projects/linux·blob master · refs

502 lines · 14.2 KiB

1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Generic MIDI synth driver for ALSA sequencer
4 * Copyright (c) 1998 by Frank van de Pol <[email protected]>
5 * Jaroslav Kysela <[email protected]>
6 */
7
8/*
9Possible options for midisynth module:
10 - automatic opening of midi ports on first received event or subscription
11 (close will be performed when client leaves)
12*/
13
14
15#include <linux/init.h>
16#include <linux/slab.h>
17#include <linux/errno.h>
18#include <linux/string.h>
19#include <linux/module.h>
20#include <linux/mutex.h>
21#include <sound/core.h>
22#include <sound/rawmidi.h>
23#include <sound/seq_kernel.h>
24#include <sound/seq_device.h>
25#include <sound/seq_midi_event.h>
26#include <sound/initval.h>
27#include "seq_lock.h"
28
29MODULE_AUTHOR("Frank van de Pol <[email protected]>, Jaroslav Kysela <[email protected]>");
30MODULE_DESCRIPTION("Advanced Linux Sound Architecture sequencer MIDI synth.");
31MODULE_LICENSE("GPL");
32static int output_buffer_size = PAGE_SIZE;
33module_param(output_buffer_size, int, 0644);
34MODULE_PARM_DESC(output_buffer_size, "Output buffer size in bytes.");
35static int input_buffer_size = PAGE_SIZE;
36module_param(input_buffer_size, int, 0644);
37MODULE_PARM_DESC(input_buffer_size, "Input buffer size in bytes.");
38
39/* data for this midi synth driver */
40struct seq_midisynth {
41 struct snd_card *card;
42 struct snd_rawmidi *rmidi;
43 int device;
44 int subdevice;
45 struct snd_rawmidi_substream __rcu *input_substream;
46 snd_use_lock_t input_use_lock; /* in-flight event_input users */
47 struct snd_rawmidi_file input_rfile;
48 snd_use_lock_t output_use_lock; /* in-flight event_input users */
49 struct snd_rawmidi_substream __rcu *output_substream;
50 struct snd_rawmidi_file output_rfile;
51 int seq_client;
52 int seq_port;
53 struct snd_midi_event *parser;
54};
55
56struct seq_midisynth_client {
57 int seq_client;
58 int num_ports;
59 int ports_per_device[SNDRV_RAWMIDI_DEVICES];
60 struct seq_midisynth *ports[SNDRV_RAWMIDI_DEVICES];
61};
62
63static struct seq_midisynth_client *synths[SNDRV_CARDS];
64static DEFINE_MUTEX(register_mutex);
65
66/* handle rawmidi input event (MIDI v1.0 stream) */
67static void snd_midi_input_event(struct snd_rawmidi_substream *substream)
68{
69 struct snd_rawmidi_runtime *runtime;
70 struct seq_midisynth *msynth;
71 struct snd_seq_event ev;
72 char buf[16], *pbuf;
73 long res;
74
75 if (substream == NULL)
76 return;
77 runtime = substream->runtime;
78 msynth = runtime->private_data;
79 if (msynth == NULL)
80 return;
81
82 scoped_guard(rcu) {
83 if (rcu_dereference(msynth->input_substream) != substream)
84 return;
85
86 snd_use_lock_use(&msynth->input_use_lock);
87 }
88
89 memset(&ev, 0, sizeof(ev));
90 while (runtime->avail > 0) {
91 res = snd_rawmidi_kernel_read(substream, buf, sizeof(buf));
92 if (res <= 0)
93 continue;
94 if (msynth->parser == NULL)
95 continue;
96 pbuf = buf;
97 while (res-- > 0) {
98 if (!snd_midi_event_encode_byte(msynth->parser,
99 *pbuf++, &ev))
100 continue;
101 ev.source.port = msynth->seq_port;
102 ev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
103 snd_seq_kernel_client_dispatch(msynth->seq_client, &ev, 1, 0);
104 /* clear event and reset header */
105 memset(&ev, 0, sizeof(ev));
106 }
107 }
108
109 snd_use_lock_free(&msynth->input_use_lock);
110}
111
112static int dump_midi(struct snd_rawmidi_substream *substream, const char *buf, int count)
113{
114 struct snd_rawmidi_runtime *runtime;
115 int tmp;
116
117 if (snd_BUG_ON(!substream || !buf))
118 return -EINVAL;
119 runtime = substream->runtime;
120 tmp = runtime->avail;
121 if (tmp < count) {
122 if (printk_ratelimit())
123 pr_err("ALSA: seq_midi: MIDI output buffer overrun\n");
124 return -ENOMEM;
125 }
126 if (snd_rawmidi_kernel_write(substream, buf, count) < count)
127 return -EINVAL;
128 return 0;
129}
130
131/* callback for snd_seq_dump_var_event(), bridging to dump_midi() */
132static int __dump_midi(void *ptr, void *buf, int count)
133{
134 return dump_midi(ptr, buf, count);
135}
136
137static int event_process_midi(struct snd_seq_event *ev, int direct,
138 void *private_data, int atomic, int hop)
139{
140 struct seq_midisynth *msynth = private_data;
141 unsigned char msg[10]; /* buffer for constructing midi messages */
142 struct snd_rawmidi_substream *substream;
143 int err = 0;
144 int len;
145
146 if (snd_BUG_ON(!msynth))
147 return -EINVAL;
148
149 scoped_guard(rcu) {
150 substream = rcu_dereference(msynth->output_substream);
151 if (!substream)
152 return -ENODEV;
153 snd_use_lock_use(&msynth->output_use_lock);
154 }
155
156 if (ev->type == SNDRV_SEQ_EVENT_SYSEX) { /* special case, to save space */
157 if ((ev->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) != SNDRV_SEQ_EVENT_LENGTH_VARIABLE) {
158 /* invalid event */
159 pr_debug("ALSA: seq_midi: invalid sysex event flags = 0x%x\n", ev->flags);
160 goto out;
161 }
162 snd_seq_dump_var_event(ev, __dump_midi, substream);
163 snd_midi_event_reset_decode(msynth->parser);
164 } else {
165 if (!msynth->parser) {
166 err = -EIO;
167 goto out;
168 }
169 len = snd_midi_event_decode(msynth->parser, msg, sizeof(msg), ev);
170 if (len < 0)
171 goto out;
172 if (dump_midi(substream, msg, len) < 0)
173 snd_midi_event_reset_decode(msynth->parser);
174 }
175
176out:
177 snd_use_lock_free(&msynth->output_use_lock);
178 return err;
179}
180
181
182static int snd_seq_midisynth_new(struct seq_midisynth *msynth,
183 struct snd_card *card,
184 int device,
185 int subdevice)
186{
187 if (snd_midi_event_new(MAX_MIDI_EVENT_BUF, &msynth->parser) < 0)
188 return -ENOMEM;
189 msynth->card = card;
190 msynth->device = device;
191 msynth->subdevice = subdevice;
192 snd_use_lock_init(&msynth->input_use_lock);
193 snd_use_lock_init(&msynth->output_use_lock);
194 return 0;
195}
196
197/* open associated midi device for input */
198static int midisynth_subscribe(void *private_data, struct snd_seq_port_subscribe *info)
199{
200 int err;
201 struct seq_midisynth *msynth = private_data;
202 struct snd_rawmidi_runtime *runtime;
203 struct snd_rawmidi_file rfile = {};
204 struct snd_rawmidi_params params;
205
206 /* open midi port */
207 err = snd_rawmidi_kernel_open(msynth->rmidi, msynth->subdevice,
208 SNDRV_RAWMIDI_LFLG_INPUT,
209 &rfile);
210 if (err < 0) {
211 pr_debug("ALSA: seq_midi: midi input open failed!!!\n");
212 return err;
213 }
214 runtime = rfile.input->runtime;
215 memset(&params, 0, sizeof(params));
216 params.avail_min = 1;
217 params.buffer_size = input_buffer_size;
218 err = snd_rawmidi_input_params(rfile.input, &params);
219 if (err < 0) {
220 snd_rawmidi_kernel_release(&rfile);
221 return err;
222 }
223 snd_midi_event_reset_encode(msynth->parser);
224 runtime->event = snd_midi_input_event;
225 runtime->private_data = msynth;
226 msynth->input_rfile = rfile;
227 rcu_assign_pointer(msynth->input_substream, rfile.input);
228 snd_rawmidi_kernel_read(msynth->input_rfile.input, NULL, 0);
229 return 0;
230}
231
232/* close associated midi device for input */
233static int midisynth_unsubscribe(void *private_data, struct snd_seq_port_subscribe *info)
234{
235 int err;
236 struct seq_midisynth *msynth = private_data;
237 struct snd_rawmidi_file rfile;
238
239 rcu_assign_pointer(msynth->input_substream, NULL);
240 synchronize_rcu();
241 snd_use_lock_sync(&msynth->input_use_lock);
242
243 rfile = msynth->input_rfile;
244 msynth->input_rfile = (struct snd_rawmidi_file){};
245
246 if (snd_BUG_ON(!rfile.input))
247 return -EINVAL;
248
249 err = snd_rawmidi_kernel_release(&rfile);
250 return err;
251}
252
253/* open associated midi device for output */
254static int midisynth_use(void *private_data, struct snd_seq_port_subscribe *info)
255{
256 int err;
257 struct seq_midisynth *msynth = private_data;
258 struct snd_rawmidi_file rfile = {};
259 struct snd_rawmidi_params params;
260
261 /* open midi port */
262 err = snd_rawmidi_kernel_open(msynth->rmidi, msynth->subdevice,
263 SNDRV_RAWMIDI_LFLG_OUTPUT,
264 &rfile);
265 if (err < 0) {
266 pr_debug("ALSA: seq_midi: midi output open failed!!!\n");
267 return err;
268 }
269 memset(&params, 0, sizeof(params));
270 params.avail_min = 1;
271 params.buffer_size = output_buffer_size;
272 params.no_active_sensing = 1;
273 err = snd_rawmidi_output_params(rfile.output, &params);
274 if (err < 0) {
275 snd_rawmidi_kernel_release(&rfile);
276 return err;
277 }
278 snd_midi_event_reset_decode(msynth->parser);
279 msynth->output_rfile = rfile;
280 rcu_assign_pointer(msynth->output_substream, rfile.output);
281 return 0;
282}
283
284/* close associated midi device for output */
285static int midisynth_unuse(void *private_data, struct snd_seq_port_subscribe *info)
286{
287 struct seq_midisynth *msynth = private_data;
288 struct snd_rawmidi_file rfile;
289
290 rcu_assign_pointer(msynth->output_substream, NULL);
291 synchronize_rcu();
292 snd_use_lock_sync(&msynth->output_use_lock);
293 rfile = msynth->output_rfile;
294 msynth->output_rfile = (struct snd_rawmidi_file){};
295
296 if (snd_BUG_ON(!rfile.output))
297 return -EINVAL;
298 snd_rawmidi_drain_output(rfile.output);
299 return snd_rawmidi_kernel_release(&rfile);
300}
301
302/* delete given midi synth port */
303static void snd_seq_midisynth_delete(struct seq_midisynth *msynth)
304{
305 if (msynth == NULL)
306 return;
307
308 if (msynth->seq_client > 0) {
309 /* delete port */
310 snd_seq_event_port_detach(msynth->seq_client, msynth->seq_port);
311 }
312
313 snd_midi_event_free(msynth->parser);
314}
315
316/* register new midi synth port */
317static int
318snd_seq_midisynth_probe(struct snd_seq_device *dev)
319{
320 struct seq_midisynth_client *client;
321 struct seq_midisynth *msynth, *ms;
322 struct snd_rawmidi *rmidi = dev->private_data;
323 int newclient = 0;
324 unsigned int p, ports;
325 struct snd_seq_port_callback pcallbacks;
326 struct snd_card *card = dev->card;
327 int device = dev->device;
328 unsigned int input_count = 0, output_count = 0;
329
330 if (snd_BUG_ON(!card || device < 0 || device >= SNDRV_RAWMIDI_DEVICES))
331 return -EINVAL;
332
333 struct snd_rawmidi_info *info __free(kfree) =
334 kmalloc_obj(*info);
335 if (! info)
336 return -ENOMEM;
337 info->device = device;
338 info->stream = SNDRV_RAWMIDI_STREAM_OUTPUT;
339 info->subdevice = 0;
340 if (snd_rawmidi_info_select(card, info) >= 0)
341 output_count = info->subdevices_count;
342 info->stream = SNDRV_RAWMIDI_STREAM_INPUT;
343 if (snd_rawmidi_info_select(card, info) >= 0) {
344 input_count = info->subdevices_count;
345 }
346 ports = output_count;
347 if (ports < input_count)
348 ports = input_count;
349 if (ports == 0)
350 return -ENODEV;
351 if (ports > (256 / SNDRV_RAWMIDI_DEVICES))
352 ports = 256 / SNDRV_RAWMIDI_DEVICES;
353
354 guard(mutex)(&register_mutex);
355 client = synths[card->number];
356 if (client == NULL) {
357 newclient = 1;
358 client = kzalloc_obj(*client);
359 if (client == NULL)
360 return -ENOMEM;
361 client->seq_client =
362 snd_seq_create_kernel_client(
363 card, 0, "%s", card->shortname[0] ?
364 (const char *)card->shortname : "External MIDI");
365 if (client->seq_client < 0) {
366 kfree(client);
367 return -ENOMEM;
368 }
369 }
370
371 msynth = kzalloc_objs(struct seq_midisynth, ports);
372
373 struct snd_seq_port_info *port __free(kfree) =
374 kmalloc_obj(*port);
375 if (msynth == NULL || port == NULL)
376 goto __nomem;
377
378 for (p = 0; p < ports; p++) {
379 ms = &msynth[p];
380 ms->rmidi = rmidi;
381
382 if (snd_seq_midisynth_new(ms, card, device, p) < 0)
383 goto __nomem;
384
385 /* declare port */
386 memset(port, 0, sizeof(*port));
387 port->addr.client = client->seq_client;
388 port->addr.port = device * (256 / SNDRV_RAWMIDI_DEVICES) + p;
389 port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT;
390 memset(info, 0, sizeof(*info));
391 info->device = device;
392 if (p < output_count)
393 info->stream = SNDRV_RAWMIDI_STREAM_OUTPUT;
394 else
395 info->stream = SNDRV_RAWMIDI_STREAM_INPUT;
396 info->subdevice = p;
397 if (snd_rawmidi_info_select(card, info) >= 0)
398 strscpy(port->name, info->subname);
399 if (! port->name[0]) {
400 if (info->name[0]) {
401 if (ports > 1)
402 scnprintf(port->name, sizeof(port->name), "%s-%u", info->name, p);
403 else
404 scnprintf(port->name, sizeof(port->name), "%s", info->name);
405 } else {
406 /* last resort */
407 if (ports > 1)
408 sprintf(port->name, "MIDI %d-%d-%u", card->number, device, p);
409 else
410 sprintf(port->name, "MIDI %d-%d", card->number, device);
411 }
412 }
413 if ((info->flags & SNDRV_RAWMIDI_INFO_OUTPUT) && p < output_count)
414 port->capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SYNC_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE;
415 if ((info->flags & SNDRV_RAWMIDI_INFO_INPUT) && p < input_count)
416 port->capability |= SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SYNC_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ;
417 if ((port->capability & (SNDRV_SEQ_PORT_CAP_WRITE|SNDRV_SEQ_PORT_CAP_READ)) == (SNDRV_SEQ_PORT_CAP_WRITE|SNDRV_SEQ_PORT_CAP_READ) &&
418 info->flags & SNDRV_RAWMIDI_INFO_DUPLEX)
419 port->capability |= SNDRV_SEQ_PORT_CAP_DUPLEX;
420 if (port->capability & SNDRV_SEQ_PORT_CAP_READ)
421 port->direction |= SNDRV_SEQ_PORT_DIR_INPUT;
422 if (port->capability & SNDRV_SEQ_PORT_CAP_WRITE)
423 port->direction |= SNDRV_SEQ_PORT_DIR_OUTPUT;
424 port->type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC
425 | SNDRV_SEQ_PORT_TYPE_HARDWARE
426 | SNDRV_SEQ_PORT_TYPE_PORT;
427 port->midi_channels = 16;
428 memset(&pcallbacks, 0, sizeof(pcallbacks));
429 pcallbacks.owner = THIS_MODULE;
430 pcallbacks.private_data = ms;
431 pcallbacks.subscribe = midisynth_subscribe;
432 pcallbacks.unsubscribe = midisynth_unsubscribe;
433 pcallbacks.use = midisynth_use;
434 pcallbacks.unuse = midisynth_unuse;
435 pcallbacks.event_input = event_process_midi;
436 port->kernel = &pcallbacks;
437 if (rmidi->ops && rmidi->ops->get_port_info)
438 rmidi->ops->get_port_info(rmidi, p, port);
439 if (snd_seq_kernel_client_ctl(client->seq_client, SNDRV_SEQ_IOCTL_CREATE_PORT, port)<0)
440 goto __nomem;
441 ms->seq_client = client->seq_client;
442 ms->seq_port = port->addr.port;
443 }
444 client->ports_per_device[device] = ports;
445 client->ports[device] = msynth;
446 client->num_ports++;
447 if (newclient)
448 synths[card->number] = client;
449 return 0; /* success */
450
451 __nomem:
452 if (msynth != NULL) {
453 for (p = 0; p < ports; p++)
454 snd_seq_midisynth_delete(&msynth[p]);
455 kfree(msynth);
456 }
457 if (newclient) {
458 snd_seq_delete_kernel_client(client->seq_client);
459 kfree(client);
460 }
461 return -ENOMEM;
462}
463
464/* release midi synth port */
465static void
466snd_seq_midisynth_remove(struct snd_seq_device *dev)
467{
468 struct seq_midisynth_client *client;
469 struct seq_midisynth *msynth;
470 struct snd_card *card = dev->card;
471 int device = dev->device, p, ports;
472
473 guard(mutex)(&register_mutex);
474 client = synths[card->number];
475 if (client == NULL || client->ports[device] == NULL)
476 return;
477 ports = client->ports_per_device[device];
478 client->ports_per_device[device] = 0;
479 msynth = client->ports[device];
480 client->ports[device] = NULL;
481 for (p = 0; p < ports; p++)
482 snd_seq_midisynth_delete(&msynth[p]);
483 kfree(msynth);
484 client->num_ports--;
485 if (client->num_ports <= 0) {
486 snd_seq_delete_kernel_client(client->seq_client);
487 synths[card->number] = NULL;
488 kfree(client);
489 }
490}
491
492static struct snd_seq_driver seq_midisynth_driver = {
493 .probe = snd_seq_midisynth_probe,
494 .remove = snd_seq_midisynth_remove,
495 .driver = {
496 .name = KBUILD_MODNAME,
497 },
498 .id = SNDRV_SEQ_DEV_ID_MIDISYNTH,
499 .argsize = 0,
500};
501
502module_snd_seq_driver(seq_midisynth_driver);