Free Electrons

Embedded Linux Experts

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
/*
 * sound/soc/samsung/idma.c
 *
 * Copyright (c) 2011 Samsung Electronics Co., Ltd.
 *		http://www.samsung.com
 *
 * I2S0's Internal DMA driver
 *
 * This program is free software; you can redistribute  it and/or modify it
 * under  the terms of  the GNU General  Public License as published by the
 * Free Software Foundation;  either version 2 of the  License, or (at your
 * option) any later version.
 */
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>

#include "i2s.h"
#include "idma.h"
#include "i2s-regs.h"

#define ST_RUNNING		(1<<0)
#define ST_OPENED		(1<<1)

static const struct snd_pcm_hardware idma_hardware = {
	.info = SNDRV_PCM_INFO_INTERLEAVED |
		    SNDRV_PCM_INFO_BLOCK_TRANSFER |
		    SNDRV_PCM_INFO_MMAP |
		    SNDRV_PCM_INFO_MMAP_VALID |
		    SNDRV_PCM_INFO_PAUSE |
		    SNDRV_PCM_INFO_RESUME,
	.buffer_bytes_max = MAX_IDMA_BUFFER,
	.period_bytes_min = 128,
	.period_bytes_max = MAX_IDMA_PERIOD,
	.periods_min = 1,
	.periods_max = 2,
};

struct idma_ctrl {
	spinlock_t	lock;
	int		state;
	dma_addr_t	start;
	dma_addr_t	pos;
	dma_addr_t	end;
	dma_addr_t	period;
	dma_addr_t	periodsz;
	void		*token;
	void		(*cb)(void *dt, int bytes_xfer);
};

static struct idma_info {
	spinlock_t	lock;
	void		 __iomem  *regs;
	dma_addr_t	lp_tx_addr;
} idma;

static int idma_irq;

static void idma_getpos(dma_addr_t *src)
{
	*src = idma.lp_tx_addr +
		(readl(idma.regs + I2STRNCNT) & 0xffffff) * 4;
}

static int idma_enqueue(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct idma_ctrl *prtd = substream->runtime->private_data;
	u32 val;

	spin_lock(&prtd->lock);
	prtd->token = (void *) substream;
	spin_unlock(&prtd->lock);

	/* Internal DMA Level0 Interrupt Address */
	val = idma.lp_tx_addr + prtd->periodsz;
	writel(val, idma.regs + I2SLVL0ADDR);

	/* Start address0 of I2S internal DMA operation. */
	val = idma.lp_tx_addr;
	writel(val, idma.regs + I2SSTR0);

	/*
	 * Transfer block size for I2S internal DMA.
	 * Should decide transfer size before start dma operation
	 */
	val = readl(idma.regs + I2SSIZE);
	val &= ~(I2SSIZE_TRNMSK << I2SSIZE_SHIFT);
	val |= (((runtime->dma_bytes >> 2) &
			I2SSIZE_TRNMSK) << I2SSIZE_SHIFT);
	writel(val, idma.regs + I2SSIZE);

	val = readl(idma.regs + I2SAHB);
	val |= AHB_INTENLVL0;
	writel(val, idma.regs + I2SAHB);

	return 0;
}

static void idma_setcallbk(struct snd_pcm_substream *substream,
				void (*cb)(void *, int))
{
	struct idma_ctrl *prtd = substream->runtime->private_data;

	spin_lock(&prtd->lock);
	prtd->cb = cb;
	spin_unlock(&prtd->lock);
}

static void idma_control(int op)
{
	u32 val = readl(idma.regs + I2SAHB);

	spin_lock(&idma.lock);

	switch (op) {
	case LPAM_DMA_START:
		val |= (AHB_INTENLVL0 | AHB_DMAEN);
		break;
	case LPAM_DMA_STOP:
		val &= ~(AHB_INTENLVL0 | AHB_DMAEN);
		break;
	default:
		spin_unlock(&idma.lock);
		return;
	}

	writel(val, idma.regs + I2SAHB);
	spin_unlock(&idma.lock);
}

static void idma_done(void *id, int bytes_xfer)
{
	struct snd_pcm_substream *substream = id;
	struct idma_ctrl *prtd = substream->runtime->private_data;

	if (prtd && (prtd->state & ST_RUNNING))
		snd_pcm_period_elapsed(substream);
}

static int idma_hw_params(struct snd_pcm_substream *substream,
				struct snd_pcm_hw_params *params)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct idma_ctrl *prtd = substream->runtime->private_data;
	u32 mod = readl(idma.regs + I2SMOD);
	u32 ahb = readl(idma.regs + I2SAHB);

	ahb |= (AHB_DMARLD | AHB_INTMASK);
	mod |= MOD_TXS_IDMA;
	writel(ahb, idma.regs + I2SAHB);
	writel(mod, idma.regs + I2SMOD);

	snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
	runtime->dma_bytes = params_buffer_bytes(params);

	prtd->start = prtd->pos = runtime->dma_addr;
	prtd->period = params_periods(params);
	prtd->periodsz = params_period_bytes(params);
	prtd->end = runtime->dma_addr + runtime->dma_bytes;

	idma_setcallbk(substream, idma_done);

	return 0;
}

static int idma_hw_free(struct snd_pcm_substream *substream)
{
	snd_pcm_set_runtime_buffer(substream, NULL);

	return 0;
}

static int idma_prepare(struct snd_pcm_substream *substream)
{
	struct idma_ctrl *prtd = substream->runtime->private_data;

	prtd->pos = prtd->start;

	/* flush the DMA channel */
	idma_control(LPAM_DMA_STOP);
	idma_enqueue(substream);

	return 0;
}

static int idma_trigger(struct snd_pcm_substream *substream, int cmd)
{
	struct idma_ctrl *prtd = substream->runtime->private_data;
	int ret = 0;

	spin_lock(&prtd->lock);

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_RESUME:
	case SNDRV_PCM_TRIGGER_START:
	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
		prtd->state |= ST_RUNNING;
		idma_control(LPAM_DMA_START);
		break;

	case SNDRV_PCM_TRIGGER_SUSPEND:
	case SNDRV_PCM_TRIGGER_STOP:
	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
		prtd->state &= ~ST_RUNNING;
		idma_control(LPAM_DMA_STOP);
		break;

	default:
		ret = -EINVAL;
		break;
	}

	spin_unlock(&prtd->lock);

	return ret;
}

static snd_pcm_uframes_t
	idma_pointer(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct idma_ctrl *prtd = runtime->private_data;
	dma_addr_t src;
	unsigned long res;

	spin_lock(&prtd->lock);

	idma_getpos(&src);
	res = src - prtd->start;

	spin_unlock(&prtd->lock);

	return bytes_to_frames(substream->runtime, res);
}

static int idma_mmap(struct snd_pcm_substream *substream,
	struct vm_area_struct *vma)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	unsigned long size, offset;
	int ret;

	/* From snd_pcm_lib_mmap_iomem */
	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
	size = vma->vm_end - vma->vm_start;
	offset = vma->vm_pgoff << PAGE_SHIFT;
	ret = io_remap_pfn_range(vma, vma->vm_start,
			(runtime->dma_addr + offset) >> PAGE_SHIFT,
			size, vma->vm_page_prot);

	return ret;
}

static irqreturn_t iis_irq(int irqno, void *dev_id)
{
	struct idma_ctrl *prtd = (struct idma_ctrl *)dev_id;
	u32 iisahb, val, addr;

	iisahb  = readl(idma.regs + I2SAHB);

	val = (iisahb & AHB_LVL0INT) ? AHB_CLRLVL0INT : 0;

	if (val) {
		iisahb |= val;
		writel(iisahb, idma.regs + I2SAHB);

		addr = readl(idma.regs + I2SLVL0ADDR) - idma.lp_tx_addr;
		addr += prtd->periodsz;
		addr %= (u32)(prtd->end - prtd->start);
		addr += idma.lp_tx_addr;

		writel(addr, idma.regs + I2SLVL0ADDR);

		if (prtd->cb)
			prtd->cb(prtd->token, prtd->period);
	}

	return IRQ_HANDLED;
}

static int idma_open(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct idma_ctrl *prtd;
	int ret;

	snd_soc_set_runtime_hwparams(substream, &idma_hardware);

	prtd = kzalloc(sizeof(struct idma_ctrl), GFP_KERNEL);
	if (prtd == NULL)
		return -ENOMEM;

	ret = request_irq(idma_irq, iis_irq, 0, "i2s", prtd);
	if (ret < 0) {
		pr_err("fail to claim i2s irq , ret = %d\n", ret);
		kfree(prtd);
		return ret;
	}

	spin_lock_init(&prtd->lock);

	runtime->private_data = prtd;

	return 0;
}

static int idma_close(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct idma_ctrl *prtd = runtime->private_data;

	free_irq(idma_irq, prtd);

	if (!prtd)
		pr_err("idma_close called with prtd == NULL\n");

	kfree(prtd);

	return 0;
}

static struct snd_pcm_ops idma_ops = {
	.open		= idma_open,
	.close		= idma_close,
	.ioctl		= snd_pcm_lib_ioctl,
	.trigger	= idma_trigger,
	.pointer	= idma_pointer,
	.mmap		= idma_mmap,
	.hw_params	= idma_hw_params,
	.hw_free	= idma_hw_free,
	.prepare	= idma_prepare,
};

static void idma_free(struct snd_pcm *pcm)
{
	struct snd_pcm_substream *substream;
	struct snd_dma_buffer *buf;

	substream = pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream;
	if (!substream)
		return;

	buf = &substream->dma_buffer;
	if (!buf->area)
		return;

	iounmap((void __iomem *)buf->area);

	buf->area = NULL;
	buf->addr = 0;
}

static int preallocate_idma_buffer(struct snd_pcm *pcm, int stream)
{
	struct snd_pcm_substream *substream = pcm->streams[stream].substream;
	struct snd_dma_buffer *buf = &substream->dma_buffer;

	buf->dev.dev = pcm->card->dev;
	buf->private_data = NULL;

	/* Assign PCM buffer pointers */
	buf->dev.type = SNDRV_DMA_TYPE_CONTINUOUS;
	buf->addr = idma.lp_tx_addr;
	buf->bytes = idma_hardware.buffer_bytes_max;
	buf->area = (unsigned char * __force)ioremap(buf->addr, buf->bytes);

	return 0;
}

static int idma_new(struct snd_soc_pcm_runtime *rtd)
{
	struct snd_card *card = rtd->card->snd_card;
	struct snd_pcm *pcm = rtd->pcm;
	int ret;

	ret = dma_coerce_mask_and_coherent(card->dev, DMA_BIT_MASK(32));
	if (ret)
		return ret;

	if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream) {
		ret = preallocate_idma_buffer(pcm,
				SNDRV_PCM_STREAM_PLAYBACK);
	}

	return ret;
}

void idma_reg_addr_init(void __iomem *regs, dma_addr_t addr)
{
	spin_lock_init(&idma.lock);
	idma.regs = regs;
	idma.lp_tx_addr = addr;
}
EXPORT_SYMBOL_GPL(idma_reg_addr_init);

static struct snd_soc_platform_driver asoc_idma_platform = {
	.ops = &idma_ops,
	.pcm_new = idma_new,
	.pcm_free = idma_free,
};

static int asoc_idma_platform_probe(struct platform_device *pdev)
{
	idma_irq = platform_get_irq(pdev, 0);
	if (idma_irq < 0)
		return idma_irq;

	return devm_snd_soc_register_platform(&pdev->dev, &asoc_idma_platform);
}

static struct platform_driver asoc_idma_driver = {
	.driver = {
		.name = "samsung-idma",
	},

	.probe = asoc_idma_platform_probe,
};

module_platform_driver(asoc_idma_driver);

MODULE_AUTHOR("Jaswinder Singh, <jassisinghbrar@gmail.com>");
MODULE_DESCRIPTION("Samsung ASoC IDMA Driver");
MODULE_LICENSE("GPL");