2 * Driver for the Atmel on-chip Audio Bitstream DAC (ABDAC)
4 * Copyright (C) 2006-2009 Atmel Corporation
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.
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>
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>
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
36 /* Bitfields in CTRL */
37 #define DAC_SWAP_OFFSET 30
38 #define DAC_SWAP_SIZE 1
39 #define DAC_EN_OFFSET 31
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
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))
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)
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
73 #define MAX_NUM_RATES 6
74 /* ALSA seems to use rates between 192000 Hz and 5112 Hz. */
75 #define RATE_MAX 192000
82 struct atmel_abdac_dma {
83 struct dma_chan *chan;
84 struct dw_cyclic_desc *cdesc;
89 struct clk *sample_clk;
90 struct platform_device *pdev;
91 struct atmel_abdac_dma dma;
93 struct snd_pcm_hw_constraint_list constraints_rates;
94 struct snd_pcm_substream *substream;
95 struct snd_card *card;
100 unsigned int rates[MAX_NUM_RATES];
101 unsigned int rates_num;
105 #define get_dac(card) ((struct atmel_abdac *)(card)->private_data)
107 /* This function is called by the DMA driver. */
108 static void atmel_abdac_dma_period_done(void *arg)
110 struct atmel_abdac *dac = arg;
111 snd_pcm_period_elapsed(dac->substream);
114 static int atmel_abdac_prepare_dma(struct atmel_abdac *dac,
115 struct snd_pcm_substream *substream,
116 enum dma_data_direction direction)
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;
124 * We don't do DMA on "complex" transfers, i.e. with
125 * non-halfword-aligned buffers or lengths.
127 if (runtime->dma_addr & 1 || runtime->buffer_size & 1) {
128 dev_dbg(&dac->pdev->dev, "too complex transfer\n");
132 buffer_len = frames_to_bytes(runtime, runtime->buffer_size);
133 period_len = frames_to_bytes(runtime, runtime->period_size);
135 cdesc = dw_dma_cyclic_prep(chan, runtime->dma_addr, buffer_len,
136 period_len, DMA_MEM_TO_DEV);
138 dev_dbg(&dac->pdev->dev, "could not prepare cyclic DMA\n");
139 return PTR_ERR(cdesc);
142 cdesc->period_callback = atmel_abdac_dma_period_done;
143 cdesc->period_callback_param = dac;
145 dac->dma.cdesc = cdesc;
147 set_bit(DMA_READY, &dac->flags);
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,
165 .buffer_bytes_max = 64 * 4096,
166 .period_bytes_min = 4096,
167 .period_bytes_max = 4096,
172 static int atmel_abdac_open(struct snd_pcm_substream *substream)
174 struct atmel_abdac *dac = snd_pcm_substream_chip(substream);
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;
181 return snd_pcm_hw_constraint_list(substream->runtime, 0,
182 SNDRV_PCM_HW_PARAM_RATE, &dac->constraints_rates);
185 static int atmel_abdac_close(struct snd_pcm_substream *substream)
187 struct atmel_abdac *dac = snd_pcm_substream_chip(substream);
188 dac->substream = NULL;
192 static int atmel_abdac_hw_params(struct snd_pcm_substream *substream,
193 struct snd_pcm_hw_params *hw_params)
195 struct atmel_abdac *dac = snd_pcm_substream_chip(substream);
198 retval = snd_pcm_lib_malloc_pages(substream,
199 params_buffer_bytes(hw_params));
202 /* snd_pcm_lib_malloc_pages returns 1 if buffer is changed. */
204 if (test_and_clear_bit(DMA_READY, &dac->flags))
205 dw_dma_cyclic_free(dac->dma.chan);
210 static int atmel_abdac_hw_free(struct snd_pcm_substream *substream)
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);
218 static int atmel_abdac_prepare(struct snd_pcm_substream *substream)
220 struct atmel_abdac *dac = snd_pcm_substream_chip(substream);
223 retval = clk_set_rate(dac->sample_clk, 256 * substream->runtime->rate);
227 if (!test_bit(DMA_READY, &dac->flags))
228 retval = atmel_abdac_prepare_dma(dac, substream, DMA_TO_DEVICE);
233 static int atmel_abdac_trigger(struct snd_pcm_substream *substream, int cmd)
235 struct atmel_abdac *dac = snd_pcm_substream_chip(substream);
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);
246 dac_writel(dac, CTRL, DAC_BIT(EN));
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);
264 static snd_pcm_uframes_t
265 atmel_abdac_pointer(struct snd_pcm_substream *substream)
267 struct atmel_abdac *dac = snd_pcm_substream_chip(substream);
268 struct snd_pcm_runtime *runtime = substream->runtime;
269 snd_pcm_uframes_t frames;
272 bytes = dw_dma_get_src_addr(dac->dma.chan);
273 bytes -= runtime->dma_addr;
275 frames = bytes_to_frames(runtime, bytes);
276 if (frames >= runtime->buffer_size)
277 frames -= runtime->buffer_size;
282 static irqreturn_t abdac_interrupt(int irq, void *dev_id)
284 struct atmel_abdac *dac = dev_id;
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));
292 dev_err(&dac->pdev->dev, "spurious interrupt (status=0x%x)\n",
294 dac_writel(dac, INT_CLR, status);
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,
311 static int __devinit atmel_abdac_pcm_new(struct atmel_abdac *dac)
313 struct snd_pcm_hardware hw = atmel_abdac_hw;
317 retval = snd_pcm_new(dac->card, dac->card->shortname,
318 dac->pdev->id, 1, 0, &pcm);
322 strcpy(pcm->name, dac->card->shortname);
323 pcm->private_data = dac;
327 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &atmel_abdac_ops);
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);
336 static bool filter(struct dma_chan *chan, void *slave)
338 struct dw_dma_slave *dws = slave;
340 if (dws->dma_dev == chan->device->dev) {
347 static int set_sample_rates(struct atmel_abdac *dac)
349 long new_rate = RATE_MAX;
350 int retval = -EINVAL;
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);
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;
363 /* divide by 256 and then by two to get next rate */
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];
377 dac->constraints_rates.count = index;
378 dac->constraints_rates.list = dac->rates;
379 dac->constraints_rates.mask = 0;
380 dac->rates_num = index;
388 static int __devinit atmel_abdac_probe(struct platform_device *pdev)
390 struct snd_card *card;
391 struct atmel_abdac *dac;
392 struct resource *regs;
393 struct atmel_abdac_pdata *pdata;
395 struct clk *sample_clk;
399 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
401 dev_dbg(&pdev->dev, "no memory resource\n");
405 irq = platform_get_irq(pdev, 0);
407 dev_dbg(&pdev->dev, "could not get IRQ number\n");
411 pdata = pdev->dev.platform_data;
413 dev_dbg(&pdev->dev, "no platform data\n");
417 pclk = clk_get(&pdev->dev, "pclk");
419 dev_dbg(&pdev->dev, "no peripheral clock\n");
420 return PTR_ERR(pclk);
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);
430 retval = snd_card_create(SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1,
431 THIS_MODULE, sizeof(struct atmel_abdac), &card);
433 dev_dbg(&pdev->dev, "could not create sound card device\n");
434 goto out_put_sample_clk;
442 dac->sample_clk = sample_clk;
445 retval = set_sample_rates(dac);
447 dev_dbg(&pdev->dev, "could not set supported rates\n");
451 dac->regs = ioremap(regs->start, resource_size(regs));
453 dev_dbg(&pdev->dev, "could not remap register memory\n");
457 /* make sure the DAC is silent and disabled */
458 dac_writel(dac, DATA, 0);
459 dac_writel(dac, CTRL, 0);
461 retval = request_irq(irq, abdac_interrupt, 0, "abdac", dac);
463 dev_dbg(&pdev->dev, "could not request irq\n");
467 snd_card_set_dev(card, &pdev->dev);
469 if (pdata->dws.dma_dev) {
470 struct dw_dma_slave *dws = &pdata->dws;
473 dws->tx_reg = regs->start + DAC_DATA;
476 dma_cap_set(DMA_SLAVE, mask);
478 dac->dma.chan = dma_request_channel(mask, filter, dws);
480 if (!pdata->dws.dma_dev || !dac->dma.chan) {
481 dev_dbg(&pdev->dev, "DMA not available\n");
483 goto out_unset_card_dev;
486 strcpy(card->driver, "Atmel ABDAC");
487 strcpy(card->shortname, "Atmel ABDAC");
488 sprintf(card->longname, "Atmel Audio Bitstream DAC");
490 retval = atmel_abdac_pcm_new(dac);
492 dev_dbg(&pdev->dev, "could not register ABDAC pcm device\n");
493 goto out_release_dma;
496 retval = snd_card_register(card);
498 dev_dbg(&pdev->dev, "could not register sound card\n");
499 goto out_release_dma;
502 platform_set_drvdata(pdev, card);
504 dev_info(&pdev->dev, "Atmel ABDAC at 0x%p using %s\n",
505 dac->regs, dev_name(&dac->dma.chan->dev->device));
510 dma_release_channel(dac->dma.chan);
511 dac->dma.chan = NULL;
513 snd_card_set_dev(card, NULL);
528 static int atmel_abdac_suspend(struct platform_device *pdev, pm_message_t msg)
530 struct snd_card *card = platform_get_drvdata(pdev);
531 struct atmel_abdac *dac = card->private_data;
533 dw_dma_cyclic_stop(dac->dma.chan);
534 clk_disable(dac->sample_clk);
535 clk_disable(dac->pclk);
540 static int atmel_abdac_resume(struct platform_device *pdev)
542 struct snd_card *card = platform_get_drvdata(pdev);
543 struct atmel_abdac *dac = card->private_data;
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);
553 #define atmel_abdac_suspend NULL
554 #define atmel_abdac_resume NULL
557 static int __devexit atmel_abdac_remove(struct platform_device *pdev)
559 struct snd_card *card = platform_get_drvdata(pdev);
560 struct atmel_abdac *dac = get_dac(card);
562 clk_put(dac->sample_clk);
563 clk_disable(dac->pclk);
566 dma_release_channel(dac->dma.chan);
567 dac->dma.chan = NULL;
568 snd_card_set_dev(card, NULL);
570 free_irq(dac->irq, dac);
573 platform_set_drvdata(pdev, NULL);
578 static struct platform_driver atmel_abdac_driver = {
579 .remove = __devexit_p(atmel_abdac_remove),
581 .name = "atmel_abdac",
583 .suspend = atmel_abdac_suspend,
584 .resume = atmel_abdac_resume,
587 static int __init atmel_abdac_init(void)
589 return platform_driver_probe(&atmel_abdac_driver,
592 module_init(atmel_abdac_init);
594 static void __exit atmel_abdac_exit(void)
596 platform_driver_unregister(&atmel_abdac_driver);
598 module_exit(atmel_abdac_exit);
600 MODULE_LICENSE("GPL");
601 MODULE_DESCRIPTION("Driver for Atmel Audio Bitstream DAC (ABDAC)");
602 MODULE_AUTHOR("Hans-Christian Egtvedt <egtvedt@samfundet.no>");