sound/firewire/fireworks/fireworks_pcm.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * fireworks_pcm.c - a part of driver for Fireworks based devices
  *
  * Copyright (c) 2009-2010 Clemens Ladisch
  * Copyright (c) 2013-2014 Takashi Sakamoto
  */
 #include "./fireworks.h"

 /*
  * NOTE:
  * Fireworks changes its AMDTP channels for PCM data according to its sampling
  * rate. There are three modes. Here _XX is either _rx or _tx.
  *  0:  32.0- 48.0 kHz then snd_efw_hwinfo.amdtp_XX_pcm_channels applied
  *  1:  88.2- 96.0 kHz then snd_efw_hwinfo.amdtp_XX_pcm_channels_2x applied
  *  2: 176.4-192.0 kHz then snd_efw_hwinfo.amdtp_XX_pcm_channels_4x applied
  *
  * The number of PCM channels for analog input and output are always fixed but
  * the number of PCM channels for digital input and output are differed.
  *
  * Additionally, according to "AudioFire Owner's Manual Version 2.2", in some
  * model, the number of PCM channels for digital input has more restriction
  * depending on which digital interface is selected.
  *  - S/PDIF coaxial and optical	: use input 1-2
  *  - ADAT optical at 32.0-48.0 kHz	: use input 1-8
  *  - ADAT optical at 88.2-96.0 kHz	: use input 1-4 (S/MUX format)
  *
  * The data in AMDTP channels for blank PCM channels are zero.
  */
 static const unsigned int freq_table[] = {
 	/* multiplier mode 0 */
 	[0] = 32000,
 	[1] = 44100,
 	[2] = 48000,
 	/* multiplier mode 1 */
 	[3] = 88200,
 	[4] = 96000,
 	/* multiplier mode 2 */
 	[5] = 176400,
 	[6] = 192000,
 };

 static inline unsigned int
 get_multiplier_mode_with_index(unsigned int index)
 {
 	return ((int)index - 1) / 2;
 }

 int snd_efw_get_multiplier_mode(unsigned int sampling_rate, unsigned int *mode)
 {
 	unsigned int i;

 	for (i = 0; i < ARRAY_SIZE(freq_table); i++) {
 		if (freq_table[i] == sampling_rate) {
 			*mode = get_multiplier_mode_with_index(i);
 			return 0;
 		}
 	}

 	return -EINVAL;
 }

 static int
 hw_rule_rate(struct snd_pcm_hw_params *params, struct snd_pcm_hw_rule *rule)
 {
 	unsigned int *pcm_channels = rule->private;
 	struct snd_interval *r =
 		hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
 	const struct snd_interval *c =
 		hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_CHANNELS);
 	struct snd_interval t = {
 		.min = UINT_MAX, .max = 0, .integer = 1
 	};
 	unsigned int i, mode;

 	for (i = 0; i < ARRAY_SIZE(freq_table); i++) {
 		mode = get_multiplier_mode_with_index(i);
 		if (!snd_interval_test(c, pcm_channels[mode]))
 			continue;

 		t.min = min(t.min, freq_table[i]);
 		t.max = max(t.max, freq_table[i]);
 	}

 	return snd_interval_refine(r, &t);
 }

 static int
 hw_rule_channels(struct snd_pcm_hw_params *params, struct snd_pcm_hw_rule *rule)
 {
 	unsigned int *pcm_channels = rule->private;
 	struct snd_interval *c =
 		hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
 	const struct snd_interval *r =
 		hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_RATE);
 	struct snd_interval t = {
 		.min = UINT_MAX, .max = 0, .integer = 1
 	};
 	unsigned int i, mode;

 	for (i = 0; i < ARRAY_SIZE(freq_table); i++) {
 		mode = get_multiplier_mode_with_index(i);
 		if (!snd_interval_test(r, freq_table[i]))
 			continue;

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

 	return snd_interval_refine(c, &t);
 }

 static void
 limit_channels(struct snd_pcm_hardware *hw, unsigned int *pcm_channels)
 {
 	unsigned int i, mode;

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

 	for (i = 0; i < ARRAY_SIZE(freq_table); i++) {
 		mode = get_multiplier_mode_with_index(i);
 		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]);
 	}
 }

 static int
 pcm_init_hw_params(struct snd_efw *efw,
 		   struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct amdtp_stream *s;
 	unsigned int *pcm_channels;
 	int err;

 	if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
 		runtime->hw.formats = AM824_IN_PCM_FORMAT_BITS;
 		s = &efw->tx_stream;
 		pcm_channels = efw->pcm_capture_channels;
 	} else {
 		runtime->hw.formats = AM824_OUT_PCM_FORMAT_BITS;
 		s = &efw->rx_stream;
 		pcm_channels = efw->pcm_playback_channels;
 	}

 	/* limit rates */
 	runtime->hw.rates = efw->supported_sampling_rate,
 	snd_pcm_limit_hw_rates(runtime);

 	limit_channels(&runtime->hw, pcm_channels);

 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
 				  hw_rule_channels, pcm_channels,
 				  SNDRV_PCM_HW_PARAM_RATE, -1);
 	if (err < 0)
 		goto end;

 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
 				  hw_rule_rate, pcm_channels,
 				  SNDRV_PCM_HW_PARAM_CHANNELS, -1);
 	if (err < 0)
 		goto end;

 	err = amdtp_am824_add_pcm_hw_constraints(s, runtime);
 end:
 	return err;
 }

 static int pcm_open(struct snd_pcm_substream *substream)
 {
 	struct snd_efw *efw = substream->private_data;
 	unsigned int sampling_rate;
 	enum snd_efw_clock_source clock_source;
 	int err;

 	err = snd_efw_stream_lock_try(efw);
 	if (err < 0)
 		goto end;

 	err = pcm_init_hw_params(efw, substream);
 	if (err < 0)
 		goto err_locked;

 	err = snd_efw_command_get_clock_source(efw, &clock_source);
 	if (err < 0)
 		goto err_locked;

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

 	snd_pcm_set_sync(substream);
 end:
 	return err;
 err_locked:
 	snd_efw_stream_lock_release(efw);
 	return err;
 }

 static int pcm_close(struct snd_pcm_substream *substream)
 {
 	struct snd_efw *efw = substream->private_data;
 	snd_efw_stream_lock_release(efw);
 	return 0;
 }

 static int pcm_hw_params(struct snd_pcm_substream *substream,
 				 struct snd_pcm_hw_params *hw_params)
 {
 	struct snd_efw *efw = substream->private_data;
 	int err;

 	err = snd_pcm_lib_alloc_vmalloc_buffer(substream,
 					       params_buffer_bytes(hw_params));
 	if (err < 0)
 		return err;

 	if (substream->runtime->status->state == SNDRV_PCM_STATE_OPEN) {
 		unsigned int rate = params_rate(hw_params);

 		mutex_lock(&efw->mutex);
 		err = snd_efw_stream_reserve_duplex(efw, rate);
 		if (err >= 0)
 			++efw->substreams_counter;
 		mutex_unlock(&efw->mutex);
 	}

 	return err;
 }

 static int pcm_hw_free(struct snd_pcm_substream *substream)
 {
 	struct snd_efw *efw = substream->private_data;

 	mutex_lock(&efw->mutex);

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

 	snd_efw_stream_stop_duplex(efw);

 	mutex_unlock(&efw->mutex);

 	return snd_pcm_lib_free_vmalloc_buffer(substream);
 }

 static int pcm_capture_prepare(struct snd_pcm_substream *substream)
 {
 	struct snd_efw *efw = substream->private_data;
 	int err;

 	err = snd_efw_stream_start_duplex(efw);
 	if (err >= 0)
 		amdtp_stream_pcm_prepare(&efw->tx_stream);

 	return err;
 }
 static int pcm_playback_prepare(struct snd_pcm_substream *substream)
 {
 	struct snd_efw *efw = substream->private_data;
 	int err;

 	err = snd_efw_stream_start_duplex(efw);
 	if (err >= 0)
 		amdtp_stream_pcm_prepare(&efw->rx_stream);

 	return err;
 }

 static int pcm_capture_trigger(struct snd_pcm_substream *substream, int cmd)
 {
 	struct snd_efw *efw = substream->private_data;

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

 	return 0;
 }
 static int pcm_playback_trigger(struct snd_pcm_substream *substream, int cmd)
 {
 	struct snd_efw *efw = substream->private_data;

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

 	return 0;
 }

 static snd_pcm_uframes_t pcm_capture_pointer(struct snd_pcm_substream *sbstrm)
 {
 	struct snd_efw *efw = sbstrm->private_data;
 	return amdtp_stream_pcm_pointer(&efw->tx_stream);
 }
 static snd_pcm_uframes_t pcm_playback_pointer(struct snd_pcm_substream *sbstrm)
 {
 	struct snd_efw *efw = sbstrm->private_data;
 	return amdtp_stream_pcm_pointer(&efw->rx_stream);
 }

 static int pcm_capture_ack(struct snd_pcm_substream *substream)
 {
 	struct snd_efw *efw = substream->private_data;

 	return amdtp_stream_pcm_ack(&efw->tx_stream);
 }

 static int pcm_playback_ack(struct snd_pcm_substream *substream)
 {
 	struct snd_efw *efw = substream->private_data;

 	return amdtp_stream_pcm_ack(&efw->rx_stream);
 }

 int snd_efw_create_pcm_devices(struct snd_efw *efw)
 {
 	static const struct snd_pcm_ops capture_ops = {
 		.open		= pcm_open,
 		.close		= pcm_close,
 		.ioctl		= snd_pcm_lib_ioctl,
 		.hw_params	= pcm_hw_params,
 		.hw_free	= pcm_hw_free,
 		.prepare	= pcm_capture_prepare,
 		.trigger	= pcm_capture_trigger,
 		.pointer	= pcm_capture_pointer,
 		.ack		= pcm_capture_ack,
 		.page		= snd_pcm_lib_get_vmalloc_page,
 	};
 	static const struct snd_pcm_ops playback_ops = {
 		.open		= pcm_open,
 		.close		= pcm_close,
 		.ioctl		= snd_pcm_lib_ioctl,
 		.hw_params	= pcm_hw_params,
 		.hw_free	= pcm_hw_free,
 		.prepare	= pcm_playback_prepare,
 		.trigger	= pcm_playback_trigger,
 		.pointer	= pcm_playback_pointer,
 		.ack		= pcm_playback_ack,
 		.page		= snd_pcm_lib_get_vmalloc_page,
 	};
 	struct snd_pcm *pcm;
 	int err;

 	err = snd_pcm_new(efw->card, efw->card->driver, 0, 1, 1, &pcm);
 	if (err < 0)
 		goto end;

 	pcm->private_data = efw;
 	snprintf(pcm->name, sizeof(pcm->name), "%s PCM", efw->card->shortname);
 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &playback_ops);
 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &capture_ops);
 end:
 	return err;
 }
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* fireworks_pcm.c - a part of driver for Fireworks based devices
	*
	* Copyright (c) 2009-2010 Clemens Ladisch
	* Copyright (c) 2013-2014 Takashi Sakamoto
	*/
	#include "./fireworks.h"

	/*
	* NOTE:
	* Fireworks changes its AMDTP channels for PCM data according to its sampling
	* rate. There are three modes. Here _XX is either _rx or _tx.
	* 0: 32.0- 48.0 kHz then snd_efw_hwinfo.amdtp_XX_pcm_channels applied
	* 1: 88.2- 96.0 kHz then snd_efw_hwinfo.amdtp_XX_pcm_channels_2x applied
	* 2: 176.4-192.0 kHz then snd_efw_hwinfo.amdtp_XX_pcm_channels_4x applied
	*
	* The number of PCM channels for analog input and output are always fixed but
	* the number of PCM channels for digital input and output are differed.
	*
	* Additionally, according to "AudioFire Owner's Manual Version 2.2", in some
	* model, the number of PCM channels for digital input has more restriction
	* depending on which digital interface is selected.
	* - S/PDIF coaxial and optical : use input 1-2
	* - ADAT optical at 32.0-48.0 kHz : use input 1-8
	* - ADAT optical at 88.2-96.0 kHz : use input 1-4 (S/MUX format)
	*
	* The data in AMDTP channels for blank PCM channels are zero.
	*/
	static const unsigned int freq_table[] = {
	/* multiplier mode 0 */
	[0] = 32000,
	[1] = 44100,
	[2] = 48000,
	/* multiplier mode 1 */
	[3] = 88200,
	[4] = 96000,
	/* multiplier mode 2 */
	[5] = 176400,
	[6] = 192000,
	};

	static inline unsigned int
	get_multiplier_mode_with_index(unsigned int index)
	{
	return ((int)index - 1) / 2;
	}

	int snd_efw_get_multiplier_mode(unsigned int sampling_rate, unsigned int *mode)
	{
	unsigned int i;

	for (i = 0; i < ARRAY_SIZE(freq_table); i++) {
	if (freq_table[i] == sampling_rate) {
	*mode = get_multiplier_mode_with_index(i);
	return 0;
	}
	}

	return -EINVAL;
	}

	static int
	hw_rule_rate(struct snd_pcm_hw_params params, struct snd_pcm_hw_rule rule)
	{
	unsigned int *pcm_channels = rule->private;
	struct snd_interval *r =
	hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
	const struct snd_interval *c =
	hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_CHANNELS);
	struct snd_interval t = {
	.min = UINT_MAX, .max = 0, .integer = 1
	};
	unsigned int i, mode;

	for (i = 0; i < ARRAY_SIZE(freq_table); i++) {
	mode = get_multiplier_mode_with_index(i);
	if (!snd_interval_test(c, pcm_channels[mode]))
	continue;

	t.min = min(t.min, freq_table[i]);
	t.max = max(t.max, freq_table[i]);
	}

	return snd_interval_refine(r, &t);
	}

	static int
	hw_rule_channels(struct snd_pcm_hw_params params, struct snd_pcm_hw_rule rule)
	{
	unsigned int *pcm_channels = rule->private;
	struct snd_interval *c =
	hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
	const struct snd_interval *r =
	hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_RATE);
	struct snd_interval t = {
	.min = UINT_MAX, .max = 0, .integer = 1
	};
	unsigned int i, mode;

	for (i = 0; i < ARRAY_SIZE(freq_table); i++) {
	mode = get_multiplier_mode_with_index(i);
	if (!snd_interval_test(r, freq_table[i]))
	continue;

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

	return snd_interval_refine(c, &t);
	}

	static void
	limit_channels(struct snd_pcm_hardware hw, unsigned int pcm_channels)
	{
	unsigned int i, mode;

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

	for (i = 0; i < ARRAY_SIZE(freq_table); i++) {
	mode = get_multiplier_mode_with_index(i);
	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]);
	}
	}

	static int
	pcm_init_hw_params(struct snd_efw *efw,
	struct snd_pcm_substream *substream)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct amdtp_stream *s;
	unsigned int *pcm_channels;
	int err;

	if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
	runtime->hw.formats = AM824_IN_PCM_FORMAT_BITS;
	s = &efw->tx_stream;
	pcm_channels = efw->pcm_capture_channels;
	} else {
	runtime->hw.formats = AM824_OUT_PCM_FORMAT_BITS;
	s = &efw->rx_stream;
	pcm_channels = efw->pcm_playback_channels;
	}

	/* limit rates */
	runtime->hw.rates = efw->supported_sampling_rate,
	snd_pcm_limit_hw_rates(runtime);

	limit_channels(&runtime->hw, pcm_channels);

	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
	hw_rule_channels, pcm_channels,
	SNDRV_PCM_HW_PARAM_RATE, -1);
	if (err < 0)
	goto end;

	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
	hw_rule_rate, pcm_channels,
	SNDRV_PCM_HW_PARAM_CHANNELS, -1);
	if (err < 0)
	goto end;

	err = amdtp_am824_add_pcm_hw_constraints(s, runtime);
	end:
	return err;
	}

	static int pcm_open(struct snd_pcm_substream *substream)
	{
	struct snd_efw *efw = substream->private_data;
	unsigned int sampling_rate;
	enum snd_efw_clock_source clock_source;
	int err;

	err = snd_efw_stream_lock_try(efw);
	if (err < 0)
	goto end;

	err = pcm_init_hw_params(efw, substream);
	if (err < 0)
	goto err_locked;

	err = snd_efw_command_get_clock_source(efw, &clock_source);
	if (err < 0)
	goto err_locked;

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

	snd_pcm_set_sync(substream);
	end:
	return err;
	err_locked:
	snd_efw_stream_lock_release(efw);
	return err;
	}

	static int pcm_close(struct snd_pcm_substream *substream)
	{
	struct snd_efw *efw = substream->private_data;
	snd_efw_stream_lock_release(efw);
	return 0;
	}

	static int pcm_hw_params(struct snd_pcm_substream *substream,
	struct snd_pcm_hw_params *hw_params)
	{
	struct snd_efw *efw = substream->private_data;
	int err;

	err = snd_pcm_lib_alloc_vmalloc_buffer(substream,
	params_buffer_bytes(hw_params));
	if (err < 0)
	return err;

	if (substream->runtime->status->state == SNDRV_PCM_STATE_OPEN) {
	unsigned int rate = params_rate(hw_params);

	mutex_lock(&efw->mutex);
	err = snd_efw_stream_reserve_duplex(efw, rate);
	if (err >= 0)
	++efw->substreams_counter;
	mutex_unlock(&efw->mutex);
	}

	return err;
	}

	static int pcm_hw_free(struct snd_pcm_substream *substream)
	{
	struct snd_efw *efw = substream->private_data;

	mutex_lock(&efw->mutex);

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

	snd_efw_stream_stop_duplex(efw);

	mutex_unlock(&efw->mutex);

	return snd_pcm_lib_free_vmalloc_buffer(substream);
	}

	static int pcm_capture_prepare(struct snd_pcm_substream *substream)
	{
	struct snd_efw *efw = substream->private_data;
	int err;

	err = snd_efw_stream_start_duplex(efw);
	if (err >= 0)
	amdtp_stream_pcm_prepare(&efw->tx_stream);

	return err;
	}
	static int pcm_playback_prepare(struct snd_pcm_substream *substream)
	{
	struct snd_efw *efw = substream->private_data;
	int err;

	err = snd_efw_stream_start_duplex(efw);
	if (err >= 0)
	amdtp_stream_pcm_prepare(&efw->rx_stream);

	return err;
	}

	static int pcm_capture_trigger(struct snd_pcm_substream *substream, int cmd)
	{
	struct snd_efw *efw = substream->private_data;

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

	return 0;
	}
	static int pcm_playback_trigger(struct snd_pcm_substream *substream, int cmd)
	{
	struct snd_efw *efw = substream->private_data;

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

	return 0;
	}

	static snd_pcm_uframes_t pcm_capture_pointer(struct snd_pcm_substream *sbstrm)
	{
	struct snd_efw *efw = sbstrm->private_data;
	return amdtp_stream_pcm_pointer(&efw->tx_stream);
	}
	static snd_pcm_uframes_t pcm_playback_pointer(struct snd_pcm_substream *sbstrm)
	{
	struct snd_efw *efw = sbstrm->private_data;
	return amdtp_stream_pcm_pointer(&efw->rx_stream);
	}

	static int pcm_capture_ack(struct snd_pcm_substream *substream)
	{
	struct snd_efw *efw = substream->private_data;

	return amdtp_stream_pcm_ack(&efw->tx_stream);
	}

	static int pcm_playback_ack(struct snd_pcm_substream *substream)
	{
	struct snd_efw *efw = substream->private_data;

	return amdtp_stream_pcm_ack(&efw->rx_stream);
	}

	int snd_efw_create_pcm_devices(struct snd_efw *efw)
	{
	static const struct snd_pcm_ops capture_ops = {
	.open = pcm_open,
	.close = pcm_close,
	.ioctl = snd_pcm_lib_ioctl,
	.hw_params = pcm_hw_params,
	.hw_free = pcm_hw_free,
	.prepare = pcm_capture_prepare,
	.trigger = pcm_capture_trigger,
	.pointer = pcm_capture_pointer,
	.ack = pcm_capture_ack,
	.page = snd_pcm_lib_get_vmalloc_page,
	};
	static const struct snd_pcm_ops playback_ops = {
	.open = pcm_open,
	.close = pcm_close,
	.ioctl = snd_pcm_lib_ioctl,
	.hw_params = pcm_hw_params,
	.hw_free = pcm_hw_free,
	.prepare = pcm_playback_prepare,
	.trigger = pcm_playback_trigger,
	.pointer = pcm_playback_pointer,
	.ack = pcm_playback_ack,
	.page = snd_pcm_lib_get_vmalloc_page,
	};
	struct snd_pcm *pcm;
	int err;

	err = snd_pcm_new(efw->card, efw->card->driver, 0, 1, 1, &pcm);
	if (err < 0)
	goto end;

	pcm->private_data = efw;
	snprintf(pcm->name, sizeof(pcm->name), "%s PCM", efw->card->shortname);
	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &playback_ops);
	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &capture_ops);
	end:
	return err;
	}