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 int device; 42 int subdevice; 43 struct snd_rawmidi_file input_rfile; 44 struct snd_rawmidi_file output_rfile; 45 int seq_client; 46 int seq_port; 47 struct snd_midi_event *parser; 48 }; 49 50 struct seq_midisynth_client { 51 int seq_client; 52 int num_ports; 53 int ports_per_device[SNDRV_RAWMIDI_DEVICES]; 54 struct seq_midisynth *ports[SNDRV_RAWMIDI_DEVICES]; 55 }; 56 57 static struct seq_midisynth_client *synths[SNDRV_CARDS]; 58 static DEFINE_MUTEX(register_mutex); 59 60 /* handle rawmidi input event (MIDI v1.0 stream) */ 61 static void snd_midi_input_event(struct snd_rawmidi_substream *substream) 62 { 63 struct snd_rawmidi_runtime *runtime; 64 struct seq_midisynth *msynth; 65 struct snd_seq_event ev; 66 char buf[16], *pbuf; 67 long res; 68 69 if (substream == NULL) 70 return; 71 runtime = substream->runtime; 72 msynth = runtime->private_data; 73 if (msynth == NULL) 74 return; 75 memset(&ev, 0, sizeof(ev)); 76 while (runtime->avail > 0) { 77 res = snd_rawmidi_kernel_read(substream, buf, sizeof(buf)); 78 if (res <= 0) 79 continue; 80 if (msynth->parser == NULL) 81 continue; 82 pbuf = buf; 83 while (res-- > 0) { 84 if (!snd_midi_event_encode_byte(msynth->parser, 85 *pbuf++, &ev)) 86 continue; 87 ev.source.port = msynth->seq_port; 88 ev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS; 89 snd_seq_kernel_client_dispatch(msynth->seq_client, &ev, 1, 0); 90 /* clear event and reset header */ 91 memset(&ev, 0, sizeof(ev)); 92 } 93 } 94 } 95 96 static int dump_midi(struct snd_rawmidi_substream *substream, const char *buf, int count) 97 { 98 struct snd_rawmidi_runtime *runtime; 99 int tmp; 100 101 if (snd_BUG_ON(!substream || !buf)) 102 return -EINVAL; 103 runtime = substream->runtime; 104 tmp = runtime->avail; 105 if (tmp < count) { 106 if (printk_ratelimit()) 107 pr_err("ALSA: seq_midi: MIDI output buffer overrun\n"); 108 return -ENOMEM; 109 } 110 if (snd_rawmidi_kernel_write(substream, buf, count) < count) 111 return -EINVAL; 112 return 0; 113 } 114 115 static int event_process_midi(struct snd_seq_event *ev, int direct, 116 void *private_data, int atomic, int hop) 117 { 118 struct seq_midisynth *msynth = private_data; 119 unsigned char msg[10]; /* buffer for constructing midi messages */ 120 struct snd_rawmidi_substream *substream; 121 int len; 122 123 if (snd_BUG_ON(!msynth)) 124 return -EINVAL; 125 substream = msynth->output_rfile.output; 126 if (substream == NULL) 127 return -ENODEV; 128 if (ev->type == SNDRV_SEQ_EVENT_SYSEX) { /* special case, to save space */ 129 if ((ev->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) != SNDRV_SEQ_EVENT_LENGTH_VARIABLE) { 130 /* invalid event */ 131 pr_debug("ALSA: seq_midi: invalid sysex event flags = 0x%x\n", ev->flags); 132 return 0; 133 } 134 snd_seq_dump_var_event(ev, (snd_seq_dump_func_t)dump_midi, substream); 135 snd_midi_event_reset_decode(msynth->parser); 136 } else { 137 if (msynth->parser == NULL) 138 return -EIO; 139 len = snd_midi_event_decode(msynth->parser, msg, sizeof(msg), ev); 140 if (len < 0) 141 return 0; 142 if (dump_midi(substream, msg, len) < 0) 143 snd_midi_event_reset_decode(msynth->parser); 144 } 145 return 0; 146 } 147 148 149 static int snd_seq_midisynth_new(struct seq_midisynth *msynth, 150 struct snd_card *card, 151 int device, 152 int subdevice) 153 { 154 if (snd_midi_event_new(MAX_MIDI_EVENT_BUF, &msynth->parser) < 0) 155 return -ENOMEM; 156 msynth->card = card; 157 msynth->device = device; 158 msynth->subdevice = subdevice; 159 return 0; 160 } 161 162 /* open associated midi device for input */ 163 static int midisynth_subscribe(void *private_data, struct snd_seq_port_subscribe *info) 164 { 165 int err; 166 struct seq_midisynth *msynth = private_data; 167 struct snd_rawmidi_runtime *runtime; 168 struct snd_rawmidi_params params; 169 170 /* open midi port */ 171 err = snd_rawmidi_kernel_open(msynth->card, msynth->device, 172 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->card, msynth->device, 216 msynth->subdevice, 217 SNDRV_RAWMIDI_LFLG_OUTPUT, 218 &msynth->output_rfile); 219 if (err < 0) { 220 pr_debug("ALSA: seq_midi: midi output open failed!!!\n"); 221 return err; 222 } 223 memset(¶ms, 0, sizeof(params)); 224 params.avail_min = 1; 225 params.buffer_size = output_buffer_size; 226 params.no_active_sensing = 1; 227 err = snd_rawmidi_output_params(msynth->output_rfile.output, ¶ms); 228 if (err < 0) { 229 snd_rawmidi_kernel_release(&msynth->output_rfile); 230 return err; 231 } 232 snd_midi_event_reset_decode(msynth->parser); 233 return 0; 234 } 235 236 /* close associated midi device for output */ 237 static int midisynth_unuse(void *private_data, struct snd_seq_port_subscribe *info) 238 { 239 struct seq_midisynth *msynth = private_data; 240 241 if (snd_BUG_ON(!msynth->output_rfile.output)) 242 return -EINVAL; 243 snd_rawmidi_drain_output(msynth->output_rfile.output); 244 return snd_rawmidi_kernel_release(&msynth->output_rfile); 245 } 246 247 /* delete given midi synth port */ 248 static void snd_seq_midisynth_delete(struct seq_midisynth *msynth) 249 { 250 if (msynth == NULL) 251 return; 252 253 if (msynth->seq_client > 0) { 254 /* delete port */ 255 snd_seq_event_port_detach(msynth->seq_client, msynth->seq_port); 256 } 257 258 snd_midi_event_free(msynth->parser); 259 } 260 261 /* register new midi synth port */ 262 static int 263 snd_seq_midisynth_probe(struct device *_dev) 264 { 265 struct snd_seq_device *dev = to_seq_dev(_dev); 266 struct seq_midisynth_client *client; 267 struct seq_midisynth *msynth, *ms; 268 struct snd_seq_port_info *port; 269 struct snd_rawmidi_info *info; 270 struct snd_rawmidi *rmidi = dev->private_data; 271 int newclient = 0; 272 unsigned int p, ports; 273 struct snd_seq_port_callback pcallbacks; 274 struct snd_card *card = dev->card; 275 int device = dev->device; 276 unsigned int input_count = 0, output_count = 0; 277 278 if (snd_BUG_ON(!card || device < 0 || device >= SNDRV_RAWMIDI_DEVICES)) 279 return -EINVAL; 280 info = kmalloc(sizeof(*info), GFP_KERNEL); 281 if (! info) 282 return -ENOMEM; 283 info->device = device; 284 info->stream = SNDRV_RAWMIDI_STREAM_OUTPUT; 285 info->subdevice = 0; 286 if (snd_rawmidi_info_select(card, info) >= 0) 287 output_count = info->subdevices_count; 288 info->stream = SNDRV_RAWMIDI_STREAM_INPUT; 289 if (snd_rawmidi_info_select(card, info) >= 0) { 290 input_count = info->subdevices_count; 291 } 292 ports = output_count; 293 if (ports < input_count) 294 ports = input_count; 295 if (ports == 0) { 296 kfree(info); 297 return -ENODEV; 298 } 299 if (ports > (256 / SNDRV_RAWMIDI_DEVICES)) 300 ports = 256 / SNDRV_RAWMIDI_DEVICES; 301 302 mutex_lock(®ister_mutex); 303 client = synths[card->number]; 304 if (client == NULL) { 305 newclient = 1; 306 client = kzalloc(sizeof(*client), GFP_KERNEL); 307 if (client == NULL) { 308 mutex_unlock(®ister_mutex); 309 kfree(info); 310 return -ENOMEM; 311 } 312 client->seq_client = 313 snd_seq_create_kernel_client( 314 card, 0, "%s", card->shortname[0] ? 315 (const char *)card->shortname : "External MIDI"); 316 if (client->seq_client < 0) { 317 kfree(client); 318 mutex_unlock(®ister_mutex); 319 kfree(info); 320 return -ENOMEM; 321 } 322 } 323 324 msynth = kcalloc(ports, sizeof(struct seq_midisynth), GFP_KERNEL); 325 port = kmalloc(sizeof(*port), GFP_KERNEL); 326 if (msynth == NULL || port == NULL) 327 goto __nomem; 328 329 for (p = 0; p < ports; p++) { 330 ms = &msynth[p]; 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 port->type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC 371 | SNDRV_SEQ_PORT_TYPE_HARDWARE 372 | SNDRV_SEQ_PORT_TYPE_PORT; 373 port->midi_channels = 16; 374 memset(&pcallbacks, 0, sizeof(pcallbacks)); 375 pcallbacks.owner = THIS_MODULE; 376 pcallbacks.private_data = ms; 377 pcallbacks.subscribe = midisynth_subscribe; 378 pcallbacks.unsubscribe = midisynth_unsubscribe; 379 pcallbacks.use = midisynth_use; 380 pcallbacks.unuse = midisynth_unuse; 381 pcallbacks.event_input = event_process_midi; 382 port->kernel = &pcallbacks; 383 if (rmidi->ops && rmidi->ops->get_port_info) 384 rmidi->ops->get_port_info(rmidi, p, port); 385 if (snd_seq_kernel_client_ctl(client->seq_client, SNDRV_SEQ_IOCTL_CREATE_PORT, port)<0) 386 goto __nomem; 387 ms->seq_client = client->seq_client; 388 ms->seq_port = port->addr.port; 389 } 390 client->ports_per_device[device] = ports; 391 client->ports[device] = msynth; 392 client->num_ports++; 393 if (newclient) 394 synths[card->number] = client; 395 mutex_unlock(®ister_mutex); 396 kfree(info); 397 kfree(port); 398 return 0; /* success */ 399 400 __nomem: 401 if (msynth != NULL) { 402 for (p = 0; p < ports; p++) 403 snd_seq_midisynth_delete(&msynth[p]); 404 kfree(msynth); 405 } 406 if (newclient) { 407 snd_seq_delete_kernel_client(client->seq_client); 408 kfree(client); 409 } 410 kfree(info); 411 kfree(port); 412 mutex_unlock(®ister_mutex); 413 return -ENOMEM; 414 } 415 416 /* release midi synth port */ 417 static int 418 snd_seq_midisynth_remove(struct device *_dev) 419 { 420 struct snd_seq_device *dev = to_seq_dev(_dev); 421 struct seq_midisynth_client *client; 422 struct seq_midisynth *msynth; 423 struct snd_card *card = dev->card; 424 int device = dev->device, p, ports; 425 426 mutex_lock(®ister_mutex); 427 client = synths[card->number]; 428 if (client == NULL || client->ports[device] == NULL) { 429 mutex_unlock(®ister_mutex); 430 return -ENODEV; 431 } 432 ports = client->ports_per_device[device]; 433 client->ports_per_device[device] = 0; 434 msynth = client->ports[device]; 435 client->ports[device] = NULL; 436 for (p = 0; p < ports; p++) 437 snd_seq_midisynth_delete(&msynth[p]); 438 kfree(msynth); 439 client->num_ports--; 440 if (client->num_ports <= 0) { 441 snd_seq_delete_kernel_client(client->seq_client); 442 synths[card->number] = NULL; 443 kfree(client); 444 } 445 mutex_unlock(®ister_mutex); 446 return 0; 447 } 448 449 static struct snd_seq_driver seq_midisynth_driver = { 450 .driver = { 451 .name = KBUILD_MODNAME, 452 .probe = snd_seq_midisynth_probe, 453 .remove = snd_seq_midisynth_remove, 454 }, 455 .id = SNDRV_SEQ_DEV_ID_MIDISYNTH, 456 .argsize = 0, 457 }; 458 459 module_snd_seq_driver(seq_midisynth_driver); 460