*
  * 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 <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"
 #include "pod.h"

 #ifdef CONFIG_LINE6_USB_IMPULSE_RESPONSE

 static struct snd_line6_pcm *dev2pcm(struct device *dev)
 {
 	struct usb_interface *interface = to_usb_interface(dev);
 	struct usb_line6 *line6 = usb_get_intfdata(interface);
 	struct snd_line6_pcm *line6pcm = line6->line6pcm;
 	return line6pcm;
 }

 /*
 	"read" request on "impulse_volume" special file.
 */
 static ssize_t pcm_get_impulse_volume(struct device *dev,
 				      struct device_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%d\n", dev2pcm(dev)->impulse_volume);
 }

 /*
 	"write" request on "impulse_volume" special file.
 */
 static ssize_t pcm_set_impulse_volume(struct device *dev,
 				      struct device_attribute *attr,
 				      const char *buf, size_t count)
 {
 	struct snd_line6_pcm *line6pcm = dev2pcm(dev);
 	int value;
 	int ret;

 	ret = kstrtoint(buf, 10, &value);
 	if (ret < 0)
 		return ret;

 	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 count;
 }

 /*
 	"read" request on "impulse_period" special file.
 */
 static ssize_t pcm_get_impulse_period(struct device *dev,
 				      struct device_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%d\n", dev2pcm(dev)->impulse_period);
 }

 /*
 	"write" request on "impulse_period" special file.
 */
 static ssize_t pcm_set_impulse_period(struct device *dev,
 				      struct device_attribute *attr,
 				      const char *buf, size_t count)
 {
 	int value;
 	int ret;

 	ret = kstrtoint(buf, 10, &value);
 	if (ret < 0)
 		return ret;

 	dev2pcm(dev)->impulse_period = value;
 	return count;
 }

 static DEVICE_ATTR(impulse_volume, S_IWUSR | S_IRUGO, pcm_get_impulse_volume,
 		   pcm_set_impulse_volume);
 static DEVICE_ATTR(impulse_period, S_IWUSR | S_IRUGO, pcm_get_impulse_period,
 		   pcm_set_impulse_period);

 #endif

 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;
 }

 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;
 }

 /* 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) {
 		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_control_playback = {
 	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
 	.name = "PCM Playback Volume",
 	.index = 0,
 	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
 	.info = snd_line6_control_playback_info,
 	.get = snd_line6_control_playback_get,
 	.put = snd_line6_control_playback_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);

 #ifdef CONFIG_LINE6_USB_IMPULSE_RESPONSE
 	device_remove_file(line6pcm->line6->ifcdev, &dev_attr_impulse_volume);
 	device_remove_file(line6pcm->line6->ifcdev, &dev_attr_impulse_period);
 #endif

 	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]);
 		}
 	}
 }

 /* create a PCM device */
 static int snd_line6_new_pcm(struct snd_line6_pcm *line6pcm)
 {
 	struct snd_pcm *pcm;
 	int err;

 	err = snd_pcm_new(line6pcm->line6->card,
 			  (char *)line6pcm->line6->properties->name,
 			  0, 1, 1, &pcm);
 	if (err < 0)
 		return err;

 	pcm->private_data = line6pcm;
 	pcm->private_free = line6_cleanup_pcm;
 	line6pcm->pcm = pcm;
 	strcpy(pcm->name, line6pcm->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;
 }

 /* PCM device destructor */
 static int snd_line6_pcm_free(struct snd_device *device)
 {
 	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_stop(substream, SNDRV_PCM_STATE_DISCONNECTED);
 }

 /*
 	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);
 }

 /*
 	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)
 {
 	static struct snd_device_ops pcm_ops = {
 		.dev_free = snd_line6_pcm_free,
 	};

 	int err;
 	int ep_read = 0, ep_write = 0;
 	struct snd_line6_pcm *line6pcm;

 	if (!(line6->properties->capabilities & LINE6_BIT_PCM))
 		return 0;	/* skip PCM initialization and report success */

 	/* initialize PCM subsystem based on product id: */
 	switch (line6->product) {
 	case LINE6_DEVID_BASSPODXT:
 	case LINE6_DEVID_BASSPODXTLIVE:
 	case LINE6_DEVID_BASSPODXTPRO:
 	case LINE6_DEVID_PODXT:
 	case LINE6_DEVID_PODXTLIVE:
 	case LINE6_DEVID_PODXTPRO:
 	case LINE6_DEVID_PODHD300:
 		ep_read = 0x82;
 		ep_write = 0x01;
 		break;

 	case LINE6_DEVID_PODHD500:
 	case LINE6_DEVID_PODX3:
 	case LINE6_DEVID_PODX3LIVE:
 		ep_read = 0x86;
 		ep_write = 0x02;
 		break;

 	case LINE6_DEVID_POCKETPOD:
 		ep_read = 0x82;
 		ep_write = 0x02;
 		break;

 	case LINE6_DEVID_GUITARPORT:
 	case LINE6_DEVID_PODSTUDIO_GX:
 	case LINE6_DEVID_PODSTUDIO_UX1:
 	case LINE6_DEVID_PODSTUDIO_UX2:
 	case LINE6_DEVID_TONEPORT_GX:
 	case LINE6_DEVID_TONEPORT_UX1:
 	case LINE6_DEVID_TONEPORT_UX2:
 		ep_read = 0x82;
 		ep_write = 0x01;
 		break;

 	/* this is for interface_number == 1:
 	case LINE6_DEVID_TONEPORT_UX2:
 	case LINE6_DEVID_PODSTUDIO_UX2:
 		ep_read  = 0x87;
 		ep_write = 0x00;
 		break; */

 	default:
 		MISSING_CASE;
 	}

 	line6pcm = kzalloc(sizeof(struct snd_line6_pcm), GFP_KERNEL);

 	if (line6pcm == NULL)
 		return -ENOMEM;

 	line6pcm->volume_playback[0] = line6pcm->volume_playback[1] = 255;
 	line6pcm->volume_monitor = 255;
 	line6pcm->line6 = line6;
 	line6pcm->ep_audio_read = ep_read;
 	line6pcm->ep_audio_write = ep_write;

 	/* 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));

 	line6pcm->properties = properties;
 	line6->line6pcm = line6pcm;

 	/* PCM device: */
 	err = snd_device_new(line6->card, SNDRV_DEV_PCM, line6, &pcm_ops);
 	if (err < 0)
 		return err;

 	snd_card_set_dev(line6->card, line6->ifcdev);

 	err = snd_line6_new_pcm(line6pcm);
 	if (err < 0)
 		return err;

 	spin_lock_init(&line6pcm->lock_audio_out);
 	spin_lock_init(&line6pcm->lock_audio_in);
 	spin_lock_init(&line6pcm->lock_trigger);

 	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: */
 	err =
 	    snd_ctl_add(line6->card,
 			snd_ctl_new1(&line6_control_playback, line6pcm));
 	if (err < 0)
 		return err;

 #ifdef CONFIG_LINE6_USB_IMPULSE_RESPONSE
 	/* impulse response test: */
 	err = device_create_file(line6->ifcdev, &dev_attr_impulse_volume);
 	if (err < 0)
 		return err;

 	err = device_create_file(line6->ifcdev, &dev_attr_impulse_period);
 	if (err < 0)
 		return err;

 	line6pcm->impulse_period = LINE6_IMPULSE_DEFAULT_PERIOD;
 #endif

 	return 0;
 }

 /* 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 <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"
	#include "pod.h"

	#ifdef CONFIG_LINE6_USB_IMPULSE_RESPONSE

	static struct snd_line6_pcm dev2pcm(struct device dev)
	{
	struct usb_interface *interface = to_usb_interface(dev);
	struct usb_line6 *line6 = usb_get_intfdata(interface);
	struct snd_line6_pcm *line6pcm = line6->line6pcm;
	return line6pcm;
	}

	/*
	"read" request on "impulse_volume" special file.
	*/
	static ssize_t pcm_get_impulse_volume(struct device *dev,
	struct device_attribute attr, char buf)
	{
	return sprintf(buf, "%d\n", dev2pcm(dev)->impulse_volume);
	}

	/*
	"write" request on "impulse_volume" special file.
	*/
	static ssize_t pcm_set_impulse_volume(struct device *dev,
	struct device_attribute *attr,
	const char *buf, size_t count)
	{
	struct snd_line6_pcm *line6pcm = dev2pcm(dev);
	int value;
	int ret;

	ret = kstrtoint(buf, 10, &value);
	if (ret < 0)
	return ret;

	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 count;
	}

	/*
	"read" request on "impulse_period" special file.
	*/
	static ssize_t pcm_get_impulse_period(struct device *dev,
	struct device_attribute attr, char buf)
	{
	return sprintf(buf, "%d\n", dev2pcm(dev)->impulse_period);
	}

	/*
	"write" request on "impulse_period" special file.
	*/
	static ssize_t pcm_set_impulse_period(struct device *dev,
	struct device_attribute *attr,
	const char *buf, size_t count)
	{
	int value;
	int ret;

	ret = kstrtoint(buf, 10, &value);
	if (ret < 0)
	return ret;

	dev2pcm(dev)->impulse_period = value;
	return count;
	}

	static DEVICE_ATTR(impulse_volume, S_IWUSR \| S_IRUGO, pcm_get_impulse_volume,
	pcm_set_impulse_volume);
	static DEVICE_ATTR(impulse_period, S_IWUSR \| S_IRUGO, pcm_get_impulse_period,
	pcm_set_impulse_period);

	#endif

	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;
	}

	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;
	}

	/* 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) {
	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_control_playback = {
	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
	.name = "PCM Playback Volume",
	.index = 0,
	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
	.info = snd_line6_control_playback_info,
	.get = snd_line6_control_playback_get,
	.put = snd_line6_control_playback_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);

	#ifdef CONFIG_LINE6_USB_IMPULSE_RESPONSE
	device_remove_file(line6pcm->line6->ifcdev, &dev_attr_impulse_volume);
	device_remove_file(line6pcm->line6->ifcdev, &dev_attr_impulse_period);
	#endif

	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]);
	}
	}
	}

	/* create a PCM device */
	static int snd_line6_new_pcm(struct snd_line6_pcm *line6pcm)
	{
	struct snd_pcm *pcm;
	int err;

	err = snd_pcm_new(line6pcm->line6->card,
	(char *)line6pcm->line6->properties->name,
	0, 1, 1, &pcm);
	if (err < 0)
	return err;

	pcm->private_data = line6pcm;
	pcm->private_free = line6_cleanup_pcm;
	line6pcm->pcm = pcm;
	strcpy(pcm->name, line6pcm->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;
	}

	/* PCM device destructor */
	static int snd_line6_pcm_free(struct snd_device *device)
	{
	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_stop(substream, SNDRV_PCM_STATE_DISCONNECTED);
	}

	/*
	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);
	}

	/*
	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)
	{
	static struct snd_device_ops pcm_ops = {
	.dev_free = snd_line6_pcm_free,
	};

	int err;
	int ep_read = 0, ep_write = 0;
	struct snd_line6_pcm *line6pcm;

	if (!(line6->properties->capabilities & LINE6_BIT_PCM))
	return 0; /* skip PCM initialization and report success */

	/* initialize PCM subsystem based on product id: */
	switch (line6->product) {
	case LINE6_DEVID_BASSPODXT:
	case LINE6_DEVID_BASSPODXTLIVE:
	case LINE6_DEVID_BASSPODXTPRO:
	case LINE6_DEVID_PODXT:
	case LINE6_DEVID_PODXTLIVE:
	case LINE6_DEVID_PODXTPRO:
	case LINE6_DEVID_PODHD300:
	ep_read = 0x82;
	ep_write = 0x01;
	break;

	case LINE6_DEVID_PODHD500:
	case LINE6_DEVID_PODX3:
	case LINE6_DEVID_PODX3LIVE:
	ep_read = 0x86;
	ep_write = 0x02;
	break;

	case LINE6_DEVID_POCKETPOD:
	ep_read = 0x82;
	ep_write = 0x02;
	break;

	case LINE6_DEVID_GUITARPORT:
	case LINE6_DEVID_PODSTUDIO_GX:
	case LINE6_DEVID_PODSTUDIO_UX1:
	case LINE6_DEVID_PODSTUDIO_UX2:
	case LINE6_DEVID_TONEPORT_GX:
	case LINE6_DEVID_TONEPORT_UX1:
	case LINE6_DEVID_TONEPORT_UX2:
	ep_read = 0x82;
	ep_write = 0x01;
	break;

	/* this is for interface_number == 1:
	case LINE6_DEVID_TONEPORT_UX2:
	case LINE6_DEVID_PODSTUDIO_UX2:
	ep_read = 0x87;
	ep_write = 0x00;
	break; */

	default:
	MISSING_CASE;
	}

	line6pcm = kzalloc(sizeof(struct snd_line6_pcm), GFP_KERNEL);

	if (line6pcm == NULL)
	return -ENOMEM;

	line6pcm->volume_playback[0] = line6pcm->volume_playback[1] = 255;
	line6pcm->volume_monitor = 255;
	line6pcm->line6 = line6;
	line6pcm->ep_audio_read = ep_read;
	line6pcm->ep_audio_write = ep_write;

	/* 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));

	line6pcm->properties = properties;
	line6->line6pcm = line6pcm;

	/* PCM device: */
	err = snd_device_new(line6->card, SNDRV_DEV_PCM, line6, &pcm_ops);
	if (err < 0)
	return err;

	snd_card_set_dev(line6->card, line6->ifcdev);

	err = snd_line6_new_pcm(line6pcm);
	if (err < 0)
	return err;

	spin_lock_init(&line6pcm->lock_audio_out);
	spin_lock_init(&line6pcm->lock_audio_in);
	spin_lock_init(&line6pcm->lock_trigger);

	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: */
	err =
	snd_ctl_add(line6->card,
	snd_ctl_new1(&line6_control_playback, line6pcm));
	if (err < 0)
	return err;

	#ifdef CONFIG_LINE6_USB_IMPULSE_RESPONSE
	/* impulse response test: */
	err = device_create_file(line6->ifcdev, &dev_attr_impulse_volume);
	if (err < 0)
	return err;

	err = device_create_file(line6->ifcdev, &dev_attr_impulse_period);
	if (err < 0)
	return err;

	line6pcm->impulse_period = LINE6_IMPULSE_DEFAULT_PERIOD;
	#endif

	return 0;
	}

	/* 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;
	}