sound/drivers/serial-generic.c

   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 int snd_serial_generic_receive_buf(struct serdev_device *serdev,
 104                                 const unsigned char *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);