xref: /openbmc/linux/sound/core/seq/seq_midi.c (revision e23feb16)
1 /*
2  *   Generic MIDI synth driver for ALSA sequencer
3  *   Copyright (c) 1998 by Frank van de Pol <fvdpol@coil.demon.nl>
4  *                         Jaroslav Kysela <perex@perex.cz>
5  *
6  *   This program is free software; you can redistribute it and/or modify
7  *   it under the terms of the GNU General Public License as published by
8  *   the Free Software Foundation; either version 2 of the License, or
9  *   (at your option) any later version.
10  *
11  *   This program is distributed in the hope that it will be useful,
12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *   GNU General Public License for more details.
15  *
16  *   You should have received a copy of the GNU General Public License
17  *   along with this program; if not, write to the Free Software
18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
19  *
20  */
21 
22 /*
23 Possible options for midisynth module:
24 	- automatic opening of midi ports on first received event or subscription
25 	  (close will be performed when client leaves)
26 */
27 
28 
29 #include <linux/init.h>
30 #include <linux/slab.h>
31 #include <linux/errno.h>
32 #include <linux/string.h>
33 #include <linux/module.h>
34 #include <linux/mutex.h>
35 #include <sound/core.h>
36 #include <sound/rawmidi.h>
37 #include <sound/seq_kernel.h>
38 #include <sound/seq_device.h>
39 #include <sound/seq_midi_event.h>
40 #include <sound/initval.h>
41 
42 MODULE_AUTHOR("Frank van de Pol <fvdpol@coil.demon.nl>, Jaroslav Kysela <perex@perex.cz>");
43 MODULE_DESCRIPTION("Advanced Linux Sound Architecture sequencer MIDI synth.");
44 MODULE_LICENSE("GPL");
45 static int output_buffer_size = PAGE_SIZE;
46 module_param(output_buffer_size, int, 0644);
47 MODULE_PARM_DESC(output_buffer_size, "Output buffer size in bytes.");
48 static int input_buffer_size = PAGE_SIZE;
49 module_param(input_buffer_size, int, 0644);
50 MODULE_PARM_DESC(input_buffer_size, "Input buffer size in bytes.");
51 
52 /* data for this midi synth driver */
53 struct seq_midisynth {
54 	struct snd_card *card;
55 	int device;
56 	int subdevice;
57 	struct snd_rawmidi_file input_rfile;
58 	struct snd_rawmidi_file output_rfile;
59 	int seq_client;
60 	int seq_port;
61 	struct snd_midi_event *parser;
62 };
63 
64 struct seq_midisynth_client {
65 	int seq_client;
66 	int num_ports;
67 	int ports_per_device[SNDRV_RAWMIDI_DEVICES];
68  	struct seq_midisynth *ports[SNDRV_RAWMIDI_DEVICES];
69 };
70 
71 static struct seq_midisynth_client *synths[SNDRV_CARDS];
72 static DEFINE_MUTEX(register_mutex);
73 
74 /* handle rawmidi input event (MIDI v1.0 stream) */
75 static void snd_midi_input_event(struct snd_rawmidi_substream *substream)
76 {
77 	struct snd_rawmidi_runtime *runtime;
78 	struct seq_midisynth *msynth;
79 	struct snd_seq_event ev;
80 	char buf[16], *pbuf;
81 	long res, count;
82 
83 	if (substream == NULL)
84 		return;
85 	runtime = substream->runtime;
86 	msynth = runtime->private_data;
87 	if (msynth == NULL)
88 		return;
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 			count = snd_midi_event_encode(msynth->parser, pbuf, res, &ev);
99 			if (count < 0)
100 				break;
101 			pbuf += count;
102 			res -= count;
103 			if (ev.type != SNDRV_SEQ_EVENT_NONE) {
104 				ev.source.port = msynth->seq_port;
105 				ev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
106 				snd_seq_kernel_client_dispatch(msynth->seq_client, &ev, 1, 0);
107 				/* clear event and reset header */
108 				memset(&ev, 0, sizeof(ev));
109 			}
110 		}
111 	}
112 }
113 
114 static int dump_midi(struct snd_rawmidi_substream *substream, const char *buf, int count)
115 {
116 	struct snd_rawmidi_runtime *runtime;
117 	int tmp;
118 
119 	if (snd_BUG_ON(!substream || !buf))
120 		return -EINVAL;
121 	runtime = substream->runtime;
122 	if ((tmp = runtime->avail) < count) {
123 		if (printk_ratelimit())
124 			snd_printk(KERN_ERR "MIDI output buffer overrun\n");
125 		return -ENOMEM;
126 	}
127 	if (snd_rawmidi_kernel_write(substream, buf, count) < count)
128 		return -EINVAL;
129 	return 0;
130 }
131 
132 static int event_process_midi(struct snd_seq_event *ev, int direct,
133 			      void *private_data, int atomic, int hop)
134 {
135 	struct seq_midisynth *msynth = private_data;
136 	unsigned char msg[10];	/* buffer for constructing midi messages */
137 	struct snd_rawmidi_substream *substream;
138 	int len;
139 
140 	if (snd_BUG_ON(!msynth))
141 		return -EINVAL;
142 	substream = msynth->output_rfile.output;
143 	if (substream == NULL)
144 		return -ENODEV;
145 	if (ev->type == SNDRV_SEQ_EVENT_SYSEX) {	/* special case, to save space */
146 		if ((ev->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) != SNDRV_SEQ_EVENT_LENGTH_VARIABLE) {
147 			/* invalid event */
148 			snd_printd("seq_midi: invalid sysex event flags = 0x%x\n", ev->flags);
149 			return 0;
150 		}
151 		snd_seq_dump_var_event(ev, (snd_seq_dump_func_t)dump_midi, substream);
152 		snd_midi_event_reset_decode(msynth->parser);
153 	} else {
154 		if (msynth->parser == NULL)
155 			return -EIO;
156 		len = snd_midi_event_decode(msynth->parser, msg, sizeof(msg), ev);
157 		if (len < 0)
158 			return 0;
159 		if (dump_midi(substream, msg, len) < 0)
160 			snd_midi_event_reset_decode(msynth->parser);
161 	}
162 	return 0;
163 }
164 
165 
166 static int snd_seq_midisynth_new(struct seq_midisynth *msynth,
167 				 struct snd_card *card,
168 				 int device,
169 				 int subdevice)
170 {
171 	if (snd_midi_event_new(MAX_MIDI_EVENT_BUF, &msynth->parser) < 0)
172 		return -ENOMEM;
173 	msynth->card = card;
174 	msynth->device = device;
175 	msynth->subdevice = subdevice;
176 	return 0;
177 }
178 
179 /* open associated midi device for input */
180 static int midisynth_subscribe(void *private_data, struct snd_seq_port_subscribe *info)
181 {
182 	int err;
183 	struct seq_midisynth *msynth = private_data;
184 	struct snd_rawmidi_runtime *runtime;
185 	struct snd_rawmidi_params params;
186 
187 	/* open midi port */
188 	if ((err = snd_rawmidi_kernel_open(msynth->card, msynth->device,
189 					   msynth->subdevice,
190 					   SNDRV_RAWMIDI_LFLG_INPUT,
191 					   &msynth->input_rfile)) < 0) {
192 		snd_printd("midi input open failed!!!\n");
193 		return err;
194 	}
195 	runtime = msynth->input_rfile.input->runtime;
196 	memset(&params, 0, sizeof(params));
197 	params.avail_min = 1;
198 	params.buffer_size = input_buffer_size;
199 	if ((err = snd_rawmidi_input_params(msynth->input_rfile.input, &params)) < 0) {
200 		snd_rawmidi_kernel_release(&msynth->input_rfile);
201 		return err;
202 	}
203 	snd_midi_event_reset_encode(msynth->parser);
204 	runtime->event = snd_midi_input_event;
205 	runtime->private_data = msynth;
206 	snd_rawmidi_kernel_read(msynth->input_rfile.input, NULL, 0);
207 	return 0;
208 }
209 
210 /* close associated midi device for input */
211 static int midisynth_unsubscribe(void *private_data, struct snd_seq_port_subscribe *info)
212 {
213 	int err;
214 	struct seq_midisynth *msynth = private_data;
215 
216 	if (snd_BUG_ON(!msynth->input_rfile.input))
217 		return -EINVAL;
218 	err = snd_rawmidi_kernel_release(&msynth->input_rfile);
219 	return err;
220 }
221 
222 /* open associated midi device for output */
223 static int midisynth_use(void *private_data, struct snd_seq_port_subscribe *info)
224 {
225 	int err;
226 	struct seq_midisynth *msynth = private_data;
227 	struct snd_rawmidi_params params;
228 
229 	/* open midi port */
230 	if ((err = snd_rawmidi_kernel_open(msynth->card, msynth->device,
231 					   msynth->subdevice,
232 					   SNDRV_RAWMIDI_LFLG_OUTPUT,
233 					   &msynth->output_rfile)) < 0) {
234 		snd_printd("midi output open failed!!!\n");
235 		return err;
236 	}
237 	memset(&params, 0, sizeof(params));
238 	params.avail_min = 1;
239 	params.buffer_size = output_buffer_size;
240 	params.no_active_sensing = 1;
241 	if ((err = snd_rawmidi_output_params(msynth->output_rfile.output, &params)) < 0) {
242 		snd_rawmidi_kernel_release(&msynth->output_rfile);
243 		return err;
244 	}
245 	snd_midi_event_reset_decode(msynth->parser);
246 	return 0;
247 }
248 
249 /* close associated midi device for output */
250 static int midisynth_unuse(void *private_data, struct snd_seq_port_subscribe *info)
251 {
252 	struct seq_midisynth *msynth = private_data;
253 
254 	if (snd_BUG_ON(!msynth->output_rfile.output))
255 		return -EINVAL;
256 	snd_rawmidi_drain_output(msynth->output_rfile.output);
257 	return snd_rawmidi_kernel_release(&msynth->output_rfile);
258 }
259 
260 /* delete given midi synth port */
261 static void snd_seq_midisynth_delete(struct seq_midisynth *msynth)
262 {
263 	if (msynth == NULL)
264 		return;
265 
266 	if (msynth->seq_client > 0) {
267 		/* delete port */
268 		snd_seq_event_port_detach(msynth->seq_client, msynth->seq_port);
269 	}
270 
271 	if (msynth->parser)
272 		snd_midi_event_free(msynth->parser);
273 }
274 
275 /* register new midi synth port */
276 static int
277 snd_seq_midisynth_register_port(struct snd_seq_device *dev)
278 {
279 	struct seq_midisynth_client *client;
280 	struct seq_midisynth *msynth, *ms;
281 	struct snd_seq_port_info *port;
282 	struct snd_rawmidi_info *info;
283 	struct snd_rawmidi *rmidi = dev->private_data;
284 	int newclient = 0;
285 	unsigned int p, ports;
286 	struct snd_seq_port_callback pcallbacks;
287 	struct snd_card *card = dev->card;
288 	int device = dev->device;
289 	unsigned int input_count = 0, output_count = 0;
290 
291 	if (snd_BUG_ON(!card || device < 0 || device >= SNDRV_RAWMIDI_DEVICES))
292 		return -EINVAL;
293 	info = kmalloc(sizeof(*info), GFP_KERNEL);
294 	if (! info)
295 		return -ENOMEM;
296 	info->device = device;
297 	info->stream = SNDRV_RAWMIDI_STREAM_OUTPUT;
298 	info->subdevice = 0;
299 	if (snd_rawmidi_info_select(card, info) >= 0)
300 		output_count = info->subdevices_count;
301 	info->stream = SNDRV_RAWMIDI_STREAM_INPUT;
302 	if (snd_rawmidi_info_select(card, info) >= 0) {
303 		input_count = info->subdevices_count;
304 	}
305 	ports = output_count;
306 	if (ports < input_count)
307 		ports = input_count;
308 	if (ports == 0) {
309 		kfree(info);
310 		return -ENODEV;
311 	}
312 	if (ports > (256 / SNDRV_RAWMIDI_DEVICES))
313 		ports = 256 / SNDRV_RAWMIDI_DEVICES;
314 
315 	mutex_lock(&register_mutex);
316 	client = synths[card->number];
317 	if (client == NULL) {
318 		newclient = 1;
319 		client = kzalloc(sizeof(*client), GFP_KERNEL);
320 		if (client == NULL) {
321 			mutex_unlock(&register_mutex);
322 			kfree(info);
323 			return -ENOMEM;
324 		}
325 		client->seq_client =
326 			snd_seq_create_kernel_client(
327 				card, 0, "%s", card->shortname[0] ?
328 				(const char *)card->shortname : "External MIDI");
329 		if (client->seq_client < 0) {
330 			kfree(client);
331 			mutex_unlock(&register_mutex);
332 			kfree(info);
333 			return -ENOMEM;
334 		}
335 	}
336 
337 	msynth = kcalloc(ports, sizeof(struct seq_midisynth), GFP_KERNEL);
338 	port = kmalloc(sizeof(*port), GFP_KERNEL);
339 	if (msynth == NULL || port == NULL)
340 		goto __nomem;
341 
342 	for (p = 0; p < ports; p++) {
343 		ms = &msynth[p];
344 
345 		if (snd_seq_midisynth_new(ms, card, device, p) < 0)
346 			goto __nomem;
347 
348 		/* declare port */
349 		memset(port, 0, sizeof(*port));
350 		port->addr.client = client->seq_client;
351 		port->addr.port = device * (256 / SNDRV_RAWMIDI_DEVICES) + p;
352 		port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT;
353 		memset(info, 0, sizeof(*info));
354 		info->device = device;
355 		if (p < output_count)
356 			info->stream = SNDRV_RAWMIDI_STREAM_OUTPUT;
357 		else
358 			info->stream = SNDRV_RAWMIDI_STREAM_INPUT;
359 		info->subdevice = p;
360 		if (snd_rawmidi_info_select(card, info) >= 0)
361 			strcpy(port->name, info->subname);
362 		if (! port->name[0]) {
363 			if (info->name[0]) {
364 				if (ports > 1)
365 					snprintf(port->name, sizeof(port->name), "%s-%d", info->name, p);
366 				else
367 					snprintf(port->name, sizeof(port->name), "%s", info->name);
368 			} else {
369 				/* last resort */
370 				if (ports > 1)
371 					sprintf(port->name, "MIDI %d-%d-%d", card->number, device, p);
372 				else
373 					sprintf(port->name, "MIDI %d-%d", card->number, device);
374 			}
375 		}
376 		if ((info->flags & SNDRV_RAWMIDI_INFO_OUTPUT) && p < output_count)
377 			port->capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SYNC_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE;
378 		if ((info->flags & SNDRV_RAWMIDI_INFO_INPUT) && p < input_count)
379 			port->capability |= SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SYNC_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ;
380 		if ((port->capability & (SNDRV_SEQ_PORT_CAP_WRITE|SNDRV_SEQ_PORT_CAP_READ)) == (SNDRV_SEQ_PORT_CAP_WRITE|SNDRV_SEQ_PORT_CAP_READ) &&
381 		    info->flags & SNDRV_RAWMIDI_INFO_DUPLEX)
382 			port->capability |= SNDRV_SEQ_PORT_CAP_DUPLEX;
383 		port->type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC
384 			| SNDRV_SEQ_PORT_TYPE_HARDWARE
385 			| SNDRV_SEQ_PORT_TYPE_PORT;
386 		port->midi_channels = 16;
387 		memset(&pcallbacks, 0, sizeof(pcallbacks));
388 		pcallbacks.owner = THIS_MODULE;
389 		pcallbacks.private_data = ms;
390 		pcallbacks.subscribe = midisynth_subscribe;
391 		pcallbacks.unsubscribe = midisynth_unsubscribe;
392 		pcallbacks.use = midisynth_use;
393 		pcallbacks.unuse = midisynth_unuse;
394 		pcallbacks.event_input = event_process_midi;
395 		port->kernel = &pcallbacks;
396 		if (rmidi->ops && rmidi->ops->get_port_info)
397 			rmidi->ops->get_port_info(rmidi, p, port);
398 		if (snd_seq_kernel_client_ctl(client->seq_client, SNDRV_SEQ_IOCTL_CREATE_PORT, port)<0)
399 			goto __nomem;
400 		ms->seq_client = client->seq_client;
401 		ms->seq_port = port->addr.port;
402 	}
403 	client->ports_per_device[device] = ports;
404 	client->ports[device] = msynth;
405 	client->num_ports++;
406 	if (newclient)
407 		synths[card->number] = client;
408 	mutex_unlock(&register_mutex);
409 	kfree(info);
410 	kfree(port);
411 	return 0;	/* success */
412 
413       __nomem:
414 	if (msynth != NULL) {
415 	      	for (p = 0; p < ports; p++)
416 	      		snd_seq_midisynth_delete(&msynth[p]);
417 		kfree(msynth);
418 	}
419 	if (newclient) {
420 		snd_seq_delete_kernel_client(client->seq_client);
421 		kfree(client);
422 	}
423 	kfree(info);
424 	kfree(port);
425 	mutex_unlock(&register_mutex);
426 	return -ENOMEM;
427 }
428 
429 /* release midi synth port */
430 static int
431 snd_seq_midisynth_unregister_port(struct snd_seq_device *dev)
432 {
433 	struct seq_midisynth_client *client;
434 	struct seq_midisynth *msynth;
435 	struct snd_card *card = dev->card;
436 	int device = dev->device, p, ports;
437 
438 	mutex_lock(&register_mutex);
439 	client = synths[card->number];
440 	if (client == NULL || client->ports[device] == NULL) {
441 		mutex_unlock(&register_mutex);
442 		return -ENODEV;
443 	}
444 	ports = client->ports_per_device[device];
445 	client->ports_per_device[device] = 0;
446 	msynth = client->ports[device];
447 	client->ports[device] = NULL;
448 	for (p = 0; p < ports; p++)
449 		snd_seq_midisynth_delete(&msynth[p]);
450 	kfree(msynth);
451 	client->num_ports--;
452 	if (client->num_ports <= 0) {
453 		snd_seq_delete_kernel_client(client->seq_client);
454 		synths[card->number] = NULL;
455 		kfree(client);
456 	}
457 	mutex_unlock(&register_mutex);
458 	return 0;
459 }
460 
461 
462 static int __init alsa_seq_midi_init(void)
463 {
464 	static struct snd_seq_dev_ops ops = {
465 		snd_seq_midisynth_register_port,
466 		snd_seq_midisynth_unregister_port,
467 	};
468 	memset(&synths, 0, sizeof(synths));
469 	snd_seq_autoload_lock();
470 	snd_seq_device_register_driver(SNDRV_SEQ_DEV_ID_MIDISYNTH, &ops, 0);
471 	snd_seq_autoload_unlock();
472 	return 0;
473 }
474 
475 static void __exit alsa_seq_midi_exit(void)
476 {
477 	snd_seq_device_unregister_driver(SNDRV_SEQ_DEV_ID_MIDISYNTH);
478 }
479 
480 module_init(alsa_seq_midi_init)
481 module_exit(alsa_seq_midi_exit)
482