1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * serial-generic.c 4 * Copyright (c) by Daniel Kaehn <kaehndan@gmail.com 5 * Based on serial-u16550.c by Jaroslav Kysela <perex@perex.cz>, 6 * Isaku Yamahata <yamahata@private.email.ne.jp>, 7 * George Hansper <ghansper@apana.org.au>, 8 * Hannu Savolainen 9 * 10 * Generic serial MIDI driver using the serdev serial bus API for hardware interaction 11 */ 12 13 #include <linux/err.h> 14 #include <linux/init.h> 15 #include <linux/interrupt.h> 16 #include <linux/io.h> 17 #include <linux/ioport.h> 18 #include <linux/module.h> 19 #include <linux/of.h> 20 #include <linux/serdev.h> 21 #include <linux/serial_reg.h> 22 #include <linux/slab.h> 23 #include <linux/dev_printk.h> 24 25 #include <sound/core.h> 26 #include <sound/rawmidi.h> 27 #include <sound/initval.h> 28 29 MODULE_DESCRIPTION("Generic serial MIDI driver"); 30 MODULE_LICENSE("GPL"); 31 32 #define SERIAL_MODE_INPUT_OPEN 1 33 #define SERIAL_MODE_OUTPUT_OPEN 2 34 #define SERIAL_MODE_INPUT_TRIGGERED 3 35 #define SERIAL_MODE_OUTPUT_TRIGGERED 4 36 37 #define SERIAL_TX_STATE_ACTIVE 1 38 #define SERIAL_TX_STATE_WAKEUP 2 39 40 struct snd_serial_generic { 41 struct serdev_device *serdev; 42 43 struct snd_card *card; 44 struct snd_rawmidi *rmidi; 45 struct snd_rawmidi_substream *midi_output; 46 struct snd_rawmidi_substream *midi_input; 47 48 unsigned int baudrate; 49 50 unsigned long filemode; /* open status of file */ 51 struct work_struct tx_work; 52 unsigned long tx_state; 53 54 }; 55 56 static void snd_serial_generic_tx_wakeup(struct snd_serial_generic *drvdata) 57 { 58 if (test_and_set_bit(SERIAL_TX_STATE_ACTIVE, &drvdata->tx_state)) 59 set_bit(SERIAL_TX_STATE_WAKEUP, &drvdata->tx_state); 60 61 schedule_work(&drvdata->tx_work); 62 } 63 64 #define INTERNAL_BUF_SIZE 256 65 66 static void snd_serial_generic_tx_work(struct work_struct *work) 67 { 68 static char buf[INTERNAL_BUF_SIZE]; 69 int num_bytes; 70 struct snd_serial_generic *drvdata = container_of(work, struct snd_serial_generic, 71 tx_work); 72 struct snd_rawmidi_substream *substream = drvdata->midi_output; 73 74 clear_bit(SERIAL_TX_STATE_WAKEUP, &drvdata->tx_state); 75 76 while (!snd_rawmidi_transmit_empty(substream)) { 77 78 if (!test_bit(SERIAL_MODE_OUTPUT_OPEN, &drvdata->filemode)) 79 break; 80 81 num_bytes = snd_rawmidi_transmit_peek(substream, buf, INTERNAL_BUF_SIZE); 82 num_bytes = serdev_device_write_buf(drvdata->serdev, buf, num_bytes); 83 84 if (!num_bytes) 85 break; 86 87 snd_rawmidi_transmit_ack(substream, num_bytes); 88 89 if (!test_bit(SERIAL_TX_STATE_WAKEUP, &drvdata->tx_state)) 90 break; 91 } 92 93 clear_bit(SERIAL_TX_STATE_ACTIVE, &drvdata->tx_state); 94 } 95 96 static void snd_serial_generic_write_wakeup(struct serdev_device *serdev) 97 { 98 struct snd_serial_generic *drvdata = serdev_device_get_drvdata(serdev); 99 100 snd_serial_generic_tx_wakeup(drvdata); 101 } 102 103 static ssize_t snd_serial_generic_receive_buf(struct serdev_device *serdev, 104 const u8 *buf, size_t count) 105 { 106 int ret; 107 struct snd_serial_generic *drvdata = serdev_device_get_drvdata(serdev); 108 109 if (!test_bit(SERIAL_MODE_INPUT_OPEN, &drvdata->filemode)) 110 return 0; 111 112 ret = snd_rawmidi_receive(drvdata->midi_input, buf, count); 113 return ret < 0 ? 0 : ret; 114 } 115 116 static const struct serdev_device_ops snd_serial_generic_serdev_device_ops = { 117 .receive_buf = snd_serial_generic_receive_buf, 118 .write_wakeup = snd_serial_generic_write_wakeup 119 }; 120 121 static int snd_serial_generic_ensure_serdev_open(struct snd_serial_generic *drvdata) 122 { 123 int err; 124 unsigned int actual_baud; 125 126 if (drvdata->filemode) 127 return 0; 128 129 dev_dbg(drvdata->card->dev, "Opening serial port for card %s\n", 130 drvdata->card->shortname); 131 err = serdev_device_open(drvdata->serdev); 132 if (err < 0) 133 return err; 134 135 actual_baud = serdev_device_set_baudrate(drvdata->serdev, 136 drvdata->baudrate); 137 if (actual_baud != drvdata->baudrate) { 138 dev_warn(drvdata->card->dev, "requested %d baud for card %s but it was actually set to %d\n", 139 drvdata->baudrate, drvdata->card->shortname, actual_baud); 140 } 141 142 return 0; 143 } 144 145 static int snd_serial_generic_input_open(struct snd_rawmidi_substream *substream) 146 { 147 int err; 148 struct snd_serial_generic *drvdata = substream->rmidi->card->private_data; 149 150 dev_dbg(drvdata->card->dev, "Opening input for card %s\n", 151 drvdata->card->shortname); 152 153 err = snd_serial_generic_ensure_serdev_open(drvdata); 154 if (err < 0) 155 return err; 156 157 set_bit(SERIAL_MODE_INPUT_OPEN, &drvdata->filemode); 158 drvdata->midi_input = substream; 159 return 0; 160 } 161 162 static int snd_serial_generic_input_close(struct snd_rawmidi_substream *substream) 163 { 164 struct snd_serial_generic *drvdata = substream->rmidi->card->private_data; 165 166 dev_dbg(drvdata->card->dev, "Closing input for card %s\n", 167 drvdata->card->shortname); 168 169 clear_bit(SERIAL_MODE_INPUT_OPEN, &drvdata->filemode); 170 clear_bit(SERIAL_MODE_INPUT_TRIGGERED, &drvdata->filemode); 171 172 drvdata->midi_input = NULL; 173 174 if (!drvdata->filemode) 175 serdev_device_close(drvdata->serdev); 176 return 0; 177 } 178 179 static void snd_serial_generic_input_trigger(struct snd_rawmidi_substream *substream, 180 int up) 181 { 182 struct snd_serial_generic *drvdata = substream->rmidi->card->private_data; 183 184 if (up) 185 set_bit(SERIAL_MODE_INPUT_TRIGGERED, &drvdata->filemode); 186 else 187 clear_bit(SERIAL_MODE_INPUT_TRIGGERED, &drvdata->filemode); 188 } 189 190 static int snd_serial_generic_output_open(struct snd_rawmidi_substream *substream) 191 { 192 struct snd_serial_generic *drvdata = substream->rmidi->card->private_data; 193 int err; 194 195 dev_dbg(drvdata->card->dev, "Opening output for card %s\n", 196 drvdata->card->shortname); 197 198 err = snd_serial_generic_ensure_serdev_open(drvdata); 199 if (err < 0) 200 return err; 201 202 set_bit(SERIAL_MODE_OUTPUT_OPEN, &drvdata->filemode); 203 204 drvdata->midi_output = substream; 205 return 0; 206 }; 207 208 static int snd_serial_generic_output_close(struct snd_rawmidi_substream *substream) 209 { 210 struct snd_serial_generic *drvdata = substream->rmidi->card->private_data; 211 212 dev_dbg(drvdata->card->dev, "Closing output for card %s\n", 213 drvdata->card->shortname); 214 215 clear_bit(SERIAL_MODE_OUTPUT_OPEN, &drvdata->filemode); 216 clear_bit(SERIAL_MODE_OUTPUT_TRIGGERED, &drvdata->filemode); 217 218 if (!drvdata->filemode) 219 serdev_device_close(drvdata->serdev); 220 221 drvdata->midi_output = NULL; 222 223 return 0; 224 }; 225 226 static void snd_serial_generic_output_trigger(struct snd_rawmidi_substream *substream, 227 int up) 228 { 229 struct snd_serial_generic *drvdata = substream->rmidi->card->private_data; 230 231 if (up) 232 set_bit(SERIAL_MODE_OUTPUT_TRIGGERED, &drvdata->filemode); 233 else 234 clear_bit(SERIAL_MODE_OUTPUT_TRIGGERED, &drvdata->filemode); 235 236 if (up) 237 snd_serial_generic_tx_wakeup(drvdata); 238 } 239 240 static void snd_serial_generic_output_drain(struct snd_rawmidi_substream *substream) 241 { 242 struct snd_serial_generic *drvdata = substream->rmidi->card->private_data; 243 244 /* Flush any pending characters */ 245 serdev_device_write_flush(drvdata->serdev); 246 cancel_work_sync(&drvdata->tx_work); 247 } 248 249 static const struct snd_rawmidi_ops snd_serial_generic_output = { 250 .open = snd_serial_generic_output_open, 251 .close = snd_serial_generic_output_close, 252 .trigger = snd_serial_generic_output_trigger, 253 .drain = snd_serial_generic_output_drain, 254 }; 255 256 static const struct snd_rawmidi_ops snd_serial_generic_input = { 257 .open = snd_serial_generic_input_open, 258 .close = snd_serial_generic_input_close, 259 .trigger = snd_serial_generic_input_trigger, 260 }; 261 262 static void snd_serial_generic_parse_dt(struct serdev_device *serdev, 263 struct snd_serial_generic *drvdata) 264 { 265 int err; 266 267 err = of_property_read_u32(serdev->dev.of_node, "current-speed", 268 &drvdata->baudrate); 269 if (err < 0) { 270 dev_dbg(drvdata->card->dev, 271 "MIDI device reading of current-speed DT param failed with error %d, using default of 38400\n", 272 err); 273 drvdata->baudrate = 38400; 274 } 275 276 } 277 278 static void snd_serial_generic_substreams(struct snd_rawmidi_str *stream, int dev_num) 279 { 280 struct snd_rawmidi_substream *substream; 281 282 list_for_each_entry(substream, &stream->substreams, list) { 283 sprintf(substream->name, "Serial MIDI %d-%d", dev_num, substream->number); 284 } 285 } 286 287 static int snd_serial_generic_rmidi(struct snd_serial_generic *drvdata, 288 int outs, int ins, struct snd_rawmidi **rmidi) 289 { 290 struct snd_rawmidi *rrawmidi; 291 int err; 292 293 err = snd_rawmidi_new(drvdata->card, drvdata->card->driver, 0, 294 outs, ins, &rrawmidi); 295 296 if (err < 0) 297 return err; 298 299 snd_rawmidi_set_ops(rrawmidi, SNDRV_RAWMIDI_STREAM_INPUT, 300 &snd_serial_generic_input); 301 snd_rawmidi_set_ops(rrawmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, 302 &snd_serial_generic_output); 303 strcpy(rrawmidi->name, drvdata->card->shortname); 304 305 snd_serial_generic_substreams(&rrawmidi->streams[SNDRV_RAWMIDI_STREAM_OUTPUT], 306 drvdata->serdev->ctrl->nr); 307 snd_serial_generic_substreams(&rrawmidi->streams[SNDRV_RAWMIDI_STREAM_INPUT], 308 drvdata->serdev->ctrl->nr); 309 310 rrawmidi->info_flags = SNDRV_RAWMIDI_INFO_OUTPUT | 311 SNDRV_RAWMIDI_INFO_INPUT | 312 SNDRV_RAWMIDI_INFO_DUPLEX; 313 314 if (rmidi) 315 *rmidi = rrawmidi; 316 return 0; 317 } 318 319 static int snd_serial_generic_probe(struct serdev_device *serdev) 320 { 321 struct snd_card *card; 322 struct snd_serial_generic *drvdata; 323 int err; 324 325 err = snd_devm_card_new(&serdev->dev, SNDRV_DEFAULT_IDX1, 326 SNDRV_DEFAULT_STR1, THIS_MODULE, 327 sizeof(struct snd_serial_generic), &card); 328 329 if (err < 0) 330 return err; 331 332 strcpy(card->driver, "SerialMIDI"); 333 sprintf(card->shortname, "SerialMIDI-%d", serdev->ctrl->nr); 334 sprintf(card->longname, "Serial MIDI device at serial%d", serdev->ctrl->nr); 335 336 drvdata = card->private_data; 337 338 drvdata->serdev = serdev; 339 drvdata->card = card; 340 341 snd_serial_generic_parse_dt(serdev, drvdata); 342 343 INIT_WORK(&drvdata->tx_work, snd_serial_generic_tx_work); 344 345 err = snd_serial_generic_rmidi(drvdata, 1, 1, &drvdata->rmidi); 346 if (err < 0) 347 return err; 348 349 serdev_device_set_client_ops(serdev, &snd_serial_generic_serdev_device_ops); 350 serdev_device_set_drvdata(drvdata->serdev, drvdata); 351 352 err = snd_card_register(card); 353 if (err < 0) 354 return err; 355 356 return 0; 357 } 358 359 static const struct of_device_id snd_serial_generic_dt_ids[] = { 360 { .compatible = "serial-midi" }, 361 {}, 362 }; 363 364 MODULE_DEVICE_TABLE(of, snd_serial_generic_dt_ids); 365 366 static struct serdev_device_driver snd_serial_generic_driver = { 367 .driver = { 368 .name = "snd-serial-generic", 369 .of_match_table = snd_serial_generic_dt_ids, 370 }, 371 .probe = snd_serial_generic_probe, 372 }; 373 374 module_serdev_device_driver(snd_serial_generic_driver); 375