sound/drivers/virmidi.c

   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                 struct snd_virmidi_dev *rdev;
  94
  95                 err = snd_virmidi_new(card, idx, &rmidi);
  96                 if (err < 0)
  97                         return err;
  98                 rdev = rmidi->private_data;
  99                 vmidi->midi[idx] = rmidi;
 100                 strcpy(rmidi->name, "Virtual Raw MIDI");
 101                 rdev->seq_mode = SNDRV_VIRMIDI_SEQ_DISPATCH;
 102         }
 103
 104         strcpy(card->driver, "VirMIDI");
 105         strcpy(card->shortname, "VirMIDI");
 106         sprintf(card->longname, "Virtual MIDI Card %i", dev + 1);
 107
 108         err = snd_card_register(card);
 109         if (err)
 110                 return err;
 111
 112         platform_set_drvdata(devptr, card);
 113         return 0;
 114 }
 115
 116 #define SND_VIRMIDI_DRIVER      "snd_virmidi"
 117
 118 static struct platform_driver snd_virmidi_driver = {
 119         .probe          = snd_virmidi_probe,
 120         .driver         = {
 121                 .name   = SND_VIRMIDI_DRIVER,
 122         },
 123 };
 124
 125 static void snd_virmidi_unregister_all(void)
 126 {
 127         int i;
 128
 129         for (i = 0; i < ARRAY_SIZE(devices); ++i)
 130                 platform_device_unregister(devices[i]);
 131         platform_driver_unregister(&snd_virmidi_driver);
 132 }
 133
 134 static int __init alsa_card_virmidi_init(void)
 135 {
 136         int i, cards, err;
 137
 138         err = platform_driver_register(&snd_virmidi_driver);
 139         if (err < 0)
 140                 return err;
 141
 142         cards = 0;
 143         for (i = 0; i < SNDRV_CARDS; i++) {
 144                 struct platform_device *device;
 145
 146                 if (!enable[i])
 147                         continue;
 148                 device = platform_device_register_simple(SND_VIRMIDI_DRIVER,
 149                                                          i, NULL, 0);
 150                 if (IS_ERR(device))
 151                         continue;
 152                 if (!platform_get_drvdata(device)) {
 153                         platform_device_unregister(device);
 154                         continue;
 155                 }
 156                 devices[i] = device;
 157                 cards++;
 158         }
 159         if (!cards) {
 160 #ifdef MODULE
 161                 printk(KERN_ERR "Card-VirMIDI soundcard not found or device busy\n");
 162 #endif
 163                 snd_virmidi_unregister_all();
 164                 return -ENODEV;
 165         }
 166         return 0;
 167 }
 168
 169 static void __exit alsa_card_virmidi_exit(void)
 170 {
 171         snd_virmidi_unregister_all();
 172 }
 173
 174 module_init(alsa_card_virmidi_init)
 175 module_exit(alsa_card_virmidi_exit)