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) */ 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 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 } 115 116 /* callback for snd_seq_dump_var_event(), bridging to dump_midi() */ 117 static int __dump_midi(void *ptr, void *buf, int count) 118 { 119 return dump_midi(ptr, buf, count); 120 } 121 122 static 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(ev, __dump_midi, substream); 142 snd_midi_event_reset_decode(msynth->parser); 143 } else { 144 if (msynth->parser == NULL) 145 return -EIO; 146 len = snd_midi_event_decode(msynth->parser, msg, sizeof(msg), ev); 147 if (len < 0) 148 return 0; 149 if (dump_midi(substream, msg, len) < 0) 150 snd_midi_event_reset_decode(msynth->parser); 151 } 152 return 0; 153 } 154 155 156 static 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, &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 */ 170 static 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(msynth->rmidi, msynth->subdevice, 179 SNDRV_RAWMIDI_LFLG_INPUT, 180 &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(¶ms, 0, sizeof(params)); 187 params.avail_min = 1; 188 params.buffer_size = input_buffer_size; 189 err = snd_rawmidi_input_params(msynth->input_rfile.input, ¶ms); 190 if (err < 0) { 191 snd_rawmidi_kernel_release(&msynth->input_rfile); 192 return err; 193 } 194 snd_midi_event_reset_encode(msynth->parser); 195 runtime->event = snd_midi_input_event; 196 runtime->private_data = msynth; 197 snd_rawmidi_kernel_read(msynth->input_rfile.input, NULL, 0); 198 return 0; 199 } 200 201 /* close associated midi device for input */ 202 static 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(&msynth->input_rfile); 210 return err; 211 } 212 213 /* open associated midi device for output */ 214 static 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(msynth->rmidi, msynth->subdevice, 222 SNDRV_RAWMIDI_LFLG_OUTPUT, 223 &msynth->output_rfile); 224 if (err < 0) { 225 pr_debug("ALSA: seq_midi: midi output open failed!!!\n"); 226 return err; 227 } 228 memset(¶ms, 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(msynth->output_rfile.output, ¶ms); 233 if (err < 0) { 234 snd_rawmidi_kernel_release(&msynth->output_rfile); 235 return err; 236 } 237 snd_midi_event_reset_decode(msynth->parser); 238 return 0; 239 } 240 241 /* close associated midi device for output */ 242 static 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(msynth->output_rfile.output); 249 return snd_rawmidi_kernel_release(&msynth->output_rfile); 250 } 251 252 /* delete given midi synth port */ 253 static 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(msynth->seq_client, msynth->seq_port); 261 } 262 263 snd_midi_event_free(msynth->parser); 264 } 265 266 /* register new midi synth port */ 267 static int 268 snd_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; 274 struct snd_rawmidi_info *info; 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 kfree(info); 302 return -ENODEV; 303 } 304 if (ports > (256 / SNDRV_RAWMIDI_DEVICES)) 305 ports = 256 / SNDRV_RAWMIDI_DEVICES; 306 307 mutex_lock(®ister_mutex); 308 client = synths[card->number]; 309 if (client == NULL) { 310 newclient = 1; 311 client = kzalloc(sizeof(*client), GFP_KERNEL); 312 if (client == NULL) { 313 mutex_unlock(®ister_mutex); 314 kfree(info); 315 return -ENOMEM; 316 } 317 client->seq_client = 318 snd_seq_create_kernel_client( 319 card, 0, "%s", card->shortname[0] ? 320 (const char *)card->shortname : "External MIDI"); 321 if (client->seq_client < 0) { 322 kfree(client); 323 mutex_unlock(®ister_mutex); 324 kfree(info); 325 return -ENOMEM; 326 } 327 } 328 329 msynth = kcalloc(ports, sizeof(struct seq_midisynth), GFP_KERNEL); 330 port = kmalloc(sizeof(*port), GFP_KERNEL); 331 if (msynth == NULL || port == NULL) 332 goto __nomem; 333 334 for (p = 0; p < ports; p++) { 335 ms = &msynth[p]; 336 ms->rmidi = rmidi; 337 338 if (snd_seq_midisynth_new(ms, card, device, p) < 0) 339 goto __nomem; 340 341 /* declare port */ 342 memset(port, 0, sizeof(*port)); 343 port->addr.client = client->seq_client; 344 port->addr.port = device * (256 / SNDRV_RAWMIDI_DEVICES) + p; 345 port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT; 346 memset(info, 0, sizeof(*info)); 347 info->device = device; 348 if (p < output_count) 349 info->stream = SNDRV_RAWMIDI_STREAM_OUTPUT; 350 else 351 info->stream = SNDRV_RAWMIDI_STREAM_INPUT; 352 info->subdevice = p; 353 if (snd_rawmidi_info_select(card, info) >= 0) 354 strcpy(port->name, info->subname); 355 if (! port->name[0]) { 356 if (info->name[0]) { 357 if (ports > 1) 358 scnprintf(port->name, sizeof(port->name), "%s-%u", info->name, p); 359 else 360 scnprintf(port->name, sizeof(port->name), "%s", info->name); 361 } else { 362 /* last resort */ 363 if (ports > 1) 364 sprintf(port->name, "MIDI %d-%d-%u", card->number, device, p); 365 else 366 sprintf(port->name, "MIDI %d-%d", card->number, device); 367 } 368 } 369 if ((info->flags & SNDRV_RAWMIDI_INFO_OUTPUT) && p < output_count) 370 port->capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SYNC_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE; 371 if ((info->flags & SNDRV_RAWMIDI_INFO_INPUT) && p < input_count) 372 port->capability |= SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SYNC_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ; 373 if ((port->capability & (SNDRV_SEQ_PORT_CAP_WRITE|SNDRV_SEQ_PORT_CAP_READ)) == (SNDRV_SEQ_PORT_CAP_WRITE|SNDRV_SEQ_PORT_CAP_READ) && 374 info->flags & SNDRV_RAWMIDI_INFO_DUPLEX) 375 port->capability |= SNDRV_SEQ_PORT_CAP_DUPLEX; 376 if (port->capability & SNDRV_SEQ_PORT_CAP_READ) 377 port->direction |= SNDRV_SEQ_PORT_DIR_INPUT; 378 if (port->capability & SNDRV_SEQ_PORT_CAP_WRITE) 379 port->direction |= SNDRV_SEQ_PORT_DIR_OUTPUT; 380 port->type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC 381 | SNDRV_SEQ_PORT_TYPE_HARDWARE 382 | SNDRV_SEQ_PORT_TYPE_PORT; 383 port->midi_channels = 16; 384 memset(&pcallbacks, 0, sizeof(pcallbacks)); 385 pcallbacks.owner = THIS_MODULE; 386 pcallbacks.private_data = ms; 387 pcallbacks.subscribe = midisynth_subscribe; 388 pcallbacks.unsubscribe = midisynth_unsubscribe; 389 pcallbacks.use = midisynth_use; 390 pcallbacks.unuse = midisynth_unuse; 391 pcallbacks.event_input = event_process_midi; 392 port->kernel = &pcallbacks; 393 if (rmidi->ops && rmidi->ops->get_port_info) 394 rmidi->ops->get_port_info(rmidi, p, port); 395 if (snd_seq_kernel_client_ctl(client->seq_client, SNDRV_SEQ_IOCTL_CREATE_PORT, port)<0) 396 goto __nomem; 397 ms->seq_client = client->seq_client; 398 ms->seq_port = port->addr.port; 399 } 400 client->ports_per_device[device] = ports; 401 client->ports[device] = msynth; 402 client->num_ports++; 403 if (newclient) 404 synths[card->number] = client; 405 mutex_unlock(®ister_mutex); 406 kfree(info); 407 kfree(port); 408 return 0; /* success */ 409 410 __nomem: 411 if (msynth != NULL) { 412 for (p = 0; p < ports; p++) 413 snd_seq_midisynth_delete(&msynth[p]); 414 kfree(msynth); 415 } 416 if (newclient) { 417 snd_seq_delete_kernel_client(client->seq_client); 418 kfree(client); 419 } 420 kfree(info); 421 kfree(port); 422 mutex_unlock(®ister_mutex); 423 return -ENOMEM; 424 } 425 426 /* release midi synth port */ 427 static int 428 snd_seq_midisynth_remove(struct device *_dev) 429 { 430 struct snd_seq_device *dev = to_seq_dev(_dev); 431 struct seq_midisynth_client *client; 432 struct seq_midisynth *msynth; 433 struct snd_card *card = dev->card; 434 int device = dev->device, p, ports; 435 436 mutex_lock(®ister_mutex); 437 client = synths[card->number]; 438 if (client == NULL || client->ports[device] == NULL) { 439 mutex_unlock(®ister_mutex); 440 return -ENODEV; 441 } 442 ports = client->ports_per_device[device]; 443 client->ports_per_device[device] = 0; 444 msynth = client->ports[device]; 445 client->ports[device] = NULL; 446 for (p = 0; p < ports; p++) 447 snd_seq_midisynth_delete(&msynth[p]); 448 kfree(msynth); 449 client->num_ports--; 450 if (client->num_ports <= 0) { 451 snd_seq_delete_kernel_client(client->seq_client); 452 synths[card->number] = NULL; 453 kfree(client); 454 } 455 mutex_unlock(®ister_mutex); 456 return 0; 457 } 458 459 static struct snd_seq_driver seq_midisynth_driver = { 460 .driver = { 461 .name = KBUILD_MODNAME, 462 .probe = snd_seq_midisynth_probe, 463 .remove = snd_seq_midisynth_remove, 464 }, 465 .id = SNDRV_SEQ_DEV_ID_MIDISYNTH, 466 .argsize = 0, 467 }; 468 469 module_snd_seq_driver(seq_midisynth_driver); 470