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 int device;
42 int subdevice;
43 struct snd_rawmidi_file input_rfile;
44 struct snd_rawmidi_file output_rfile;
45 int seq_client;
46 int seq_port;
47 struct snd_midi_event *parser;
48 };
49
50 struct seq_midisynth_client {
51 int seq_client;
52 int num_ports;
53 int ports_per_device[SNDRV_RAWMIDI_DEVICES];
54 struct seq_midisynth *ports[SNDRV_RAWMIDI_DEVICES];
55 };
56
57 static struct seq_midisynth_client *synths[SNDRV_CARDS];
58 static DEFINE_MUTEX(register_mutex);
59
60 /* handle rawmidi input event (MIDI v1.0 stream) */
snd_midi_input_event(struct snd_rawmidi_substream * substream)61 static void snd_midi_input_event(struct snd_rawmidi_substream *substream)
62 {
63 struct snd_rawmidi_runtime *runtime;
64 struct seq_midisynth *msynth;
65 struct snd_seq_event ev;
66 char buf[16], *pbuf;
67 long res;
68
69 if (substream == NULL)
70 return;
71 runtime = substream->runtime;
72 msynth = runtime->private_data;
73 if (msynth == NULL)
74 return;
75 memset(&ev, 0, sizeof(ev));
76 while (runtime->avail > 0) {
77 res = snd_rawmidi_kernel_read(substream, buf, sizeof(buf));
78 if (res <= 0)
79 continue;
80 if (msynth->parser == NULL)
81 continue;
82 pbuf = buf;
83 while (res-- > 0) {
84 if (!snd_midi_event_encode_byte(msynth->parser,
85 *pbuf++, &ev))
86 continue;
87 ev.source.port = msynth->seq_port;
88 ev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
89 snd_seq_kernel_client_dispatch(msynth->seq_client, &ev, 1, 0);
90 /* clear event and reset header */
91 memset(&ev, 0, sizeof(ev));
92 }
93 }
94 }
95
dump_midi(struct snd_rawmidi_substream * substream,const char * buf,int count)96 static int dump_midi(struct snd_rawmidi_substream *substream, const char *buf, int count)
97 {
98 struct snd_rawmidi_runtime *runtime;
99 int tmp;
100
101 if (snd_BUG_ON(!substream || !buf))
102 return -EINVAL;
103 runtime = substream->runtime;
104 tmp = runtime->avail;
105 if (tmp < count) {
106 if (printk_ratelimit())
107 pr_err("ALSA: seq_midi: MIDI output buffer overrun\n");
108 return -ENOMEM;
109 }
110 if (snd_rawmidi_kernel_write(substream, buf, count) < count)
111 return -EINVAL;
112 return 0;
113 }
114
event_process_midi(struct snd_seq_event * ev,int direct,void * private_data,int atomic,int hop)115 static int event_process_midi(struct snd_seq_event *ev, int direct,
116 void *private_data, int atomic, int hop)
117 {
118 struct seq_midisynth *msynth = private_data;
119 unsigned char msg[10]; /* buffer for constructing midi messages */
120 struct snd_rawmidi_substream *substream;
121 int len;
122
123 if (snd_BUG_ON(!msynth))
124 return -EINVAL;
125 substream = msynth->output_rfile.output;
126 if (substream == NULL)
127 return -ENODEV;
128 if (ev->type == SNDRV_SEQ_EVENT_SYSEX) { /* special case, to save space */
129 if ((ev->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) != SNDRV_SEQ_EVENT_LENGTH_VARIABLE) {
130 /* invalid event */
131 pr_debug("ALSA: seq_midi: invalid sysex event flags = 0x%x\n", ev->flags);
132 return 0;
133 }
134 snd_seq_dump_var_event(ev, (snd_seq_dump_func_t)dump_midi, substream);
135 snd_midi_event_reset_decode(msynth->parser);
136 } else {
137 if (msynth->parser == NULL)
138 return -EIO;
139 len = snd_midi_event_decode(msynth->parser, msg, sizeof(msg), ev);
140 if (len < 0)
141 return 0;
142 if (dump_midi(substream, msg, len) < 0)
143 snd_midi_event_reset_decode(msynth->parser);
144 }
145 return 0;
146 }
147
148
snd_seq_midisynth_new(struct seq_midisynth * msynth,struct snd_card * card,int device,int subdevice)149 static int snd_seq_midisynth_new(struct seq_midisynth *msynth,
150 struct snd_card *card,
151 int device,
152 int subdevice)
153 {
154 if (snd_midi_event_new(MAX_MIDI_EVENT_BUF, &msynth->parser) < 0)
155 return -ENOMEM;
156 msynth->card = card;
157 msynth->device = device;
158 msynth->subdevice = subdevice;
159 return 0;
160 }
161
162 /* open associated midi device for input */
midisynth_subscribe(void * private_data,struct snd_seq_port_subscribe * info)163 static int midisynth_subscribe(void *private_data, struct snd_seq_port_subscribe *info)
164 {
165 int err;
166 struct seq_midisynth *msynth = private_data;
167 struct snd_rawmidi_runtime *runtime;
168 struct snd_rawmidi_params params;
169
170 /* open midi port */
171 err = snd_rawmidi_kernel_open(msynth->card, msynth->device,
172 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->card, msynth->device,
216 msynth->subdevice,
217 SNDRV_RAWMIDI_LFLG_OUTPUT,
218 &msynth->output_rfile);
219 if (err < 0) {
220 pr_debug("ALSA: seq_midi: midi output open failed!!!\n");
221 return err;
222 }
223 memset(¶ms, 0, sizeof(params));
224 params.avail_min = 1;
225 params.buffer_size = output_buffer_size;
226 params.no_active_sensing = 1;
227 err = snd_rawmidi_output_params(msynth->output_rfile.output, ¶ms);
228 if (err < 0) {
229 snd_rawmidi_kernel_release(&msynth->output_rfile);
230 return err;
231 }
232 snd_midi_event_reset_decode(msynth->parser);
233 return 0;
234 }
235
236 /* close associated midi device for output */
midisynth_unuse(void * private_data,struct snd_seq_port_subscribe * info)237 static int midisynth_unuse(void *private_data, struct snd_seq_port_subscribe *info)
238 {
239 struct seq_midisynth *msynth = private_data;
240
241 if (snd_BUG_ON(!msynth->output_rfile.output))
242 return -EINVAL;
243 snd_rawmidi_drain_output(msynth->output_rfile.output);
244 return snd_rawmidi_kernel_release(&msynth->output_rfile);
245 }
246
247 /* delete given midi synth port */
snd_seq_midisynth_delete(struct seq_midisynth * msynth)248 static void snd_seq_midisynth_delete(struct seq_midisynth *msynth)
249 {
250 if (msynth == NULL)
251 return;
252
253 if (msynth->seq_client > 0) {
254 /* delete port */
255 snd_seq_event_port_detach(msynth->seq_client, msynth->seq_port);
256 }
257
258 snd_midi_event_free(msynth->parser);
259 }
260
261 /* register new midi synth port */
262 static int
snd_seq_midisynth_probe(struct device * _dev)263 snd_seq_midisynth_probe(struct device *_dev)
264 {
265 struct snd_seq_device *dev = to_seq_dev(_dev);
266 struct seq_midisynth_client *client;
267 struct seq_midisynth *msynth, *ms;
268 struct snd_seq_port_info *port;
269 struct snd_rawmidi_info *info;
270 struct snd_rawmidi *rmidi = dev->private_data;
271 int newclient = 0;
272 unsigned int p, ports;
273 struct snd_seq_port_callback pcallbacks;
274 struct snd_card *card = dev->card;
275 int device = dev->device;
276 unsigned int input_count = 0, output_count = 0;
277
278 if (snd_BUG_ON(!card || device < 0 || device >= SNDRV_RAWMIDI_DEVICES))
279 return -EINVAL;
280 info = kmalloc(sizeof(*info), GFP_KERNEL);
281 if (! info)
282 return -ENOMEM;
283 info->device = device;
284 info->stream = SNDRV_RAWMIDI_STREAM_OUTPUT;
285 info->subdevice = 0;
286 if (snd_rawmidi_info_select(card, info) >= 0)
287 output_count = info->subdevices_count;
288 info->stream = SNDRV_RAWMIDI_STREAM_INPUT;
289 if (snd_rawmidi_info_select(card, info) >= 0) {
290 input_count = info->subdevices_count;
291 }
292 ports = output_count;
293 if (ports < input_count)
294 ports = input_count;
295 if (ports == 0) {
296 kfree(info);
297 return -ENODEV;
298 }
299 if (ports > (256 / SNDRV_RAWMIDI_DEVICES))
300 ports = 256 / SNDRV_RAWMIDI_DEVICES;
301
302 mutex_lock(®ister_mutex);
303 client = synths[card->number];
304 if (client == NULL) {
305 newclient = 1;
306 client = kzalloc(sizeof(*client), GFP_KERNEL);
307 if (client == NULL) {
308 mutex_unlock(®ister_mutex);
309 kfree(info);
310 return -ENOMEM;
311 }
312 client->seq_client =
313 snd_seq_create_kernel_client(
314 card, 0, "%s", card->shortname[0] ?
315 (const char *)card->shortname : "External MIDI");
316 if (client->seq_client < 0) {
317 kfree(client);
318 mutex_unlock(®ister_mutex);
319 kfree(info);
320 return -ENOMEM;
321 }
322 }
323
324 msynth = kcalloc(ports, sizeof(struct seq_midisynth), GFP_KERNEL);
325 port = kmalloc(sizeof(*port), GFP_KERNEL);
326 if (msynth == NULL || port == NULL)
327 goto __nomem;
328
329 for (p = 0; p < ports; p++) {
330 ms = &msynth[p];
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 snprintf(port->name, sizeof(port->name), "%s-%u", info->name, p);
353 else
354 snprintf(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 port->type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC
371 | SNDRV_SEQ_PORT_TYPE_HARDWARE
372 | SNDRV_SEQ_PORT_TYPE_PORT;
373 port->midi_channels = 16;
374 memset(&pcallbacks, 0, sizeof(pcallbacks));
375 pcallbacks.owner = THIS_MODULE;
376 pcallbacks.private_data = ms;
377 pcallbacks.subscribe = midisynth_subscribe;
378 pcallbacks.unsubscribe = midisynth_unsubscribe;
379 pcallbacks.use = midisynth_use;
380 pcallbacks.unuse = midisynth_unuse;
381 pcallbacks.event_input = event_process_midi;
382 port->kernel = &pcallbacks;
383 if (rmidi->ops && rmidi->ops->get_port_info)
384 rmidi->ops->get_port_info(rmidi, p, port);
385 if (snd_seq_kernel_client_ctl(client->seq_client, SNDRV_SEQ_IOCTL_CREATE_PORT, port)<0)
386 goto __nomem;
387 ms->seq_client = client->seq_client;
388 ms->seq_port = port->addr.port;
389 }
390 client->ports_per_device[device] = ports;
391 client->ports[device] = msynth;
392 client->num_ports++;
393 if (newclient)
394 synths[card->number] = client;
395 mutex_unlock(®ister_mutex);
396 kfree(info);
397 kfree(port);
398 return 0; /* success */
399
400 __nomem:
401 if (msynth != NULL) {
402 for (p = 0; p < ports; p++)
403 snd_seq_midisynth_delete(&msynth[p]);
404 kfree(msynth);
405 }
406 if (newclient) {
407 snd_seq_delete_kernel_client(client->seq_client);
408 kfree(client);
409 }
410 kfree(info);
411 kfree(port);
412 mutex_unlock(®ister_mutex);
413 return -ENOMEM;
414 }
415
416 /* release midi synth port */
417 static int
snd_seq_midisynth_remove(struct device * _dev)418 snd_seq_midisynth_remove(struct device *_dev)
419 {
420 struct snd_seq_device *dev = to_seq_dev(_dev);
421 struct seq_midisynth_client *client;
422 struct seq_midisynth *msynth;
423 struct snd_card *card = dev->card;
424 int device = dev->device, p, ports;
425
426 mutex_lock(®ister_mutex);
427 client = synths[card->number];
428 if (client == NULL || client->ports[device] == NULL) {
429 mutex_unlock(®ister_mutex);
430 return -ENODEV;
431 }
432 ports = client->ports_per_device[device];
433 client->ports_per_device[device] = 0;
434 msynth = client->ports[device];
435 client->ports[device] = NULL;
436 for (p = 0; p < ports; p++)
437 snd_seq_midisynth_delete(&msynth[p]);
438 kfree(msynth);
439 client->num_ports--;
440 if (client->num_ports <= 0) {
441 snd_seq_delete_kernel_client(client->seq_client);
442 synths[card->number] = NULL;
443 kfree(client);
444 }
445 mutex_unlock(®ister_mutex);
446 return 0;
447 }
448
449 static struct snd_seq_driver seq_midisynth_driver = {
450 .driver = {
451 .name = KBUILD_MODNAME,
452 .probe = snd_seq_midisynth_probe,
453 .remove = snd_seq_midisynth_remove,
454 },
455 .id = SNDRV_SEQ_DEV_ID_MIDISYNTH,
456 .argsize = 0,
457 };
458
459 module_snd_seq_driver(seq_midisynth_driver);
460