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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Generic MIDI synth driver for ALSA sequencer4 * 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 subscription11 (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 struct snd_rawmidi *rmidi;42 int device;43 int subdevice;44 struct snd_rawmidi_file input_rfile;45 struct snd_rawmidi_file output_rfile;46 int seq_client;47 int seq_port;48 struct snd_midi_event *parser;49};50 51struct seq_midisynth_client {52 int seq_client;53 int num_ports;54 int ports_per_device[SNDRV_RAWMIDI_DEVICES];55 struct seq_midisynth *ports[SNDRV_RAWMIDI_DEVICES];56};57 58static struct seq_midisynth_client *synths[SNDRV_CARDS];59static DEFINE_MUTEX(register_mutex);60 61/* handle rawmidi input event (MIDI v1.0 stream) */62static void snd_midi_input_event(struct snd_rawmidi_substream *substream)63{64 struct snd_rawmidi_runtime *runtime;65 struct seq_midisynth *msynth;66 struct snd_seq_event ev;67 char buf[16], *pbuf;68 long res;69 70 if (substream == NULL)71 return;72 runtime = substream->runtime;73 msynth = runtime->private_data;74 if (msynth == NULL)75 return;76 memset(&ev, 0, sizeof(ev));77 while (runtime->avail > 0) {78 res = snd_rawmidi_kernel_read(substream, buf, sizeof(buf));79 if (res <= 0)80 continue;81 if (msynth->parser == NULL)82 continue;83 pbuf = buf;84 while (res-- > 0) {85 if (!snd_midi_event_encode_byte(msynth->parser,86 *pbuf++, &ev))87 continue;88 ev.source.port = msynth->seq_port;89 ev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;90 snd_seq_kernel_client_dispatch(msynth->seq_client, &ev, 1, 0);91 /* clear event and reset header */92 memset(&ev, 0, sizeof(ev));93 }94 }95}96 97static int dump_midi(struct snd_rawmidi_substream *substream, const char *buf, int count)98{99 struct snd_rawmidi_runtime *runtime;100 int tmp;101 102 if (snd_BUG_ON(!substream || !buf))103 return -EINVAL;104 runtime = substream->runtime;105 tmp = runtime->avail;106 if (tmp < count) {107 if (printk_ratelimit())108 pr_err("ALSA: seq_midi: MIDI output buffer overrun\n");109 return -ENOMEM;110 }111 if (snd_rawmidi_kernel_write(substream, buf, count) < count)112 return -EINVAL;113 return 0;114}115 116/* callback for snd_seq_dump_var_event(), bridging to dump_midi() */117static int __dump_midi(void *ptr, void *buf, int count)118{119 return dump_midi(ptr, buf, count);120}121 122static int event_process_midi(struct snd_seq_event *ev, int direct,123 void *private_data, int atomic, int hop)124{125 struct seq_midisynth *msynth = private_data;126 unsigned char msg[10]; /* buffer for constructing midi messages */127 struct snd_rawmidi_substream *substream;128 int len;129 130 if (snd_BUG_ON(!msynth))131 return -EINVAL;132 substream = msynth->output_rfile.output;133 if (substream == NULL)134 return -ENODEV;135 if (ev->type == SNDRV_SEQ_EVENT_SYSEX) { /* special case, to save space */136 if ((ev->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) != SNDRV_SEQ_EVENT_LENGTH_VARIABLE) {137 /* invalid event */138 pr_debug("ALSA: seq_midi: invalid sysex event flags = 0x%x\n", ev->flags);139 return 0;140 }141 snd_seq_dump_var_event(ev, __dump_midi, substream);142 snd_midi_event_reset_decode(msynth->parser);143 } else {144 if (msynth->parser == NULL)145 return -EIO;146 len = snd_midi_event_decode(msynth->parser, msg, sizeof(msg), ev);147 if (len < 0)148 return 0;149 if (dump_midi(substream, msg, len) < 0)150 snd_midi_event_reset_decode(msynth->parser);151 }152 return 0;153}154 155 156static int snd_seq_midisynth_new(struct seq_midisynth *msynth,157 struct snd_card *card,158 int device,159 int subdevice)160{161 if (snd_midi_event_new(MAX_MIDI_EVENT_BUF, &msynth->parser) < 0)162 return -ENOMEM;163 msynth->card = card;164 msynth->device = device;165 msynth->subdevice = subdevice;166 return 0;167}168 169/* open associated midi device for input */170static int midisynth_subscribe(void *private_data, struct snd_seq_port_subscribe *info)171{172 int err;173 struct seq_midisynth *msynth = private_data;174 struct snd_rawmidi_runtime *runtime;175 struct snd_rawmidi_params params;176 177 /* open midi port */178 err = snd_rawmidi_kernel_open(msynth->rmidi, msynth->subdevice,179 SNDRV_RAWMIDI_LFLG_INPUT,180 &msynth->input_rfile);181 if (err < 0) {182 pr_debug("ALSA: seq_midi: midi input open failed!!!\n");183 return err;184 }185 runtime = msynth->input_rfile.input->runtime;186 memset(¶ms, 0, sizeof(params));187 params.avail_min = 1;188 params.buffer_size = input_buffer_size;189 err = snd_rawmidi_input_params(msynth->input_rfile.input, ¶ms);190 if (err < 0) {191 snd_rawmidi_kernel_release(&msynth->input_rfile);192 return err;193 }194 snd_midi_event_reset_encode(msynth->parser);195 runtime->event = snd_midi_input_event;196 runtime->private_data = msynth;197 snd_rawmidi_kernel_read(msynth->input_rfile.input, NULL, 0);198 return 0;199}200 201/* close associated midi device for input */202static int midisynth_unsubscribe(void *private_data, struct snd_seq_port_subscribe *info)203{204 int err;205 struct seq_midisynth *msynth = private_data;206 207 if (snd_BUG_ON(!msynth->input_rfile.input))208 return -EINVAL;209 err = snd_rawmidi_kernel_release(&msynth->input_rfile);210 return err;211}212 213/* open associated midi device for output */214static int midisynth_use(void *private_data, struct snd_seq_port_subscribe *info)215{216 int err;217 struct seq_midisynth *msynth = private_data;218 struct snd_rawmidi_params params;219 220 /* open midi port */221 err = snd_rawmidi_kernel_open(msynth->rmidi, msynth->subdevice,222 SNDRV_RAWMIDI_LFLG_OUTPUT,223 &msynth->output_rfile);224 if (err < 0) {225 pr_debug("ALSA: seq_midi: midi output open failed!!!\n");226 return err;227 }228 memset(¶ms, 0, sizeof(params));229 params.avail_min = 1;230 params.buffer_size = output_buffer_size;231 params.no_active_sensing = 1;232 err = snd_rawmidi_output_params(msynth->output_rfile.output, ¶ms);233 if (err < 0) {234 snd_rawmidi_kernel_release(&msynth->output_rfile);235 return err;236 }237 snd_midi_event_reset_decode(msynth->parser);238 return 0;239}240 241/* close associated midi device for output */242static int midisynth_unuse(void *private_data, struct snd_seq_port_subscribe *info)243{244 struct seq_midisynth *msynth = private_data;245 246 if (snd_BUG_ON(!msynth->output_rfile.output))247 return -EINVAL;248 snd_rawmidi_drain_output(msynth->output_rfile.output);249 return snd_rawmidi_kernel_release(&msynth->output_rfile);250}251 252/* delete given midi synth port */253static void snd_seq_midisynth_delete(struct seq_midisynth *msynth)254{255 if (msynth == NULL)256 return;257 258 if (msynth->seq_client > 0) {259 /* delete port */260 snd_seq_event_port_detach(msynth->seq_client, msynth->seq_port);261 }262 263 snd_midi_event_free(msynth->parser);264}265 266/* register new midi synth port */267static int268snd_seq_midisynth_probe(struct device *_dev)269{270 struct snd_seq_device *dev = to_seq_dev(_dev);271 struct seq_midisynth_client *client;272 struct seq_midisynth *msynth, *ms;273 struct snd_seq_port_info *port __free(kfree) = NULL;274 struct snd_rawmidi_info *info __free(kfree) = NULL;275 struct snd_rawmidi *rmidi = dev->private_data;276 int newclient = 0;277 unsigned int p, ports;278 struct snd_seq_port_callback pcallbacks;279 struct snd_card *card = dev->card;280 int device = dev->device;281 unsigned int input_count = 0, output_count = 0;282 283 if (snd_BUG_ON(!card || device < 0 || device >= SNDRV_RAWMIDI_DEVICES))284 return -EINVAL;285 info = kmalloc(sizeof(*info), GFP_KERNEL);286 if (! info)287 return -ENOMEM;288 info->device = device;289 info->stream = SNDRV_RAWMIDI_STREAM_OUTPUT;290 info->subdevice = 0;291 if (snd_rawmidi_info_select(card, info) >= 0)292 output_count = info->subdevices_count;293 info->stream = SNDRV_RAWMIDI_STREAM_INPUT;294 if (snd_rawmidi_info_select(card, info) >= 0) {295 input_count = info->subdevices_count;296 }297 ports = output_count;298 if (ports < input_count)299 ports = input_count;300 if (ports == 0)301 return -ENODEV;302 if (ports > (256 / SNDRV_RAWMIDI_DEVICES))303 ports = 256 / SNDRV_RAWMIDI_DEVICES;304 305 guard(mutex)(®ister_mutex);306 client = synths[card->number];307 if (client == NULL) {308 newclient = 1;309 client = kzalloc(sizeof(*client), GFP_KERNEL);310 if (client == NULL)311 return -ENOMEM;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 return -ENOMEM;319 }320 }321 322 msynth = kcalloc(ports, sizeof(struct seq_midisynth), GFP_KERNEL);323 port = kmalloc(sizeof(*port), GFP_KERNEL);324 if (msynth == NULL || port == NULL)325 goto __nomem;326 327 for (p = 0; p < ports; p++) {328 ms = &msynth[p];329 ms->rmidi = rmidi;330 331 if (snd_seq_midisynth_new(ms, card, device, p) < 0)332 goto __nomem;333 334 /* declare port */335 memset(port, 0, sizeof(*port));336 port->addr.client = client->seq_client;337 port->addr.port = device * (256 / SNDRV_RAWMIDI_DEVICES) + p;338 port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT;339 memset(info, 0, sizeof(*info));340 info->device = device;341 if (p < output_count)342 info->stream = SNDRV_RAWMIDI_STREAM_OUTPUT;343 else344 info->stream = SNDRV_RAWMIDI_STREAM_INPUT;345 info->subdevice = p;346 if (snd_rawmidi_info_select(card, info) >= 0)347 strcpy(port->name, info->subname);348 if (! port->name[0]) {349 if (info->name[0]) {350 if (ports > 1)351 scnprintf(port->name, sizeof(port->name), "%s-%u", info->name, p);352 else353 scnprintf(port->name, sizeof(port->name), "%s", info->name);354 } else {355 /* last resort */356 if (ports > 1)357 sprintf(port->name, "MIDI %d-%d-%u", card->number, device, p);358 else359 sprintf(port->name, "MIDI %d-%d", card->number, device);360 }361 }362 if ((info->flags & SNDRV_RAWMIDI_INFO_OUTPUT) && p < output_count)363 port->capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SYNC_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE;364 if ((info->flags & SNDRV_RAWMIDI_INFO_INPUT) && p < input_count)365 port->capability |= SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SYNC_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ;366 if ((port->capability & (SNDRV_SEQ_PORT_CAP_WRITE|SNDRV_SEQ_PORT_CAP_READ)) == (SNDRV_SEQ_PORT_CAP_WRITE|SNDRV_SEQ_PORT_CAP_READ) &&367 info->flags & SNDRV_RAWMIDI_INFO_DUPLEX)368 port->capability |= SNDRV_SEQ_PORT_CAP_DUPLEX;369 if (port->capability & SNDRV_SEQ_PORT_CAP_READ)370 port->direction |= SNDRV_SEQ_PORT_DIR_INPUT;371 if (port->capability & SNDRV_SEQ_PORT_CAP_WRITE)372 port->direction |= SNDRV_SEQ_PORT_DIR_OUTPUT;373 port->type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC374 | SNDRV_SEQ_PORT_TYPE_HARDWARE375 | SNDRV_SEQ_PORT_TYPE_PORT;376 port->midi_channels = 16;377 memset(&pcallbacks, 0, sizeof(pcallbacks));378 pcallbacks.owner = THIS_MODULE;379 pcallbacks.private_data = ms;380 pcallbacks.subscribe = midisynth_subscribe;381 pcallbacks.unsubscribe = midisynth_unsubscribe;382 pcallbacks.use = midisynth_use;383 pcallbacks.unuse = midisynth_unuse;384 pcallbacks.event_input = event_process_midi;385 port->kernel = &pcallbacks;386 if (rmidi->ops && rmidi->ops->get_port_info)387 rmidi->ops->get_port_info(rmidi, p, port);388 if (snd_seq_kernel_client_ctl(client->seq_client, SNDRV_SEQ_IOCTL_CREATE_PORT, port)<0)389 goto __nomem;390 ms->seq_client = client->seq_client;391 ms->seq_port = port->addr.port;392 }393 client->ports_per_device[device] = ports;394 client->ports[device] = msynth;395 client->num_ports++;396 if (newclient)397 synths[card->number] = client;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 return -ENOMEM;411}412 413/* release midi synth port */414static int415snd_seq_midisynth_remove(struct device *_dev)416{417 struct snd_seq_device *dev = to_seq_dev(_dev);418 struct seq_midisynth_client *client;419 struct seq_midisynth *msynth;420 struct snd_card *card = dev->card;421 int device = dev->device, p, ports;422 423 guard(mutex)(®ister_mutex);424 client = synths[card->number];425 if (client == NULL || client->ports[device] == NULL)426 return -ENODEV;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 return 0;441}442 443static struct snd_seq_driver seq_midisynth_driver = {444 .driver = {445 .name = KBUILD_MODNAME,446 .probe = snd_seq_midisynth_probe,447 .remove = snd_seq_midisynth_remove,448 },449 .id = SNDRV_SEQ_DEV_ID_MIDISYNTH,450 .argsize = 0,451};452 453module_snd_seq_driver(seq_midisynth_driver);454