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/*
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
28MODULE_AUTHOR("Frank van de Pol <fvdpol@coil.demon.nl>, Jaroslav Kysela <perex@perex.cz>");
29MODULE_DESCRIPTION("Advanced Linux Sound Architecture sequencer MIDI synth.");
30MODULE_LICENSE("GPL");
31static int output_buffer_size = PAGE_SIZE;
32module_param(output_buffer_size, int, 0644);
33MODULE_PARM_DESC(output_buffer_size, "Output buffer size in bytes.");
34static int input_buffer_size = PAGE_SIZE;
35module_param(input_buffer_size, int, 0644);
36MODULE_PARM_DESC(input_buffer_size, "Input buffer size in bytes.");
37
38/* data for this midi synth driver */
39struct 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
51struct 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
58static struct seq_midisynth_client *synths[SNDRV_CARDS];
59static DEFINE_MUTEX(register_mutex);
60
61/* handle rawmidi input event (MIDI v1.0 stream) */
62static 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, count: 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(dev: msynth->parser,
86 c: *pbuf++, ev: &ev))
87 continue;
88 ev.source.port = msynth->seq_port;
89 ev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
90 snd_seq_kernel_client_dispatch(client: msynth->seq_client, ev: &ev, atomic: 1, hop: 0);
91 /* clear event and reset header */
92 memset(&ev, 0, sizeof(ev));
93 }
94 }
95}
96
97static 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() */
117static int __dump_midi(void *ptr, void *buf, int count)
118{
119 return dump_midi(substream: ptr, buf, count);
120}
121
122static 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(event: ev, func: __dump_midi, private_data: substream);
142 snd_midi_event_reset_decode(dev: msynth->parser);
143 } else {
144 if (msynth->parser == NULL)
145 return -EIO;
146 len = snd_midi_event_decode(dev: msynth->parser, buf: msg, count: sizeof(msg), ev);
147 if (len < 0)
148 return 0;
149 if (dump_midi(substream, buf: msg, count: len) < 0)
150 snd_midi_event_reset_decode(dev: msynth->parser);
151 }
152 return 0;
153}
154
155
156static 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, rdev: &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 */
170static 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(rmidi: msynth->rmidi, subdevice: msynth->subdevice,
179 SNDRV_RAWMIDI_LFLG_INPUT,
180 rfile: &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(&params, 0, sizeof(params));
187 params.avail_min = 1;
188 params.buffer_size = input_buffer_size;
189 err = snd_rawmidi_input_params(substream: msynth->input_rfile.input, params: &params);
190 if (err < 0) {
191 snd_rawmidi_kernel_release(rfile: &msynth->input_rfile);
192 return err;
193 }
194 snd_midi_event_reset_encode(dev: msynth->parser);
195 runtime->event = snd_midi_input_event;
196 runtime->private_data = msynth;
197 snd_rawmidi_kernel_read(substream: msynth->input_rfile.input, NULL, count: 0);
198 return 0;
199}
200
201/* close associated midi device for input */
202static 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(rfile: &msynth->input_rfile);
210 return err;
211}
212
213/* open associated midi device for output */
214static 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(rmidi: msynth->rmidi, subdevice: msynth->subdevice,
222 SNDRV_RAWMIDI_LFLG_OUTPUT,
223 rfile: &msynth->output_rfile);
224 if (err < 0) {
225 pr_debug("ALSA: seq_midi: midi output open failed!!!\n");
226 return err;
227 }
228 memset(&params, 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(substream: msynth->output_rfile.output, params: &params);
233 if (err < 0) {
234 snd_rawmidi_kernel_release(rfile: &msynth->output_rfile);
235 return err;
236 }
237 snd_midi_event_reset_decode(dev: msynth->parser);
238 return 0;
239}
240
241/* close associated midi device for output */
242static 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(substream: msynth->output_rfile.output);
249 return snd_rawmidi_kernel_release(rfile: &msynth->output_rfile);
250}
251
252/* delete given midi synth port */
253static 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(client: msynth->seq_client, port: msynth->seq_port);
261 }
262
263 snd_midi_event_free(dev: msynth->parser);
264}
265
266/* register new midi synth port */
267static int
268snd_seq_midisynth_probe(struct device *_dev)
269{
270 struct snd_seq_device *dev = to_seq_dev(_dev);
271 struct seq_midisynth_client *client;
272 struct seq_midisynth *msynth, *ms;
273 struct snd_seq_port_info *port __free(kfree) = NULL;
274 struct snd_rawmidi_info *info __free(kfree) = NULL;
275 struct snd_rawmidi *rmidi = dev->private_data;
276 int newclient = 0;
277 unsigned int p, ports;
278 struct snd_seq_port_callback pcallbacks;
279 struct snd_card *card = dev->card;
280 int device = dev->device;
281 unsigned int input_count = 0, output_count = 0;
282
283 if (snd_BUG_ON(!card || device < 0 || device >= SNDRV_RAWMIDI_DEVICES))
284 return -EINVAL;
285 info = kmalloc(sizeof(*info), GFP_KERNEL);
286 if (! info)
287 return -ENOMEM;
288 info->device = device;
289 info->stream = SNDRV_RAWMIDI_STREAM_OUTPUT;
290 info->subdevice = 0;
291 if (snd_rawmidi_info_select(card, info) >= 0)
292 output_count = info->subdevices_count;
293 info->stream = SNDRV_RAWMIDI_STREAM_INPUT;
294 if (snd_rawmidi_info_select(card, info) >= 0) {
295 input_count = info->subdevices_count;
296 }
297 ports = output_count;
298 if (ports < input_count)
299 ports = input_count;
300 if (ports == 0)
301 return -ENODEV;
302 if (ports > (256 / SNDRV_RAWMIDI_DEVICES))
303 ports = 256 / SNDRV_RAWMIDI_DEVICES;
304
305 guard(mutex)(T: &register_mutex);
306 client = synths[card->number];
307 if (client == NULL) {
308 newclient = 1;
309 client = kzalloc(sizeof(*client), GFP_KERNEL);
310 if (client == NULL)
311 return -ENOMEM;
312 client->seq_client =
313 snd_seq_create_kernel_client(
314 card, client_index: 0, name_fmt: "%s", card->shortname[0] ?
315 (const char *)card->shortname : "External MIDI");
316 if (client->seq_client < 0) {
317 kfree(objp: client);
318 return -ENOMEM;
319 }
320 }
321
322 msynth = kcalloc(ports, sizeof(struct seq_midisynth), GFP_KERNEL);
323 port = kmalloc(sizeof(*port), GFP_KERNEL);
324 if (msynth == NULL || port == NULL)
325 goto __nomem;
326
327 for (p = 0; p < ports; p++) {
328 ms = &msynth[p];
329 ms->rmidi = rmidi;
330
331 if (snd_seq_midisynth_new(msynth: ms, card, device, subdevice: p) < 0)
332 goto __nomem;
333
334 /* declare port */
335 memset(port, 0, sizeof(*port));
336 port->addr.client = client->seq_client;
337 port->addr.port = device * (256 / SNDRV_RAWMIDI_DEVICES) + p;
338 port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT;
339 memset(info, 0, sizeof(*info));
340 info->device = device;
341 if (p < output_count)
342 info->stream = SNDRV_RAWMIDI_STREAM_OUTPUT;
343 else
344 info->stream = SNDRV_RAWMIDI_STREAM_INPUT;
345 info->subdevice = p;
346 if (snd_rawmidi_info_select(card, info) >= 0)
347 strscpy(port->name, info->subname);
348 if (! port->name[0]) {
349 if (info->name[0]) {
350 if (ports > 1)
351 scnprintf(buf: port->name, size: sizeof(port->name), fmt: "%s-%u", info->name, p);
352 else
353 scnprintf(buf: port->name, size: sizeof(port->name), fmt: "%s", info->name);
354 } else {
355 /* last resort */
356 if (ports > 1)
357 sprintf(buf: port->name, fmt: "MIDI %d-%d-%u", card->number, device, p);
358 else
359 sprintf(buf: port->name, fmt: "MIDI %d-%d", card->number, device);
360 }
361 }
362 if ((info->flags & SNDRV_RAWMIDI_INFO_OUTPUT) && p < output_count)
363 port->capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SYNC_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE;
364 if ((info->flags & SNDRV_RAWMIDI_INFO_INPUT) && p < input_count)
365 port->capability |= SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SYNC_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ;
366 if ((port->capability & (SNDRV_SEQ_PORT_CAP_WRITE|SNDRV_SEQ_PORT_CAP_READ)) == (SNDRV_SEQ_PORT_CAP_WRITE|SNDRV_SEQ_PORT_CAP_READ) &&
367 info->flags & SNDRV_RAWMIDI_INFO_DUPLEX)
368 port->capability |= SNDRV_SEQ_PORT_CAP_DUPLEX;
369 if (port->capability & SNDRV_SEQ_PORT_CAP_READ)
370 port->direction |= SNDRV_SEQ_PORT_DIR_INPUT;
371 if (port->capability & SNDRV_SEQ_PORT_CAP_WRITE)
372 port->direction |= SNDRV_SEQ_PORT_DIR_OUTPUT;
373 port->type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC
374 | SNDRV_SEQ_PORT_TYPE_HARDWARE
375 | SNDRV_SEQ_PORT_TYPE_PORT;
376 port->midi_channels = 16;
377 memset(&pcallbacks, 0, sizeof(pcallbacks));
378 pcallbacks.owner = THIS_MODULE;
379 pcallbacks.private_data = ms;
380 pcallbacks.subscribe = midisynth_subscribe;
381 pcallbacks.unsubscribe = midisynth_unsubscribe;
382 pcallbacks.use = midisynth_use;
383 pcallbacks.unuse = midisynth_unuse;
384 pcallbacks.event_input = event_process_midi;
385 port->kernel = &pcallbacks;
386 if (rmidi->ops && rmidi->ops->get_port_info)
387 rmidi->ops->get_port_info(rmidi, p, port);
388 if (snd_seq_kernel_client_ctl(client: client->seq_client, SNDRV_SEQ_IOCTL_CREATE_PORT, arg: port)<0)
389 goto __nomem;
390 ms->seq_client = client->seq_client;
391 ms->seq_port = port->addr.port;
392 }
393 client->ports_per_device[device] = ports;
394 client->ports[device] = msynth;
395 client->num_ports++;
396 if (newclient)
397 synths[card->number] = client;
398 return 0; /* success */
399
400 __nomem:
401 if (msynth != NULL) {
402 for (p = 0; p < ports; p++)
403 snd_seq_midisynth_delete(msynth: &msynth[p]);
404 kfree(objp: msynth);
405 }
406 if (newclient) {
407 snd_seq_delete_kernel_client(client: client->seq_client);
408 kfree(objp: client);
409 }
410 return -ENOMEM;
411}
412
413/* release midi synth port */
414static int
415snd_seq_midisynth_remove(struct device *_dev)
416{
417 struct snd_seq_device *dev = to_seq_dev(_dev);
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)(T: &register_mutex);
424 client = synths[card->number];
425 if (client == NULL || client->ports[device] == NULL)
426 return -ENODEV;
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: &msynth[p]);
433 kfree(objp: msynth);
434 client->num_ports--;
435 if (client->num_ports <= 0) {
436 snd_seq_delete_kernel_client(client: client->seq_client);
437 synths[card->number] = NULL;
438 kfree(objp: client);
439 }
440 return 0;
441}
442
443static struct snd_seq_driver seq_midisynth_driver = {
444 .driver = {
445 .name = KBUILD_MODNAME,
446 .probe = snd_seq_midisynth_probe,
447 .remove = snd_seq_midisynth_remove,
448 },
449 .id = SNDRV_SEQ_DEV_ID_MIDISYNTH,
450 .argsize = 0,
451};
452
453module_snd_seq_driver(seq_midisynth_driver);
454

source code of linux/sound/core/seq/seq_midi.c