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 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 }; 121 122 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 } 130 131 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 } 165 166 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