linux/sound/core/seq/seq_midi.c
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   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/* 
   9Possible 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
  28MODULE_AUTHOR("Frank van de Pol <fvdpol@coil.demon.nl>, Jaroslav Kysela <perex@perex.cz>");
  29MODULE_DESCRIPTION("Advanced Linux Sound Architecture sequencer MIDI synth.");
  30MODULE_LICENSE("GPL");
  31static int output_buffer_size = PAGE_SIZE;
  32module_param(output_buffer_size, int, 0644);
  33MODULE_PARM_DESC(output_buffer_size, "Output buffer size in bytes.");
  34static int input_buffer_size = PAGE_SIZE;
  35module_param(input_buffer_size, int, 0644);
  36MODULE_PARM_DESC(input_buffer_size, "Input buffer size in bytes.");
  37
  38/* data for this midi synth driver */
  39struct 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
  50struct 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
  57static struct seq_midisynth_client *synths[SNDRV_CARDS];
  58static DEFINE_MUTEX(register_mutex);
  59
  60/* handle rawmidi input event (MIDI v1.0 stream) */
  61static 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
  96static 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
 115static 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
 149static 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 */
 163static 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(&params, 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, &params);
 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 */
 196static 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 */
 208static 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(&params, 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, &params);
 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 */
 237static 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 */
 248static 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 */
 262static int
 263snd_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(&register_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(&register_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(&register_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(&register_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(&register_mutex);
 413        return -ENOMEM;
 414}
 415
 416/* release midi synth port */
 417static int
 418snd_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(&register_mutex);
 427        client = synths[card->number];
 428        if (client == NULL || client->ports[device] == NULL) {
 429                mutex_unlock(&register_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(&register_mutex);
 446        return 0;
 447}
 448
 449static 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
 459module_snd_seq_driver(seq_midisynth_driver);
 460