virmidi.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 *  Dummy soundcard for virtual rawmidi devices
  4 *
  5 *  Copyright (c) 2000 by Takashi Iwai <tiwai@suse.de>
  6 */
  7
  8/*
  9 * VIRTUAL RAW MIDI DEVICE CARDS
 10 *
 11 * This dummy card contains up to 4 virtual rawmidi devices.
 12 * They are not real rawmidi devices but just associated with sequencer
 13 * clients, so that any input/output sources can be connected as a raw
 14 * MIDI device arbitrary.
 15 * Also, multiple access is allowed to a single rawmidi device.
 16 *
 17 * Typical usage is like following:
 18 * - Load snd-virmidi module.
 19 *	# modprobe snd-virmidi index=2
 20 *   Then, sequencer clients 72:0 to 75:0 will be created, which are
 21 *   mapped from /dev/snd/midiC1D0 to /dev/snd/midiC1D3, respectively.
 22 *
 23 * - Connect input/output via aconnect.
 24 *	% aconnect 64:0 72:0	# keyboard input redirection 64:0 -> 72:0
 25 *	% aconnect 72:0 65:0	# output device redirection 72:0 -> 65:0
 26 *
 27 * - Run application using a midi device (eg. /dev/snd/midiC1D0)
 28 */
 29
 30#include <linux/init.h>
 31#include <linux/wait.h>
 32#include <linux/err.h>
 33#include <linux/platform_device.h>
 34#include <linux/module.h>
 35#include <sound/core.h>
 36#include <sound/seq_kernel.h>
 37#include <sound/seq_virmidi.h>
 38#include <sound/initval.h>
 39
 40/* hack: OSS defines midi_devs, so undefine it (versioned symbols) */
 41#undef midi_devs
 42
 43MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
 44MODULE_DESCRIPTION("Dummy soundcard for virtual rawmidi devices");
 45MODULE_LICENSE("GPL");
 46
 47#define MAX_MIDI_DEVICES	4
 48
 49static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;	/* Index 0-MAX */
 50static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;	/* ID for this card */
 51static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
 52static int midi_devs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 4};
 53
 54module_param_array(index, int, NULL, 0444);
 55MODULE_PARM_DESC(index, "Index value for virmidi soundcard.");
 56module_param_array(id, charp, NULL, 0444);
 57MODULE_PARM_DESC(id, "ID string for virmidi soundcard.");
 58module_param_array(enable, bool, NULL, 0444);
 59MODULE_PARM_DESC(enable, "Enable this soundcard.");
 60module_param_array(midi_devs, int, NULL, 0444);
 61MODULE_PARM_DESC(midi_devs, "MIDI devices # (1-4)");
 62
 63struct snd_card_virmidi {
 64	struct snd_card *card;
 65	struct snd_rawmidi *midi[MAX_MIDI_DEVICES];
 66};
 67
 68static struct platform_device *devices[SNDRV_CARDS];
 69
 70
 71static int snd_virmidi_probe(struct platform_device *devptr)
 72{
 73	struct snd_card *card;
 74	struct snd_card_virmidi *vmidi;
 75	int idx, err;
 76	int dev = devptr->id;
 77
 78	err = snd_devm_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
 79				sizeof(struct snd_card_virmidi), &card);
 80	if (err < 0)
 81		return err;
 82	vmidi = card->private_data;
 83	vmidi->card = card;
 84
 85	if (midi_devs[dev] > MAX_MIDI_DEVICES) {
 86		dev_warn(&devptr->dev,
 87			 "too much midi devices for virmidi %d: force to use %d\n",
 88			 dev, MAX_MIDI_DEVICES);
 89		midi_devs[dev] = MAX_MIDI_DEVICES;
 90	}
 91	for (idx = 0; idx < midi_devs[dev]; idx++) {
 92		struct snd_rawmidi *rmidi;
 93
 94		err = snd_virmidi_new(card, idx, &rmidi);
 95		if (err < 0)
 96			return err;
 97		vmidi->midi[idx] = rmidi;
 98		strscpy(rmidi->name, "Virtual Raw MIDI");
 99	}
100
101	strscpy(card->driver, "VirMIDI");
102	strscpy(card->shortname, "VirMIDI");
103	sprintf(card->longname, "Virtual MIDI Card %i", dev + 1);
104
105	err = snd_card_register(card);
106	if (err)
107		return err;
108
109	platform_set_drvdata(devptr, card);
110	return 0;
111}
112
113#define SND_VIRMIDI_DRIVER	"snd_virmidi"
114
115static struct platform_driver snd_virmidi_driver = {
116	.probe		= snd_virmidi_probe,
117	.driver		= {
118		.name	= SND_VIRMIDI_DRIVER,
119	},
120};
121
122static void snd_virmidi_unregister_all(void)
123{
124	int i;
125
126	for (i = 0; i < ARRAY_SIZE(devices); ++i)
127		platform_device_unregister(devices[i]);
128	platform_driver_unregister(&snd_virmidi_driver);
129}
130
131static int __init alsa_card_virmidi_init(void)
132{
133	int i, cards, err;
134
135	err = platform_driver_register(&snd_virmidi_driver);
136	if (err < 0)
137		return err;
138
139	cards = 0;
140	for (i = 0; i < SNDRV_CARDS; i++) {
141		struct platform_device *device;
142
143		if (!enable[i])
144			continue;
145		device = platform_device_register_simple(SND_VIRMIDI_DRIVER,
146							 i, NULL, 0);
147		if (IS_ERR(device))
148			continue;
149		if (!platform_get_drvdata(device)) {
150			platform_device_unregister(device);
151			continue;
152		}
153		devices[i] = device;
154		cards++;
155	}
156	if (!cards) {
157#ifdef MODULE
158		pr_err("Card-VirMIDI soundcard not found or device busy\n");
159#endif
160		snd_virmidi_unregister_all();
161		return -ENODEV;
162	}
163	return 0;
164}
165
166static void __exit alsa_card_virmidi_exit(void)
167{
168	snd_virmidi_unregister_all();
169}
170
171module_init(alsa_card_virmidi_init)
172module_exit(alsa_card_virmidi_exit)