root/sound/drivers/virmidi.c

DEFINITIONS

1. snd_virmidi_probe
2. snd_virmidi_remove
3. snd_virmidi_unregister_all
4. alsa_card_virmidi_init
5. alsa_card_virmidi_exit

   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)