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