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
43 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
44 MODULE_DESCRIPTION("Dummy soundcard for virtual rawmidi devices");
45 MODULE_LICENSE("GPL");
46
47 #define MAX_MIDI_DEVICES 4
48
49 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX; /* Index 0-MAX */
50 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR; /* ID for this card */
51 static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
52 static int midi_devs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 4};
53
54 module_param_array(index, int, NULL, 0444);
55 MODULE_PARM_DESC(index, "Index value for virmidi soundcard.");
56 module_param_array(id, charp, NULL, 0444);
57 MODULE_PARM_DESC(id, "ID string for virmidi soundcard.");
58 module_param_array(enable, bool, NULL, 0444);
59 MODULE_PARM_DESC(enable, "Enable this soundcard.");
60 module_param_array(midi_devs, int, NULL, 0444);
61 MODULE_PARM_DESC(midi_devs, "MIDI devices # (1-4)");
62
63 struct snd_card_virmidi {
64 struct snd_card *card;
65 struct snd_rawmidi *midi[MAX_MIDI_DEVICES];
66 };
67
68 static struct platform_device *devices[SNDRV_CARDS];
69
70
snd_virmidi_probe(struct platform_device * devptr)71 static 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 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, idx, &rmidi);
95 if (err < 0)
96 return err;
97 vmidi->midi[idx] = rmidi;
98 strcpy(rmidi->name, "Virtual Raw MIDI");
99 }
100
101 strcpy(card->driver, "VirMIDI");
102 strcpy(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
115 static struct platform_driver snd_virmidi_driver = {
116 .probe = snd_virmidi_probe,
117 .driver = {
118 .name = SND_VIRMIDI_DRIVER,
119 },
120 };
121
snd_virmidi_unregister_all(void)122 static 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
alsa_card_virmidi_init(void)131 static 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 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
alsa_card_virmidi_exit(void)166 static void __exit alsa_card_virmidi_exit(void)
167 {
168 snd_virmidi_unregister_all();
169 }
170
171 module_init(alsa_card_virmidi_init)
172 module_exit(alsa_card_virmidi_exit)
173