1 /*
2 * Driver for the Atmel on-chip Audio Bitstream DAC (ABDAC)
3 *
4 * Copyright (C) 2006-2009 Atmel Corporation
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published by
8 * the Free Software Foundation.
9 */
10 #include <linux/clk.h>
11 #include <linux/bitmap.h>
12 #include <linux/dw_dmac.h>
13 #include <linux/dmaengine.h>
14 #include <linux/dma-mapping.h>
15 #include <linux/init.h>
16 #include <linux/interrupt.h>
17 #include <linux/module.h>
18 #include <linux/platform_device.h>
19 #include <linux/io.h>
20
21 #include <sound/core.h>
22 #include <sound/initval.h>
23 #include <sound/pcm.h>
24 #include <sound/pcm_params.h>
25 #include <sound/atmel-abdac.h>
26
27 /* DAC register offsets */
28 #define DAC_DATA 0x0000
29 #define DAC_CTRL 0x0008
30 #define DAC_INT_MASK 0x000c
31 #define DAC_INT_EN 0x0010
32 #define DAC_INT_DIS 0x0014
33 #define DAC_INT_CLR 0x0018
34 #define DAC_INT_STATUS 0x001c
35
36 /* Bitfields in CTRL */
37 #define DAC_SWAP_OFFSET 30
38 #define DAC_SWAP_SIZE 1
39 #define DAC_EN_OFFSET 31
40 #define DAC_EN_SIZE 1
41
42 /* Bitfields in INT_MASK/INT_EN/INT_DIS/INT_STATUS/INT_CLR */
43 #define DAC_UNDERRUN_OFFSET 28
44 #define DAC_UNDERRUN_SIZE 1
45 #define DAC_TX_READY_OFFSET 29
46 #define DAC_TX_READY_SIZE 1
47
48 /* Bit manipulation macros */
49 #define DAC_BIT(name) \
50 (1 << DAC_##name##_OFFSET)
51 #define DAC_BF(name, value) \
52 (((value) & ((1 << DAC_##name##_SIZE) - 1)) \
53 << DAC_##name##_OFFSET)
54 #define DAC_BFEXT(name, value) \
55 (((value) >> DAC_##name##_OFFSET) \
56 & ((1 << DAC_##name##_SIZE) - 1))
57 #define DAC_BFINS(name, value, old) \
58 (((old) & ~(((1 << DAC_##name##_SIZE) - 1) \
59 << DAC_##name##_OFFSET)) \
60 | DAC_BF(name, value))
61
62 /* Register access macros */
63 #define dac_readl(port, reg) \
64 __raw_readl((port)->regs + DAC_##reg)
65 #define dac_writel(port, reg, value) \
66 __raw_writel((value), (port)->regs + DAC_##reg)
67
68 /*
69 * ABDAC supports a maximum of 6 different rates from a generic clock. The
70 * generic clock has a power of two divider, which gives 6 steps from 192 kHz
71 * to 5112 Hz.
72 */
73 #define MAX_NUM_RATES 6
74 /* ALSA seems to use rates between 192000 Hz and 5112 Hz. */
75 #define RATE_MAX 192000
76 #define RATE_MIN 5112
77
78 enum {
79 DMA_READY = 0,
80 };
81
82 struct atmel_abdac_dma {
83 struct dma_chan *chan;
84 struct dw_cyclic_desc *cdesc;
85 };
86
87 struct atmel_abdac {
88 struct clk *pclk;
89 struct clk *sample_clk;
90 struct platform_device *pdev;
91 struct atmel_abdac_dma dma;
92
93 struct snd_pcm_hw_constraint_list constraints_rates;
94 struct snd_pcm_substream *substream;
95 struct snd_card *card;
96 struct snd_pcm *pcm;
97
98 void __iomem *regs;
99 unsigned long flags;
100 unsigned int rates[MAX_NUM_RATES];
101 unsigned int rates_num;
102 int irq;
103 };
104
105 #define get_dac(card) ((struct atmel_abdac *)(card)->private_data)
106
107 /* This function is called by the DMA driver. */
atmel_abdac_dma_period_done(void * arg)108 static void atmel_abdac_dma_period_done(void *arg)
109 {
110 struct atmel_abdac *dac = arg;
111 snd_pcm_period_elapsed(dac->substream);
112 }
113
atmel_abdac_prepare_dma(struct atmel_abdac * dac,struct snd_pcm_substream * substream,enum dma_data_direction direction)114 static int atmel_abdac_prepare_dma(struct atmel_abdac *dac,
115 struct snd_pcm_substream *substream,
116 enum dma_data_direction direction)
117 {
118 struct dma_chan *chan = dac->dma.chan;
119 struct dw_cyclic_desc *cdesc;
120 struct snd_pcm_runtime *runtime = substream->runtime;
121 unsigned long buffer_len, period_len;
122
123 /*
124 * We don't do DMA on "complex" transfers, i.e. with
125 * non-halfword-aligned buffers or lengths.
126 */
127 if (runtime->dma_addr & 1 || runtime->buffer_size & 1) {
128 dev_dbg(&dac->pdev->dev, "too complex transfer\n");
129 return -EINVAL;
130 }
131
132 buffer_len = frames_to_bytes(runtime, runtime->buffer_size);
133 period_len = frames_to_bytes(runtime, runtime->period_size);
134
135 cdesc = dw_dma_cyclic_prep(chan, runtime->dma_addr, buffer_len,
136 period_len, DMA_MEM_TO_DEV);
137 if (IS_ERR(cdesc)) {
138 dev_dbg(&dac->pdev->dev, "could not prepare cyclic DMA\n");
139 return PTR_ERR(cdesc);
140 }
141
142 cdesc->period_callback = atmel_abdac_dma_period_done;
143 cdesc->period_callback_param = dac;
144
145 dac->dma.cdesc = cdesc;
146
147 set_bit(DMA_READY, &dac->flags);
148
149 return 0;
150 }
151
152 static struct snd_pcm_hardware atmel_abdac_hw = {
153 .info = (SNDRV_PCM_INFO_MMAP
154 | SNDRV_PCM_INFO_MMAP_VALID
155 | SNDRV_PCM_INFO_INTERLEAVED
156 | SNDRV_PCM_INFO_BLOCK_TRANSFER
157 | SNDRV_PCM_INFO_RESUME
158 | SNDRV_PCM_INFO_PAUSE),
159 .formats = (SNDRV_PCM_FMTBIT_S16_BE),
160 .rates = (SNDRV_PCM_RATE_KNOT),
161 .rate_min = RATE_MIN,
162 .rate_max = RATE_MAX,
163 .channels_min = 2,
164 .channels_max = 2,
165 .buffer_bytes_max = 64 * 4096,
166 .period_bytes_min = 4096,
167 .period_bytes_max = 4096,
168 .periods_min = 6,
169 .periods_max = 64,
170 };
171
atmel_abdac_open(struct snd_pcm_substream * substream)172 static int atmel_abdac_open(struct snd_pcm_substream *substream)
173 {
174 struct atmel_abdac *dac = snd_pcm_substream_chip(substream);
175
176 dac->substream = substream;
177 atmel_abdac_hw.rate_max = dac->rates[dac->rates_num - 1];
178 atmel_abdac_hw.rate_min = dac->rates[0];
179 substream->runtime->hw = atmel_abdac_hw;
180
181 return snd_pcm_hw_constraint_list(substream->runtime, 0,
182 SNDRV_PCM_HW_PARAM_RATE, &dac->constraints_rates);
183 }
184
atmel_abdac_close(struct snd_pcm_substream * substream)185 static int atmel_abdac_close(struct snd_pcm_substream *substream)
186 {
187 struct atmel_abdac *dac = snd_pcm_substream_chip(substream);
188 dac->substream = NULL;
189 return 0;
190 }
191
atmel_abdac_hw_params(struct snd_pcm_substream * substream,struct snd_pcm_hw_params * hw_params)192 static int atmel_abdac_hw_params(struct snd_pcm_substream *substream,
193 struct snd_pcm_hw_params *hw_params)
194 {
195 struct atmel_abdac *dac = snd_pcm_substream_chip(substream);
196 int retval;
197
198 retval = snd_pcm_lib_malloc_pages(substream,
199 params_buffer_bytes(hw_params));
200 if (retval < 0)
201 return retval;
202 /* snd_pcm_lib_malloc_pages returns 1 if buffer is changed. */
203 if (retval == 1)
204 if (test_and_clear_bit(DMA_READY, &dac->flags))
205 dw_dma_cyclic_free(dac->dma.chan);
206
207 return retval;
208 }
209
atmel_abdac_hw_free(struct snd_pcm_substream * substream)210 static int atmel_abdac_hw_free(struct snd_pcm_substream *substream)
211 {
212 struct atmel_abdac *dac = snd_pcm_substream_chip(substream);
213 if (test_and_clear_bit(DMA_READY, &dac->flags))
214 dw_dma_cyclic_free(dac->dma.chan);
215 return snd_pcm_lib_free_pages(substream);
216 }
217
atmel_abdac_prepare(struct snd_pcm_substream * substream)218 static int atmel_abdac_prepare(struct snd_pcm_substream *substream)
219 {
220 struct atmel_abdac *dac = snd_pcm_substream_chip(substream);
221 int retval;
222
223 retval = clk_set_rate(dac->sample_clk, 256 * substream->runtime->rate);
224 if (retval)
225 return retval;
226
227 if (!test_bit(DMA_READY, &dac->flags))
228 retval = atmel_abdac_prepare_dma(dac, substream, DMA_TO_DEVICE);
229
230 return retval;
231 }
232
atmel_abdac_trigger(struct snd_pcm_substream * substream,int cmd)233 static int atmel_abdac_trigger(struct snd_pcm_substream *substream, int cmd)
234 {
235 struct atmel_abdac *dac = snd_pcm_substream_chip(substream);
236 int retval = 0;
237
238 switch (cmd) {
239 case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: /* fall through */
240 case SNDRV_PCM_TRIGGER_RESUME: /* fall through */
241 case SNDRV_PCM_TRIGGER_START:
242 clk_enable(dac->sample_clk);
243 retval = dw_dma_cyclic_start(dac->dma.chan);
244 if (retval)
245 goto out;
246 dac_writel(dac, CTRL, DAC_BIT(EN));
247 break;
248 case SNDRV_PCM_TRIGGER_PAUSE_PUSH: /* fall through */
249 case SNDRV_PCM_TRIGGER_SUSPEND: /* fall through */
250 case SNDRV_PCM_TRIGGER_STOP:
251 dw_dma_cyclic_stop(dac->dma.chan);
252 dac_writel(dac, DATA, 0);
253 dac_writel(dac, CTRL, 0);
254 clk_disable(dac->sample_clk);
255 break;
256 default:
257 retval = -EINVAL;
258 break;
259 }
260 out:
261 return retval;
262 }
263
264 static snd_pcm_uframes_t
atmel_abdac_pointer(struct snd_pcm_substream * substream)265 atmel_abdac_pointer(struct snd_pcm_substream *substream)
266 {
267 struct atmel_abdac *dac = snd_pcm_substream_chip(substream);
268 struct snd_pcm_runtime *runtime = substream->runtime;
269 snd_pcm_uframes_t frames;
270 unsigned long bytes;
271
272 bytes = dw_dma_get_src_addr(dac->dma.chan);
273 bytes -= runtime->dma_addr;
274
275 frames = bytes_to_frames(runtime, bytes);
276 if (frames >= runtime->buffer_size)
277 frames -= runtime->buffer_size;
278
279 return frames;
280 }
281
abdac_interrupt(int irq,void * dev_id)282 static irqreturn_t abdac_interrupt(int irq, void *dev_id)
283 {
284 struct atmel_abdac *dac = dev_id;
285 u32 status;
286
287 status = dac_readl(dac, INT_STATUS);
288 if (status & DAC_BIT(UNDERRUN)) {
289 dev_err(&dac->pdev->dev, "underrun detected\n");
290 dac_writel(dac, INT_CLR, DAC_BIT(UNDERRUN));
291 } else {
292 dev_err(&dac->pdev->dev, "spurious interrupt (status=0x%x)\n",
293 status);
294 dac_writel(dac, INT_CLR, status);
295 }
296
297 return IRQ_HANDLED;
298 }
299
300 static struct snd_pcm_ops atmel_abdac_ops = {
301 .open = atmel_abdac_open,
302 .close = atmel_abdac_close,
303 .ioctl = snd_pcm_lib_ioctl,
304 .hw_params = atmel_abdac_hw_params,
305 .hw_free = atmel_abdac_hw_free,
306 .prepare = atmel_abdac_prepare,
307 .trigger = atmel_abdac_trigger,
308 .pointer = atmel_abdac_pointer,
309 };
310
atmel_abdac_pcm_new(struct atmel_abdac * dac)311 static int __devinit atmel_abdac_pcm_new(struct atmel_abdac *dac)
312 {
313 struct snd_pcm_hardware hw = atmel_abdac_hw;
314 struct snd_pcm *pcm;
315 int retval;
316
317 retval = snd_pcm_new(dac->card, dac->card->shortname,
318 dac->pdev->id, 1, 0, &pcm);
319 if (retval)
320 return retval;
321
322 strcpy(pcm->name, dac->card->shortname);
323 pcm->private_data = dac;
324 pcm->info_flags = 0;
325 dac->pcm = pcm;
326
327 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &atmel_abdac_ops);
328
329 retval = snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV,
330 &dac->pdev->dev, hw.periods_min * hw.period_bytes_min,
331 hw.buffer_bytes_max);
332
333 return retval;
334 }
335
filter(struct dma_chan * chan,void * slave)336 static bool filter(struct dma_chan *chan, void *slave)
337 {
338 struct dw_dma_slave *dws = slave;
339
340 if (dws->dma_dev == chan->device->dev) {
341 chan->private = dws;
342 return true;
343 } else
344 return false;
345 }
346
set_sample_rates(struct atmel_abdac * dac)347 static int set_sample_rates(struct atmel_abdac *dac)
348 {
349 long new_rate = RATE_MAX;
350 int retval = -EINVAL;
351 int index = 0;
352
353 /* we start at 192 kHz and work our way down to 5112 Hz */
354 while (new_rate >= RATE_MIN && index < (MAX_NUM_RATES + 1)) {
355 new_rate = clk_round_rate(dac->sample_clk, 256 * new_rate);
356 if (new_rate < 0)
357 break;
358 /* make sure we are below the ABDAC clock */
359 if (new_rate <= clk_get_rate(dac->pclk)) {
360 dac->rates[index] = new_rate / 256;
361 index++;
362 }
363 /* divide by 256 and then by two to get next rate */
364 new_rate /= 256 * 2;
365 }
366
367 if (index) {
368 int i;
369
370 /* reverse array, smallest go first */
371 for (i = 0; i < (index / 2); i++) {
372 unsigned int tmp = dac->rates[index - 1 - i];
373 dac->rates[index - 1 - i] = dac->rates[i];
374 dac->rates[i] = tmp;
375 }
376
377 dac->constraints_rates.count = index;
378 dac->constraints_rates.list = dac->rates;
379 dac->constraints_rates.mask = 0;
380 dac->rates_num = index;
381
382 retval = 0;
383 }
384
385 return retval;
386 }
387
atmel_abdac_probe(struct platform_device * pdev)388 static int __devinit atmel_abdac_probe(struct platform_device *pdev)
389 {
390 struct snd_card *card;
391 struct atmel_abdac *dac;
392 struct resource *regs;
393 struct atmel_abdac_pdata *pdata;
394 struct clk *pclk;
395 struct clk *sample_clk;
396 int retval;
397 int irq;
398
399 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
400 if (!regs) {
401 dev_dbg(&pdev->dev, "no memory resource\n");
402 return -ENXIO;
403 }
404
405 irq = platform_get_irq(pdev, 0);
406 if (irq < 0) {
407 dev_dbg(&pdev->dev, "could not get IRQ number\n");
408 return irq;
409 }
410
411 pdata = pdev->dev.platform_data;
412 if (!pdata) {
413 dev_dbg(&pdev->dev, "no platform data\n");
414 return -ENXIO;
415 }
416
417 pclk = clk_get(&pdev->dev, "pclk");
418 if (IS_ERR(pclk)) {
419 dev_dbg(&pdev->dev, "no peripheral clock\n");
420 return PTR_ERR(pclk);
421 }
422 sample_clk = clk_get(&pdev->dev, "sample_clk");
423 if (IS_ERR(sample_clk)) {
424 dev_dbg(&pdev->dev, "no sample clock\n");
425 retval = PTR_ERR(sample_clk);
426 goto out_put_pclk;
427 }
428 clk_enable(pclk);
429
430 retval = snd_card_create(SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1,
431 THIS_MODULE, sizeof(struct atmel_abdac), &card);
432 if (retval) {
433 dev_dbg(&pdev->dev, "could not create sound card device\n");
434 goto out_put_sample_clk;
435 }
436
437 dac = get_dac(card);
438
439 dac->irq = irq;
440 dac->card = card;
441 dac->pclk = pclk;
442 dac->sample_clk = sample_clk;
443 dac->pdev = pdev;
444
445 retval = set_sample_rates(dac);
446 if (retval < 0) {
447 dev_dbg(&pdev->dev, "could not set supported rates\n");
448 goto out_free_card;
449 }
450
451 dac->regs = ioremap(regs->start, resource_size(regs));
452 if (!dac->regs) {
453 dev_dbg(&pdev->dev, "could not remap register memory\n");
454 goto out_free_card;
455 }
456
457 /* make sure the DAC is silent and disabled */
458 dac_writel(dac, DATA, 0);
459 dac_writel(dac, CTRL, 0);
460
461 retval = request_irq(irq, abdac_interrupt, 0, "abdac", dac);
462 if (retval) {
463 dev_dbg(&pdev->dev, "could not request irq\n");
464 goto out_unmap_regs;
465 }
466
467 snd_card_set_dev(card, &pdev->dev);
468
469 if (pdata->dws.dma_dev) {
470 struct dw_dma_slave *dws = &pdata->dws;
471 dma_cap_mask_t mask;
472
473 dws->tx_reg = regs->start + DAC_DATA;
474
475 dma_cap_zero(mask);
476 dma_cap_set(DMA_SLAVE, mask);
477
478 dac->dma.chan = dma_request_channel(mask, filter, dws);
479 }
480 if (!pdata->dws.dma_dev || !dac->dma.chan) {
481 dev_dbg(&pdev->dev, "DMA not available\n");
482 retval = -ENODEV;
483 goto out_unset_card_dev;
484 }
485
486 strcpy(card->driver, "Atmel ABDAC");
487 strcpy(card->shortname, "Atmel ABDAC");
488 sprintf(card->longname, "Atmel Audio Bitstream DAC");
489
490 retval = atmel_abdac_pcm_new(dac);
491 if (retval) {
492 dev_dbg(&pdev->dev, "could not register ABDAC pcm device\n");
493 goto out_release_dma;
494 }
495
496 retval = snd_card_register(card);
497 if (retval) {
498 dev_dbg(&pdev->dev, "could not register sound card\n");
499 goto out_release_dma;
500 }
501
502 platform_set_drvdata(pdev, card);
503
504 dev_info(&pdev->dev, "Atmel ABDAC at 0x%p using %s\n",
505 dac->regs, dev_name(&dac->dma.chan->dev->device));
506
507 return retval;
508
509 out_release_dma:
510 dma_release_channel(dac->dma.chan);
511 dac->dma.chan = NULL;
512 out_unset_card_dev:
513 snd_card_set_dev(card, NULL);
514 free_irq(irq, dac);
515 out_unmap_regs:
516 iounmap(dac->regs);
517 out_free_card:
518 snd_card_free(card);
519 out_put_sample_clk:
520 clk_put(sample_clk);
521 clk_disable(pclk);
522 out_put_pclk:
523 clk_put(pclk);
524 return retval;
525 }
526
527 #ifdef CONFIG_PM
atmel_abdac_suspend(struct platform_device * pdev,pm_message_t msg)528 static int atmel_abdac_suspend(struct platform_device *pdev, pm_message_t msg)
529 {
530 struct snd_card *card = platform_get_drvdata(pdev);
531 struct atmel_abdac *dac = card->private_data;
532
533 dw_dma_cyclic_stop(dac->dma.chan);
534 clk_disable(dac->sample_clk);
535 clk_disable(dac->pclk);
536
537 return 0;
538 }
539
atmel_abdac_resume(struct platform_device * pdev)540 static int atmel_abdac_resume(struct platform_device *pdev)
541 {
542 struct snd_card *card = platform_get_drvdata(pdev);
543 struct atmel_abdac *dac = card->private_data;
544
545 clk_enable(dac->pclk);
546 clk_enable(dac->sample_clk);
547 if (test_bit(DMA_READY, &dac->flags))
548 dw_dma_cyclic_start(dac->dma.chan);
549
550 return 0;
551 }
552 #else
553 #define atmel_abdac_suspend NULL
554 #define atmel_abdac_resume NULL
555 #endif
556
atmel_abdac_remove(struct platform_device * pdev)557 static int __devexit atmel_abdac_remove(struct platform_device *pdev)
558 {
559 struct snd_card *card = platform_get_drvdata(pdev);
560 struct atmel_abdac *dac = get_dac(card);
561
562 clk_put(dac->sample_clk);
563 clk_disable(dac->pclk);
564 clk_put(dac->pclk);
565
566 dma_release_channel(dac->dma.chan);
567 dac->dma.chan = NULL;
568 snd_card_set_dev(card, NULL);
569 iounmap(dac->regs);
570 free_irq(dac->irq, dac);
571 snd_card_free(card);
572
573 platform_set_drvdata(pdev, NULL);
574
575 return 0;
576 }
577
578 static struct platform_driver atmel_abdac_driver = {
579 .remove = __devexit_p(atmel_abdac_remove),
580 .driver = {
581 .name = "atmel_abdac",
582 },
583 .suspend = atmel_abdac_suspend,
584 .resume = atmel_abdac_resume,
585 };
586
atmel_abdac_init(void)587 static int __init atmel_abdac_init(void)
588 {
589 return platform_driver_probe(&atmel_abdac_driver,
590 atmel_abdac_probe);
591 }
592 module_init(atmel_abdac_init);
593
atmel_abdac_exit(void)594 static void __exit atmel_abdac_exit(void)
595 {
596 platform_driver_unregister(&atmel_abdac_driver);
597 }
598 module_exit(atmel_abdac_exit);
599
600 MODULE_LICENSE("GPL");
601 MODULE_DESCRIPTION("Driver for Atmel Audio Bitstream DAC (ABDAC)");
602 MODULE_AUTHOR("Hans-Christian Egtvedt <egtvedt@samfundet.no>");
603