linux/sound/drivers/virmidi.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Dummy soundcard for virtual rawmidi devices
*
* Copyright (c) 2000 by Takashi Iwai <tiwai@suse.de>
*/
/*
* 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("Takashi Iwai <tiwai@suse.de>");
MODULE_DESCRIPTION("Dummy soundcard for virtual rawmidi devices");
MODULE_LICENSE("GPL");
MODULE_SUPPORTED_DEVICE("{{ALSA,Virtual rawmidi device}}");
#define MAX_MIDI_DEVICES 4
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 int midi_devs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 4};
module_param_array(index, int, NULL, 0444);
MODULE_PARM_DESC(index, "Index value for virmidi soundcard.");
module_param_array(id, charp, NULL, 0444);
MODULE_PARM_DESC(id, "ID string for virmidi soundcard.");
module_param_array(enable, bool, NULL, 0444);
MODULE_PARM_DESC(enable, "Enable this soundcard.");
module_param_array(midi_devs, int, NULL, 0444);
MODULE_PARM_DESC(midi_devs, "MIDI devices # (1-4)");
struct snd_card_virmidi {
struct snd_card *card;
struct snd_rawmidi *midi[MAX_MIDI_DEVICES];
};
static struct platform_device *devices[SNDRV_CARDS];
static int snd_virmidi_probe(struct platform_device *devptr)
{
struct snd_card *card;
struct snd_card_virmidi *vmidi;
int idx, err;
int dev = devptr->id;
err = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
sizeof(struct snd_card_virmidi), &card);
if (err < 0)
return err;
vmidi = card->private_data;
vmidi->card = card;
if (midi_devs[dev] > MAX_MIDI_DEVICES) {
snd_printk(KERN_WARNING
"too much midi devices for virmidi %d: force to use %d\n",
dev, MAX_MIDI_DEVICES);
midi_devs[dev] = MAX_MIDI_DEVICES;
}
for (idx = 0; idx < midi_devs[dev]; idx++) {
struct snd_rawmidi *rmidi;
struct snd_virmidi_dev *rdev;
err = snd_virmidi_new(card, idx, &rmidi);
if (err < 0)
goto __nodev;
rdev = rmidi->private_data;
vmidi->midi[idx] = rmidi;
strcpy(rmidi->name, "Virtual Raw MIDI");
rdev->seq_mode = SNDRV_VIRMIDI_SEQ_DISPATCH;
}
strcpy(card->driver, "VirMIDI");
strcpy(card->shortname, "VirMIDI");
sprintf(card->longname, "Virtual MIDI Card %i", dev + 1);
err = snd_card_register(card);
if (!err) {
platform_set_drvdata(devptr, card);
return 0;
}
__nodev:
snd_card_free(card);
return err;
}
static int snd_virmidi_remove(struct platform_device *devptr)
{
snd_card_free(platform_get_drvdata(devptr));
return 0;
}
#define SND_VIRMIDI_DRIVER "snd_virmidi"
static struct platform_driver snd_virmidi_driver = {
.probe = snd_virmidi_probe,
.remove = snd_virmidi_remove,
.driver = {
.name = SND_VIRMIDI_DRIVER,
},
};
static void snd_virmidi_unregister_all(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(devices); ++i)
platform_device_unregister(devices[i]);
platform_driver_unregister(&snd_virmidi_driver);
}
static int __init alsa_card_virmidi_init(void)
{
int i, cards, err;
err = platform_driver_register(&snd_virmidi_driver);
if (err < 0)
return err;
cards = 0;
for (i = 0; i < SNDRV_CARDS; i++) {
struct platform_device *device;
if (!enable[i])
continue;
device = platform_device_register_simple(SND_VIRMIDI_DRIVER,
i, NULL, 0);
if (IS_ERR(device))
continue;
if (!platform_get_drvdata(device)) {
platform_device_unregister(device);
continue;
}
devices[i] = device;
cards++;
}
if (!cards) {
#ifdef MODULE
printk(KERN_ERR "Card-VirMIDI soundcard not found or device busy\n");
#endif
snd_virmidi_unregister_all();
return -ENODEV;
}
return 0;
}
static void __exit alsa_card_virmidi_exit(void)
{
snd_virmidi_unregister_all();
}
module_init(alsa_card_virmidi_init)
module_exit(alsa_card_virmidi_exit)