/**

 * \file pcm/pcm_iec958.c

 * \ingroup PCM_Plugins

 * \brief PCM IEC958 Subframe Conversion Plugin Interface

 * \author Takashi Iwai <tiwai@suse.de>

 * \date 2004

 */

/*

 *  PCM - IEC958 Subframe Conversion Plugin

 *  Copyright (c) 2004 by Takashi Iwai <tiwai@suse.de>

 *

 *

 *   This library is free software; you can redistribute it and/or modify

 *   it under the terms of the GNU Lesser General Public License as

 *   published by the Free Software Foundation; either version 2.1 of

 *   the License, or (at your option) any later version.

 *

 *   This program is distributed in the hope that it will be useful,

 *   but WITHOUT ANY WARRANTY; without even the implied warranty of

 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *   GNU Lesser General Public License for more details.

 *

 *   You should have received a copy of the GNU Lesser General Public

 *   License along with this library; if not, write to the Free Software

 *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

 *

 */

#include "bswap.h"

#include "pcm_local.h"

#include "pcm_plugin.h"

#include "plugin_ops.h"

#ifndef PIC

/* entry for static linking */

const char *_snd_module_pcm_iec958 = "";

#endif

/*

 */

#ifndef DOC_HIDDEN

typedef struct snd_pcm_iec958 snd_pcm_iec958_t;

typedef void (*iec958_f)(snd_pcm_iec958_t *iec,

			 const snd_pcm_channel_area_t *dst_areas,

			 snd_pcm_uframes_t dst_offset,

			 const snd_pcm_channel_area_t *src_areas,

			 snd_pcm_uframes_t src_offset,

			 unsigned int channels, snd_pcm_uframes_t frames);

struct snd_pcm_iec958 {

	/* This field need to be the first */

	snd_pcm_plugin_t plug;

	unsigned int getput_idx;

	iec958_f func;

	snd_pcm_format_t sformat;

	snd_pcm_format_t format;

	unsigned int counter;

	unsigned char status[24];

	unsigned int byteswap;

	unsigned char preamble[3];	/* B/M/W or Z/X/Y */

	snd_pcm_fast_ops_t fops;

};

enum { PREAMBLE_Z, PREAMBLE_X, PREAMBLE_Y };

#endif /* DOC_HIDDEN */

/*

 * Determine parity for time slots 4 upto 30

 * to be sure that bit 4 upt 31 will carry

 * an even number of ones and zeros.

 */

static unsigned int iec958_parity(unsigned int data)

{

	unsigned int parity;

	int bit;

	data >>= 4;     /* start from bit 4 */

	parity = 0;

	for (bit = 4; bit <= 30; bit++) {

		if (data & 1)

			parity++;

		data >>= 1;

	}

	return (parity & 1);

}

/*

 * Compose 32bit IEC958 subframe, two sub frames

 * build one frame with two channels.

 *

 * bit 0-3  = preamble

 *     4-7  = AUX (=0)

 *     8-27 = data (12-27 for 16bit, 8-27 for 20bit, and 24bit without AUX)

 *     28   = validity (0 for valid data, else 'in error')

 *     29   = user data (0)

 *     30   = channel status (24 bytes for 192 frames)

 *     31   = parity

 */

static inline uint32_t iec958_subframe(snd_pcm_iec958_t *iec, uint32_t data, int channel)

{

	unsigned int byte = iec->counter >> 3;

	unsigned int mask = 1 << (iec->counter - (byte << 3));

	/* bit 4-27 */

	data >>= 4;

	data &= ~0xf;

	/* set IEC status bits (up to 192 bits) */

	if (iec->status[byte] & mask)

		data |= 0x40000000;

	if (iec958_parity(data))	/* parity bit 4-30 */

		data |= 0x80000000;

	/* Preamble */

	if (channel)

		data |= iec->preamble[PREAMBLE_Y];	/* odd sub frame, 'Y' */

	else if (! iec->counter)

		data |= iec->preamble[PREAMBLE_Z];	/* Block start, 'Z' */

	else

		data |= iec->preamble[PREAMBLE_X];	/* even sub frame, 'X' */

	if (iec->byteswap)

		data = bswap_32(data);

	return data;

}

static inline int32_t iec958_to_s32(snd_pcm_iec958_t *iec, uint32_t data)

{

	if (iec->byteswap)

		data = bswap_32(data);

	data &= ~0xf;

	data <<= 4;

	return (int32_t)data;

}

#ifndef DOC_HIDDEN

static void snd_pcm_iec958_decode(snd_pcm_iec958_t *iec,

				  const snd_pcm_channel_area_t *dst_areas,

				  snd_pcm_uframes_t dst_offset,

				  const snd_pcm_channel_area_t *src_areas,

				  snd_pcm_uframes_t src_offset,

				  unsigned int channels, snd_pcm_uframes_t frames)

{

#define PUT32_LABELS

#include "plugin_ops.h"

#undef PUT32_LABELS

	void *put = put32_labels[iec->getput_idx];

	unsigned int channel;

	for (channel = 0; channel < channels; ++channel) {

		const uint32_t *src;

		char *dst;

		int src_step, dst_step;

		snd_pcm_uframes_t frames1;

		const snd_pcm_channel_area_t *src_area = &src_areas[channel];

		const snd_pcm_channel_area_t *dst_area = &dst_areas[channel];

		src = snd_pcm_channel_area_addr(src_area, src_offset);

		dst = snd_pcm_channel_area_addr(dst_area, dst_offset);

		src_step = snd_pcm_channel_area_step(src_area) / sizeof(uint32_t);

		dst_step = snd_pcm_channel_area_step(dst_area);

		frames1 = frames;

		while (frames1-- > 0) {

			int32_t sample = iec958_to_s32(iec, *src);

			goto *put;

#define PUT32_END after

#include "plugin_ops.h"

#undef PUT32_END

		after:

			src += src_step;

			dst += dst_step;

		}

	}

}

static void snd_pcm_iec958_encode(snd_pcm_iec958_t *iec,

				  const snd_pcm_channel_area_t *dst_areas,

				  snd_pcm_uframes_t dst_offset,

				  const snd_pcm_channel_area_t *src_areas,

				  snd_pcm_uframes_t src_offset,

				  unsigned int channels, snd_pcm_uframes_t frames)

{

#define GET32_LABELS

#include "plugin_ops.h"

#undef GET32_LABELS

	void *get = get32_labels[iec->getput_idx];

	unsigned int channel;

	int32_t sample = 0;

	int counter = iec->counter;

	for (channel = 0; channel < channels; ++channel) {

		const char *src;

		uint32_t *dst;

		int src_step, dst_step;

		snd_pcm_uframes_t frames1;

		const snd_pcm_channel_area_t *src_area = &src_areas[channel];

		const snd_pcm_channel_area_t *dst_area = &dst_areas[channel];

		src = snd_pcm_channel_area_addr(src_area, src_offset);

		dst = snd_pcm_channel_area_addr(dst_area, dst_offset);

		src_step = snd_pcm_channel_area_step(src_area);

		dst_step = snd_pcm_channel_area_step(dst_area) / sizeof(uint32_t);

		frames1 = frames;

		iec->counter = counter;

		while (frames1-- > 0) {

			goto *get;

#define GET32_END after

#include "plugin_ops.h"

#undef GET32_END

		after:

			sample = iec958_subframe(iec, sample, channel);

			// fprintf(stderr, "%d:%08x\n", frames1, sample);

			*dst = sample;

			src += src_step;

			dst += dst_step;

			iec->counter++;

			iec->counter %= 192;

		}

	}

}

#endif /* DOC_HIDDEN */

static int snd_pcm_iec958_hw_refine_cprepare(snd_pcm_t *pcm, snd_pcm_hw_params_t *params)

{

	snd_pcm_iec958_t *iec = pcm->private_data;

	int err;

	snd_pcm_access_mask_t access_mask = { SND_PCM_ACCBIT_SHM };

	err = _snd_pcm_hw_param_set_mask(params, SND_PCM_HW_PARAM_ACCESS,

					 &access_mask);

	if (err < 0)

		return err;

	if (iec->sformat == SND_PCM_FORMAT_IEC958_SUBFRAME_LE ||

	    iec->sformat == SND_PCM_FORMAT_IEC958_SUBFRAME_BE) {

		snd_pcm_format_mask_t format_mask = { SND_PCM_FMTBIT_LINEAR };

		err = _snd_pcm_hw_param_set_mask(params, SND_PCM_HW_PARAM_FORMAT,

						 &format_mask);

	} else {

		snd_pcm_format_mask_t format_mask = {

			{ (1U << SND_PCM_FORMAT_IEC958_SUBFRAME_LE) |

			  (1U << SND_PCM_FORMAT_IEC958_SUBFRAME_BE) }

		};

		err = _snd_pcm_hw_param_set_mask(params, SND_PCM_HW_PARAM_FORMAT,

						 &format_mask);

	}

	if (err < 0)

		return err;

	err = _snd_pcm_hw_params_set_subformat(params, SND_PCM_SUBFORMAT_STD);

	if (err < 0)

		return err;

	params->info &= ~(SND_PCM_INFO_MMAP | SND_PCM_INFO_MMAP_VALID);

	return 0;

}

static int snd_pcm_iec958_hw_refine_sprepare(snd_pcm_t *pcm, snd_pcm_hw_params_t *sparams)

{

	snd_pcm_iec958_t *iec = pcm->private_data;

	snd_pcm_access_mask_t saccess_mask = { SND_PCM_ACCBIT_MMAP };

	_snd_pcm_hw_params_any(sparams);

	_snd_pcm_hw_param_set_mask(sparams, SND_PCM_HW_PARAM_ACCESS,

				   &saccess_mask);

	_snd_pcm_hw_params_set_format(sparams, iec->sformat);

	_snd_pcm_hw_params_set_subformat(sparams, SND_PCM_SUBFORMAT_STD);

	return 0;

}

static int snd_pcm_iec958_hw_refine_schange(snd_pcm_t *pcm ATTRIBUTE_UNUSED, snd_pcm_hw_params_t *params,

					    snd_pcm_hw_params_t *sparams)

{

	int err;

	unsigned int links = (SND_PCM_HW_PARBIT_CHANNELS |

			      SND_PCM_HW_PARBIT_RATE |

			      SND_PCM_HW_PARBIT_PERIOD_SIZE |

			      SND_PCM_HW_PARBIT_BUFFER_SIZE |

			      SND_PCM_HW_PARBIT_PERIODS |

			      SND_PCM_HW_PARBIT_PERIOD_TIME |

			      SND_PCM_HW_PARBIT_BUFFER_TIME |

			      SND_PCM_HW_PARBIT_TICK_TIME);

	err = _snd_pcm_hw_params_refine(sparams, links, params);

	if (err < 0)

		return err;

	return 0;

}

static int snd_pcm_iec958_hw_refine_cchange(snd_pcm_t *pcm ATTRIBUTE_UNUSED, snd_pcm_hw_params_t *params,

					    snd_pcm_hw_params_t *sparams)

{

	int err;

	unsigned int links = (SND_PCM_HW_PARBIT_CHANNELS |

			      SND_PCM_HW_PARBIT_RATE |

			      SND_PCM_HW_PARBIT_PERIOD_SIZE |

			      SND_PCM_HW_PARBIT_BUFFER_SIZE |

			      SND_PCM_HW_PARBIT_PERIODS |

			      SND_PCM_HW_PARBIT_PERIOD_TIME |

			      SND_PCM_HW_PARBIT_BUFFER_TIME |

			      SND_PCM_HW_PARBIT_TICK_TIME);

	err = _snd_pcm_hw_params_refine(params, links, sparams);

	if (err < 0)

		return err;

	return 0;

}

static int snd_pcm_iec958_hw_refine(snd_pcm_t *pcm, snd_pcm_hw_params_t *params)

{

	return snd_pcm_hw_refine_slave(pcm, params,

				       snd_pcm_iec958_hw_refine_cprepare,

				       snd_pcm_iec958_hw_refine_cchange,

				       snd_pcm_iec958_hw_refine_sprepare,

				       snd_pcm_iec958_hw_refine_schange,

				       snd_pcm_generic_hw_refine);

}

static int snd_pcm_iec958_hw_params(snd_pcm_t *pcm, snd_pcm_hw_params_t * params)

{

	snd_pcm_iec958_t *iec = pcm->private_data;

	snd_pcm_format_t format;

	int err = snd_pcm_hw_params_slave(pcm, params,

					  snd_pcm_iec958_hw_refine_cchange,

					  snd_pcm_iec958_hw_refine_sprepare,

					  snd_pcm_iec958_hw_refine_schange,

					  snd_pcm_generic_hw_params);

	if (err < 0)

		return err;

	err = INTERNAL(snd_pcm_hw_params_get_format)(params, &format);

	if (err < 0)

		return err;

	iec->format = format;

	if (pcm->stream == SND_PCM_STREAM_PLAYBACK) {

		if (iec->sformat == SND_PCM_FORMAT_IEC958_SUBFRAME_LE ||

		    iec->sformat == SND_PCM_FORMAT_IEC958_SUBFRAME_BE) {

			iec->getput_idx = snd_pcm_linear_get_index(format, SND_PCM_FORMAT_S32);

			iec->func = snd_pcm_iec958_encode;

			iec->byteswap = iec->sformat != SND_PCM_FORMAT_IEC958_SUBFRAME;

		} else {

			iec->getput_idx = snd_pcm_linear_put_index(SND_PCM_FORMAT_S32, iec->sformat);

			iec->func = snd_pcm_iec958_decode;

			iec->byteswap = format != SND_PCM_FORMAT_IEC958_SUBFRAME;

		}

	} else {

		if (iec->sformat == SND_PCM_FORMAT_IEC958_SUBFRAME_LE ||

		    iec->sformat == SND_PCM_FORMAT_IEC958_SUBFRAME_BE) {

			iec->getput_idx = snd_pcm_linear_put_index(SND_PCM_FORMAT_S32, format);

			iec->func = snd_pcm_iec958_decode;

			iec->byteswap = iec->sformat != SND_PCM_FORMAT_IEC958_SUBFRAME;

		} else {

			iec->getput_idx = snd_pcm_linear_get_index(iec->sformat, SND_PCM_FORMAT_S32);

			iec->func = snd_pcm_iec958_encode;

			iec->byteswap = format != SND_PCM_FORMAT_IEC958_SUBFRAME;

		}

	}

	/* FIXME: needs to adjust status_bits according to the format

	 *        and sample rate

	 */

	return 0;

}

static snd_pcm_uframes_t

snd_pcm_iec958_write_areas(snd_pcm_t *pcm,

			   const snd_pcm_channel_area_t *areas,

			   snd_pcm_uframes_t offset,

			   snd_pcm_uframes_t size,

			   const snd_pcm_channel_area_t *slave_areas,

			   snd_pcm_uframes_t slave_offset,

			   snd_pcm_uframes_t *slave_sizep)

{

	snd_pcm_iec958_t *iec = pcm->private_data;

	if (size > *slave_sizep)

		size = *slave_sizep;

	iec->func(iec, slave_areas, slave_offset,

		  areas, offset, 

		  pcm->channels, size);

	*slave_sizep = size;

	return size;

}

static snd_pcm_uframes_t

snd_pcm_iec958_read_areas(snd_pcm_t *pcm,

			  const snd_pcm_channel_area_t *areas,

			  snd_pcm_uframes_t offset,

			  snd_pcm_uframes_t size,

			  const snd_pcm_channel_area_t *slave_areas,

			  snd_pcm_uframes_t slave_offset,

			  snd_pcm_uframes_t *slave_sizep)

{

	snd_pcm_iec958_t *iec = pcm->private_data;

	if (size > *slave_sizep)

		size = *slave_sizep;

	iec->func(iec, areas, offset, 

		  slave_areas, slave_offset,

		  pcm->channels, size);

	*slave_sizep = size;

	return size;

}

static int snd_pcm_iec958_init(snd_pcm_t *pcm)

{

	snd_pcm_iec958_t *iec = pcm->private_data;

	iec->counter = 0;

	return 0;

}

static void snd_pcm_iec958_dump(snd_pcm_t *pcm, snd_output_t *out)

{

	snd_pcm_iec958_t *iec = pcm->private_data;

	snd_output_printf(out, "IEC958 subframe conversion PCM (%s)\n", 

			  snd_pcm_format_name(iec->sformat));

	if (pcm->setup) {

		snd_output_printf(out, "Its setup is:\n");

		snd_pcm_dump_setup(pcm, out);

	}

	snd_output_printf(out, "Slave: ");

	snd_pcm_dump(iec->plug.gen.slave, out);

}

static snd_pcm_sframes_t snd_pcm_iec958_rewind(snd_pcm_t *pcm, snd_pcm_uframes_t frames)

{

	unsigned int counter_decrement;

	snd_pcm_iec958_t *iec = pcm->private_data;

	snd_pcm_sframes_t result = snd_pcm_plugin_rewind(pcm, frames);

	if (result <= 0)

		return result;

	counter_decrement = result % 192;

	iec->counter += 192 - counter_decrement;

	iec->counter %= 192;

	return result;

}

static snd_pcm_sframes_t snd_pcm_iec958_forward(snd_pcm_t *pcm, snd_pcm_uframes_t frames)

{

	unsigned int counter_increment;

	snd_pcm_iec958_t *iec = pcm->private_data;

	snd_pcm_sframes_t result = snd_pcm_plugin_rewind(pcm, frames);

	if (result <= 0)

		return result;

	counter_increment = result % 192;

	iec->counter += counter_increment;

	iec->counter %= 192;

	return result;

}

static const snd_pcm_ops_t snd_pcm_iec958_ops = {

	.close = snd_pcm_generic_close,

	.info = snd_pcm_generic_info,

	.hw_refine = snd_pcm_iec958_hw_refine,

	.hw_params = snd_pcm_iec958_hw_params,

	.hw_free = snd_pcm_generic_hw_free,

	.sw_params = snd_pcm_generic_sw_params,

	.channel_info = snd_pcm_generic_channel_info,

	.dump = snd_pcm_iec958_dump,

	.nonblock = snd_pcm_generic_nonblock,

	.async = snd_pcm_generic_async,

	.mmap = snd_pcm_generic_mmap,

	.munmap = snd_pcm_generic_munmap,

	.query_chmaps = snd_pcm_generic_query_chmaps,

	.get_chmap = snd_pcm_generic_get_chmap,

	.set_chmap = snd_pcm_generic_set_chmap,

};

/**

 * \brief Creates a new IEC958 subframe conversion PCM

 * \param pcmp Returns created PCM handle

 * \param name Name of PCM

 * \param sformat Slave (destination) format

 * \param slave Slave PCM handle

 * \param close_slave When set, the slave PCM handle is closed with copy PCM

 * \param status_bits The IEC958 status bits

 * \param preamble_vals The preamble byte values

 * \retval zero on success otherwise a negative error code

 * \warning Using of this function might be dangerous in the sense

 *          of compatibility reasons. The prototype might be freely

 *          changed in future.

 */           

int snd_pcm_iec958_open(snd_pcm_t **pcmp, const char *name, snd_pcm_format_t sformat,

			snd_pcm_t *slave, int close_slave,

			const unsigned char *status_bits,

			const unsigned char *preamble_vals)

{

	snd_pcm_t *pcm;

	snd_pcm_iec958_t *iec;

	int err;

	static const unsigned char default_status_bits[] = {

		IEC958_AES0_CON_EMPHASIS_NONE,

		IEC958_AES1_CON_ORIGINAL | IEC958_AES1_CON_PCM_CODER,

		0,

		IEC958_AES3_CON_FS_48000

	};

	assert(pcmp && slave);

	if (snd_pcm_format_linear(sformat) != 1 &&

	    sformat != SND_PCM_FORMAT_IEC958_SUBFRAME_LE &&

	    sformat != SND_PCM_FORMAT_IEC958_SUBFRAME_BE)

		return -EINVAL;

	iec = calloc(1, sizeof(snd_pcm_iec958_t));

	if (!iec) {

		return -ENOMEM;

	}

	snd_pcm_plugin_init(&iec->plug);

	iec->sformat = sformat;

	iec->plug.read = snd_pcm_iec958_read_areas;

	iec->plug.write = snd_pcm_iec958_write_areas;

	iec->plug.init = snd_pcm_iec958_init;

	iec->plug.undo_read = snd_pcm_plugin_undo_read_generic;

	iec->plug.undo_write = snd_pcm_plugin_undo_write_generic;

	iec->plug.gen.slave = slave;

	iec->plug.gen.close_slave = close_slave;

	if (status_bits)

		memcpy(iec->status, status_bits, sizeof(iec->status));

	else

		memcpy(iec->status, default_status_bits, sizeof(default_status_bits));

	memcpy(iec->preamble, preamble_vals, 3);

	err = snd_pcm_new(&pcm, SND_PCM_TYPE_IEC958, name, slave->stream, slave->mode);

	if (err < 0) {

		free(iec);

		return err;

	}

	pcm->ops = &snd_pcm_iec958_ops;

	iec->fops = snd_pcm_plugin_fast_ops;

	iec->fops.rewind = snd_pcm_iec958_rewind;

	iec->fops.forward = snd_pcm_iec958_forward;

	pcm->fast_ops = &iec->fops;

	pcm->private_data = iec;

	pcm->poll_fd = slave->poll_fd;

	pcm->poll_events = slave->poll_events;

	pcm->tstamp_type = slave->tstamp_type;

	snd_pcm_set_hw_ptr(pcm, &iec->plug.hw_ptr, -1, 0);

	snd_pcm_set_appl_ptr(pcm, &iec->plug.appl_ptr, -1, 0);

	*pcmp = pcm;

	return 0;

}

/*! \page pcm_plugins

\section pcm_plugins_iec958 Plugin: IEC958

This plugin converts 32bit IEC958 subframe samples to linear, or linear to

32bit IEC958 subframe samples.

\code

pcm.name {

        type iec958             # IEC958 subframe conversion PCM

        slave STR               # Slave name

        # or

        slave {                 # Slave definition

                pcm STR         # Slave PCM name

                # or

                pcm { }         # Slave PCM definition

        }

	[status status-bytes]	# IEC958 status bits (given in byte array)

	# IEC958 preamble bits definitions

	# B/M/W or Z/X/Y, B = block start, M = even subframe, W = odd subframe

	# As default, Z = 0x08, Y = 0x04, X = 0x02

	[preamble.z or preamble.b val]

	[preamble.x or preamble.m val]

	[preamble.y or preamble.w val]

}

\endcode

\subsection pcm_plugins_iec958_funcref Function reference

  
snd_pcm_iec958_open()

  
_snd_pcm_iec958_open()

*/

/**

 * \brief Creates a new IEC958 subframe conversion PCM

 * \param pcmp Returns created PCM handle

 * \param name Name of PCM

 * \param root Root configuration node

 * \param conf Configuration node with copy PCM description

 * \param stream Stream type

 * \param mode Stream mode

 * \retval zero on success otherwise a negative error code

 * \warning Using of this function might be dangerous in the sense

 *          of compatibility reasons. The prototype might be freely

 *          changed in future.

 */

int _snd_pcm_iec958_open(snd_pcm_t **pcmp, const char *name,

			 snd_config_t *root, snd_config_t *conf, 

			 snd_pcm_stream_t stream, int mode)

{

	snd_config_iterator_t i, next;

	int err;

	snd_pcm_t *spcm;

	snd_config_t *slave = NULL, *sconf;

	snd_config_t *status = NULL, *preamble = NULL;

	snd_pcm_format_t sformat;

	unsigned char status_bits[24];

	unsigned char preamble_vals[3] = {

		0x08, 0x02, 0x04 /* Z, X, Y */

	};

	snd_config_for_each(i, next, conf) {

		snd_config_t *n = snd_config_iterator_entry(i);

		const char *id;

		if (snd_config_get_id(n, &id) < 0)

			continue;

		if (snd_pcm_conf_generic_id(id))

			continue;

		if (strcmp(id, "slave") == 0) {

			slave = n;

			continue;

		}

		if (strcmp(id, "status") == 0) {

			if (snd_config_get_type(n) != SND_CONFIG_TYPE_COMPOUND) {

				SNDERR("Invalid type for %s", id);

				return -EINVAL;

			}

			status = n;

			continue;

		}

		if (strcmp(id, "preamble") == 0) {

			if (snd_config_get_type(n) != SND_CONFIG_TYPE_COMPOUND) {

				SNDERR("Invalid type for %s", id);

				return -EINVAL;

			}

			preamble = n;

			continue;

		}

		SNDERR("Unknown field %s", id);

		return -EINVAL;

	}

	memset(status_bits, 0, sizeof(status_bits));

	if (status) {

		snd_config_iterator_t i, inext;

		int bytes = 0;

		snd_config_for_each(i, inext, status) {

			long val;

			snd_config_t *n = snd_config_iterator_entry(i);

			if (snd_config_get_type(n) != SND_CONFIG_TYPE_INTEGER) {

				SNDERR("invalid IEC958 status bits");

				return -EINVAL;

			}

			err = snd_config_get_integer(n, &val;;

			if (err < 0) {

				SNDERR("invalid IEC958 status bits");

				return err;

			}

			status_bits[bytes] = val;

			bytes++;

			if (bytes >= (int)sizeof(status_bits))

				break;

		}

		// fprintf(stderr, "STATUS bits: %02x %02x %02x %02x\n", status_bits[0], status_bits[1], status_bits[2], status_bits[3]);

	}

	if (preamble) {

		snd_config_iterator_t i, inext;

		snd_config_for_each(i, inext, preamble) {

			long val;

			snd_config_t *n = snd_config_iterator_entry(i);

			const char *id;

			int idx;

			if (snd_config_get_id(n, &id) < 0)

				continue;

			if (strcmp(id, "b") == 0 || strcmp(id, "z") == 0)

				idx = PREAMBLE_Z;

			else if (strcmp(id, "m") == 0 || strcmp(id, "x") == 0)

				idx = PREAMBLE_X;

			else if (strcmp(id, "w") == 0 || strcmp(id, "y") == 0)

				idx = PREAMBLE_Y;

			else {

				SNDERR("invalid IEC958 preamble type %s", id);

				return -EINVAL;

			}

			err = snd_config_get_integer(n, &val;;

			if (err < 0) {

				SNDERR("invalid IEC958 preamble value");

				return err;

			}

			preamble_vals[idx] = val;

		}

	}

	if (!slave) {

		SNDERR("slave is not defined");

		return -EINVAL;

	}

	err = snd_pcm_slave_conf(root, slave, &sconf, 1,

				 SND_PCM_HW_PARAM_FORMAT, SCONF_MANDATORY, &sformat);

	if (err < 0)

		return err;

	if (snd_pcm_format_linear(sformat) != 1 &&

	    sformat != SND_PCM_FORMAT_IEC958_SUBFRAME_LE &&

	    sformat != SND_PCM_FORMAT_IEC958_SUBFRAME_BE) {

	    	snd_config_delete(sconf);

		SNDERR("invalid slave format");

		return -EINVAL;

	}

	err = snd_pcm_open_slave(&spcm, root, sconf, stream, mode, conf);

	snd_config_delete(sconf);

	if (err < 0)

		return err;

	err = snd_pcm_iec958_open(pcmp, name, sformat, spcm, 1,

				  status ? status_bits : NULL,

				  preamble_vals);

	if (err < 0)

		snd_pcm_close(spcm);

	return err;

}

#ifndef DOC_HIDDEN

SND_DLSYM_BUILD_VERSION(_snd_pcm_iec958_open, SND_PCM_DLSYM_VERSION);

#endif