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");
46MODULE_SUPPORTED_DEVICE("{{ALSA,Virtual rawmidi device}}");
47
48#define MAX_MIDI_DEVICES	4
49
50static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;	/* Index 0-MAX */
51static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;	/* ID for this card */
52static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
53static int midi_devs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 4};
54
55module_param_array(index, int, NULL, 0444);
56MODULE_PARM_DESC(index, "Index value for virmidi soundcard.");
57module_param_array(id, charp, NULL, 0444);
58MODULE_PARM_DESC(id, "ID string for virmidi soundcard.");
59module_param_array(enable, bool, NULL, 0444);
60MODULE_PARM_DESC(enable, "Enable this soundcard.");
61module_param_array(midi_devs, int, NULL, 0444);
62MODULE_PARM_DESC(midi_devs, "MIDI devices # (1-4)");
63
64struct snd_card_virmidi {
65	struct snd_card *card;
66	struct snd_rawmidi *midi[MAX_MIDI_DEVICES];
67};
68
69static struct platform_device *devices[SNDRV_CARDS];
70
71
72static int snd_virmidi_probe(struct platform_device *devptr)
73{
74	struct snd_card *card;
75	struct snd_card_virmidi *vmidi;
76	int idx, err;
77	int dev = devptr->id;
78
79	err = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
80			   sizeof(struct snd_card_virmidi), &card);
81	if (err < 0)
82		return err;
83	vmidi = card->private_data;
84	vmidi->card = card;
85
86	if (midi_devs[dev] > MAX_MIDI_DEVICES) {
87		snd_printk(KERN_WARNING
88			   "too much midi devices for virmidi %d: force to use %d\n",
89			   dev, MAX_MIDI_DEVICES);
90		midi_devs[dev] = MAX_MIDI_DEVICES;
91	}
92	for (idx = 0; idx < midi_devs[dev]; idx++) {
93		struct snd_rawmidi *rmidi;
94		struct snd_virmidi_dev *rdev;
95
96		err = snd_virmidi_new(card, idx, &rmidi);
97		if (err < 0)
98			goto __nodev;
99		rdev = rmidi->private_data;
100		vmidi->midi[idx] = rmidi;
101		strcpy(rmidi->name, "Virtual Raw MIDI");
102		rdev->seq_mode = SNDRV_VIRMIDI_SEQ_DISPATCH;
103	}
104
105	strcpy(card->driver, "VirMIDI");
106	strcpy(card->shortname, "VirMIDI");
107	sprintf(card->longname, "Virtual MIDI Card %i", dev + 1);
108
109	err = snd_card_register(card);
110	if (!err) {
111		platform_set_drvdata(devptr, card);
112		return 0;
113	}
114__nodev:
115	snd_card_free(card);
116	return err;
117}
118
119static int snd_virmidi_remove(struct platform_device *devptr)
120{
121	snd_card_free(platform_get_drvdata(devptr));
122	return 0;
123}
124
125#define SND_VIRMIDI_DRIVER	"snd_virmidi"
126
127static struct platform_driver snd_virmidi_driver = {
128	.probe		= snd_virmidi_probe,
129	.remove		= snd_virmidi_remove,
130	.driver		= {
131		.name	= SND_VIRMIDI_DRIVER,
132	},
133};
134
135static void snd_virmidi_unregister_all(void)
136{
137	int i;
138
139	for (i = 0; i < ARRAY_SIZE(devices); ++i)
140		platform_device_unregister(devices[i]);
141	platform_driver_unregister(&snd_virmidi_driver);
142}
143
144static int __init alsa_card_virmidi_init(void)
145{
146	int i, cards, err;
147
148	err = platform_driver_register(&snd_virmidi_driver);
149	if (err < 0)
150		return err;
151
152	cards = 0;
153	for (i = 0; i < SNDRV_CARDS; i++) {
154		struct platform_device *device;
155
156		if (!enable[i])
157			continue;
158		device = platform_device_register_simple(SND_VIRMIDI_DRIVER,
159							 i, NULL, 0);
160		if (IS_ERR(device))
161			continue;
162		if (!platform_get_drvdata(device)) {
163			platform_device_unregister(device);
164			continue;
165		}
166		devices[i] = device;
167		cards++;
168	}
169	if (!cards) {
170#ifdef MODULE
171		printk(KERN_ERR "Card-VirMIDI soundcard not found or device busy\n");
172#endif
173		snd_virmidi_unregister_all();
174		return -ENODEV;
175	}
176	return 0;
177}
178
179static void __exit alsa_card_virmidi_exit(void)
180{
181	snd_virmidi_unregister_all();
182}
183
184module_init(alsa_card_virmidi_init)
185module_exit(alsa_card_virmidi_exit)
186