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seq_midi.c
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1 /*
2  * Generic MIDI synth driver for ALSA sequencer
3  * Copyright (c) 1998 by Frank van de Pol <[email protected]>
4  * Jaroslav Kysela <[email protected]>
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 <[email protected]>, Jaroslav Kysela <[email protected]>");
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)
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