sh_dac_audio.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * sh_dac_audio.c - SuperH DAC audio driver for ALSA
  4 *
  5 * Copyright (c) 2009 by Rafael Ignacio Zurita <rizurita@yahoo.com>
  6 *
  7 * Based on sh_dac_audio.c (Copyright (C) 2004, 2005 by Andriy Skulysh)
  8 */
  9
 10#include <linux/hrtimer.h>
 11#include <linux/interrupt.h>
 12#include <linux/io.h>
 13#include <linux/platform_device.h>
 14#include <linux/slab.h>
 15#include <linux/module.h>
 16#include <sound/core.h>
 17#include <sound/initval.h>
 18#include <sound/pcm.h>
 19#include <sound/sh_dac_audio.h>
 20#include <asm/clock.h>
 21#include <asm/hd64461.h>
 22#include <mach/hp6xx.h>
 23#include <cpu/dac.h>
 24
 25MODULE_AUTHOR("Rafael Ignacio Zurita <rizurita@yahoo.com>");
 26MODULE_DESCRIPTION("SuperH DAC audio driver");
 27MODULE_LICENSE("GPL");
 28
 29/* Module Parameters */
 30static int index = SNDRV_DEFAULT_IDX1;
 31static char *id = SNDRV_DEFAULT_STR1;
 32module_param(index, int, 0444);
 33MODULE_PARM_DESC(index, "Index value for SuperH DAC audio.");
 34module_param(id, charp, 0444);
 35MODULE_PARM_DESC(id, "ID string for SuperH DAC audio.");
 36
 37/* main struct */
 38struct snd_sh_dac {
 39	struct snd_card *card;
 40	struct snd_pcm_substream *substream;
 41	struct hrtimer hrtimer;
 42	ktime_t wakeups_per_second;
 43
 44	int rate;
 45	int empty;
 46	char *data_buffer, *buffer_begin, *buffer_end;
 47	int processed; /* bytes proccesed, to compare with period_size */
 48	int buffer_size;
 49	struct dac_audio_pdata *pdata;
 50};
 51
 52
 53static void dac_audio_start_timer(struct snd_sh_dac *chip)
 54{
 55	hrtimer_start(&chip->hrtimer, chip->wakeups_per_second,
 56		      HRTIMER_MODE_REL);
 57}
 58
 59static void dac_audio_stop_timer(struct snd_sh_dac *chip)
 60{
 61	hrtimer_cancel(&chip->hrtimer);
 62}
 63
 64static void dac_audio_reset(struct snd_sh_dac *chip)
 65{
 66	dac_audio_stop_timer(chip);
 67	chip->buffer_begin = chip->buffer_end = chip->data_buffer;
 68	chip->processed = 0;
 69	chip->empty = 1;
 70}
 71
 72static void dac_audio_set_rate(struct snd_sh_dac *chip)
 73{
 74	chip->wakeups_per_second = 1000000000 / chip->rate;
 75}
 76
 77
 78/* PCM INTERFACE */
 79
 80static const struct snd_pcm_hardware snd_sh_dac_pcm_hw = {
 81	.info			= (SNDRV_PCM_INFO_MMAP |
 82					SNDRV_PCM_INFO_MMAP_VALID |
 83					SNDRV_PCM_INFO_INTERLEAVED |
 84					SNDRV_PCM_INFO_HALF_DUPLEX),
 85	.formats		= SNDRV_PCM_FMTBIT_U8,
 86	.rates			= SNDRV_PCM_RATE_8000,
 87	.rate_min		= 8000,
 88	.rate_max		= 8000,
 89	.channels_min		= 1,
 90	.channels_max		= 1,
 91	.buffer_bytes_max	= (48*1024),
 92	.period_bytes_min	= 1,
 93	.period_bytes_max	= (48*1024),
 94	.periods_min		= 1,
 95	.periods_max		= 1024,
 96};
 97
 98static int snd_sh_dac_pcm_open(struct snd_pcm_substream *substream)
 99{
100	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
101	struct snd_pcm_runtime *runtime = substream->runtime;
102
103	runtime->hw = snd_sh_dac_pcm_hw;
104
105	chip->substream = substream;
106	chip->buffer_begin = chip->buffer_end = chip->data_buffer;
107	chip->processed = 0;
108	chip->empty = 1;
109
110	chip->pdata->start(chip->pdata);
111
112	return 0;
113}
114
115static int snd_sh_dac_pcm_close(struct snd_pcm_substream *substream)
116{
117	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
118
119	chip->substream = NULL;
120
121	dac_audio_stop_timer(chip);
122	chip->pdata->stop(chip->pdata);
123
124	return 0;
125}
126
127static int snd_sh_dac_pcm_prepare(struct snd_pcm_substream *substream)
128{
129	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
130	struct snd_pcm_runtime *runtime = chip->substream->runtime;
131
132	chip->buffer_size = runtime->buffer_size;
133	memset(chip->data_buffer, 0, chip->pdata->buffer_size);
134
135	return 0;
136}
137
138static int snd_sh_dac_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
139{
140	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
141
142	switch (cmd) {
143	case SNDRV_PCM_TRIGGER_START:
144		dac_audio_start_timer(chip);
145		break;
146	case SNDRV_PCM_TRIGGER_STOP:
147		chip->buffer_begin = chip->buffer_end = chip->data_buffer;
148		chip->processed = 0;
149		chip->empty = 1;
150		dac_audio_stop_timer(chip);
151		break;
152	default:
153		 return -EINVAL;
154	}
155
156	return 0;
157}
158
159static int snd_sh_dac_pcm_copy(struct snd_pcm_substream *substream,
160			       int channel, unsigned long pos,
161			       struct iov_iter *src, unsigned long count)
162{
163	/* channel is not used (interleaved data) */
164	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
165
166	if (copy_from_iter(chip->data_buffer + pos, count, src) != count)
167		return -EFAULT;
168	chip->buffer_end = chip->data_buffer + pos + count;
169
170	if (chip->empty) {
171		chip->empty = 0;
172		dac_audio_start_timer(chip);
173	}
174
175	return 0;
176}
177
178static int snd_sh_dac_pcm_silence(struct snd_pcm_substream *substream,
179				  int channel, unsigned long pos,
180				  unsigned long count)
181{
182	/* channel is not used (interleaved data) */
183	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
184
185	memset(chip->data_buffer + pos, 0, count);
186	chip->buffer_end = chip->data_buffer + pos + count;
187
188	if (chip->empty) {
189		chip->empty = 0;
190		dac_audio_start_timer(chip);
191	}
192
193	return 0;
194}
195
196static
197snd_pcm_uframes_t snd_sh_dac_pcm_pointer(struct snd_pcm_substream *substream)
198{
199	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
200	int pointer = chip->buffer_begin - chip->data_buffer;
201
202	return pointer;
203}
204
205/* pcm ops */
206static const struct snd_pcm_ops snd_sh_dac_pcm_ops = {
207	.open		= snd_sh_dac_pcm_open,
208	.close		= snd_sh_dac_pcm_close,
209	.prepare	= snd_sh_dac_pcm_prepare,
210	.trigger	= snd_sh_dac_pcm_trigger,
211	.pointer	= snd_sh_dac_pcm_pointer,
212	.copy		= snd_sh_dac_pcm_copy,
213	.fill_silence	= snd_sh_dac_pcm_silence,
214};
215
216static int snd_sh_dac_pcm(struct snd_sh_dac *chip, int device)
217{
218	int err;
219	struct snd_pcm *pcm;
220
221	/* device should be always 0 for us */
222	err = snd_pcm_new(chip->card, "SH_DAC PCM", device, 1, 0, &pcm);
223	if (err < 0)
224		return err;
225
226	pcm->private_data = chip;
227	strscpy(pcm->name, "SH_DAC PCM");
228	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &snd_sh_dac_pcm_ops);
229
230	/* buffer size=48K */
231	snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
232				       NULL, 48 * 1024, 48 * 1024);
233
234	return 0;
235}
236/* END OF PCM INTERFACE */
237
238
239/* driver .remove  --  destructor */
240static void snd_sh_dac_remove(struct platform_device *devptr)
241{
242	snd_card_free(platform_get_drvdata(devptr));
243}
244
245/* free -- it has been defined by create */
246static int snd_sh_dac_free(struct snd_sh_dac *chip)
247{
248	/* release the data */
249	kfree(chip->data_buffer);
250	kfree(chip);
251
252	return 0;
253}
254
255static int snd_sh_dac_dev_free(struct snd_device *device)
256{
257	struct snd_sh_dac *chip = device->device_data;
258
259	return snd_sh_dac_free(chip);
260}
261
262static enum hrtimer_restart sh_dac_audio_timer(struct hrtimer *handle)
263{
264	struct snd_sh_dac *chip = container_of(handle, struct snd_sh_dac,
265					       hrtimer);
266	struct snd_pcm_runtime *runtime = chip->substream->runtime;
267	ssize_t b_ps = frames_to_bytes(runtime, runtime->period_size);
268
269	if (!chip->empty) {
270		sh_dac_output(*chip->buffer_begin, chip->pdata->channel);
271		chip->buffer_begin++;
272
273		chip->processed++;
274		if (chip->processed >= b_ps) {
275			chip->processed -= b_ps;
276			snd_pcm_period_elapsed(chip->substream);
277		}
278
279		if (chip->buffer_begin == (chip->data_buffer +
280					   chip->buffer_size - 1))
281			chip->buffer_begin = chip->data_buffer;
282
283		if (chip->buffer_begin == chip->buffer_end)
284			chip->empty = 1;
285
286	}
287
288	if (!chip->empty)
289		hrtimer_start(&chip->hrtimer, chip->wakeups_per_second,
290			      HRTIMER_MODE_REL);
291
292	return HRTIMER_NORESTART;
293}
294
295/* create  --  chip-specific constructor for the cards components */
296static int snd_sh_dac_create(struct snd_card *card,
297			     struct platform_device *devptr,
298			     struct snd_sh_dac **rchip)
299{
300	struct snd_sh_dac *chip;
301	int err;
302
303	static const struct snd_device_ops ops = {
304		   .dev_free = snd_sh_dac_dev_free,
305	};
306
307	*rchip = NULL;
308
309	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
310	if (chip == NULL)
311		return -ENOMEM;
312
313	chip->card = card;
314
315	hrtimer_setup(&chip->hrtimer, sh_dac_audio_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
316
317	dac_audio_reset(chip);
318	chip->rate = 8000;
319	dac_audio_set_rate(chip);
320
321	chip->pdata = devptr->dev.platform_data;
322
323	chip->data_buffer = kmalloc(chip->pdata->buffer_size, GFP_KERNEL);
324	if (chip->data_buffer == NULL) {
325		kfree(chip);
326		return -ENOMEM;
327	}
328
329	err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops);
330	if (err < 0) {
331		snd_sh_dac_free(chip);
332		return err;
333	}
334
335	*rchip = chip;
336
337	return 0;
338}
339
340/* driver .probe  --  constructor */
341static int snd_sh_dac_probe(struct platform_device *devptr)
342{
343	struct snd_sh_dac *chip;
344	struct snd_card *card;
345	int err;
346
347	err = snd_card_new(&devptr->dev, index, id, THIS_MODULE, 0, &card);
348	if (err < 0) {
349		dev_err(&devptr->dev, "cannot allocate the card\n");
350		return err;
351	}
352
353	err = snd_sh_dac_create(card, devptr, &chip);
354	if (err < 0)
355		goto probe_error;
356
357	err = snd_sh_dac_pcm(chip, 0);
358	if (err < 0)
359		goto probe_error;
360
361	strscpy(card->driver, "snd_sh_dac");
362	strscpy(card->shortname, "SuperH DAC audio driver");
363	dev_info(&devptr->dev, "%s %s\n", card->longname, card->shortname);
364
365	err = snd_card_register(card);
366	if (err < 0)
367		goto probe_error;
368
369	dev_info(&devptr->dev, "ALSA driver for SuperH DAC audio\n");
370
371	platform_set_drvdata(devptr, card);
372	return 0;
373
374probe_error:
375	snd_card_free(card);
376	return err;
377}
378
379/*
380 * "driver" definition
381 */
382static struct platform_driver sh_dac_driver = {
383	.probe	= snd_sh_dac_probe,
384	.remove = snd_sh_dac_remove,
385	.driver = {
386		.name = "dac_audio",
387	},
388};
389
390module_platform_driver(sh_dac_driver);