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 if ((tmp = runtime->avail) < count) { 105 if (printk_ratelimit()) 106 pr_err("ALSA: seq_midi: MIDI output buffer overrun\n"); 107 return -ENOMEM; 108 } 109 if (snd_rawmidi_kernel_write(substream, buf, count) < count) 110 return -EINVAL; 111 return 0; 112 } 113 114 static int event_process_midi(struct snd_seq_event *ev, int direct, 115 void *private_data, int atomic, int hop) 116 { 117 struct seq_midisynth *msynth = private_data; 118 unsigned char msg[10]; /* buffer for constructing midi messages */ 119 struct snd_rawmidi_substream *substream; 120 int len; 121 122 if (snd_BUG_ON(!msynth)) 123 return -EINVAL; 124 substream = msynth->output_rfile.output; 125 if (substream == NULL) 126 return -ENODEV; 127 if (ev->type == SNDRV_SEQ_EVENT_SYSEX) { /* special case, to save space */ 128 if ((ev->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) != SNDRV_SEQ_EVENT_LENGTH_VARIABLE) { 129 /* invalid event */ 130 pr_debug("ALSA: seq_midi: invalid sysex event flags = 0x%x\n", ev->flags); 131 return 0; 132 } 133 snd_seq_dump_var_event(ev, (snd_seq_dump_func_t)dump_midi, substream); 134 snd_midi_event_reset_decode(msynth->parser); 135 } else { 136 if (msynth->parser == NULL) 137 return -EIO; 138 len = snd_midi_event_decode(msynth->parser, msg, sizeof(msg), ev); 139 if (len < 0) 140 return 0; 141 if (dump_midi(substream, msg, len) < 0) 142 snd_midi_event_reset_decode(msynth->parser); 143 } 144 return 0; 145 } 146 147 148 static int snd_seq_midisynth_new(struct seq_midisynth *msynth, 149 struct snd_card *card, 150 int device, 151 int subdevice) 152 { 153 if (snd_midi_event_new(MAX_MIDI_EVENT_BUF, &msynth->parser) < 0) 154 return -ENOMEM; 155 msynth->card = card; 156 msynth->device = device; 157 msynth->subdevice = subdevice; 158 return 0; 159 } 160 161 /* open associated midi device for input */ 162 static int midisynth_subscribe(void *private_data, struct snd_seq_port_subscribe *info) 163 { 164 int err; 165 struct seq_midisynth *msynth = private_data; 166 struct snd_rawmidi_runtime *runtime; 167 struct snd_rawmidi_params params; 168 169 /* open midi port */ 170 if ((err = snd_rawmidi_kernel_open(msynth->card, msynth->device, 171 msynth->subdevice, 172 SNDRV_RAWMIDI_LFLG_INPUT, 173 &msynth->input_rfile)) < 0) { 174 pr_debug("ALSA: seq_midi: midi input open failed!!!\n"); 175 return err; 176 } 177 runtime = msynth->input_rfile.input->runtime; 178 memset(¶ms, 0, sizeof(params)); 179 params.avail_min = 1; 180 params.buffer_size = input_buffer_size; 181 if ((err = snd_rawmidi_input_params(msynth->input_rfile.input, ¶ms)) < 0) { 182 snd_rawmidi_kernel_release(&msynth->input_rfile); 183 return err; 184 } 185 snd_midi_event_reset_encode(msynth->parser); 186 runtime->event = snd_midi_input_event; 187 runtime->private_data = msynth; 188 snd_rawmidi_kernel_read(msynth->input_rfile.input, NULL, 0); 189 return 0; 190 } 191 192 /* close associated midi device for input */ 193 static int midisynth_unsubscribe(void *private_data, struct snd_seq_port_subscribe *info) 194 { 195 int err; 196 struct seq_midisynth *msynth = private_data; 197 198 if (snd_BUG_ON(!msynth->input_rfile.input)) 199 return -EINVAL; 200 err = snd_rawmidi_kernel_release(&msynth->input_rfile); 201 return err; 202 } 203 204 /* open associated midi device for output */ 205 static int midisynth_use(void *private_data, struct snd_seq_port_subscribe *info) 206 { 207 int err; 208 struct seq_midisynth *msynth = private_data; 209 struct snd_rawmidi_params params; 210 211 /* open midi port */ 212 if ((err = snd_rawmidi_kernel_open(msynth->card, msynth->device, 213 msynth->subdevice, 214 SNDRV_RAWMIDI_LFLG_OUTPUT, 215 &msynth->output_rfile)) < 0) { 216 pr_debug("ALSA: seq_midi: midi output open failed!!!\n"); 217 return err; 218 } 219 memset(¶ms, 0, sizeof(params)); 220 params.avail_min = 1; 221 params.buffer_size = output_buffer_size; 222 params.no_active_sensing = 1; 223 if ((err = snd_rawmidi_output_params(msynth->output_rfile.output, ¶ms)) < 0) { 224 snd_rawmidi_kernel_release(&msynth->output_rfile); 225 return err; 226 } 227 snd_midi_event_reset_decode(msynth->parser); 228 return 0; 229 } 230 231 /* close associated midi device for output */ 232 static int midisynth_unuse(void *private_data, struct snd_seq_port_subscribe *info) 233 { 234 struct seq_midisynth *msynth = private_data; 235 236 if (snd_BUG_ON(!msynth->output_rfile.output)) 237 return -EINVAL; 238 snd_rawmidi_drain_output(msynth->output_rfile.output); 239 return snd_rawmidi_kernel_release(&msynth->output_rfile); 240 } 241 242 /* delete given midi synth port */ 243 static void snd_seq_midisynth_delete(struct seq_midisynth *msynth) 244 { 245 if (msynth == NULL) 246 return; 247 248 if (msynth->seq_client > 0) { 249 /* delete port */ 250 snd_seq_event_port_detach(msynth->seq_client, msynth->seq_port); 251 } 252 253 snd_midi_event_free(msynth->parser); 254 } 255 256 /* register new midi synth port */ 257 static int 258 snd_seq_midisynth_probe(struct device *_dev) 259 { 260 struct snd_seq_device *dev = to_seq_dev(_dev); 261 struct seq_midisynth_client *client; 262 struct seq_midisynth *msynth, *ms; 263 struct snd_seq_port_info *port; 264 struct snd_rawmidi_info *info; 265 struct snd_rawmidi *rmidi = dev->private_data; 266 int newclient = 0; 267 unsigned int p, ports; 268 struct snd_seq_port_callback pcallbacks; 269 struct snd_card *card = dev->card; 270 int device = dev->device; 271 unsigned int input_count = 0, output_count = 0; 272 273 if (snd_BUG_ON(!card || device < 0 || device >= SNDRV_RAWMIDI_DEVICES)) 274 return -EINVAL; 275 info = kmalloc(sizeof(*info), GFP_KERNEL); 276 if (! info) 277 return -ENOMEM; 278 info->device = device; 279 info->stream = SNDRV_RAWMIDI_STREAM_OUTPUT; 280 info->subdevice = 0; 281 if (snd_rawmidi_info_select(card, info) >= 0) 282 output_count = info->subdevices_count; 283 info->stream = SNDRV_RAWMIDI_STREAM_INPUT; 284 if (snd_rawmidi_info_select(card, info) >= 0) { 285 input_count = info->subdevices_count; 286 } 287 ports = output_count; 288 if (ports < input_count) 289 ports = input_count; 290 if (ports == 0) { 291 kfree(info); 292 return -ENODEV; 293 } 294 if (ports > (256 / SNDRV_RAWMIDI_DEVICES)) 295 ports = 256 / SNDRV_RAWMIDI_DEVICES; 296 297 mutex_lock(®ister_mutex); 298 client = synths[card->number]; 299 if (client == NULL) { 300 newclient = 1; 301 client = kzalloc(sizeof(*client), GFP_KERNEL); 302 if (client == NULL) { 303 mutex_unlock(®ister_mutex); 304 kfree(info); 305 return -ENOMEM; 306 } 307 client->seq_client = 308 snd_seq_create_kernel_client( 309 card, 0, "%s", card->shortname[0] ? 310 (const char *)card->shortname : "External MIDI"); 311 if (client->seq_client < 0) { 312 kfree(client); 313 mutex_unlock(®ister_mutex); 314 kfree(info); 315 return -ENOMEM; 316 } 317 } 318 319 msynth = kcalloc(ports, sizeof(struct seq_midisynth), GFP_KERNEL); 320 port = kmalloc(sizeof(*port), GFP_KERNEL); 321 if (msynth == NULL || port == NULL) 322 goto __nomem; 323 324 for (p = 0; p < ports; p++) { 325 ms = &msynth[p]; 326 327 if (snd_seq_midisynth_new(ms, card, device, p) < 0) 328 goto __nomem; 329 330 /* declare port */ 331 memset(port, 0, sizeof(*port)); 332 port->addr.client = client->seq_client; 333 port->addr.port = device * (256 / SNDRV_RAWMIDI_DEVICES) + p; 334 port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT; 335 memset(info, 0, sizeof(*info)); 336 info->device = device; 337 if (p < output_count) 338 info->stream = SNDRV_RAWMIDI_STREAM_OUTPUT; 339 else 340 info->stream = SNDRV_RAWMIDI_STREAM_INPUT; 341 info->subdevice = p; 342 if (snd_rawmidi_info_select(card, info) >= 0) 343 strcpy(port->name, info->subname); 344 if (! port->name[0]) { 345 if (info->name[0]) { 346 if (ports > 1) 347 snprintf(port->name, sizeof(port->name), "%s-%u", info->name, p); 348 else 349 snprintf(port->name, sizeof(port->name), "%s", info->name); 350 } else { 351 /* last resort */ 352 if (ports > 1) 353 sprintf(port->name, "MIDI %d-%d-%u", card->number, device, p); 354 else 355 sprintf(port->name, "MIDI %d-%d", card->number, device); 356 } 357 } 358 if ((info->flags & SNDRV_RAWMIDI_INFO_OUTPUT) && p < output_count) 359 port->capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SYNC_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE; 360 if ((info->flags & SNDRV_RAWMIDI_INFO_INPUT) && p < input_count) 361 port->capability |= SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SYNC_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ; 362 if ((port->capability & (SNDRV_SEQ_PORT_CAP_WRITE|SNDRV_SEQ_PORT_CAP_READ)) == (SNDRV_SEQ_PORT_CAP_WRITE|SNDRV_SEQ_PORT_CAP_READ) && 363 info->flags & SNDRV_RAWMIDI_INFO_DUPLEX) 364 port->capability |= SNDRV_SEQ_PORT_CAP_DUPLEX; 365 port->type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC 366 | SNDRV_SEQ_PORT_TYPE_HARDWARE 367 | SNDRV_SEQ_PORT_TYPE_PORT; 368 port->midi_channels = 16; 369 memset(&pcallbacks, 0, sizeof(pcallbacks)); 370 pcallbacks.owner = THIS_MODULE; 371 pcallbacks.private_data = ms; 372 pcallbacks.subscribe = midisynth_subscribe; 373 pcallbacks.unsubscribe = midisynth_unsubscribe; 374 pcallbacks.use = midisynth_use; 375 pcallbacks.unuse = midisynth_unuse; 376 pcallbacks.event_input = event_process_midi; 377 port->kernel = &pcallbacks; 378 if (rmidi->ops && rmidi->ops->get_port_info) 379 rmidi->ops->get_port_info(rmidi, p, port); 380 if (snd_seq_kernel_client_ctl(client->seq_client, SNDRV_SEQ_IOCTL_CREATE_PORT, port)<0) 381 goto __nomem; 382 ms->seq_client = client->seq_client; 383 ms->seq_port = port->addr.port; 384 } 385 client->ports_per_device[device] = ports; 386 client->ports[device] = msynth; 387 client->num_ports++; 388 if (newclient) 389 synths[card->number] = client; 390 mutex_unlock(®ister_mutex); 391 kfree(info); 392 kfree(port); 393 return 0; /* success */ 394 395 __nomem: 396 if (msynth != NULL) { 397 for (p = 0; p < ports; p++) 398 snd_seq_midisynth_delete(&msynth[p]); 399 kfree(msynth); 400 } 401 if (newclient) { 402 snd_seq_delete_kernel_client(client->seq_client); 403 kfree(client); 404 } 405 kfree(info); 406 kfree(port); 407 mutex_unlock(®ister_mutex); 408 return -ENOMEM; 409 } 410 411 /* release midi synth port */ 412 static int 413 snd_seq_midisynth_remove(struct device *_dev) 414 { 415 struct snd_seq_device *dev = to_seq_dev(_dev); 416 struct seq_midisynth_client *client; 417 struct seq_midisynth *msynth; 418 struct snd_card *card = dev->card; 419 int device = dev->device, p, ports; 420 421 mutex_lock(®ister_mutex); 422 client = synths[card->number]; 423 if (client == NULL || client->ports[device] == NULL) { 424 mutex_unlock(®ister_mutex); 425 return -ENODEV; 426 } 427 ports = client->ports_per_device[device]; 428 client->ports_per_device[device] = 0; 429 msynth = client->ports[device]; 430 client->ports[device] = NULL; 431 for (p = 0; p < ports; p++) 432 snd_seq_midisynth_delete(&msynth[p]); 433 kfree(msynth); 434 client->num_ports--; 435 if (client->num_ports <= 0) { 436 snd_seq_delete_kernel_client(client->seq_client); 437 synths[card->number] = NULL; 438 kfree(client); 439 } 440 mutex_unlock(®ister_mutex); 441 return 0; 442 } 443 444 static struct snd_seq_driver seq_midisynth_driver = { 445 .driver = { 446 .name = KBUILD_MODNAME, 447 .probe = snd_seq_midisynth_probe, 448 .remove = snd_seq_midisynth_remove, 449 }, 450 .id = SNDRV_SEQ_DEV_ID_MIDISYNTH, 451 .argsize = 0, 452 }; 453 454 module_snd_seq_driver(seq_midisynth_driver); 455