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, addr: &drvdata->tx_state)) |
59 | set_bit(SERIAL_TX_STATE_WAKEUP, addr: &drvdata->tx_state); |
60 | |
61 | schedule_work(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, addr: &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, buffer: 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, count: 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, addr: &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 size_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(substream: drvdata->midi_input, buffer: 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, addr: &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, addr: &drvdata->filemode); |
170 | clear_bit(SERIAL_MODE_INPUT_TRIGGERED, addr: &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, addr: &drvdata->filemode); |
186 | else |
187 | clear_bit(SERIAL_MODE_INPUT_TRIGGERED, addr: &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, addr: &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, addr: &drvdata->filemode); |
216 | clear_bit(SERIAL_MODE_OUTPUT_TRIGGERED, addr: &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, addr: &drvdata->filemode); |
233 | else |
234 | clear_bit(SERIAL_MODE_OUTPUT_TRIGGERED, addr: &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(work: &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(np: serdev->dev.of_node, propname: "current-speed" , |
268 | out_value: &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(buf: substream->name, fmt: "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(card: drvdata->card, id: drvdata->card->driver, device: 0, |
294 | output_count: outs, input_count: ins, rmidi: &rrawmidi); |
295 | |
296 | if (err < 0) |
297 | return err; |
298 | |
299 | snd_rawmidi_set_ops(rmidi: rrawmidi, stream: SNDRV_RAWMIDI_STREAM_INPUT, |
300 | ops: &snd_serial_generic_input); |
301 | snd_rawmidi_set_ops(rmidi: rrawmidi, stream: SNDRV_RAWMIDI_STREAM_OUTPUT, |
302 | ops: &snd_serial_generic_output); |
303 | strcpy(p: rrawmidi->name, q: drvdata->card->shortname); |
304 | |
305 | snd_serial_generic_substreams(stream: &rrawmidi->streams[SNDRV_RAWMIDI_STREAM_OUTPUT], |
306 | dev_num: drvdata->serdev->ctrl->nr); |
307 | snd_serial_generic_substreams(stream: &rrawmidi->streams[SNDRV_RAWMIDI_STREAM_INPUT], |
308 | dev_num: 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(parent: &serdev->dev, SNDRV_DEFAULT_IDX1, |
326 | SNDRV_DEFAULT_STR1, THIS_MODULE, |
327 | extra_size: sizeof(struct snd_serial_generic), card_ret: &card); |
328 | |
329 | if (err < 0) |
330 | return err; |
331 | |
332 | strcpy(p: card->driver, q: "SerialMIDI" ); |
333 | sprintf(buf: card->shortname, fmt: "SerialMIDI-%d" , serdev->ctrl->nr); |
334 | sprintf(buf: card->longname, fmt: "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, outs: 1, ins: 1, rmidi: &drvdata->rmidi); |
346 | if (err < 0) |
347 | return err; |
348 | |
349 | serdev_device_set_client_ops(serdev, ops: &snd_serial_generic_serdev_device_ops); |
350 | serdev_device_set_drvdata(serdev: drvdata->serdev, data: 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 | |