linux/sound/drivers/virmidi.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Dummy soundcard for virtual rawmidi devices
 *
 *  Copyright (c) 2000 by Takashi Iwai <[email protected]>
 */

/*
 * VIRTUAL RAW MIDI DEVICE CARDS
 *
 * This dummy card contains up to 4 virtual rawmidi devices.
 * They are not real rawmidi devices but just associated with sequencer
 * clients, so that any input/output sources can be connected as a raw
 * MIDI device arbitrary.
 * Also, multiple access is allowed to a single rawmidi device.
 *
 * Typical usage is like following:
 * - Load snd-virmidi module.
 *	# modprobe snd-virmidi index=2
 *   Then, sequencer clients 72:0 to 75:0 will be created, which are
 *   mapped from /dev/snd/midiC1D0 to /dev/snd/midiC1D3, respectively.
 *
 * - Connect input/output via aconnect.
 *	% aconnect 64:0 72:0	# keyboard input redirection 64:0 -> 72:0
 *	% aconnect 72:0 65:0	# output device redirection 72:0 -> 65:0
 *
 * - Run application using a midi device (eg. /dev/snd/midiC1D0)
 */

#include <linux/init.h>
#include <linux/wait.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/module.h>
#include <sound/core.h>
#include <sound/seq_kernel.h>
#include <sound/seq_virmidi.h>
#include <sound/initval.h>

/* hack: OSS defines midi_devs, so undefine it (versioned symbols) */
#undef midi_devs

MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;

#define MAX_MIDI_DEVICES …

static int index[SNDRV_CARDS] = …;	/* Index 0-MAX */
static char *id[SNDRV_CARDS] = …;	/* ID for this card */
static bool enable[SNDRV_CARDS] = …;
static int midi_devs[SNDRV_CARDS] = …;

module_param_array(…);
MODULE_PARM_DESC(…) …;
module_param_array(…);
MODULE_PARM_DESC(…) …;
module_param_array(…);
MODULE_PARM_DESC(…) …;
module_param_array(…);
MODULE_PARM_DESC(…) …;

struct snd_card_virmidi { … };

static struct platform_device *devices[SNDRV_CARDS];


static int snd_virmidi_probe(struct platform_device *devptr)
{ … }

#define SND_VIRMIDI_DRIVER …

static struct platform_driver snd_virmidi_driver = …;

static void snd_virmidi_unregister_all(void)
{ … }

static int __init alsa_card_virmidi_init(void)
{ … }

static void __exit alsa_card_virmidi_exit(void)
{ … }

module_init(…) …
module_exit(…)