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