path: root/sound/drivers/dummy.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Dummy soundcard
 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
 */

#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/hrtimer.h>
#include <linux/math64.h>
#include <linux/module.h>
#include <sound/core.h>
#include <sound/control.h>
#include <sound/tlv.h>
#include <sound/pcm.h>
#include <sound/rawmidi.h>
#include <sound/info.h>
#include <sound/initval.h>

MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
MODULE_DESCRIPTION("Dummy soundcard (/dev/null)");
MODULE_LICENSE("GPL");

#define MAX_PCM_DEVICES		4
#define MAX_PCM_SUBSTREAMS	128
#define MAX_MIDI_DEVICES	2

/* defaults */
#define MAX_BUFFER_SIZE		(64*1024)
#define MIN_PERIOD_SIZE		64
#define MAX_PERIOD_SIZE		MAX_BUFFER_SIZE
#define USE_FORMATS 		(SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S16_LE)
#define USE_RATE		SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_48000
#define USE_RATE_MIN		5500
#define USE_RATE_MAX		48000
#define USE_CHANNELS_MIN 	1
#define USE_CHANNELS_MAX 	2
#define USE_PERIODS_MIN 	1
#define USE_PERIODS_MAX 	1024
#define USE_MIXER_VOLUME_LEVEL_MIN	-50
#define USE_MIXER_VOLUME_LEVEL_MAX	100

static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;	/* Index 0-MAX */
static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;	/* ID for this card */
static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
static char *model[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = NULL};
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};
static int mixer_volume_level_min = USE_MIXER_VOLUME_LEVEL_MIN;
static int mixer_volume_level_max = USE_MIXER_VOLUME_LEVEL_MAX;
#ifdef CONFIG_HIGH_RES_TIMERS
static bool hrtimer = 1;
#endif
static bool fake_buffer = 1;

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(model, charp, NULL, 0444);
MODULE_PARM_DESC(model, "Soundcard model.");
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 # (1-128) for dummy driver.");
//module_param_array(midi_devs, int, NULL, 0444);
//MODULE_PARM_DESC(midi_devs, "MIDI devices # (0-2) for dummy driver.");
module_param(mixer_volume_level_min, int, 0444);
MODULE_PARM_DESC(mixer_volume_level_min, "Minimum mixer volume level for dummy driver. Default: -50");
module_param(mixer_volume_level_max, int, 0444);
MODULE_PARM_DESC(mixer_volume_level_max, "Maximum mixer volume level for dummy driver. Default: 100");
module_param(fake_buffer, bool, 0444);
MODULE_PARM_DESC(fake_buffer, "Fake buffer allocations.");
#ifdef CONFIG_HIGH_RES_TIMERS
module_param(hrtimer, bool, 0644);
MODULE_PARM_DESC(hrtimer, "Use hrtimer as the timer source.");
#endif

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 dummy_timer_ops {
	int (*create)(struct snd_pcm_substream *);
	void (*free)(struct snd_pcm_substream *);
	int (*prepare)(struct snd_pcm_substream *);
	int (*start)(struct snd_pcm_substream *);
	int (*stop)(struct snd_pcm_substream *);
	snd_pcm_uframes_t (*pointer)(struct snd_pcm_substream *);
};

#define get_dummy_ops(substream) \
	(*(const struct dummy_timer_ops **)(substream)->runtime->private_data)

struct dummy_model {
	const char *name;
	int (*playback_constraints)(struct snd_pcm_runtime *runtime);
	int (*capture_constraints)(struct snd_pcm_runtime *runtime);
	u64 formats;
	size_t buffer_bytes_max;
	size_t period_bytes_min;
	size_t period_bytes_max;
	unsigned int periods_min;
	unsigned int per