dummy.c

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/*
 *  Dummy soundcard
 *  Copyright (c) by Jaroslav Kysela <[e-mail]>
 *
 *   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/err.h>
#include <linux/platform_device.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/tlv.h>
#include <sound/pcm.h>
#include <sound/rawmidi.h>
#include <sound/initval.h>

MODULE_AUTHOR("Jaroslav Kysela <[e-mail]>");
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(struct snd_pcm_runtime *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

#if 0 /* CA0106 */
#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|SNDRV_PCM_RATE_96000|SNDRV_PCM_RATE_192000) 
#define USE_RATE_MIN		48000 
#define USE_RATE_MAX		192000
#define MAX_BUFFER_SIZE		((65536-64)*8)
#define MAX_PERIOD_SIZE		(65536-64)
#define USE_PERIODS_MIN		2
#define USE_PERIODS_MAX		8
#endif


/* defaults */
#ifndef MAX_BUFFER_SIZE
#define MAX_BUFFER_SIZE		(64*1024)
#endif
#ifndef MAX_PERIOD_SIZE
#define MAX_PERIOD_SIZE		MAX_BUFFER_SIZE
#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.");

static struct platform_device *devices[SNDRV_CARDS];

#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

struct snd_dummy {
	struct snd_card *card;
	struct snd_pcm *pcm;
	spinlock_t mixer_lock;
	int mixer_volume[MIXER_ADDR_LAST+1][2];
	int capture_source[MIXER_ADDR_LAST+1][2];
};

struct snd_dummy_pcm {
	struct snd_dummy *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 */
	struct snd_pcm_substream *substream;
};


static inline void snd_card_dummy_pcm_timer_start(struct snd_dummy_pcm *dpcm)
{
	dpcm->timer.expires = 1 + jiffies;
	add_timer(&dpcm->timer);
}

static inline void snd_card_dummy_pcm_timer_stop(struct snd_dummy_pcm *dpcm)
{
	del_timer(&dpcm->timer);
}

static int snd_card_dummy_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct snd_dummy_pcm *dpcm = runtime->private_data;
	int err = 0;

	spin_lock(&dpcm->lock);
	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
	case SNDRV_PCM_TRIGGER_RESUME:
		snd_card_dummy_pcm_timer_start(dpcm);
		break;
	case SNDRV_PCM_TRIGGER_STOP:
	case SNDRV_PCM_TRIGGER_SUSPEND:
		snd_card_dummy_pcm_timer_stop(dpcm);
		break;
	default:
		err = -EINVAL;
		break;
	}
	spin_unlock(&dpcm->lock);
	return 0;
}

static int snd_card_dummy_pcm_prepare(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct snd_dummy_pcm *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 void snd_card_dummy_pcm_timer_function(unsigned long data)
{
	struct snd_dummy_pcm *dpcm = (struct snd_dummy_pcm *)data;
	unsigned long flags;
	
	spin_lock_irqsave(&dpcm->lock, flags);
	dpcm->timer.expires = 1 + jiffies;
	add_timer(&dpcm->timer);
	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;
		spin_unlock_irqrestore(&dpcm->lock, flags);
		snd_pcm_period_elapsed(dpcm->substream);
	} else
		spin_unlock_irqrestore(&dpcm->lock, flags);
}

static snd_pcm_uframes_t snd_card_dummy_pcm_pointer(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct snd_dummy_pcm *dpcm = runtime->private_data;

	return bytes_to_frames(runtime, dpcm->pcm_buf_pos);
}

static struct snd_pcm_hardware snd_card_dummy_playback =
{
	.info =			(SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
				 SNDRV_PCM_INFO_RESUME | 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_PERIOD_SIZE,
	.periods_min =		USE_PERIODS_MIN,
	.periods_max =		USE_PERIODS_MAX,
	.fifo_size =		0,
};

static struct snd_pcm_hardware snd_card_dummy_capture =
{
	.info =			(SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
				 SNDRV_PCM_INFO_RESUME | 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_PERIOD_SIZE,
	.periods_min =		USE_PERIODS_MIN,
	.periods_max =		USE_PERIODS_MAX,
	.fifo_size =		0,
};

static void snd_card_dummy_runtime_free(struct snd_pcm_runtime *runtime)
{
	kfree(runtime->private_data);
}

static int snd_card_dummy_hw_params(struct snd_pcm_substream *substream,
				    struct snd_pcm_hw_params *hw_params)
{
	return snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(hw_params));
}

static int snd_card_dummy_hw_free(struct snd_pcm_substream *substream)
{
	return snd_pcm_lib_free_pages(substream);
}

static struct snd_dummy_pcm *new_pcm_stream(struct snd_pcm_substream *substream)
{
	struct snd_dummy_pcm *dpcm;

	dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
	if (! dpcm)
		return dpcm;
	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;
	return dpcm;
}

static int snd_card_dummy_playback_open(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct snd_dummy_pcm *dpcm;
	int err;

	if ((dpcm = new_pcm_stream(substream)) == NULL)
		return -ENOMEM;
	runtime->private_data = dpcm;