sound/core/seq/seq_midi.c

   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(&params, 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, &params)) < 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(&params, 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, &params)) < 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(&register_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(&register_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(&register_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(&register_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(&register_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(&register_mutex);
 422         client = synths[card->number];
 423         if (client == NULL || client->ports[device] == NULL) {
 424                 mutex_unlock(&register_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(&register_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);