1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Virtual Raw MIDI client on Sequencer
5 * Copyright (c) 2000 by Takashi Iwai <tiwai@suse.de>,
6 * Jaroslav Kysela <perex@perex.cz>
10 * Virtual Raw MIDI client
12 * The virtual rawmidi client is a sequencer client which associate
13 * a rawmidi device file. The created rawmidi device file can be
14 * accessed as a normal raw midi, but its MIDI source and destination
15 * are arbitrary. For example, a user-client software synth connected
16 * to this port can be used as a normal midi device as well.
18 * The virtual rawmidi device accepts also multiple opens. Each file
19 * has its own input buffer, so that no conflict would occur. The drain
20 * of input/output buffer acts only to the local buffer.
24 #include <linux/init.h>
25 #include <linux/wait.h>
26 #include <linux/module.h>
27 #include <linux/slab.h>
28 #include <sound/core.h>
29 #include <sound/rawmidi.h>
30 #include <sound/info.h>
31 #include <sound/control.h>
32 #include <sound/minors.h>
33 #include <sound/seq_kernel.h>
34 #include <sound/seq_midi_event.h>
35 #include <sound/seq_virmidi.h>
37 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
38 MODULE_DESCRIPTION("Virtual Raw MIDI client on Sequencer");
39 MODULE_LICENSE("GPL");
42 * initialize an event record
44 static void snd_virmidi_init_event(struct snd_virmidi *vmidi,
45 struct snd_seq_event *ev)
47 memset(ev, 0, sizeof(*ev));
48 ev->source.port = vmidi->port;
49 switch (vmidi->seq_mode) {
50 case SNDRV_VIRMIDI_SEQ_DISPATCH:
51 ev->dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
53 case SNDRV_VIRMIDI_SEQ_ATTACH:
54 /* FIXME: source and destination are same - not good.. */
55 ev->dest.client = vmidi->client;
56 ev->dest.port = vmidi->port;
59 ev->type = SNDRV_SEQ_EVENT_NONE;
63 * decode input event and put to read buffer of each opened file
65 static int snd_virmidi_dev_receive_event(struct snd_virmidi_dev *rdev,
66 struct snd_seq_event *ev,
69 struct snd_virmidi *vmidi;
74 read_lock(&rdev->filelist_lock);
76 down_read(&rdev->filelist_sem);
77 list_for_each_entry(vmidi, &rdev->filelist, list) {
78 if (!READ_ONCE(vmidi->trigger))
80 if (ev->type == SNDRV_SEQ_EVENT_SYSEX) {
81 if ((ev->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) != SNDRV_SEQ_EVENT_LENGTH_VARIABLE)
83 snd_seq_dump_var_event(ev, (snd_seq_dump_func_t)snd_rawmidi_receive, vmidi->substream);
85 len = snd_midi_event_decode(vmidi->parser, msg, sizeof(msg), ev);
87 snd_rawmidi_receive(vmidi->substream, msg, len);
91 read_unlock(&rdev->filelist_lock);
93 up_read(&rdev->filelist_sem);
99 * event handler of virmidi port
101 static int snd_virmidi_event_input(struct snd_seq_event *ev, int direct,
102 void *private_data, int atomic, int hop)
104 struct snd_virmidi_dev *rdev;
107 if (!(rdev->flags & SNDRV_VIRMIDI_USE))
108 return 0; /* ignored */
109 return snd_virmidi_dev_receive_event(rdev, ev, atomic);
113 * trigger rawmidi stream for input
115 static void snd_virmidi_input_trigger(struct snd_rawmidi_substream *substream, int up)
117 struct snd_virmidi *vmidi = substream->runtime->private_data;
119 WRITE_ONCE(vmidi->trigger, !!up);
122 /* process rawmidi bytes and send events;
123 * we need no lock here for vmidi->event since it's handled only in this work
125 static void snd_vmidi_output_work(struct work_struct *work)
127 struct snd_virmidi *vmidi;
128 struct snd_rawmidi_substream *substream;
132 vmidi = container_of(work, struct snd_virmidi, output_work);
133 substream = vmidi->substream;
135 /* discard the outputs in dispatch mode unless subscribed */
136 if (vmidi->seq_mode == SNDRV_VIRMIDI_SEQ_DISPATCH &&
137 !(vmidi->rdev->flags & SNDRV_VIRMIDI_SUBSCRIBE)) {
138 snd_rawmidi_proceed(substream);
142 while (READ_ONCE(vmidi->trigger)) {
143 if (snd_rawmidi_transmit(substream, &input, 1) != 1)
145 if (!snd_midi_event_encode_byte(vmidi->parser, input,
148 if (vmidi->event.type != SNDRV_SEQ_EVENT_NONE) {
149 ret = snd_seq_kernel_client_dispatch(vmidi->client,
152 vmidi->event.type = SNDRV_SEQ_EVENT_NONE;
156 /* rawmidi input might be huge, allow to have a break */
162 * trigger rawmidi stream for output
164 static void snd_virmidi_output_trigger(struct snd_rawmidi_substream *substream, int up)
166 struct snd_virmidi *vmidi = substream->runtime->private_data;
168 WRITE_ONCE(vmidi->trigger, !!up);
170 queue_work(system_highpri_wq, &vmidi->output_work);
174 * open rawmidi handle for input
176 static int snd_virmidi_input_open(struct snd_rawmidi_substream *substream)
178 struct snd_virmidi_dev *rdev = substream->rmidi->private_data;
179 struct snd_rawmidi_runtime *runtime = substream->runtime;
180 struct snd_virmidi *vmidi;
182 vmidi = kzalloc(sizeof(*vmidi), GFP_KERNEL);
185 vmidi->substream = substream;
186 if (snd_midi_event_new(0, &vmidi->parser) < 0) {
190 vmidi->seq_mode = rdev->seq_mode;
191 vmidi->client = rdev->client;
192 vmidi->port = rdev->port;
193 runtime->private_data = vmidi;
194 down_write(&rdev->filelist_sem);
195 write_lock_irq(&rdev->filelist_lock);
196 list_add_tail(&vmidi->list, &rdev->filelist);
197 write_unlock_irq(&rdev->filelist_lock);
198 up_write(&rdev->filelist_sem);
204 * open rawmidi handle for output
206 static int snd_virmidi_output_open(struct snd_rawmidi_substream *substream)
208 struct snd_virmidi_dev *rdev = substream->rmidi->private_data;
209 struct snd_rawmidi_runtime *runtime = substream->runtime;
210 struct snd_virmidi *vmidi;
212 vmidi = kzalloc(sizeof(*vmidi), GFP_KERNEL);
215 vmidi->substream = substream;
216 if (snd_midi_event_new(MAX_MIDI_EVENT_BUF, &vmidi->parser) < 0) {
220 vmidi->seq_mode = rdev->seq_mode;
221 vmidi->client = rdev->client;
222 vmidi->port = rdev->port;
223 snd_virmidi_init_event(vmidi, &vmidi->event);
225 INIT_WORK(&vmidi->output_work, snd_vmidi_output_work);
226 runtime->private_data = vmidi;
231 * close rawmidi handle for input
233 static int snd_virmidi_input_close(struct snd_rawmidi_substream *substream)
235 struct snd_virmidi_dev *rdev = substream->rmidi->private_data;
236 struct snd_virmidi *vmidi = substream->runtime->private_data;
238 down_write(&rdev->filelist_sem);
239 write_lock_irq(&rdev->filelist_lock);
240 list_del(&vmidi->list);
241 write_unlock_irq(&rdev->filelist_lock);
242 up_write(&rdev->filelist_sem);
243 snd_midi_event_free(vmidi->parser);
244 substream->runtime->private_data = NULL;
250 * close rawmidi handle for output
252 static int snd_virmidi_output_close(struct snd_rawmidi_substream *substream)
254 struct snd_virmidi *vmidi = substream->runtime->private_data;
256 WRITE_ONCE(vmidi->trigger, false); /* to be sure */
257 cancel_work_sync(&vmidi->output_work);
258 snd_midi_event_free(vmidi->parser);
259 substream->runtime->private_data = NULL;
265 * subscribe callback - allow output to rawmidi device
267 static int snd_virmidi_subscribe(void *private_data,
268 struct snd_seq_port_subscribe *info)
270 struct snd_virmidi_dev *rdev;
273 if (!try_module_get(rdev->card->module))
275 rdev->flags |= SNDRV_VIRMIDI_SUBSCRIBE;
280 * unsubscribe callback - disallow output to rawmidi device
282 static int snd_virmidi_unsubscribe(void *private_data,
283 struct snd_seq_port_subscribe *info)
285 struct snd_virmidi_dev *rdev;
288 rdev->flags &= ~SNDRV_VIRMIDI_SUBSCRIBE;
289 module_put(rdev->card->module);
295 * use callback - allow input to rawmidi device
297 static int snd_virmidi_use(void *private_data,
298 struct snd_seq_port_subscribe *info)
300 struct snd_virmidi_dev *rdev;
303 if (!try_module_get(rdev->card->module))
305 rdev->flags |= SNDRV_VIRMIDI_USE;
310 * unuse callback - disallow input to rawmidi device
312 static int snd_virmidi_unuse(void *private_data,
313 struct snd_seq_port_subscribe *info)
315 struct snd_virmidi_dev *rdev;
318 rdev->flags &= ~SNDRV_VIRMIDI_USE;
319 module_put(rdev->card->module);
328 static const struct snd_rawmidi_ops snd_virmidi_input_ops = {
329 .open = snd_virmidi_input_open,
330 .close = snd_virmidi_input_close,
331 .trigger = snd_virmidi_input_trigger,
334 static const struct snd_rawmidi_ops snd_virmidi_output_ops = {
335 .open = snd_virmidi_output_open,
336 .close = snd_virmidi_output_close,
337 .trigger = snd_virmidi_output_trigger,
341 * create a sequencer client and a port
343 static int snd_virmidi_dev_attach_seq(struct snd_virmidi_dev *rdev)
346 struct snd_seq_port_callback pcallbacks;
347 struct snd_seq_port_info *pinfo;
350 if (rdev->client >= 0)
353 pinfo = kzalloc(sizeof(*pinfo), GFP_KERNEL);
359 client = snd_seq_create_kernel_client(rdev->card, rdev->device,
360 "%s %d-%d", rdev->rmidi->name,
367 rdev->client = client;
370 pinfo->addr.client = client;
371 sprintf(pinfo->name, "VirMIDI %d-%d", rdev->card->number, rdev->device);
372 /* set all capabilities */
373 pinfo->capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SYNC_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE;
374 pinfo->capability |= SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SYNC_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ;
375 pinfo->capability |= SNDRV_SEQ_PORT_CAP_DUPLEX;
376 pinfo->type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC
377 | SNDRV_SEQ_PORT_TYPE_SOFTWARE
378 | SNDRV_SEQ_PORT_TYPE_PORT;
379 pinfo->midi_channels = 16;
380 memset(&pcallbacks, 0, sizeof(pcallbacks));
381 pcallbacks.owner = THIS_MODULE;
382 pcallbacks.private_data = rdev;
383 pcallbacks.subscribe = snd_virmidi_subscribe;
384 pcallbacks.unsubscribe = snd_virmidi_unsubscribe;
385 pcallbacks.use = snd_virmidi_use;
386 pcallbacks.unuse = snd_virmidi_unuse;
387 pcallbacks.event_input = snd_virmidi_event_input;
388 pinfo->kernel = &pcallbacks;
389 err = snd_seq_kernel_client_ctl(client, SNDRV_SEQ_IOCTL_CREATE_PORT, pinfo);
391 snd_seq_delete_kernel_client(client);
396 rdev->port = pinfo->addr.port;
397 err = 0; /* success */
406 * release the sequencer client
408 static void snd_virmidi_dev_detach_seq(struct snd_virmidi_dev *rdev)
410 if (rdev->client >= 0) {
411 snd_seq_delete_kernel_client(rdev->client);
417 * register the device
419 static int snd_virmidi_dev_register(struct snd_rawmidi *rmidi)
421 struct snd_virmidi_dev *rdev = rmidi->private_data;
424 switch (rdev->seq_mode) {
425 case SNDRV_VIRMIDI_SEQ_DISPATCH:
426 err = snd_virmidi_dev_attach_seq(rdev);
430 case SNDRV_VIRMIDI_SEQ_ATTACH:
431 if (rdev->client == 0)
433 /* should check presence of port more strictly.. */
436 pr_err("ALSA: seq_virmidi: seq_mode is not set: %d\n", rdev->seq_mode);
444 * unregister the device
446 static int snd_virmidi_dev_unregister(struct snd_rawmidi *rmidi)
448 struct snd_virmidi_dev *rdev = rmidi->private_data;
450 if (rdev->seq_mode == SNDRV_VIRMIDI_SEQ_DISPATCH)
451 snd_virmidi_dev_detach_seq(rdev);
458 static const struct snd_rawmidi_global_ops snd_virmidi_global_ops = {
459 .dev_register = snd_virmidi_dev_register,
460 .dev_unregister = snd_virmidi_dev_unregister,
466 static void snd_virmidi_free(struct snd_rawmidi *rmidi)
468 struct snd_virmidi_dev *rdev = rmidi->private_data;
473 * create a new device
477 int snd_virmidi_new(struct snd_card *card, int device, struct snd_rawmidi **rrmidi)
479 struct snd_rawmidi *rmidi;
480 struct snd_virmidi_dev *rdev;
484 if ((err = snd_rawmidi_new(card, "VirMidi", device,
485 16, /* may be configurable */
486 16, /* may be configurable */
489 strcpy(rmidi->name, rmidi->id);
490 rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
492 snd_device_free(card, rmidi);
497 rdev->device = device;
499 init_rwsem(&rdev->filelist_sem);
500 rwlock_init(&rdev->filelist_lock);
501 INIT_LIST_HEAD(&rdev->filelist);
502 rdev->seq_mode = SNDRV_VIRMIDI_SEQ_DISPATCH;
503 rmidi->private_data = rdev;
504 rmidi->private_free = snd_virmidi_free;
505 rmidi->ops = &snd_virmidi_global_ops;
506 snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &snd_virmidi_input_ops);
507 snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &snd_virmidi_output_ops);
508 rmidi->info_flags = SNDRV_RAWMIDI_INFO_INPUT |
509 SNDRV_RAWMIDI_INFO_OUTPUT |
510 SNDRV_RAWMIDI_INFO_DUPLEX;
514 EXPORT_SYMBOL(snd_virmidi_new);