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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Virtual Raw MIDI client on Sequencer4 *5 * Copyright (c) 2000 by Takashi Iwai <tiwai@suse.de>,6 * Jaroslav Kysela <perex@perex.cz>7 */8 9/*10 * Virtual Raw MIDI client11 *12 * The virtual rawmidi client is a sequencer client which associate13 * a rawmidi device file. The created rawmidi device file can be14 * accessed as a normal raw midi, but its MIDI source and destination15 * are arbitrary. For example, a user-client software synth connected16 * to this port can be used as a normal midi device as well.17 *18 * The virtual rawmidi device accepts also multiple opens. Each file19 * has its own input buffer, so that no conflict would occur. The drain20 * of input/output buffer acts only to the local buffer.21 *22 */23 24#include <linux/init.h>25#include <linux/wait.h>26#include <linux/module.h>27#include <linux/slab.h>28#include <sound/core.h>29#include <sound/rawmidi.h>30#include <sound/info.h>31#include <sound/control.h>32#include <sound/minors.h>33#include <sound/seq_kernel.h>34#include <sound/seq_midi_event.h>35#include <sound/seq_virmidi.h>36 37MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");38MODULE_DESCRIPTION("Virtual Raw MIDI client on Sequencer");39MODULE_LICENSE("GPL");40 41/*42 * initialize an event record43 */44static void snd_virmidi_init_event(struct snd_virmidi *vmidi,45 struct snd_seq_event *ev)46{47 memset(ev, 0, sizeof(*ev));48 ev->source.port = vmidi->port;49 switch (vmidi->seq_mode) {50 case SNDRV_VIRMIDI_SEQ_DISPATCH:51 ev->dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;52 break;53 case SNDRV_VIRMIDI_SEQ_ATTACH:54 /* FIXME: source and destination are same - not good.. */55 ev->dest.client = vmidi->client;56 ev->dest.port = vmidi->port;57 break;58 }59 ev->type = SNDRV_SEQ_EVENT_NONE;60}61 62/*63 * decode input event and put to read buffer of each opened file64 */65 66/* callback for snd_seq_dump_var_event(), bridging to snd_rawmidi_receive() */67static int dump_to_rawmidi(void *ptr, void *buf, int count)68{69 return snd_rawmidi_receive(ptr, buf, count);70}71 72static int snd_virmidi_dev_receive_event(struct snd_virmidi_dev *rdev,73 struct snd_seq_event *ev,74 bool atomic)75{76 struct snd_virmidi *vmidi;77 unsigned char msg[4];78 int len;79 80 if (atomic)81 read_lock(&rdev->filelist_lock);82 else83 down_read(&rdev->filelist_sem);84 list_for_each_entry(vmidi, &rdev->filelist, list) {85 if (!READ_ONCE(vmidi->trigger))86 continue;87 if (ev->type == SNDRV_SEQ_EVENT_SYSEX) {88 if ((ev->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) != SNDRV_SEQ_EVENT_LENGTH_VARIABLE)89 continue;90 snd_seq_dump_var_event(ev, dump_to_rawmidi, vmidi->substream);91 snd_midi_event_reset_decode(vmidi->parser);92 } else {93 len = snd_midi_event_decode(vmidi->parser, msg, sizeof(msg), ev);94 if (len > 0)95 snd_rawmidi_receive(vmidi->substream, msg, len);96 }97 }98 if (atomic)99 read_unlock(&rdev->filelist_lock);100 else101 up_read(&rdev->filelist_sem);102 103 return 0;104}105 106/*107 * event handler of virmidi port108 */109static int snd_virmidi_event_input(struct snd_seq_event *ev, int direct,110 void *private_data, int atomic, int hop)111{112 struct snd_virmidi_dev *rdev;113 114 rdev = private_data;115 if (!(rdev->flags & SNDRV_VIRMIDI_USE))116 return 0; /* ignored */117 return snd_virmidi_dev_receive_event(rdev, ev, atomic);118}119 120/*121 * trigger rawmidi stream for input122 */123static void snd_virmidi_input_trigger(struct snd_rawmidi_substream *substream, int up)124{125 struct snd_virmidi *vmidi = substream->runtime->private_data;126 127 WRITE_ONCE(vmidi->trigger, !!up);128}129 130/* process rawmidi bytes and send events;131 * we need no lock here for vmidi->event since it's handled only in this work132 */133static void snd_vmidi_output_work(struct work_struct *work)134{135 struct snd_virmidi *vmidi;136 struct snd_rawmidi_substream *substream;137 unsigned char input;138 int ret;139 140 vmidi = container_of(work, struct snd_virmidi, output_work);141 substream = vmidi->substream;142 143 /* discard the outputs in dispatch mode unless subscribed */144 if (vmidi->seq_mode == SNDRV_VIRMIDI_SEQ_DISPATCH &&145 !(vmidi->rdev->flags & SNDRV_VIRMIDI_SUBSCRIBE)) {146 snd_rawmidi_proceed(substream);147 return;148 }149 150 while (READ_ONCE(vmidi->trigger)) {151 if (snd_rawmidi_transmit(substream, &input, 1) != 1)152 break;153 if (!snd_midi_event_encode_byte(vmidi->parser, input,154 &vmidi->event))155 continue;156 if (vmidi->event.type != SNDRV_SEQ_EVENT_NONE) {157 ret = snd_seq_kernel_client_dispatch(vmidi->client,158 &vmidi->event,159 false, 0);160 vmidi->event.type = SNDRV_SEQ_EVENT_NONE;161 if (ret < 0)162 break;163 }164 /* rawmidi input might be huge, allow to have a break */165 cond_resched();166 }167}168 169/*170 * trigger rawmidi stream for output171 */172static void snd_virmidi_output_trigger(struct snd_rawmidi_substream *substream, int up)173{174 struct snd_virmidi *vmidi = substream->runtime->private_data;175 176 WRITE_ONCE(vmidi->trigger, !!up);177 if (up)178 queue_work(system_highpri_wq, &vmidi->output_work);179}180 181/*182 * open rawmidi handle for input183 */184static int snd_virmidi_input_open(struct snd_rawmidi_substream *substream)185{186 struct snd_virmidi_dev *rdev = substream->rmidi->private_data;187 struct snd_rawmidi_runtime *runtime = substream->runtime;188 struct snd_virmidi *vmidi;189 190 vmidi = kzalloc(sizeof(*vmidi), GFP_KERNEL);191 if (vmidi == NULL)192 return -ENOMEM;193 vmidi->substream = substream;194 if (snd_midi_event_new(0, &vmidi->parser) < 0) {195 kfree(vmidi);196 return -ENOMEM;197 }198 vmidi->seq_mode = rdev->seq_mode;199 vmidi->client = rdev->client;200 vmidi->port = rdev->port; 201 runtime->private_data = vmidi;202 scoped_guard(rwsem_write, &rdev->filelist_sem) {203 guard(write_lock_irq)(&rdev->filelist_lock);204 list_add_tail(&vmidi->list, &rdev->filelist);205 }206 vmidi->rdev = rdev;207 return 0;208}209 210/*211 * open rawmidi handle for output212 */213static int snd_virmidi_output_open(struct snd_rawmidi_substream *substream)214{215 struct snd_virmidi_dev *rdev = substream->rmidi->private_data;216 struct snd_rawmidi_runtime *runtime = substream->runtime;217 struct snd_virmidi *vmidi;218 219 vmidi = kzalloc(sizeof(*vmidi), GFP_KERNEL);220 if (vmidi == NULL)221 return -ENOMEM;222 vmidi->substream = substream;223 if (snd_midi_event_new(MAX_MIDI_EVENT_BUF, &vmidi->parser) < 0) {224 kfree(vmidi);225 return -ENOMEM;226 }227 vmidi->seq_mode = rdev->seq_mode;228 vmidi->client = rdev->client;229 vmidi->port = rdev->port;230 snd_virmidi_init_event(vmidi, &vmidi->event);231 vmidi->rdev = rdev;232 INIT_WORK(&vmidi->output_work, snd_vmidi_output_work);233 runtime->private_data = vmidi;234 return 0;235}236 237/*238 * close rawmidi handle for input239 */240static int snd_virmidi_input_close(struct snd_rawmidi_substream *substream)241{242 struct snd_virmidi_dev *rdev = substream->rmidi->private_data;243 struct snd_virmidi *vmidi = substream->runtime->private_data;244 245 scoped_guard(rwsem_write, &rdev->filelist_sem) {246 guard(write_lock_irq)(&rdev->filelist_lock);247 list_del(&vmidi->list);248 }249 snd_midi_event_free(vmidi->parser);250 substream->runtime->private_data = NULL;251 kfree(vmidi);252 return 0;253}254 255/*256 * close rawmidi handle for output257 */258static int snd_virmidi_output_close(struct snd_rawmidi_substream *substream)259{260 struct snd_virmidi *vmidi = substream->runtime->private_data;261 262 WRITE_ONCE(vmidi->trigger, false); /* to be sure */263 cancel_work_sync(&vmidi->output_work);264 snd_midi_event_free(vmidi->parser);265 substream->runtime->private_data = NULL;266 kfree(vmidi);267 return 0;268}269 270/*271 * drain output work queue272 */273static void snd_virmidi_output_drain(struct snd_rawmidi_substream *substream)274{275 struct snd_virmidi *vmidi = substream->runtime->private_data;276 277 flush_work(&vmidi->output_work);278}279 280/*281 * subscribe callback - allow output to rawmidi device282 */283static int snd_virmidi_subscribe(void *private_data,284 struct snd_seq_port_subscribe *info)285{286 struct snd_virmidi_dev *rdev;287 288 rdev = private_data;289 if (!try_module_get(rdev->card->module))290 return -EFAULT;291 rdev->flags |= SNDRV_VIRMIDI_SUBSCRIBE;292 return 0;293}294 295/*296 * unsubscribe callback - disallow output to rawmidi device297 */298static int snd_virmidi_unsubscribe(void *private_data,299 struct snd_seq_port_subscribe *info)300{301 struct snd_virmidi_dev *rdev;302 303 rdev = private_data;304 rdev->flags &= ~SNDRV_VIRMIDI_SUBSCRIBE;305 module_put(rdev->card->module);306 return 0;307}308 309 310/*311 * use callback - allow input to rawmidi device312 */313static int snd_virmidi_use(void *private_data,314 struct snd_seq_port_subscribe *info)315{316 struct snd_virmidi_dev *rdev;317 318 rdev = private_data;319 if (!try_module_get(rdev->card->module))320 return -EFAULT;321 rdev->flags |= SNDRV_VIRMIDI_USE;322 return 0;323}324 325/*326 * unuse callback - disallow input to rawmidi device327 */328static int snd_virmidi_unuse(void *private_data,329 struct snd_seq_port_subscribe *info)330{331 struct snd_virmidi_dev *rdev;332 333 rdev = private_data;334 rdev->flags &= ~SNDRV_VIRMIDI_USE;335 module_put(rdev->card->module);336 return 0;337}338 339 340/*341 * Register functions342 */343 344static const struct snd_rawmidi_ops snd_virmidi_input_ops = {345 .open = snd_virmidi_input_open,346 .close = snd_virmidi_input_close,347 .trigger = snd_virmidi_input_trigger,348};349 350static const struct snd_rawmidi_ops snd_virmidi_output_ops = {351 .open = snd_virmidi_output_open,352 .close = snd_virmidi_output_close,353 .trigger = snd_virmidi_output_trigger,354 .drain = snd_virmidi_output_drain,355};356 357/*358 * create a sequencer client and a port359 */360static int snd_virmidi_dev_attach_seq(struct snd_virmidi_dev *rdev)361{362 int client;363 struct snd_seq_port_callback pcallbacks;364 struct snd_seq_port_info *pinfo __free(kfree) = NULL;365 int err;366 367 if (rdev->client >= 0)368 return 0;369 370 pinfo = kzalloc(sizeof(*pinfo), GFP_KERNEL);371 if (!pinfo)372 return -ENOMEM;373 374 client = snd_seq_create_kernel_client(rdev->card, rdev->device,375 "%s %d-%d", rdev->rmidi->name,376 rdev->card->number,377 rdev->device);378 if (client < 0)379 return client;380 rdev->client = client;381 382 /* create a port */383 pinfo->addr.client = client;384 sprintf(pinfo->name, "VirMIDI %d-%d", rdev->card->number, rdev->device);385 /* set all capabilities */386 pinfo->capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SYNC_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE;387 pinfo->capability |= SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SYNC_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ;388 pinfo->capability |= SNDRV_SEQ_PORT_CAP_DUPLEX;389 pinfo->direction = SNDRV_SEQ_PORT_DIR_BIDIRECTION;390 pinfo->type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC391 | SNDRV_SEQ_PORT_TYPE_SOFTWARE392 | SNDRV_SEQ_PORT_TYPE_PORT;393 pinfo->midi_channels = 16;394 memset(&pcallbacks, 0, sizeof(pcallbacks));395 pcallbacks.owner = THIS_MODULE;396 pcallbacks.private_data = rdev;397 pcallbacks.subscribe = snd_virmidi_subscribe;398 pcallbacks.unsubscribe = snd_virmidi_unsubscribe;399 pcallbacks.use = snd_virmidi_use;400 pcallbacks.unuse = snd_virmidi_unuse;401 pcallbacks.event_input = snd_virmidi_event_input;402 pinfo->kernel = &pcallbacks;403 err = snd_seq_kernel_client_ctl(client, SNDRV_SEQ_IOCTL_CREATE_PORT, pinfo);404 if (err < 0) {405 snd_seq_delete_kernel_client(client);406 rdev->client = -1;407 return err;408 }409 410 rdev->port = pinfo->addr.port;411 return 0; /* success */412}413 414 415/*416 * release the sequencer client417 */418static void snd_virmidi_dev_detach_seq(struct snd_virmidi_dev *rdev)419{420 if (rdev->client >= 0) {421 snd_seq_delete_kernel_client(rdev->client);422 rdev->client = -1;423 }424}425 426/*427 * register the device428 */429static int snd_virmidi_dev_register(struct snd_rawmidi *rmidi)430{431 struct snd_virmidi_dev *rdev = rmidi->private_data;432 int err;433 434 switch (rdev->seq_mode) {435 case SNDRV_VIRMIDI_SEQ_DISPATCH:436 err = snd_virmidi_dev_attach_seq(rdev);437 if (err < 0)438 return err;439 break;440 case SNDRV_VIRMIDI_SEQ_ATTACH:441 if (rdev->client == 0)442 return -EINVAL;443 /* should check presence of port more strictly.. */444 break;445 default:446 pr_err("ALSA: seq_virmidi: seq_mode is not set: %d\n", rdev->seq_mode);447 return -EINVAL;448 }449 return 0;450}451 452 453/*454 * unregister the device455 */456static int snd_virmidi_dev_unregister(struct snd_rawmidi *rmidi)457{458 struct snd_virmidi_dev *rdev = rmidi->private_data;459 460 if (rdev->seq_mode == SNDRV_VIRMIDI_SEQ_DISPATCH)461 snd_virmidi_dev_detach_seq(rdev);462 return 0;463}464 465/*466 *467 */468static const struct snd_rawmidi_global_ops snd_virmidi_global_ops = {469 .dev_register = snd_virmidi_dev_register,470 .dev_unregister = snd_virmidi_dev_unregister,471};472 473/*474 * free device475 */476static void snd_virmidi_free(struct snd_rawmidi *rmidi)477{478 struct snd_virmidi_dev *rdev = rmidi->private_data;479 kfree(rdev);480}481 482/*483 * create a new device484 *485 */486/* exported */487int snd_virmidi_new(struct snd_card *card, int device, struct snd_rawmidi **rrmidi)488{489 struct snd_rawmidi *rmidi;490 struct snd_virmidi_dev *rdev;491 int err;492 493 *rrmidi = NULL;494 err = snd_rawmidi_new(card, "VirMidi", device,495 16, /* may be configurable */496 16, /* may be configurable */497 &rmidi);498 if (err < 0)499 return err;500 strcpy(rmidi->name, rmidi->id);501 rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);502 if (rdev == NULL) {503 snd_device_free(card, rmidi);504 return -ENOMEM;505 }506 rdev->card = card;507 rdev->rmidi = rmidi;508 rdev->device = device;509 rdev->client = -1;510 init_rwsem(&rdev->filelist_sem);511 rwlock_init(&rdev->filelist_lock);512 INIT_LIST_HEAD(&rdev->filelist);513 rdev->seq_mode = SNDRV_VIRMIDI_SEQ_DISPATCH;514 rmidi->private_data = rdev;515 rmidi->private_free = snd_virmidi_free;516 rmidi->ops = &snd_virmidi_global_ops;517 snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &snd_virmidi_input_ops);518 snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &snd_virmidi_output_ops);519 rmidi->info_flags = SNDRV_RAWMIDI_INFO_INPUT |520 SNDRV_RAWMIDI_INFO_OUTPUT |521 SNDRV_RAWMIDI_INFO_DUPLEX;522 *rrmidi = rmidi;523 return 0;524}525EXPORT_SYMBOL(snd_virmidi_new);526