sound/firewire/dice/dice-pcm.c - kernel/lockdown - Git at Google

 /*
  * dice_pcm.c - a part of driver for DICE based devices
  *
  * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
  * Copyright (c) 2014 Takashi Sakamoto <o-takashi@sakamocchi.jp>
  *
  * Licensed under the terms of the GNU General Public License, version 2.
  */

 #include "dice.h"

 static int dice_rate_constraint(struct snd_pcm_hw_params *params,
 				struct snd_pcm_hw_rule *rule)
 {
 	struct snd_pcm_substream *substream = rule->private;
 	struct snd_dice *dice = substream->private_data;

 	const struct snd_interval *c =
 		hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_CHANNELS);
 	struct snd_interval *r =
 		hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
 	struct snd_interval rates = {
 		.min = UINT_MAX, .max = 0, .integer = 1
 	};
 	unsigned int i, rate, mode, *pcm_channels;

 	if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
 		pcm_channels = dice->tx_channels;
 	else
 		pcm_channels = dice->rx_channels;

 	for (i = 0; i < ARRAY_SIZE(snd_dice_rates); ++i) {
 		rate = snd_dice_rates[i];
 		if (snd_dice_stream_get_rate_mode(dice, rate, &mode) < 0)
 			continue;

 		if (!snd_interval_test(c, pcm_channels[mode]))
 			continue;

 		rates.min = min(rates.min, rate);
 		rates.max = max(rates.max, rate);
 	}

 	return snd_interval_refine(r, &rates);
 }

 static int dice_channels_constraint(struct snd_pcm_hw_params *params,
 				    struct snd_pcm_hw_rule *rule)
 {
 	struct snd_pcm_substream *substream = rule->private;
 	struct snd_dice *dice = substream->private_data;

 	const struct snd_interval *r =
 		hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_RATE);
 	struct snd_interval *c =
 		hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
 	struct snd_interval channels = {
 		.min = UINT_MAX, .max = 0, .integer = 1
 	};
 	unsigned int i, rate, mode, *pcm_channels;

 	if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
 		pcm_channels = dice->tx_channels;
 	else
 		pcm_channels = dice->rx_channels;

 	for (i = 0; i < ARRAY_SIZE(snd_dice_rates); ++i) {
 		rate = snd_dice_rates[i];
 		if (snd_dice_stream_get_rate_mode(dice, rate, &mode) < 0)
 			continue;

 		if (!snd_interval_test(r, rate))
 			continue;

 		channels.min = min(channels.min, pcm_channels[mode]);
 		channels.max = max(channels.max, pcm_channels[mode]);
 	}

 	return snd_interval_refine(c, &channels);
 }

 static void limit_channels_and_rates(struct snd_dice *dice,
 				     struct snd_pcm_runtime *runtime,
 				     unsigned int *pcm_channels)
 {
 	struct snd_pcm_hardware *hw = &runtime->hw;
 	unsigned int i, rate, mode;

 	hw->channels_min = UINT_MAX;
 	hw->channels_max = 0;

 	for (i = 0; i < ARRAY_SIZE(snd_dice_rates); ++i) {
 		rate = snd_dice_rates[i];
 		if (snd_dice_stream_get_rate_mode(dice, rate, &mode) < 0)
 			continue;
 		hw->rates |= snd_pcm_rate_to_rate_bit(rate);

 		if (pcm_channels[mode] == 0)
 			continue;
 		hw->channels_min = min(hw->channels_min, pcm_channels[mode]);
 		hw->channels_max = max(hw->channels_max, pcm_channels[mode]);
 	}

 	snd_pcm_limit_hw_rates(runtime);
 }

 static void limit_period_and_buffer(struct snd_pcm_hardware *hw)
 {
 	hw->periods_min = 2;			/* SNDRV_PCM_INFO_BATCH */
 	hw->periods_max = UINT_MAX;

 	hw->period_bytes_min = 4 * hw->channels_max;    /* byte for a frame */

 	/* Just to prevent from allocating much pages. */
 	hw->period_bytes_max = hw->period_bytes_min * 2048;
 	hw->buffer_bytes_max = hw->period_bytes_max * hw->periods_min;
 }

 static int init_hw_info(struct snd_dice *dice,
 			struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct snd_pcm_hardware *hw = &runtime->hw;
 	struct amdtp_stream *stream;
 	unsigned int *pcm_channels;
 	int err;

 	hw->info = SNDRV_PCM_INFO_MMAP |
 		   SNDRV_PCM_INFO_MMAP_VALID |
 		   SNDRV_PCM_INFO_BATCH |
 		   SNDRV_PCM_INFO_INTERLEAVED |
 		   SNDRV_PCM_INFO_JOINT_DUPLEX |
 		   SNDRV_PCM_INFO_BLOCK_TRANSFER;

 	if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
 		hw->formats = AMDTP_IN_PCM_FORMAT_BITS;
 		stream = &dice->tx_stream;
 		pcm_channels = dice->tx_channels;
 	} else {
 		hw->formats = AMDTP_OUT_PCM_FORMAT_BITS;
 		stream = &dice->rx_stream;
 		pcm_channels = dice->rx_channels;
 	}

 	limit_channels_and_rates(dice, runtime, pcm_channels);
 	limit_period_and_buffer(hw);

 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
 				  dice_rate_constraint, substream,
 				  SNDRV_PCM_HW_PARAM_CHANNELS, -1);
 	if (err < 0)
 		goto end;
 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
 				  dice_channels_constraint, substream,
 				  SNDRV_PCM_HW_PARAM_RATE, -1);
 	if (err < 0)
 		goto end;

 	err = amdtp_stream_add_pcm_hw_constraints(stream, runtime);
 end:
 	return err;
 }

 static int pcm_open(struct snd_pcm_substream *substream)
 {
 	struct snd_dice *dice = substream->private_data;
 	unsigned int source, rate;
 	bool internal;
 	int err;

 	err = snd_dice_stream_lock_try(dice);
 	if (err < 0)
 		goto end;

 	err = init_hw_info(dice, substream);
 	if (err < 0)
 		goto err_locked;

 	err = snd_dice_transaction_get_clock_source(dice, &source);
 	if (err < 0)
 		goto err_locked;
 	switch (source) {
 	case CLOCK_SOURCE_AES1:
 	case CLOCK_SOURCE_AES2:
 	case CLOCK_SOURCE_AES3:
 	case CLOCK_SOURCE_AES4:
 	case CLOCK_SOURCE_AES_ANY:
 	case CLOCK_SOURCE_ADAT:
 	case CLOCK_SOURCE_TDIF:
 	case CLOCK_SOURCE_WC:
 		internal = false;
 		break;
 	default:
 		internal = true;
 		break;
 	}

 	/*
 	 * When source of clock is not internal or any PCM streams are running,
 	 * available sampling rate is limited at current sampling rate.
 	 */
 	if (!internal ||
 	    amdtp_stream_pcm_running(&dice->tx_stream) ||
 	    amdtp_stream_pcm_running(&dice->rx_stream)) {
 		err = snd_dice_transaction_get_rate(dice, &rate);
 		if (err < 0)
 			goto err_locked;
 		substream->runtime->hw.rate_min = rate;
 		substream->runtime->hw.rate_max = rate;
 	}

 	snd_pcm_set_sync(substream);
 end:
 	return err;
 err_locked:
 	snd_dice_stream_lock_release(dice);
 	return err;
 }

 static int pcm_close(struct snd_pcm_substream *substream)
 {
 	struct snd_dice *dice = substream->private_data;

 	snd_dice_stream_lock_release(dice);

 	return 0;
 }

 static int capture_hw_params(struct snd_pcm_substream *substream,
 			     struct snd_pcm_hw_params *hw_params)
 {
 	struct snd_dice *dice = substream->private_data;

 	if (substream->runtime->status->state == SNDRV_PCM_STATE_OPEN) {
 		mutex_lock(&dice->mutex);
 		dice->substreams_counter++;
 		mutex_unlock(&dice->mutex);
 	}

 	amdtp_stream_set_pcm_format(&dice->tx_stream,
 				    params_format(hw_params));

 	return snd_pcm_lib_alloc_vmalloc_buffer(substream,
 						params_buffer_bytes(hw_params));
 }
 static int playback_hw_params(struct snd_pcm_substream *substream,
 			      struct snd_pcm_hw_params *hw_params)
 {
 	struct snd_dice *dice = substream->private_data;

 	if (substream->runtime->status->state == SNDRV_PCM_STATE_OPEN) {
 		mutex_lock(&dice->mutex);
 		dice->substreams_counter++;
 		mutex_unlock(&dice->mutex);
 	}

 	amdtp_stream_set_pcm_format(&dice->rx_stream,
 				    params_format(hw_params));

 	return snd_pcm_lib_alloc_vmalloc_buffer(substream,
 						params_buffer_bytes(hw_params));
 }

 static int capture_hw_free(struct snd_pcm_substream *substream)
 {
 	struct snd_dice *dice = substream->private_data;

 	mutex_lock(&dice->mutex);

 	if (substream->runtime->status->state != SNDRV_PCM_STATE_OPEN)
 		dice->substreams_counter--;

 	snd_dice_stream_stop_duplex(dice);

 	mutex_unlock(&dice->mutex);

 	return snd_pcm_lib_free_vmalloc_buffer(substream);
 }

 static int playback_hw_free(struct snd_pcm_substream *substream)
 {
 	struct snd_dice *dice = substream->private_data;

 	mutex_lock(&dice->mutex);

 	if (substream->runtime->status->state != SNDRV_PCM_STATE_OPEN)
 		dice->substreams_counter--;

 	snd_dice_stream_stop_duplex(dice);

 	mutex_unlock(&dice->mutex);

 	return snd_pcm_lib_free_vmalloc_buffer(substream);
 }

 static int capture_prepare(struct snd_pcm_substream *substream)
 {
 	struct snd_dice *dice = substream->private_data;
 	int err;

 	mutex_lock(&dice->mutex);
 	err = snd_dice_stream_start_duplex(dice, substream->runtime->rate);
 	mutex_unlock(&dice->mutex);
 	if (err >= 0)
 		amdtp_stream_pcm_prepare(&dice->tx_stream);

 	return 0;
 }
 static int playback_prepare(struct snd_pcm_substream *substream)
 {
 	struct snd_dice *dice = substream->private_data;
 	int err;

 	mutex_lock(&dice->mutex);
 	err = snd_dice_stream_start_duplex(dice, substream->runtime->rate);
 	mutex_unlock(&dice->mutex);
 	if (err >= 0)
 		amdtp_stream_pcm_prepare(&dice->rx_stream);

 	return err;
 }

 static int capture_trigger(struct snd_pcm_substream *substream, int cmd)
 {
 	struct snd_dice *dice = substream->private_data;

 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
 		amdtp_stream_pcm_trigger(&dice->tx_stream, substream);
 		break;
 	case SNDRV_PCM_TRIGGER_STOP:
 		amdtp_stream_pcm_trigger(&dice->tx_stream, NULL);
 		break;
 	default:
 		return -EINVAL;
 	}

 	return 0;
 }
 static int playback_trigger(struct snd_pcm_substream *substream, int cmd)
 {
 	struct snd_dice *dice = substream->private_data;

 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
 		amdtp_stream_pcm_trigger(&dice->rx_stream, substream);
 		break;
 	case SNDRV_PCM_TRIGGER_STOP:
 		amdtp_stream_pcm_trigger(&dice->rx_stream, NULL);
 		break;
 	default:
 		return -EINVAL;
 	}

 	return 0;
 }

 static snd_pcm_uframes_t capture_pointer(struct snd_pcm_substream *substream)
 {
 	struct snd_dice *dice = substream->private_data;

 	return amdtp_stream_pcm_pointer(&dice->tx_stream);
 }
 static snd_pcm_uframes_t playback_pointer(struct snd_pcm_substream *substream)
 {
 	struct snd_dice *dice = substream->private_data;

 	return amdtp_stream_pcm_pointer(&dice->rx_stream);
 }

 int snd_dice_create_pcm(struct snd_dice *dice)
 {
 	static struct snd_pcm_ops capture_ops = {
 		.open      = pcm_open,
 		.close     = pcm_close,
 		.ioctl     = snd_pcm_lib_ioctl,
 		.hw_params = capture_hw_params,
 		.hw_free   = capture_hw_free,
 		.prepare   = capture_prepare,
 		.trigger   = capture_trigger,
 		.pointer   = capture_pointer,
 		.page      = snd_pcm_lib_get_vmalloc_page,
 		.mmap      = snd_pcm_lib_mmap_vmalloc,
 	};
 	static struct snd_pcm_ops playback_ops = {
 		.open      = pcm_open,
 		.close     = pcm_close,
 		.ioctl     = snd_pcm_lib_ioctl,
 		.hw_params = playback_hw_params,
 		.hw_free   = playback_hw_free,
 		.prepare   = playback_prepare,
 		.trigger   = playback_trigger,
 		.pointer   = playback_pointer,
 		.page      = snd_pcm_lib_get_vmalloc_page,
 		.mmap      = snd_pcm_lib_mmap_vmalloc,
 	};
 	struct snd_pcm *pcm;
 	unsigned int i, capture, playback;
 	int err;

 	capture = playback = 0;
 	for (i = 0; i < 3; i++) {
 		if (dice->tx_channels[i] > 0)
 			capture = 1;
 		if (dice->rx_channels[i] > 0)
 			playback = 1;
 	}

 	err = snd_pcm_new(dice->card, "DICE", 0, playback, capture, &pcm);
 	if (err < 0)
 		return err;
 	pcm->private_data = dice;
 	strcpy(pcm->name, dice->card->shortname);

 	if (capture > 0)
 		snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &capture_ops);

 	if (playback > 0)
 		snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &playback_ops);

 	return 0;
 }
	/*
	* dice_pcm.c - a part of driver for DICE based devices
	*
	* Copyright (c) Clemens Ladisch <clemens@ladisch.de>
	* Copyright (c) 2014 Takashi Sakamoto <o-takashi@sakamocchi.jp>
	*
	* Licensed under the terms of the GNU General Public License, version 2.
	*/

	#include "dice.h"

	static int dice_rate_constraint(struct snd_pcm_hw_params *params,
	struct snd_pcm_hw_rule *rule)
	{
	struct snd_pcm_substream *substream = rule->private;
	struct snd_dice *dice = substream->private_data;

	const struct snd_interval *c =
	hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_CHANNELS);
	struct snd_interval *r =
	hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
	struct snd_interval rates = {
	.min = UINT_MAX, .max = 0, .integer = 1
	};
	unsigned int i, rate, mode, *pcm_channels;

	if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
	pcm_channels = dice->tx_channels;
	else
	pcm_channels = dice->rx_channels;

	for (i = 0; i < ARRAY_SIZE(snd_dice_rates); ++i) {
	rate = snd_dice_rates[i];
	if (snd_dice_stream_get_rate_mode(dice, rate, &mode) < 0)
	continue;

	if (!snd_interval_test(c, pcm_channels[mode]))
	continue;

	rates.min = min(rates.min, rate);
	rates.max = max(rates.max, rate);
	}

	return snd_interval_refine(r, &rates);
	}

	static int dice_channels_constraint(struct snd_pcm_hw_params *params,
	struct snd_pcm_hw_rule *rule)
	{
	struct snd_pcm_substream *substream = rule->private;
	struct snd_dice *dice = substream->private_data;

	const struct snd_interval *r =
	hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_RATE);
	struct snd_interval *c =
	hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
	struct snd_interval channels = {
	.min = UINT_MAX, .max = 0, .integer = 1
	};
	unsigned int i, rate, mode, *pcm_channels;

	if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
	pcm_channels = dice->tx_channels;
	else
	pcm_channels = dice->rx_channels;

	for (i = 0; i < ARRAY_SIZE(snd_dice_rates); ++i) {
	rate = snd_dice_rates[i];
	if (snd_dice_stream_get_rate_mode(dice, rate, &mode) < 0)
	continue;

	if (!snd_interval_test(r, rate))
	continue;

	channels.min = min(channels.min, pcm_channels[mode]);
	channels.max = max(channels.max, pcm_channels[mode]);
	}

	return snd_interval_refine(c, &channels);
	}

	static void limit_channels_and_rates(struct snd_dice *dice,
	struct snd_pcm_runtime *runtime,
	unsigned int *pcm_channels)
	{
	struct snd_pcm_hardware *hw = &runtime->hw;
	unsigned int i, rate, mode;

	hw->channels_min = UINT_MAX;
	hw->channels_max = 0;

	for (i = 0; i < ARRAY_SIZE(snd_dice_rates); ++i) {
	rate = snd_dice_rates[i];
	if (snd_dice_stream_get_rate_mode(dice, rate, &mode) < 0)
	continue;
	hw->rates \|= snd_pcm_rate_to_rate_bit(rate);

	if (pcm_channels[mode] == 0)
	continue;
	hw->channels_min = min(hw->channels_min, pcm_channels[mode]);
	hw->channels_max = max(hw->channels_max, pcm_channels[mode]);
	}

	snd_pcm_limit_hw_rates(runtime);
	}

	static void limit_period_and_buffer(struct snd_pcm_hardware *hw)
	{
	hw->periods_min = 2; /* SNDRV_PCM_INFO_BATCH */
	hw->periods_max = UINT_MAX;

	hw->period_bytes_min = 4 * hw->channels_max; /* byte for a frame */

	/* Just to prevent from allocating much pages. */
	hw->period_bytes_max = hw->period_bytes_min * 2048;
	hw->buffer_bytes_max = hw->period_bytes_max * hw->periods_min;
	}

	static int init_hw_info(struct snd_dice *dice,
	struct snd_pcm_substream *substream)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct snd_pcm_hardware *hw = &runtime->hw;
	struct amdtp_stream *stream;
	unsigned int *pcm_channels;
	int err;

	hw->info = SNDRV_PCM_INFO_MMAP \|
	SNDRV_PCM_INFO_MMAP_VALID \|
	SNDRV_PCM_INFO_BATCH \|
	SNDRV_PCM_INFO_INTERLEAVED \|
	SNDRV_PCM_INFO_JOINT_DUPLEX \|
	SNDRV_PCM_INFO_BLOCK_TRANSFER;

	if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
	hw->formats = AMDTP_IN_PCM_FORMAT_BITS;
	stream = &dice->tx_stream;
	pcm_channels = dice->tx_channels;
	} else {
	hw->formats = AMDTP_OUT_PCM_FORMAT_BITS;
	stream = &dice->rx_stream;
	pcm_channels = dice->rx_channels;
	}

	limit_channels_and_rates(dice, runtime, pcm_channels);
	limit_period_and_buffer(hw);

	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
	dice_rate_constraint, substream,
	SNDRV_PCM_HW_PARAM_CHANNELS, -1);
	if (err < 0)
	goto end;
	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
	dice_channels_constraint, substream,
	SNDRV_PCM_HW_PARAM_RATE, -1);
	if (err < 0)
	goto end;

	err = amdtp_stream_add_pcm_hw_constraints(stream, runtime);
	end:
	return err;
	}

	static int pcm_open(struct snd_pcm_substream *substream)
	{
	struct snd_dice *dice = substream->private_data;
	unsigned int source, rate;
	bool internal;
	int err;

	err = snd_dice_stream_lock_try(dice);
	if (err < 0)
	goto end;

	err = init_hw_info(dice, substream);
	if (err < 0)
	goto err_locked;

	err = snd_dice_transaction_get_clock_source(dice, &source);
	if (err < 0)
	goto err_locked;
	switch (source) {
	case CLOCK_SOURCE_AES1:
	case CLOCK_SOURCE_AES2:
	case CLOCK_SOURCE_AES3:
	case CLOCK_SOURCE_AES4:
	case CLOCK_SOURCE_AES_ANY:
	case CLOCK_SOURCE_ADAT:
	case CLOCK_SOURCE_TDIF:
	case CLOCK_SOURCE_WC:
	internal = false;
	break;
	default:
	internal = true;
	break;
	}

	/*
	* When source of clock is not internal or any PCM streams are running,
	* available sampling rate is limited at current sampling rate.
	*/
	if (!internal \|\|
	amdtp_stream_pcm_running(&dice->tx_stream) \|\|
	amdtp_stream_pcm_running(&dice->rx_stream)) {
	err = snd_dice_transaction_get_rate(dice, &rate);
	if (err < 0)
	goto err_locked;
	substream->runtime->hw.rate_min = rate;
	substream->runtime->hw.rate_max = rate;
	}

	snd_pcm_set_sync(substream);
	end:
	return err;
	err_locked:
	snd_dice_stream_lock_release(dice);
	return err;
	}

	static int pcm_close(struct snd_pcm_substream *substream)
	{
	struct snd_dice *dice = substream->private_data;

	snd_dice_stream_lock_release(dice);

	return 0;
	}

	static int capture_hw_params(struct snd_pcm_substream *substream,
	struct snd_pcm_hw_params *hw_params)
	{
	struct snd_dice *dice = substream->private_data;

	if (substream->runtime->status->state == SNDRV_PCM_STATE_OPEN) {
	mutex_lock(&dice->mutex);
	dice->substreams_counter++;
	mutex_unlock(&dice->mutex);
	}

	amdtp_stream_set_pcm_format(&dice->tx_stream,
	params_format(hw_params));

	return snd_pcm_lib_alloc_vmalloc_buffer(substream,
	params_buffer_bytes(hw_params));
	}
	static int playback_hw_params(struct snd_pcm_substream *substream,
	struct snd_pcm_hw_params *hw_params)
	{
	struct snd_dice *dice = substream->private_data;

	if (substream->runtime->status->state == SNDRV_PCM_STATE_OPEN) {
	mutex_lock(&dice->mutex);
	dice->substreams_counter++;
	mutex_unlock(&dice->mutex);
	}

	amdtp_stream_set_pcm_format(&dice->rx_stream,
	params_format(hw_params));

	return snd_pcm_lib_alloc_vmalloc_buffer(substream,
	params_buffer_bytes(hw_params));
	}

	static int capture_hw_free(struct snd_pcm_substream *substream)
	{
	struct snd_dice *dice = substream->private_data;

	mutex_lock(&dice->mutex);

	if (substream->runtime->status->state != SNDRV_PCM_STATE_OPEN)
	dice->substreams_counter--;

	snd_dice_stream_stop_duplex(dice);

	mutex_unlock(&dice->mutex);

	return snd_pcm_lib_free_vmalloc_buffer(substream);
	}

	static int playback_hw_free(struct snd_pcm_substream *substream)
	{
	struct snd_dice *dice = substream->private_data;

	mutex_lock(&dice->mutex);

	if (substream->runtime->status->state != SNDRV_PCM_STATE_OPEN)
	dice->substreams_counter--;

	snd_dice_stream_stop_duplex(dice);

	mutex_unlock(&dice->mutex);

	return snd_pcm_lib_free_vmalloc_buffer(substream);
	}

	static int capture_prepare(struct snd_pcm_substream *substream)
	{
	struct snd_dice *dice = substream->private_data;
	int err;

	mutex_lock(&dice->mutex);
	err = snd_dice_stream_start_duplex(dice, substream->runtime->rate);
	mutex_unlock(&dice->mutex);
	if (err >= 0)
	amdtp_stream_pcm_prepare(&dice->tx_stream);

	return 0;
	}
	static int playback_prepare(struct snd_pcm_substream *substream)
	{
	struct snd_dice *dice = substream->private_data;
	int err;

	mutex_lock(&dice->mutex);
	err = snd_dice_stream_start_duplex(dice, substream->runtime->rate);
	mutex_unlock(&dice->mutex);
	if (err >= 0)
	amdtp_stream_pcm_prepare(&dice->rx_stream);

	return err;
	}

	static int capture_trigger(struct snd_pcm_substream *substream, int cmd)
	{
	struct snd_dice *dice = substream->private_data;

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
	amdtp_stream_pcm_trigger(&dice->tx_stream, substream);
	break;
	case SNDRV_PCM_TRIGGER_STOP:
	amdtp_stream_pcm_trigger(&dice->tx_stream, NULL);
	break;
	default:
	return -EINVAL;
	}

	return 0;
	}
	static int playback_trigger(struct snd_pcm_substream *substream, int cmd)
	{
	struct snd_dice *dice = substream->private_data;

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
	amdtp_stream_pcm_trigger(&dice->rx_stream, substream);
	break;
	case SNDRV_PCM_TRIGGER_STOP:
	amdtp_stream_pcm_trigger(&dice->rx_stream, NULL);
	break;
	default:
	return -EINVAL;
	}

	return 0;
	}

	static snd_pcm_uframes_t capture_pointer(struct snd_pcm_substream *substream)
	{
	struct snd_dice *dice = substream->private_data;

	return amdtp_stream_pcm_pointer(&dice->tx_stream);
	}
	static snd_pcm_uframes_t playback_pointer(struct snd_pcm_substream *substream)
	{
	struct snd_dice *dice = substream->private_data;

	return amdtp_stream_pcm_pointer(&dice->rx_stream);
	}

	int snd_dice_create_pcm(struct snd_dice *dice)
	{
	static struct snd_pcm_ops capture_ops = {
	.open = pcm_open,
	.close = pcm_close,
	.ioctl = snd_pcm_lib_ioctl,
	.hw_params = capture_hw_params,
	.hw_free = capture_hw_free,
	.prepare = capture_prepare,
	.trigger = capture_trigger,
	.pointer = capture_pointer,
	.page = snd_pcm_lib_get_vmalloc_page,
	.mmap = snd_pcm_lib_mmap_vmalloc,
	};
	static struct snd_pcm_ops playback_ops = {
	.open = pcm_open,
	.close = pcm_close,
	.ioctl = snd_pcm_lib_ioctl,
	.hw_params = playback_hw_params,
	.hw_free = playback_hw_free,
	.prepare = playback_prepare,
	.trigger = playback_trigger,
	.pointer = playback_pointer,
	.page = snd_pcm_lib_get_vmalloc_page,
	.mmap = snd_pcm_lib_mmap_vmalloc,
	};
	struct snd_pcm *pcm;
	unsigned int i, capture, playback;
	int err;

	capture = playback = 0;
	for (i = 0; i < 3; i++) {
	if (dice->tx_channels[i] > 0)
	capture = 1;
	if (dice->rx_channels[i] > 0)
	playback = 1;
	}

	err = snd_pcm_new(dice->card, "DICE", 0, playback, capture, &pcm);
	if (err < 0)
	return err;
	pcm->private_data = dice;
	strcpy(pcm->name, dice->card->shortname);

	if (capture > 0)
	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &capture_ops);

	if (playback > 0)
	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &playback_ops);

	return 0;
	}