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54235050 DK |
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_device.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 = of_match_ptr(snd_serial_generic_dt_ids), | |
370 | }, | |
371 | .probe = snd_serial_generic_probe, | |
372 | }; | |
373 | ||
374 | module_serdev_device_driver(snd_serial_generic_driver); |