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 static int event_process_midi(struct snd_seq_event *ev, int direct, 117 void *private_data, int atomic, int hop) 118 { 119 struct seq_midisynth *msynth = private_data; 120 unsigned char msg[10]; /* buffer for constructing midi messages */ 121 struct snd_rawmidi_substream *substream; 122 int len; 123 124 if (snd_BUG_ON(!msynth)) 125 return -EINVAL; 126 substream = msynth->output_rfile.output; 127 if (substream == NULL) 128 return -ENODEV; 129 if (ev->type == SNDRV_SEQ_EVENT_SYSEX) { /* special case, to save space */ 130 if ((ev->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) != SNDRV_SEQ_EVENT_LENGTH_VARIABLE) { 131 /* invalid event */ 132 pr_debug("ALSA: seq_midi: invalid sysex event flags = 0x%x\n", ev->flags); 133 return 0; 134 } 135 snd_seq_dump_var_event(ev, (snd_seq_dump_func_t)dump_midi, substream); 136 snd_midi_event_reset_decode(msynth->parser); 137 } else { 138 if (msynth->parser == NULL) 139 return -EIO; 140 len = snd_midi_event_decode(msynth->parser, msg, sizeof(msg), ev); 141 if (len < 0) 142 return 0; 143 if (dump_midi(substream, msg, len) < 0) 144 snd_midi_event_reset_decode(msynth->parser); 145 } 146 return 0; 147 } 148 149 150 static int snd_seq_midisynth_new(struct seq_midisynth *msynth, 151 struct snd_card *card, 152 int device, 153 int subdevice) 154 { 155 if (snd_midi_event_new(MAX_MIDI_EVENT_BUF, &msynth->parser) < 0) 156 return -ENOMEM; 157 msynth->card = card; 158 msynth->device = device; 159 msynth->subdevice = subdevice; 160 return 0; 161 } 162 163 /* open associated midi device for input */ 164 static int midisynth_subscribe(void *private_data, struct snd_seq_port_subscribe *info) 165 { 166 int err; 167 struct seq_midisynth *msynth = private_data; 168 struct snd_rawmidi_runtime *runtime; 169 struct snd_rawmidi_params params; 170 171 /* open midi port */ 172 err = snd_rawmidi_kernel_open(msynth->rmidi, 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 */ 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 */ 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->rmidi, msynth->subdevice, 216 SNDRV_RAWMIDI_LFLG_OUTPUT, 217 &msynth->output_rfile); 218 if (err < 0) { 219 pr_debug("ALSA: seq_midi: midi output open failed!!!\n"); 220 return err; 221 } 222 memset(¶ms, 0, sizeof(params)); 223 params.avail_min = 1; 224 params.buffer_size = output_buffer_size; 225 params.no_active_sensing = 1; 226 err = snd_rawmidi_output_params(msynth->output_rfile.output, ¶ms); 227 if (err < 0) { 228 snd_rawmidi_kernel_release(&msynth->output_rfile); 229 return err; 230 } 231 snd_midi_event_reset_decode(msynth->parser); 232 return 0; 233 } 234 235 /* close associated midi device for output */ 236 static int midisynth_unuse(void *private_data, struct snd_seq_port_subscribe *info) 237 { 238 struct seq_midisynth *msynth = private_data; 239 240 if (snd_BUG_ON(!msynth->output_rfile.output)) 241 return -EINVAL; 242 snd_rawmidi_drain_output(msynth->output_rfile.output); 243 return snd_rawmidi_kernel_release(&msynth->output_rfile); 244 } 245 246 /* delete given midi synth port */ 247 static void snd_seq_midisynth_delete(struct seq_midisynth *msynth) 248 { 249 if (msynth == NULL) 250 return; 251 252 if (msynth->seq_client > 0) { 253 /* delete port */ 254 snd_seq_event_port_detach(msynth->seq_client, msynth->seq_port); 255 } 256 257 snd_midi_event_free(msynth->parser); 258 } 259 260 /* register new midi synth port */ 261 static int 262 snd_seq_midisynth_probe(struct device *_dev) 263 { 264 struct snd_seq_device *dev = to_seq_dev(_dev); 265 struct seq_midisynth_client *client; 266 struct seq_midisynth *msynth, *ms; 267 struct snd_seq_port_info *port; 268 struct snd_rawmidi_info *info; 269 struct snd_rawmidi *rmidi = dev->private_data; 270 int newclient = 0; 271 unsigned int p, ports; 272 struct snd_seq_port_callback pcallbacks; 273 struct snd_card *card = dev->card; 274 int device = dev->device; 275 unsigned int input_count = 0, output_count = 0; 276 277 if (snd_BUG_ON(!card || device < 0 || device >= SNDRV_RAWMIDI_DEVICES)) 278 return -EINVAL; 279 info = kmalloc(sizeof(*info), GFP_KERNEL); 280 if (! info) 281 return -ENOMEM; 282 info->device = device; 283 info->stream = SNDRV_RAWMIDI_STREAM_OUTPUT; 284 info->subdevice = 0; 285 if (snd_rawmidi_info_select(card, info) >= 0) 286 output_count = info->subdevices_count; 287 info->stream = SNDRV_RAWMIDI_STREAM_INPUT; 288 if (snd_rawmidi_info_select(card, info) >= 0) { 289 input_count = info->subdevices_count; 290 } 291 ports = output_count; 292 if (ports < input_count) 293 ports = input_count; 294 if (ports == 0) { 295 kfree(info); 296 return -ENODEV; 297 } 298 if (ports > (256 / SNDRV_RAWMIDI_DEVICES)) 299 ports = 256 / SNDRV_RAWMIDI_DEVICES; 300 301 mutex_lock(®ister_mutex); 302 client = synths[card->number]; 303 if (client == NULL) { 304 newclient = 1; 305 client = kzalloc(sizeof(*client), GFP_KERNEL); 306 if (client == NULL) { 307 mutex_unlock(®ister_mutex); 308 kfree(info); 309 return -ENOMEM; 310 } 311 client->seq_client = 312 snd_seq_create_kernel_client( 313 card, 0, "%s", card->shortname[0] ? 314 (const char *)card->shortname : "External MIDI"); 315 if (client->seq_client < 0) { 316 kfree(client); 317 mutex_unlock(®ister_mutex); 318 kfree(info); 319 return -ENOMEM; 320 } 321 } 322 323 msynth = kcalloc(ports, sizeof(struct seq_midisynth), GFP_KERNEL); 324 port = kmalloc(sizeof(*port), GFP_KERNEL); 325 if (msynth == NULL || port == NULL) 326 goto __nomem; 327 328 for (p = 0; p < ports; p++) { 329 ms = &msynth[p]; 330 ms->rmidi = rmidi; 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 if (port->capability & SNDRV_SEQ_PORT_CAP_READ) 371 port->direction |= SNDRV_SEQ_PORT_DIR_INPUT; 372 if (port->capability & SNDRV_SEQ_PORT_CAP_WRITE) 373 port->direction |= SNDRV_SEQ_PORT_DIR_OUTPUT; 374 port->type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC 375 | SNDRV_SEQ_PORT_TYPE_HARDWARE 376 | SNDRV_SEQ_PORT_TYPE_PORT; 377 port->midi_channels = 16; 378 memset(&pcallbacks, 0, sizeof(pcallbacks)); 379 pcallbacks.owner = THIS_MODULE; 380 pcallbacks.private_data = ms; 381 pcallbacks.subscribe = midisynth_subscribe; 382 pcallbacks.unsubscribe = midisynth_unsubscribe; 383 pcallbacks.use = midisynth_use; 384 pcallbacks.unuse = midisynth_unuse; 385 pcallbacks.event_input = event_process_midi; 386 port->kernel = &pcallbacks; 387 if (rmidi->ops && rmidi->ops->get_port_info) 388 rmidi->ops->get_port_info(rmidi, p, port); 389 if (snd_seq_kernel_client_ctl(client->seq_client, SNDRV_SEQ_IOCTL_CREATE_PORT, port)<0) 390 goto __nomem; 391 ms->seq_client = client->seq_client; 392 ms->seq_port = port->addr.port; 393 } 394 client->ports_per_device[device] = ports; 395 client->ports[device] = msynth; 396 client->num_ports++; 397 if (newclient) 398 synths[card->number] = client; 399 mutex_unlock(®ister_mutex); 400 kfree(info); 401 kfree(port); 402 return 0; /* success */ 403 404 __nomem: 405 if (msynth != NULL) { 406 for (p = 0; p < ports; p++) 407 snd_seq_midisynth_delete(&msynth[p]); 408 kfree(msynth); 409 } 410 if (newclient) { 411 snd_seq_delete_kernel_client(client->seq_client); 412 kfree(client); 413 } 414 kfree(info); 415 kfree(port); 416 mutex_unlock(®ister_mutex); 417 return -ENOMEM; 418 } 419 420 /* release midi synth port */ 421 static int 422 snd_seq_midisynth_remove(struct device *_dev) 423 { 424 struct snd_seq_device *dev = to_seq_dev(_dev); 425 struct seq_midisynth_client *client; 426 struct seq_midisynth *msynth; 427 struct snd_card *card = dev->card; 428 int device = dev->device, p, ports; 429 430 mutex_lock(®ister_mutex); 431 client = synths[card->number]; 432 if (client == NULL || client->ports[device] == NULL) { 433 mutex_unlock(®ister_mutex); 434 return -ENODEV; 435 } 436 ports = client->ports_per_device[device]; 437 client->ports_per_device[device] = 0; 438 msynth = client->ports[device]; 439 client->ports[device] = NULL; 440 for (p = 0; p < ports; p++) 441 snd_seq_midisynth_delete(&msynth[p]); 442 kfree(msynth); 443 client->num_ports--; 444 if (client->num_ports <= 0) { 445 snd_seq_delete_kernel_client(client->seq_client); 446 synths[card->number] = NULL; 447 kfree(client); 448 } 449 mutex_unlock(®ister_mutex); 450 return 0; 451 } 452 453 static struct snd_seq_driver seq_midisynth_driver = { 454 .driver = { 455 .name = KBUILD_MODNAME, 456 .probe = snd_seq_midisynth_probe, 457 .remove = snd_seq_midisynth_remove, 458 }, 459 .id = SNDRV_SEQ_DEV_ID_MIDISYNTH, 460 .argsize = 0, 461 }; 462 463 module_snd_seq_driver(seq_midisynth_driver); 464