/*
   *  Dummy soundcard
   *  Copyright (c) by Jaroslav Kysela <perex@suse.cz>
   *
   *   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; either version 2 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 General Public License for more details.
   *
   *   You should have received a copy of the GNU General Public License
   *   along with this program; if not, write to the Free Software
   *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
   *
   */
  
  #include <sound/driver.h>
  #include <linux/init.h>
  #include <linux/jiffies.h>
  #include <linux/slab.h>
  #include <linux/time.h>
  #include <linux/wait.h>
  #include <linux/moduleparam.h>
  #include <sound/core.h>
  #include <sound/control.h>
  #include <sound/pcm.h>
  #include <sound/rawmidi.h>
  #include <sound/initval.h>
  
  MODULE_AUTHOR("Jaroslav Kysela <perex@suse.cz>");
  MODULE_DESCRIPTION("Dummy soundcard (/dev/null)");
  MODULE_LICENSE("GPL");
  MODULE_SUPPORTED_DEVICE("{{ALSA,Dummy soundcard}}");
  
  #define MAX_PCM_DEVICES		4
  #define MAX_PCM_SUBSTREAMS	16
  #define MAX_MIDI_DEVICES	2
  
  #if 0 /* emu10k1 emulation */
  #define MAX_BUFFER_SIZE		(128 * 1024)
  static int emu10k1_playback_constraints(snd_pcm_runtime_t *runtime)
  {
  	int err;
  	if ((err = snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS)) < 0)
  		return err;
  	if ((err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 256, UINT_MAX)) < 0)
  		return err;
  	return 0;
  }
  #define add_playback_constraints emu10k1_playback_constraints
  #endif
  
  #if 0 /* RME9652 emulation */
  #define MAX_BUFFER_SIZE		(26 * 64 * 1024)
  #define USE_FORMATS		SNDRV_PCM_FMTBIT_S32_LE
  #define USE_CHANNELS_MIN	26
  #define USE_CHANNELS_MAX	26
  #define USE_PERIODS_MIN		2
  #define USE_PERIODS_MAX		2
  #endif
  
  #if 0 /* ICE1712 emulation */
  #define MAX_BUFFER_SIZE		(256 * 1024)
  #define USE_FORMATS		SNDRV_PCM_FMTBIT_S32_LE
  #define USE_CHANNELS_MIN	10
  #define USE_CHANNELS_MAX	10
  #define USE_PERIODS_MIN		1
  #define USE_PERIODS_MAX		1024
  #endif
  
  #if 0 /* UDA1341 emulation */
  #define MAX_BUFFER_SIZE		(16380)
  #define USE_FORMATS		SNDRV_PCM_FMTBIT_S16_LE
  #define USE_CHANNELS_MIN	2
  #define USE_CHANNELS_MAX	2
  #define USE_PERIODS_MIN		2
  #define USE_PERIODS_MAX		255
  #endif
  
  #if 0 /* simple AC97 bridge (intel8x0) with 48kHz AC97 only codec */
  #define USE_FORMATS		SNDRV_PCM_FMTBIT_S16_LE
  #define USE_CHANNELS_MIN	2
  #define USE_CHANNELS_MAX	2
  #define USE_RATE		SNDRV_PCM_RATE_48000
  #define USE_RATE_MIN		48000
  #define USE_RATE_MAX		48000
  #endif
  
  
  /* defaults */
  #ifndef MAX_BUFFER_SIZE
  #define MAX_BUFFER_SIZE		(64*1024)
  #endif
  #ifndef USE_FORMATS
  #define USE_FORMATS 		(SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S16_LE)
  #endif
  #ifndef USE_RATE
  #define USE_RATE		SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_48000
  #define USE_RATE_MIN		5500
  #define USE_RATE_MAX		48000
  #endif
  #ifndef USE_CHANNELS_MIN
  #define USE_CHANNELS_MIN 	1
  #endif
  #ifndef USE_CHANNELS_MAX
  #define USE_CHANNELS_MAX 	2
  #endif
  #ifndef USE_PERIODS_MIN
  #define USE_PERIODS_MIN 	1
  #endif
  #ifndef USE_PERIODS_MAX
  #define USE_PERIODS_MAX 	1024
  #endif
  #ifndef add_playback_constraints
  #define add_playback_constraints(x) 0
  #endif
  #ifndef add_capture_constraints
  #define add_capture_constraints(x) 0
  #endif
  
  static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;	/* Index 0-MAX */
  static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;	/* ID for this card */
  static int enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
  static int pcm_devs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 1};
  static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8};
  //static int midi_devs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 2};
  
  module_param_array(index, int, NULL, 0444);
  MODULE_PARM_DESC(index, "Index value for dummy soundcard.");
  module_param_array(id, charp, NULL, 0444);
  MODULE_PARM_DESC(id, "ID string for dummy soundcard.");
  module_param_array(enable, bool, NULL, 0444);
  MODULE_PARM_DESC(enable, "Enable this dummy soundcard.");
  module_param_array(pcm_devs, int, NULL, 0444);
  MODULE_PARM_DESC(pcm_devs, "PCM devices # (0-4) for dummy driver.");
  module_param_array(pcm_substreams, int, NULL, 0444);
  MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-16) for dummy driver.");
  //module_param_array(midi_devs, int, NULL, 0444);
  //MODULE_PARM_DESC(midi_devs, "MIDI devices # (0-2) for dummy driver.");
  
  #define MIXER_ADDR_MASTER	0
  #define MIXER_ADDR_LINE		1
  #define MIXER_ADDR_MIC		2
  #define MIXER_ADDR_SYNTH	3
  #define MIXER_ADDR_CD		4
  #define MIXER_ADDR_LAST		4
  
  typedef struct snd_card_dummy {
  	snd_card_t *card;
  	spinlock_t mixer_lock;
  	int mixer_volume[MIXER_ADDR_LAST+1][2];
  	int capture_source[MIXER_ADDR_LAST+1][2];
  } snd_card_dummy_t;
  
  typedef struct snd_card_dummy_pcm {
  	snd_card_dummy_t *dummy;
  	spinlock_t lock;
  	struct timer_list timer;
  	unsigned int pcm_size;
  	unsigned int pcm_count;
  	unsigned int pcm_bps;		/* bytes per second */
  	unsigned int pcm_jiffie;	/* bytes per one jiffie */
  	unsigned int pcm_irq_pos;	/* IRQ position */
  	unsigned int pcm_buf_pos;	/* position in buffer */
  	snd_pcm_substream_t *substream;
  } snd_card_dummy_pcm_t;
  
  static snd_card_t *snd_dummy_cards[SNDRV_CARDS] = SNDRV_DEFAULT_PTR;
  
  
  static void snd_card_dummy_pcm_timer_start(snd_pcm_substream_t * substream)
  {
  	snd_pcm_runtime_t *runtime = substream->runtime;
  	snd_card_dummy_pcm_t *dpcm = runtime->private_data;
  
  	dpcm->timer.expires = 1 + jiffies;
  	add_timer(&dpcm->timer);
  }
  
  static void snd_card_dummy_pcm_timer_stop(snd_pcm_substream_t * substream)
  {
  	snd_pcm_runtime_t *runtime = substream->runtime;
  	snd_card_dummy_pcm_t *dpcm = runtime->private_data;
  
  	del_timer(&dpcm->timer);
  }
  
  static int snd_card_dummy_playback_trigger(snd_pcm_substream_t * substream,
  					   int cmd)
  {
  	if (cmd == SNDRV_PCM_TRIGGER_START) {
  		snd_card_dummy_pcm_timer_start(substream);
  	} else if (cmd == SNDRV_PCM_TRIGGER_STOP) {
  		snd_card_dummy_pcm_timer_stop(substream);
  	} else {
  		return -EINVAL;
  	}
  	return 0;
  }
  
  static int snd_card_dummy_capture_trigger(snd_pcm_substream_t * substream,
  					  int cmd)
  {
  	if (cmd == SNDRV_PCM_TRIGGER_START) {
  		snd_card_dummy_pcm_timer_start(substream);
  	} else if (cmd == SNDRV_PCM_TRIGGER_STOP) {
  		snd_card_dummy_pcm_timer_stop(substream);
  	} else {
  		return -EINVAL;
  	}
  	return 0;
  }
  
  static int snd_card_dummy_pcm_prepare(snd_pcm_substream_t * substream)
  {
  	snd_pcm_runtime_t *runtime = substream->runtime;
  	snd_card_dummy_pcm_t *dpcm = runtime->private_data;
  	unsigned int bps;
  
  	bps = runtime->rate * runtime->channels;
  	bps *= snd_pcm_format_width(runtime->format);
  	bps /= 8;
  	if (bps <= 0)
  		return -EINVAL;
  	dpcm->pcm_bps = bps;
  	dpcm->pcm_jiffie = bps / HZ;
  	dpcm->pcm_size = snd_pcm_lib_buffer_bytes(substream);
  	dpcm->pcm_count = snd_pcm_lib_period_bytes(substream);
  	dpcm->pcm_irq_pos = 0;
  	dpcm->pcm_buf_pos = 0;
  	return 0;
  }
  
  static int snd_card_dummy_playback_prepare(snd_pcm_substream_t * substream)
  {
  	return snd_card_dummy_pcm_prepare(substream);
  }
  
  static int snd_card_dummy_capture_prepare(snd_pcm_substream_t * substream)
  {
  	return snd_card_dummy_pcm_prepare(substream);
  }
  
  static void snd_card_dummy_pcm_timer_function(unsigned long data)
  {
  	snd_card_dummy_pcm_t *dpcm = (snd_card_dummy_pcm_t *)data;
  	
  	dpcm->timer.expires = 1 + jiffies;
  	add_timer(&dpcm->timer);
  	spin_lock_irq(&dpcm->lock);
  	dpcm->pcm_irq_pos += dpcm->pcm_jiffie;
  	dpcm->pcm_buf_pos += dpcm->pcm_jiffie;
  	dpcm->pcm_buf_pos %= dpcm->pcm_size;
  	if (dpcm->pcm_irq_pos >= dpcm->pcm_count) {
  		dpcm->pcm_irq_pos %= dpcm->pcm_count;
  		snd_pcm_period_elapsed(dpcm->substream);
  	}
  	spin_unlock_irq(&dpcm->lock);	
  }
  
  static snd_pcm_uframes_t snd_card_dummy_playback_pointer(snd_pcm_substream_t * substream)
  {
  	snd_pcm_runtime_t *runtime = substream->runtime;
  	snd_card_dummy_pcm_t *dpcm = runtime->private_data;
  
  	return bytes_to_frames(runtime, dpcm->pcm_buf_pos);
  }
  
  static snd_pcm_uframes_t snd_card_dummy_capture_pointer(snd_pcm_substream_t * substream)
  {
  	snd_pcm_runtime_t *runtime = substream->runtime;
  	snd_card_dummy_pcm_t *dpcm = runtime->private_data;
  
  	return bytes_to_frames(runtime, dpcm->pcm_buf_pos);
  }
  
  static snd_pcm_hardware_t snd_card_dummy_playback =
  {
  	.info =			(SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
  				 SNDRV_PCM_INFO_MMAP_VALID),
  	.formats =		USE_FORMATS,
  	.rates =		USE_RATE,
  	.rate_min =		USE_RATE_MIN,
  	.rate_max =		USE_RATE_MAX,
  	.channels_min =		USE_CHANNELS_MIN,
  	.channels_max =		USE_CHANNELS_MAX,
  	.buffer_bytes_max =	MAX_BUFFER_SIZE,
  	.period_bytes_min =	64,
  	.period_bytes_max =	MAX_BUFFER_SIZE,
  	.periods_min =		USE_PERIODS_MIN,
  	.periods_max =		USE_PERIODS_MAX,
  	.fifo_size =		0,
  };
  
  static snd_pcm_hardware_t snd_card_dummy_capture =
  {
  	.info =			(SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
  				 SNDRV_PCM_INFO_MMAP_VALID),
  	.formats =		USE_FORMATS,
  	.rates =		USE_RATE,
  	.rate_min =		USE_RATE_MIN,
  	.rate_max =		USE_RATE_MAX,
  	.channels_min =		USE_CHANNELS_MIN,
  	.channels_max =		USE_CHANNELS_MAX,
  	.buffer_bytes_max =	MAX_BUFFER_SIZE,
  	.period_bytes_min =	64,
  	.period_bytes_max =	MAX_BUFFER_SIZE,
  	.periods_min =		USE_PERIODS_MIN,
  	.periods_max =		USE_PERIODS_MAX,
  	.fifo_size =		0,
  };
  
  static void snd_card_dummy_runtime_free(snd_pcm_runtime_t *runtime)
  {
  	snd_card_dummy_pcm_t *dpcm = runtime->private_data;
  	kfree(dpcm);
  }
  
  static int snd_card_dummy_hw_params(snd_pcm_substream_t * substream,
  				    snd_pcm_hw_params_t * hw_params)
  {
  	return snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(hw_params));
  }
  
  static int snd_card_dummy_hw_free(snd_pcm_substream_t * substream)
  {
  	return snd_pcm_lib_free_pages(substream);
  }
  
  static int snd_card_dummy_playback_open(snd_pcm_substream_t * substream)
  {
  	snd_pcm_runtime_t *runtime = substream->runtime;
  	snd_card_dummy_pcm_t *dpcm;
  	int err;
  
  	dpcm = kcalloc(1, sizeof(*dpcm), GFP_KERNEL);
  	if (dpcm == NULL)
  		return -ENOMEM;
  	init_timer(&dpcm->timer);
  	dpcm->timer.data = (unsigned long) dpcm;
  	dpcm->timer.function = snd_card_dummy_pcm_timer_function;
  	spin_lock_init(&dpcm->lock);
  	dpcm->substream = substream;
  	runtime->private_data = dpcm;
  	runtime->private_free = snd_card_dummy_runtime_free;
  	runtime->hw = snd_card_dummy_playback;
  	if (substream->pcm->device & 1) {
  		runtime->hw.info &= ~SNDRV_PCM_INFO_INTERLEAVED;
  		runtime->hw.info |= SNDRV_PCM_INFO_NONINTERLEAVED;
  	}
  	if (substream->pcm->device & 2)
  		runtime->hw.info &= ~(SNDRV_PCM_INFO_MMAP|SNDRV_PCM_INFO_MMAP_VALID);
  	if ((err = add_playback_constraints(runtime)) < 0) {
  		kfree(dpcm);
  		return err;
  	}
  
  	return 0;
  }
  
  static int snd_card_dummy_capture_open(snd_pcm_substream_t * substream)
  {
  	snd_pcm_runtime_t *runtime = substream->runtime;
  	snd_card_dummy_pcm_t *dpcm;
  	int err;
  
  	dpcm = kcalloc(1, sizeof(*dpcm), GFP_KERNEL);
  	if (dpcm == NULL)
  		return -ENOMEM;
  	init_timer(&dpcm->timer);
  	dpcm->timer.data = (unsigned long) dpcm;
  	dpcm->timer.function = snd_card_dummy_pcm_timer_function;
  	spin_lock_init(&dpcm->lock);
  	dpcm->substream = substream;
  	runtime->private_data = dpcm;
  	runtime->private_free = snd_card_dummy_runtime_free;
  	runtime->hw = snd_card_dummy_capture;
  	if (substream->pcm->device == 1) {
  		runtime->hw.info &= ~SNDRV_PCM_INFO_INTERLEAVED;
  		runtime->hw.info |= SNDRV_PCM_INFO_NONINTERLEAVED;
  	}
  	if (substream->pcm->device & 2)
  		runtime->hw.info &= ~(SNDRV_PCM_INFO_MMAP|SNDRV_PCM_INFO_MMAP_VALID);
  	if ((err = add_capture_constraints(runtime)) < 0) {
  		kfree(dpcm);
  		return err;
  	}
  
  	return 0;
  }
  
  static int snd_card_dummy_playback_close(snd_pcm_substream_t * substream)
  {
  	return 0;
  }
  
  static int snd_card_dummy_capture_close(snd_pcm_substream_t * substream)
  {
  	return 0;
  }
  
  static snd_pcm_ops_t snd_card_dummy_playback_ops = {
  	.open =			snd_card_dummy_playback_open,
  	.close =		snd_card_dummy_playback_close,
  	.ioctl =		snd_pcm_lib_ioctl,
  	.hw_params =		snd_card_dummy_hw_params,
  	.hw_free =		snd_card_dummy_hw_free,
  	.prepare =		snd_card_dummy_playback_prepare,
  	.trigger =		snd_card_dummy_playback_trigger,
  	.pointer =		snd_card_dummy_playback_pointer,
  };
  
  static snd_pcm_ops_t snd_card_dummy_capture_ops = {
  	.open =			snd_card_dummy_capture_open,
  	.close =		snd_card_dummy_capture_close,
  	.ioctl =		snd_pcm_lib_ioctl,
  	.hw_params =		snd_card_dummy_hw_params,
  	.hw_free =		snd_card_dummy_hw_free,
  	.prepare =		snd_card_dummy_capture_prepare,
  	.trigger =		snd_card_dummy_capture_trigger,
  	.pointer =		snd_card_dummy_capture_pointer,
  };
  
  static int __init snd_card_dummy_pcm(snd_card_dummy_t *dummy, int device, int substreams)
  {
  	snd_pcm_t *pcm;
  	int err;
  
  	if ((err = snd_pcm_new(dummy->card, "Dummy PCM", device, substreams, substreams, &pcm)) < 0)
  		return err;
  	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &snd_card_dummy_playback_ops);
  	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &snd_card_dummy_capture_ops);
  	pcm->private_data = dummy;
  	pcm->info_flags = 0;
  	strcpy(pcm->name, "Dummy PCM");
  	snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
  					      snd_dma_continuous_data(GFP_KERNEL),
  					      0, 64*1024);
  	return 0;
  }
  
  #define DUMMY_VOLUME(xname, xindex, addr) \
  { .iface = SNDRV_CTL_ELEM_IFACE_MIXER, .name = xname, .index = xindex, \
    .info = snd_dummy_volume_info, \
    .get = snd_dummy_volume_get, .put = snd_dummy_volume_put, \
    .private_value = addr }
  
  static int snd_dummy_volume_info(snd_kcontrol_t * kcontrol, snd_ctl_elem_info_t * uinfo)
  {
  	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
  	uinfo->count = 2;
  	uinfo->value.integer.min = -50;
  	uinfo->value.integer.max = 100;
  	return 0;
  }
   
  static int snd_dummy_volume_get(snd_kcontrol_t * kcontrol, snd_ctl_elem_value_t * ucontrol)
  {
  	snd_card_dummy_t *dummy = snd_kcontrol_chip(kcontrol);
  	unsigned long flags;
  	int addr = kcontrol->private_value;
  
  	spin_lock_irqsave(&dummy->mixer_lock, flags);
  	ucontrol->value.integer.value[0] = dummy->mixer_volume[addr][0];
  	ucontrol->value.integer.value[1] = dummy->mixer_volume[addr][1];
  	spin_unlock_irqrestore(&dummy->mixer_lock, flags);
  	return 0;
  }
  
  static int snd_dummy_volume_put(snd_kcontrol_t * kcontrol, snd_ctl_elem_value_t * ucontrol)
  {
  	snd_card_dummy_t *dummy = snd_kcontrol_chip(kcontrol);
  	unsigned long flags;
  	int change, addr = kcontrol->private_value;
  	int left, right;
  
  	left = ucontrol->value.integer.value[0];
  	if (left < -50)
  		left = -50;
  	if (left > 100)
  		left = 100;
  	right = ucontrol->value.integer.value[1];
  	if (right < -50)
  		right = -50;
  	if (right > 100)
  		right = 100;
  	spin_lock_irqsave(&dummy->mixer_lock, flags);
  	change = dummy->mixer_volume[addr][0] != left ||
  	         dummy->mixer_volume[addr][1] != right;
  	dummy->mixer_volume[addr][0] = left;
  	dummy->mixer_volume[addr][1] = right;
  	spin_unlock_irqrestore(&dummy->mixer_lock, flags);
  	return change;
  }
  
  #define DUMMY_CAPSRC(xname, xindex, addr) \
  { .iface = SNDRV_CTL_ELEM_IFACE_MIXER, .name = xname, .index = xindex, \
    .info = snd_dummy_capsrc_info, \
    .get = snd_dummy_capsrc_get, .put = snd_dummy_capsrc_put, \
    .private_value = addr }
  
  static int snd_dummy_capsrc_info(snd_kcontrol_t * kcontrol, snd_ctl_elem_info_t * uinfo)
  {
  	uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
  	uinfo->count = 2;
  	uinfo->value.integer.min = 0;
  	uinfo->value.integer.max = 1;
  	return 0;
  }
   
  static int snd_dummy_capsrc_get(snd_kcontrol_t * kcontrol, snd_ctl_elem_value_t * ucontrol)
  {
  	snd_card_dummy_t *dummy = snd_kcontrol_chip(kcontrol);
  	unsigned long flags;
  	int addr = kcontrol->private_value;
  
  	spin_lock_irqsave(&dummy->mixer_lock, flags);
  	ucontrol->value.integer.value[0] = dummy->capture_source[addr][0];
  	ucontrol->value.integer.value[1] = dummy->capture_source[addr][1];
  	spin_unlock_irqrestore(&dummy->mixer_lock, flags);
  	return 0;
  }
  
  static int snd_dummy_capsrc_put(snd_kcontrol_t * kcontrol, snd_ctl_elem_value_t * ucontrol)
  {
  	snd_card_dummy_t *dummy = snd_kcontrol_chip(kcontrol);
  	unsigned long flags;
  	int change, addr = kcontrol->private_value;
  	int left, right;
  
  	left = ucontrol->value.integer.value[0] & 1;
  	right = ucontrol->value.integer.value[1] & 1;
  	spin_lock_irqsave(&dummy->mixer_lock, flags);
  	change = dummy->capture_source[addr][0] != left &&
  	         dummy->capture_source[addr][1] != right;
  	dummy->capture_source[addr][0] = left;
  	dummy->capture_source[addr][1] = right;
  	spin_unlock_irqrestore(&dummy->mixer_lock, flags);
  	return change;
  }
  
  static snd_kcontrol_new_t snd_dummy_controls[] = {
  DUMMY_VOLUME("Master Volume", 0, MIXER_ADDR_MASTER),
  DUMMY_CAPSRC("Master Capture Switch", 0, MIXER_ADDR_MASTER),
  DUMMY_VOLUME("Synth Volume", 0, MIXER_ADDR_SYNTH),
  DUMMY_CAPSRC("Synth Capture Switch", 0, MIXER_ADDR_MASTER),
  DUMMY_VOLUME("Line Volume", 0, MIXER_ADDR_LINE),
  DUMMY_CAPSRC("Line Capture Switch", 0, MIXER_ADDR_MASTER),
  DUMMY_VOLUME("Mic Volume", 0, MIXER_ADDR_MIC),
  DUMMY_CAPSRC("Mic Capture Switch", 0, MIXER_ADDR_MASTER),
  DUMMY_VOLUME("CD Volume", 0, MIXER_ADDR_CD),
  DUMMY_CAPSRC("CD Capture Switch", 0, MIXER_ADDR_MASTER)
  };
  
  static int __init snd_card_dummy_new_mixer(snd_card_dummy_t * dummy)
  {
  	snd_card_t *card = dummy->card;
  	unsigned int idx;
  	int err;
  
  	snd_assert(dummy != NULL, return -EINVAL);
  	spin_lock_init(&dummy->mixer_lock);
  	strcpy(card->mixername, "Dummy Mixer");
  
  	for (idx = 0; idx < ARRAY_SIZE(snd_dummy_controls); idx++) {
  		if ((err = snd_ctl_add(card, snd_ctl_new1(&snd_dummy_controls[idx], dummy))) < 0)
  			return err;
  	}
  	return 0;
  }
  
  static int __init snd_card_dummy_probe(int dev)
  {
  	snd_card_t *card;
  	struct snd_card_dummy *dummy;
  	int idx, err;
  
  	if (!enable[dev])
  		return -ENODEV;
  	card = snd_card_new(index[dev], id[dev], THIS_MODULE,
  			    sizeof(struct snd_card_dummy));
  	if (card == NULL)
  		return -ENOMEM;
  	dummy = (struct snd_card_dummy *)card->private_data;
  	dummy->card = card;
  	for (idx = 0; idx < MAX_PCM_DEVICES && idx < pcm_devs[dev]; idx++) {
  		if (pcm_substreams[dev] < 1)
  			pcm_substreams[dev] = 1;
  		if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
  			pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
  		if ((err = snd_card_dummy_pcm(dummy, idx, pcm_substreams[dev])) < 0)
  			goto __nodev;
  	}
  	if ((err = snd_card_dummy_new_mixer(dummy)) < 0)
  		goto __nodev;
  	strcpy(card->driver, "Dummy");
  	strcpy(card->shortname, "Dummy");
  	sprintf(card->longname, "Dummy %i", dev + 1);
  	if ((err = snd_card_register(card)) == 0) {
  		snd_dummy_cards[dev] = card;
  		return 0;
  	}
        __nodev:
  	snd_card_free(card);
  	return err;
  }
  
  static int __init alsa_card_dummy_init(void)
  {
  	int dev, cards;
  
  	for (dev = cards = 0; dev < SNDRV_CARDS && enable[dev]; dev++) {
  		if (snd_card_dummy_probe(dev) < 0) {
  #ifdef MODULE
  			printk(KERN_ERR "Dummy soundcard #%i not found or device busy
  ", dev + 1);
  #endif
  			break;
  		}
  		cards++;
  	}
  	if (!cards) {
  #ifdef MODULE
  		printk(KERN_ERR "Dummy soundcard not found or device busy
  ");
  #endif
  		return -ENODEV;
  	}
  	return 0;
  }
  
  static void __exit alsa_card_dummy_exit(void)
  {
  	int idx;
  
  	for (idx = 0; idx < SNDRV_CARDS; idx++)
  		snd_card_free(snd_dummy_cards[idx]);
  }
  
  module_init(alsa_card_dummy_init)
  module_exit(alsa_card_dummy_exit)