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
event_process_midi(struct snd_seq_event * ev,int direct,void * private_data,int atomic,int hop)116 static int event_process_midi(struct snd_seq_event *ev, int direct,
117 void *private_data, int atomic, int hop)
118 {
119 struct seq_midisynth *msynth = private_data;
120 unsigned char msg[10]; /* buffer for constructing midi messages */
121 struct snd_rawmidi_substream *substream;
122 int len;
123
124 if (snd_BUG_ON(!msynth))
125 return -EINVAL;
126 substream = msynth->output_rfile.output;
127 if (substream == NULL)
128 return -ENODEV;
129 if (ev->type == SNDRV_SEQ_EVENT_SYSEX) { /* special case, to save space */
130 if ((ev->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) != SNDRV_SEQ_EVENT_LENGTH_VARIABLE) {
131 /* invalid event */
132 pr_debug("ALSA: seq_midi: invalid sysex event flags = 0x%x\n", ev->flags);
133 return 0;
134 }
135 snd_seq_dump_var_event(ev, (snd_seq_dump_func_t)dump_midi, substream);
136 snd_midi_event_reset_decode(msynth->parser);
137 } else {
138 if (msynth->parser == NULL)
139 return -EIO;
140 len = snd_midi_event_decode(msynth->parser, msg, sizeof(msg), ev);
141 if (len < 0)
142 return 0;
143 if (dump_midi(substream, msg, len) < 0)
144 snd_midi_event_reset_decode(msynth->parser);
145 }
146 return 0;
147 }
148
149
snd_seq_midisynth_new(struct seq_midisynth * msynth,struct snd_card * card,int device,int subdevice)150 static int snd_seq_midisynth_new(struct seq_midisynth *msynth,
151 struct snd_card *card,
152 int device,
153 int subdevice)
154 {
155 if (snd_midi_event_new(MAX_MIDI_EVENT_BUF, &msynth->parser) < 0)
156 return -ENOMEM;
157 msynth->card = card;
158 msynth->device = device;
159 msynth->subdevice = subdevice;
160 return 0;
161 }
162
163 /* open associated midi device for input */
midisynth_subscribe(void * private_data,struct snd_seq_port_subscribe * info)164 static int midisynth_subscribe(void *private_data, struct snd_seq_port_subscribe *info)
165 {
166 int err;
167 struct seq_midisynth *msynth = private_data;
168 struct snd_rawmidi_runtime *runtime;
169 struct snd_rawmidi_params params;
170
171 /* open midi port */
172 err = snd_rawmidi_kernel_open(msynth->rmidi, msynth->subdevice,
173 SNDRV_RAWMIDI_LFLG_INPUT,
174 &msynth->input_rfile);
175 if (err < 0) {
176 pr_debug("ALSA: seq_midi: midi input open failed!!!\n");
177 return err;
178 }
179 runtime = msynth->input_rfile.input->runtime;
180 memset(¶ms, 0, sizeof(params));
181 params.avail_min = 1;
182 params.buffer_size = input_buffer_size;
183 err = snd_rawmidi_input_params(msynth->input_rfile.input, ¶ms);
184 if (err < 0) {
185 snd_rawmidi_kernel_release(&msynth->input_rfile);
186 return err;
187 }
188 snd_midi_event_reset_encode(msynth->parser);
189 runtime->event = snd_midi_input_event;
190 runtime->private_data = msynth;
191 snd_rawmidi_kernel_read(msynth->input_rfile.input, NULL, 0);
192 return 0;
193 }
194
195 /* close associated midi device for input */
midisynth_unsubscribe(void * private_data,struct snd_seq_port_subscribe * info)196 static int midisynth_unsubscribe(void *private_data, struct snd_seq_port_subscribe *info)
197 {
198 int err;
199 struct seq_midisynth *msynth = private_data;
200
201 if (snd_BUG_ON(!msynth->input_rfile.input))
202 return -EINVAL;
203 err = snd_rawmidi_kernel_release(&msynth->input_rfile);
204 return err;
205 }
206
207 /* open associated midi device for output */
midisynth_use(void * private_data,struct snd_seq_port_subscribe * info)208 static int midisynth_use(void *private_data, struct snd_seq_port_subscribe *info)
209 {
210 int err;
211 struct seq_midisynth *msynth = private_data;
212 struct snd_rawmidi_params params;
213
214 /* open midi port */
215 err = snd_rawmidi_kernel_open(msynth->rmidi, msynth->subdevice,
216 SNDRV_RAWMIDI_LFLG_OUTPUT,
217 &msynth->output_rfile);
218 if (err < 0) {
219 pr_debug("ALSA: seq_midi: midi output open failed!!!\n");
220 return err;
221 }
222 memset(¶ms, 0, sizeof(params));
223 params.avail_min = 1;
224 params.buffer_size = output_buffer_size;
225 params.no_active_sensing = 1;
226 err = snd_rawmidi_output_params(msynth->output_rfile.output, ¶ms);
227 if (err < 0) {
228 snd_rawmidi_kernel_release(&msynth->output_rfile);
229 return err;
230 }
231 snd_midi_event_reset_decode(msynth->parser);
232 return 0;
233 }
234
235 /* close associated midi device for output */
midisynth_unuse(void * private_data,struct snd_seq_port_subscribe * info)236 static int midisynth_unuse(void *private_data, struct snd_seq_port_subscribe *info)
237 {
238 struct seq_midisynth *msynth = private_data;
239
240 if (snd_BUG_ON(!msynth->output_rfile.output))
241 return -EINVAL;
242 snd_rawmidi_drain_output(msynth->output_rfile.output);
243 return snd_rawmidi_kernel_release(&msynth->output_rfile);
244 }
245
246 /* delete given midi synth port */
snd_seq_midisynth_delete(struct seq_midisynth * msynth)247 static void snd_seq_midisynth_delete(struct seq_midisynth *msynth)
248 {
249 if (msynth == NULL)
250 return;
251
252 if (msynth->seq_client > 0) {
253 /* delete port */
254 snd_seq_event_port_detach(msynth->seq_client, msynth->seq_port);
255 }
256
257 snd_midi_event_free(msynth->parser);
258 }
259
260 /* register new midi synth port */
261 static int
snd_seq_midisynth_probe(struct device * _dev)262 snd_seq_midisynth_probe(struct device *_dev)
263 {
264 struct snd_seq_device *dev = to_seq_dev(_dev);
265 struct seq_midisynth_client *client;
266 struct seq_midisynth *msynth, *ms;
267 struct snd_seq_port_info *port;
268 struct snd_rawmidi_info *info;
269 struct snd_rawmidi *rmidi = dev->private_data;
270 int newclient = 0;
271 unsigned int p, ports;
272 struct snd_seq_port_callback pcallbacks;
273 struct snd_card *card = dev->card;
274 int device = dev->device;
275 unsigned int input_count = 0, output_count = 0;
276
277 if (snd_BUG_ON(!card || device < 0 || device >= SNDRV_RAWMIDI_DEVICES))
278 return -EINVAL;
279 info = kmalloc(sizeof(*info), GFP_KERNEL);
280 if (! info)
281 return -ENOMEM;
282 info->device = device;
283 info->stream = SNDRV_RAWMIDI_STREAM_OUTPUT;
284 info->subdevice = 0;
285 if (snd_rawmidi_info_select(card, info) >= 0)
286 output_count = info->subdevices_count;
287 info->stream = SNDRV_RAWMIDI_STREAM_INPUT;
288 if (snd_rawmidi_info_select(card, info) >= 0) {
289 input_count = info->subdevices_count;
290 }
291 ports = output_count;
292 if (ports < input_count)
293 ports = input_count;
294 if (ports == 0) {
295 kfree(info);
296 return -ENODEV;
297 }
298 if (ports > (256 / SNDRV_RAWMIDI_DEVICES))
299 ports = 256 / SNDRV_RAWMIDI_DEVICES;
300
301 mutex_lock(®ister_mutex);
302 client = synths[card->number];
303 if (client == NULL) {
304 newclient = 1;
305 client = kzalloc(sizeof(*client), GFP_KERNEL);
306 if (client == NULL) {
307 mutex_unlock(®ister_mutex);
308 kfree(info);
309 return -ENOMEM;
310 }
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 mutex_unlock(®ister_mutex);
318 kfree(info);
319 return -ENOMEM;
320 }
321 }
322
323 msynth = kcalloc(ports, sizeof(struct seq_midisynth), GFP_KERNEL);
324 port = kmalloc(sizeof(*port), GFP_KERNEL);
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 strcpy(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 mutex_unlock(®ister_mutex);
400 kfree(info);
401 kfree(port);
402 return 0; /* success */
403
404 __nomem:
405 if (msynth != NULL) {
406 for (p = 0; p < ports; p++)
407 snd_seq_midisynth_delete(&msynth[p]);
408 kfree(msynth);
409 }
410 if (newclient) {
411 snd_seq_delete_kernel_client(client->seq_client);
412 kfree(client);
413 }
414 kfree(info);
415 kfree(port);
416 mutex_unlock(®ister_mutex);
417 return -ENOMEM;
418 }
419
420 /* release midi synth port */
421 static int
snd_seq_midisynth_remove(struct device * _dev)422 snd_seq_midisynth_remove(struct device *_dev)
423 {
424 struct snd_seq_device *dev = to_seq_dev(_dev);
425 struct seq_midisynth_client *client;
426 struct seq_midisynth *msynth;
427 struct snd_card *card = dev->card;
428 int device = dev->device, p, ports;
429
430 mutex_lock(®ister_mutex);
431 client = synths[card->number];
432 if (client == NULL || client->ports[device] == NULL) {
433 mutex_unlock(®ister_mutex);
434 return -ENODEV;
435 }
436 ports = client->ports_per_device[device];
437 client->ports_per_device[device] = 0;
438 msynth = client->ports[device];
439 client->ports[device] = NULL;
440 for (p = 0; p < ports; p++)
441 snd_seq_midisynth_delete(&msynth[p]);
442 kfree(msynth);
443 client->num_ports--;
444 if (client->num_ports <= 0) {
445 snd_seq_delete_kernel_client(client->seq_client);
446 synths[card->number] = NULL;
447 kfree(client);
448 }
449 mutex_unlock(®ister_mutex);
450 return 0;
451 }
452
453 static struct snd_seq_driver seq_midisynth_driver = {
454 .driver = {
455 .name = KBUILD_MODNAME,
456 .probe = snd_seq_midisynth_probe,
457 .remove = snd_seq_midisynth_remove,
458 },
459 .id = SNDRV_SEQ_DEV_ID_MIDISYNTH,
460 .argsize = 0,
461 };
462
463 module_snd_seq_driver(seq_midisynth_driver);
464
