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 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 } 118 119 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 }; 134 135 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 } 143 144 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 } 178 179 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