virmidi.c 4.8 KB

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  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. * VIRTUAL RAW MIDI DEVICE CARDS
  9. *
  10. * This dummy card contains up to 4 virtual rawmidi devices.
  11. * They are not real rawmidi devices but just associated with sequencer
  12. * clients, so that any input/output sources can be connected as a raw
  13. * MIDI device arbitrary.
  14. * Also, multiple access is allowed to a single rawmidi device.
  15. *
  16. * Typical usage is like following:
  17. * - Load snd-virmidi module.
  18. * # modprobe snd-virmidi index=2
  19. * Then, sequencer clients 72:0 to 75:0 will be created, which are
  20. * mapped from /dev/snd/midiC1D0 to /dev/snd/midiC1D3, respectively.
  21. *
  22. * - Connect input/output via aconnect.
  23. * % aconnect 64:0 72:0 # keyboard input redirection 64:0 -> 72:0
  24. * % aconnect 72:0 65:0 # output device redirection 72:0 -> 65:0
  25. *
  26. * - Run application using a midi device (eg. /dev/snd/midiC1D0)
  27. */
  28. #include <linux/init.h>
  29. #include <linux/wait.h>
  30. #include <linux/err.h>
  31. #include <linux/platform_device.h>
  32. #include <linux/module.h>
  33. #include <sound/core.h>
  34. #include <sound/seq_kernel.h>
  35. #include <sound/seq_virmidi.h>
  36. #include <sound/initval.h>
  37. /* hack: OSS defines midi_devs, so undefine it (versioned symbols) */
  38. #undef midi_devs
  39. MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
  40. MODULE_DESCRIPTION("Dummy soundcard for virtual rawmidi devices");
  41. MODULE_LICENSE("GPL");
  42. MODULE_SUPPORTED_DEVICE("{{ALSA,Virtual rawmidi device}}");
  43. #define MAX_MIDI_DEVICES 4
  44. static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX; /* Index 0-MAX */
  45. static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR; /* ID for this card */
  46. static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
  47. static int midi_devs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 4};
  48. module_param_array(index, int, NULL, 0444);
  49. MODULE_PARM_DESC(index, "Index value for virmidi soundcard.");
  50. module_param_array(id, charp, NULL, 0444);
  51. MODULE_PARM_DESC(id, "ID string for virmidi soundcard.");
  52. module_param_array(enable, bool, NULL, 0444);
  53. MODULE_PARM_DESC(enable, "Enable this soundcard.");
  54. module_param_array(midi_devs, int, NULL, 0444);
  55. MODULE_PARM_DESC(midi_devs, "MIDI devices # (1-4)");
  56. struct snd_card_virmidi {
  57. struct snd_card *card;
  58. struct snd_rawmidi *midi[MAX_MIDI_DEVICES];
  59. };
  60. static struct platform_device *devices[SNDRV_CARDS];
  61. static int snd_virmidi_probe(struct platform_device *devptr)
  62. {
  63. struct snd_card *card;
  64. struct snd_card_virmidi *vmidi;
  65. int idx, err;
  66. int dev = devptr->id;
  67. err = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
  68. sizeof(struct snd_card_virmidi), &card);
  69. if (err < 0)
  70. return err;
  71. vmidi = card->private_data;
  72. vmidi->card = card;
  73. if (midi_devs[dev] > MAX_MIDI_DEVICES) {
  74. snd_printk(KERN_WARNING
  75. "too much midi devices for virmidi %d: force to use %d\n",
  76. dev, MAX_MIDI_DEVICES);
  77. midi_devs[dev] = MAX_MIDI_DEVICES;
  78. }
  79. for (idx = 0; idx < midi_devs[dev]; idx++) {
  80. struct snd_rawmidi *rmidi;
  81. struct snd_virmidi_dev *rdev;
  82. err = snd_virmidi_new(card, idx, &rmidi);
  83. if (err < 0)
  84. goto __nodev;
  85. rdev = rmidi->private_data;
  86. vmidi->midi[idx] = rmidi;
  87. strcpy(rmidi->name, "Virtual Raw MIDI");
  88. rdev->seq_mode = SNDRV_VIRMIDI_SEQ_DISPATCH;
  89. }
  90. strcpy(card->driver, "VirMIDI");
  91. strcpy(card->shortname, "VirMIDI");
  92. sprintf(card->longname, "Virtual MIDI Card %i", dev + 1);
  93. err = snd_card_register(card);
  94. if (!err) {
  95. platform_set_drvdata(devptr, card);
  96. return 0;
  97. }
  98. __nodev:
  99. snd_card_free(card);
  100. return err;
  101. }
  102. static int snd_virmidi_remove(struct platform_device *devptr)
  103. {
  104. snd_card_free(platform_get_drvdata(devptr));
  105. return 0;
  106. }
  107. #define SND_VIRMIDI_DRIVER "snd_virmidi"
  108. static struct platform_driver snd_virmidi_driver = {
  109. .probe = snd_virmidi_probe,
  110. .remove = snd_virmidi_remove,
  111. .driver = {
  112. .name = SND_VIRMIDI_DRIVER,
  113. },
  114. };
  115. static void snd_virmidi_unregister_all(void)
  116. {
  117. int i;
  118. for (i = 0; i < ARRAY_SIZE(devices); ++i)
  119. platform_device_unregister(devices[i]);
  120. platform_driver_unregister(&snd_virmidi_driver);
  121. }
  122. static int __init alsa_card_virmidi_init(void)
  123. {
  124. int i, cards, err;
  125. err = platform_driver_register(&snd_virmidi_driver);
  126. if (err < 0)
  127. return err;
  128. cards = 0;
  129. for (i = 0; i < SNDRV_CARDS; i++) {
  130. struct platform_device *device;
  131. if (!enable[i])
  132. continue;
  133. device = platform_device_register_simple(SND_VIRMIDI_DRIVER,
  134. i, NULL, 0);
  135. if (IS_ERR(device))
  136. continue;
  137. if (!platform_get_drvdata(device)) {
  138. platform_device_unregister(device);
  139. continue;
  140. }
  141. devices[i] = device;
  142. cards++;
  143. }
  144. if (!cards) {
  145. #ifdef MODULE
  146. printk(KERN_ERR "Card-VirMIDI soundcard not found or device busy\n");
  147. #endif
  148. snd_virmidi_unregister_all();
  149. return -ENODEV;
  150. }
  151. return 0;
  152. }
  153. static void __exit alsa_card_virmidi_exit(void)
  154. {
  155. snd_virmidi_unregister_all();
  156. }
  157. module_init(alsa_card_virmidi_init)
  158. module_exit(alsa_card_virmidi_exit)