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(parent: &devptr->dev, idx: index[dev], xid: id[dev], THIS_MODULE,
79 extra_size: sizeof(struct snd_card_virmidi), card_ret: &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 snd_printk(KERN_WARNING
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, device: idx, rrmidi: &rmidi);
95 if (err < 0)
96 return err;
97 vmidi->midi[idx] = rmidi;
98 strcpy(p: rmidi->name, q: "Virtual Raw MIDI");
99 }
100
101 strcpy(p: card->driver, q: "VirMIDI");
102 strcpy(p: card->shortname, q: "VirMIDI");
103 sprintf(buf: card->longname, fmt: "Virtual MIDI Card %i", dev + 1);
104
105 err = snd_card_register(card);
106 if (err)
107 return err;
108
109 platform_set_drvdata(pdev: devptr, data: 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 id: i, NULL, num: 0);
147 if (IS_ERR(ptr: device))
148 continue;
149 if (!platform_get_drvdata(pdev: device)) {
150 platform_device_unregister(device);
151 continue;
152 }
153 devices[i] = device;
154 cards++;
155 }
156 if (!cards) {
157#ifdef MODULE
158 printk(KERN_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)
173

source code of linux/sound/drivers/virmidi.c