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 MODULE_SUPPORTED_DEVICE("{{ALSA,Virtual rawmidi device}}");
47
48 #define MAX_MIDI_DEVICES 4
49
50 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX; /* Index 0-MAX */
51 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR; /* ID for this card */
52 static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
53 static int midi_devs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 4};
54
55 module_param_array(index, int, NULL, 0444);
56 MODULE_PARM_DESC(index, "Index value for virmidi soundcard.");
57 module_param_array(id, charp, NULL, 0444);
58 MODULE_PARM_DESC(id, "ID string for virmidi soundcard.");
59 module_param_array(enable, bool, NULL, 0444);
60 MODULE_PARM_DESC(enable, "Enable this soundcard.");
61 module_param_array(midi_devs, int, NULL, 0444);
62 MODULE_PARM_DESC(midi_devs, "MIDI devices # (1-4)");
63
64 struct snd_card_virmidi {
65 struct snd_card *card;
66 struct snd_rawmidi *midi[MAX_MIDI_DEVICES];
67 };
68
69 static struct platform_device *devices[SNDRV_CARDS];
70
71
snd_virmidi_probe(struct platform_device * devptr)72 static 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
snd_virmidi_remove(struct platform_device * devptr)119 static 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
127 static 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
snd_virmidi_unregister_all(void)135 static 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
alsa_card_virmidi_init(void)144 static 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
alsa_card_virmidi_exit(void)179 static void __exit alsa_card_virmidi_exit(void)
180 {
181 snd_virmidi_unregister_all();
182 }
183
184 module_init(alsa_card_virmidi_init)
185 module_exit(alsa_card_virmidi_exit)
186