sound/drivers/virmidi.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  *  Dummy soundcard for virtual rawmidi devices
0004  *
0005  *  Copyright (c) 2000 by Takashi Iwai <tiwai@suse.de>
0006  */
0007
0008 /*
0009  * VIRTUAL RAW MIDI DEVICE CARDS
0010  *
0011  * This dummy card contains up to 4 virtual rawmidi devices.
0012  * They are not real rawmidi devices but just associated with sequencer
0013  * clients, so that any input/output sources can be connected as a raw
0014  * MIDI device arbitrary.
0015  * Also, multiple access is allowed to a single rawmidi device.
0016  *
0017  * Typical usage is like following:
0018  * - Load snd-virmidi module.
0019  *  # modprobe snd-virmidi index=2
0020  *   Then, sequencer clients 72:0 to 75:0 will be created, which are
0021  *   mapped from /dev/snd/midiC1D0 to /dev/snd/midiC1D3, respectively.
0022  *
0023  * - Connect input/output via aconnect.
0024  *  % aconnect 64:0 72:0    # keyboard input redirection 64:0 -> 72:0
0025  *  % aconnect 72:0 65:0    # output device redirection 72:0 -> 65:0
0026  *
0027  * - Run application using a midi device (eg. /dev/snd/midiC1D0)
0028  */
0029
0030 #include <linux/init.h>
0031 #include <linux/wait.h>
0032 #include <linux/err.h>
0033 #include <linux/platform_device.h>
0034 #include <linux/module.h>
0035 #include <sound/core.h>
0036 #include <sound/seq_kernel.h>
0037 #include <sound/seq_virmidi.h>
0038 #include <sound/initval.h>
0039
0040 /* hack: OSS defines midi_devs, so undefine it (versioned symbols) */
0041 #undef midi_devs
0042
0043 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
0044 MODULE_DESCRIPTION("Dummy soundcard for virtual rawmidi devices");
0045 MODULE_LICENSE("GPL");
0046
0047 #define MAX_MIDI_DEVICES    4
0048
0049 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;  /* Index 0-MAX */
0050 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;   /* ID for this card */
0051 static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
0052 static int midi_devs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 4};
0053
0054 module_param_array(index, int, NULL, 0444);
0055 MODULE_PARM_DESC(index, "Index value for virmidi soundcard.");
0056 module_param_array(id, charp, NULL, 0444);
0057 MODULE_PARM_DESC(id, "ID string for virmidi soundcard.");
0058 module_param_array(enable, bool, NULL, 0444);
0059 MODULE_PARM_DESC(enable, "Enable this soundcard.");
0060 module_param_array(midi_devs, int, NULL, 0444);
0061 MODULE_PARM_DESC(midi_devs, "MIDI devices # (1-4)");
0062
0063 struct snd_card_virmidi {
0064     struct snd_card *card;
0065     struct snd_rawmidi *midi[MAX_MIDI_DEVICES];
0066 };
0067
0068 static struct platform_device *devices[SNDRV_CARDS];
0069
0070
0071 static int snd_virmidi_probe(struct platform_device *devptr)
0072 {
0073     struct snd_card *card;
0074     struct snd_card_virmidi *vmidi;
0075     int idx, err;
0076     int dev = devptr->id;
0077
0078     err = snd_devm_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
0079                 sizeof(struct snd_card_virmidi), &card);
0080     if (err < 0)
0081         return err;
0082     vmidi = card->private_data;
0083     vmidi->card = card;
0084
0085     if (midi_devs[dev] > MAX_MIDI_DEVICES) {
0086         snd_printk(KERN_WARNING
0087                "too much midi devices for virmidi %d: force to use %d\n",
0088                dev, MAX_MIDI_DEVICES);
0089         midi_devs[dev] = MAX_MIDI_DEVICES;
0090     }
0091     for (idx = 0; idx < midi_devs[dev]; idx++) {
0092         struct snd_rawmidi *rmidi;
0093
0094         err = snd_virmidi_new(card, idx, &rmidi);
0095         if (err < 0)
0096             return err;
0097         vmidi->midi[idx] = rmidi;
0098         strcpy(rmidi->name, "Virtual Raw MIDI");
0099     }
0100
0101     strcpy(card->driver, "VirMIDI");
0102     strcpy(card->shortname, "VirMIDI");
0103     sprintf(card->longname, "Virtual MIDI Card %i", dev + 1);
0104
0105     err = snd_card_register(card);
0106     if (err)
0107         return err;
0108
0109     platform_set_drvdata(devptr, card);
0110     return 0;
0111 }
0112
0113 #define SND_VIRMIDI_DRIVER  "snd_virmidi"
0114
0115 static struct platform_driver snd_virmidi_driver = {
0116     .probe      = snd_virmidi_probe,
0117     .driver     = {
0118         .name   = SND_VIRMIDI_DRIVER,
0119     },
0120 };
0121
0122 static void snd_virmidi_unregister_all(void)
0123 {
0124     int i;
0125
0126     for (i = 0; i < ARRAY_SIZE(devices); ++i)
0127         platform_device_unregister(devices[i]);
0128     platform_driver_unregister(&snd_virmidi_driver);
0129 }
0130
0131 static int __init alsa_card_virmidi_init(void)
0132 {
0133     int i, cards, err;
0134
0135     err = platform_driver_register(&snd_virmidi_driver);
0136     if (err < 0)
0137         return err;
0138
0139     cards = 0;
0140     for (i = 0; i < SNDRV_CARDS; i++) {
0141         struct platform_device *device;
0142
0143         if (!enable[i])
0144             continue;
0145         device = platform_device_register_simple(SND_VIRMIDI_DRIVER,
0146                              i, NULL, 0);
0147         if (IS_ERR(device))
0148             continue;
0149         if (!platform_get_drvdata(device)) {
0150             platform_device_unregister(device);
0151             continue;
0152         }
0153         devices[i] = device;
0154         cards++;
0155     }
0156     if (!cards) {
0157 #ifdef MODULE
0158         printk(KERN_ERR "Card-VirMIDI soundcard not found or device busy\n");
0159 #endif
0160         snd_virmidi_unregister_all();
0161         return -ENODEV;
0162     }
0163     return 0;
0164 }
0165
0166 static void __exit alsa_card_virmidi_exit(void)
0167 {
0168     snd_virmidi_unregister_all();
0169 }
0170
0171 module_init(alsa_card_virmidi_init)
0172 module_exit(alsa_card_virmidi_exit)