/*++ 
 * linux/sound/soc/wmt/wmt-pcm.c
 * WonderMedia audio driver for ALSA
 *
 * Copyright c 2010  WonderMedia  Technologies, Inc.
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful, 
 * but WITHOUT ANY WARRANTY; without even the implied warranty of 
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
 * GNU General Public License for more details. 
 *
 * You should have received a copy of the GNU General Public License 
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * WonderMedia Technologies, Inc.
 * 4F, 533, Chung-Cheng Road, Hsin-Tien, Taipei 231, R.O.C
--*/

#include <linux/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>

#include <linux/dma-mapping.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>
#include <linux/delay.h>

#include <asm/dma.h>
#include "wmt-pcm-dma.h"
#include "wmt-soc.h"

#define NULL_DMA                ((dmach_t)(-1))

/*
 * Debug
 */
#define AUDIO_NAME "WMT_PCM_DMA"
//#define WMT_PCM_DEBUG 1
//#define WMT_PCM_DEBUG_DETAIL 1

#ifdef WMT_PCM_DEBUG
#define DPRINTK(format, arg...) \
	printk(KERN_INFO AUDIO_NAME ": " format "\n" , ## arg)
#else
#define DPRINTK(format, arg...) do {} while (0)
#endif

#ifdef WMT_PCM_DEBUG_DETAIL
#define DBG_DETAIL(format, arg...) \
	printk(KERN_INFO AUDIO_NAME ": [%s]" format "\n" , __FUNCTION__, ## arg)
#else
#define DBG_DETAIL(format, arg...) do {} while (0)
#endif

#define err(format, arg...) \
	printk(KERN_ERR AUDIO_NAME ": " format "\n" , ## arg)
#define info(format, arg...) \
	printk(KERN_INFO AUDIO_NAME ": " format "\n" , ## arg)
#define warn(format, arg...) \
	printk(KERN_WARNING AUDIO_NAME ": " format "\n" , ## arg)

static const struct snd_pcm_hardware wmt_pcm_dma_hardware = {
	.info			= SNDRV_PCM_INFO_MMAP |
				  SNDRV_PCM_INFO_MMAP_VALID |
				  SNDRV_PCM_INFO_INTERLEAVED |
				  SNDRV_PCM_INFO_PAUSE |
				  SNDRV_PCM_INFO_RESUME,
	.formats		= SNDRV_PCM_FMTBIT_S16_LE,
	.rate_min		= 8000,
	.rate_max		= 16000,
	.period_bytes_min	= 32,
	.period_bytes_max	= 4 * 1024,
	.periods_min		= 1,
	.periods_max		= 32,
	.buffer_bytes_max	= 16 * 1024,
};

static int audio_dma_free(struct audio_stream_a *s);

/*
 *  Main dma routine, requests dma according where you are in main alsa buffer
 */
static void audio_process_dma(struct audio_stream_a *s)
{
	struct snd_pcm_substream *substream = s->stream;
	struct snd_pcm_runtime *runtime;
	unsigned int dma_size;
	unsigned int offset;
	dma_addr_t dma_base;
	int ret = 0;
	
	DPRINTK("s: %d, dmach: %d. active: %d", (int)s, s->dmach, s->active);
	
	if (s->active) {
		substream = s->stream;
		runtime = substream->runtime;
		dma_size = frames_to_bytes(runtime, runtime->period_size);

		if (dma_size > MAX_DMA_SIZE)
			dma_size = CUT_DMA_SIZE;
		offset = dma_size * s->period;

		dma_base = __virt_to_phys((dma_addr_t)runtime->dma_area);

		if ((runtime->channels == 2 || runtime->channels == 1) && 
				(runtime->format == SNDRV_PCM_FORMAT_S16_LE)) {
			ret = wmt_start_dma(s->dmach, runtime->dma_addr + offset, 0, dma_size);
		}

		if (ret) {
			printk(KERN_ERR "audio_process_dma: cannot queue DMA buffer (%i) \n", ret);
			return;
		}

		s->period++;
		s->period %= runtime->periods;
		s->periods++;
		s->offset = offset;
	}
}

/* 
 *  This is called when dma IRQ occurs at the end of each transmited block
 */
static void audio_dma_callback(void *data)
{
	struct audio_stream_a *s = data;
	
	//DBG_DETAIL();
	
	/* 
	 * If we are getting a callback for an active stream then we inform
	 * the PCM middle layer we've finished a period
	 */
	if (s->active)
		snd_pcm_period_elapsed(s->stream);

	spin_lock(&s->dma_lock);
	if (s->periods > 0) 
		s->periods--;
	
	audio_process_dma(s);
	spin_unlock(&s->dma_lock);
}

static int audio_dma_request(struct audio_stream_a *s, void (*callback) (void *))
{
	int err;
	err = 0;

	DBG_DETAIL();
	
	//DPRINTK("s pointer: %d, dmach: %d, id: %s, dma_dev: %d", (int)s, s->dmach, s->id, s->dma_dev);
	err = wmt_request_dma(&s->dmach, s->id, s->dma_dev, callback, s);
	if (err < 0)
		printk(KERN_ERR "Unable to grab audio dma 0x%x\n", s->dmach);
	
	return err;
}

static void audio_setup_dma(struct audio_stream_a *s, int stream_id)
{
	struct snd_pcm_runtime *runtime = s->stream->runtime;

	if (stream_id == SNDRV_PCM_STREAM_PLAYBACK) {
		/* From memory to device */
		switch (runtime->channels * runtime->format) {
		case 1:
			s->dma_cfg.DefaultCCR = PCM_TX_DMA_8BITS_CFG;     /* setup 1 bytes*/
			break ;
		case 2:
			s->dma_cfg.DefaultCCR = PCM_TX_DMA_16BITS_CFG;    /* setup 2 bytes*/
			break ;
		case 4:
			s->dma_cfg.DefaultCCR = PCM_TX_DMA_32BITS_CFG;    /* setup 4 byte*/
			break ;
		}
	}
	else {
		/* From device to memory */
		switch (runtime->channels * runtime->format) {
		case 1:
			s->dma_cfg.DefaultCCR = PCM_RX_DMA_8BITS_CFG ;     /* setup 1 bytes*/
			break ;
		case 2:
			s->dma_cfg.DefaultCCR = PCM_RX_DMA_16BITS_CFG ;    /* setup 2 bytes*/
			break ;
		case 4:
			s->dma_cfg.DefaultCCR = PCM_RX_DMA_32BITS_CFG ;    /* setup 4 byte*/
			break ;
		}
	}

	s->dma_cfg.ChunkSize = 1;
	
	wmt_setup_dma(s->dmach, s->dma_cfg) ;
}

static int audio_dma_free(struct audio_stream_a *s)
{
	int err = 0;
	DBG_DETAIL();
	wmt_free_dma(s->dmach);
	s->dmach = NULL_DMA;
	return err;
}

/*
 * this stops the dma and clears the dma ptrs
 */
static void audio_stop_dma(struct audio_stream_a *s)
{
	//dump_stack();
	unsigned long flags;
	DBG_DETAIL();
	local_irq_save(flags);
	s->active = 0;
	s->period = 0;
	s->periods = 0;
	s->offset = 0;
	wmt_stop_dma(s->dmach);
	wmt_clear_dma(s->dmach);
	local_irq_restore(flags);
}

/* this may get called several times by oss emulation */
static int wmt_pcm_dma_hw_params(struct snd_pcm_substream *substream,
			      struct snd_pcm_hw_params *params)
{
	//dump_stack();
	struct snd_pcm_runtime *runtime = substream->runtime;
	int err = 0;
	DBG_DETAIL();
	snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
	runtime->dma_bytes = params_buffer_bytes(params);
	return err;
}

static int wmt_pcm_dma_hw_free(struct snd_pcm_substream *substream)
{
	DBG_DETAIL();
	snd_pcm_set_runtime_buffer(substream, NULL);
	return 0;
}

static int wmt_pcm_dma_prepare(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	int stream_id = substream->pstr->stream;
	struct audio_stream_a *prtd = runtime->private_data;
	struct audio_stream_a *s = &prtd[stream_id];
	//dump_stack();
	DBG_DETAIL();

	s->period = 0;
	s->periods = 0;
	s->offset = 0;
	audio_setup_dma(s, stream_id);

	return 0;
}

static int wmt_pcm_dma_trigger(struct snd_pcm_substream *substream, int cmd)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	int stream_id = substream->pstr->stream;
	struct audio_stream_a *prtd = runtime->private_data;
	struct audio_stream_a *s = &prtd[stream_id];
	int ret = 0;

	DPRINTK("Enter, cmd=%d", cmd);
	//dump_stack();
	spin_lock(&s->dma_lock);
	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
	case SNDRV_PCM_TRIGGER_RESUME:
	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
		s->active = 1;
		audio_process_dma(s);
		break;

	case SNDRV_PCM_TRIGGER_STOP:
	case SNDRV_PCM_TRIGGER_SUSPEND:
	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
		s->active = 0;
		audio_stop_dma(s);
		break;
	default:
		ret = -EINVAL;
	}
	spin_unlock(&s->dma_lock);

	return ret;
}

static snd_pcm_uframes_t wmt_pcm_dma_pointer(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct audio_stream_a *prtd = runtime->private_data;
	int stream_id = substream->pstr->stream;
	struct audio_stream_a *s = &prtd[stream_id];
	dma_addr_t ptr;
	snd_pcm_uframes_t offset = 0;
	//dump_stack();
	ptr = wmt_get_dma_pos(s->dmach);

	if ((runtime->channels == 1 || runtime->channels == 2) && (runtime->format == SNDRV_PCM_FORMAT_S16_LE)) {
		offset = bytes_to_frames(runtime, ptr - runtime->dma_addr);
	}

	if (offset >= runtime->buffer_size)
		offset = 0;

	spin_lock(&s->dma_lock);

	if (s->periods > 0 && s->periods < 2) {
		if (stream_id == SNDRV_PCM_STREAM_PLAYBACK) {
			if (snd_pcm_playback_hw_avail(runtime) >= 2 * runtime->period_size)
				audio_process_dma(s);
		}
		else {
			if (snd_pcm_capture_hw_avail(runtime) >= 2* runtime->period_size)
				audio_process_dma(s);
		}
		
	}
	spin_unlock(&s->dma_lock);
	
	return offset;
}

static int wmt_pcm_dma_open(struct snd_pcm_substream *substream)
{
	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	struct snd_soc_dai *cpu_dai = rtd->cpu_dai;
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct audio_stream_a *s = runtime->private_data;
	int ret;

	DBG_DETAIL();
	
	if (!cpu_dai->active) {
		audio_dma_request(&s[0], audio_dma_callback);
		audio_dma_request(&s[1], audio_dma_callback);
	}
	//dump_stack();
	snd_soc_set_runtime_hwparams(substream, &wmt_pcm_dma_hardware);

	/* Ensure that buffer size is a multiple of period size */
	ret = snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
	if (ret < 0)
		goto out;

out:
	return ret;
}

static int wmt_pcm_dma_close(struct snd_pcm_substream *substream)
{
	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	struct snd_soc_dai *cpu_dai = rtd->cpu_dai;
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct audio_stream_a *s = runtime->private_data;

	DBG_DETAIL();
	//dump_stack();
	if (!cpu_dai->active) {
		audio_dma_free(&s[0]);
		audio_dma_free(&s[1]);
	}

	return 0;
}

static int wmt_pcm_dma_mmap(struct snd_pcm_substream *substream,
	struct vm_area_struct *vma)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	
	DBG_DETAIL();
	//dump_stack();
	return dma_mmap_writecombine(substream->pcm->card->dev, vma,
				     runtime->dma_area,
				     runtime->dma_addr,
				     runtime->dma_bytes);
}

static struct snd_pcm_ops wmt_pcm_dma_ops = {
	.open		= wmt_pcm_dma_open,
	.close		= wmt_pcm_dma_close,
	.ioctl		= snd_pcm_lib_ioctl,
	.hw_params	= wmt_pcm_dma_hw_params,
	.hw_free	= wmt_pcm_dma_hw_free,
	.prepare	= wmt_pcm_dma_prepare,
	.trigger	= wmt_pcm_dma_trigger,
	.pointer	= wmt_pcm_dma_pointer,
	.mmap		= wmt_pcm_dma_mmap,
};

static u64 wmt_pcm_dma_dmamask = DMA_BIT_MASK(32);

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

	DBG_DETAIL();
	
	buf->dev.type = SNDRV_DMA_TYPE_DEV;
	buf->dev.dev = pcm->card->dev;
	buf->private_data = NULL;
	buf->area = dma_alloc_writecombine(pcm->card->dev, size,
					&buf->addr, GFP_KERNEL);
	
	DPRINTK("buf_area = %x, buf_addr = %x", (unsigned int)buf->area, buf->addr);
	if (!buf->area)
		return -ENOMEM;

	buf->bytes = size;
	
	return 0;
}

static void wmt_pcm_dma_free_dma_buffers(struct snd_pcm *pcm)
{
	struct snd_pcm_substream *substream;
	struct snd_dma_buffer *buf;
	int stream;

	DBG_DETAIL();
	
	for (stream = 0; stream < 2; stream++) {
		substream = pcm->streams[stream].substream;
		if (!substream)
			continue;

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

		dma_free_writecombine(pcm->card->dev, buf->bytes, buf->area, buf->addr);
		
		buf->area = NULL;
	}
}

static int wmt_pcm_dma_new(struct snd_soc_pcm_runtime *rtd)
{
	struct snd_card *card = rtd->card->snd_card;
	struct snd_pcm *pcm = rtd->pcm;
	int ret = 0;

	DBG_DETAIL();
	
	if (!card->dev->dma_mask)
		card->dev->dma_mask = &wmt_pcm_dma_dmamask;
	if (!card->dev->coherent_dma_mask)
		card->dev->coherent_dma_mask = DMA_BIT_MASK(32);

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

	if (pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream) {
		ret = wmt_pcm_dma_preallocate_dma_buffer(pcm,
			SNDRV_PCM_STREAM_CAPTURE);
		if (ret)
			goto out;
	}
	
out:
	/* free preallocated buffers in case of error */
	if (ret)
		wmt_pcm_dma_free_dma_buffers(pcm);
	
	return ret;
}

#ifdef CONFIG_PM
static int wmt_pcm_dma_suspend(struct snd_soc_dai *dai)
{
	struct snd_pcm_runtime *runtime = dai->runtime;
	struct audio_stream_a *prtd;
	struct audio_stream_a *s;

	DBG_DETAIL();
	
	if (!runtime)
		return 0;

	prtd = runtime->private_data;
	s = &prtd[SNDRV_PCM_STREAM_PLAYBACK];

	if (s->active) {
		udelay(5);
		wmt_stop_dma(s->dmach);
		/*
		wmt_clear_dma(s->dmach);
		audio_stop_dma(s);
		*/
	}

	s = &prtd[SNDRV_PCM_STREAM_CAPTURE];

	if (s->active) {
		udelay(5);
		wmt_stop_dma(s->dmach);
		/*
		wmt_clear_dma(s->dmach);
		audio_stop_dma(s);
		*/
	}

	return 0;
}

static int wmt_pcm_dma_resume(struct snd_soc_dai *dai)
{
	struct snd_pcm_runtime *runtime = dai->runtime;
	struct audio_stream_a *prtd;
	struct audio_stream_a *s;

	DBG_DETAIL();
	
	if (!runtime)
		return 0;
	
	prtd = runtime->private_data;
	s = &prtd[SNDRV_PCM_STREAM_PLAYBACK];
	audio_setup_dma(s, SNDRV_PCM_STREAM_PLAYBACK);
	
	if (s->active) {
		wmt_resume_dma(s->dmach) ;
	}
	
	s = &prtd[SNDRV_PCM_STREAM_CAPTURE];
	audio_setup_dma(s, SNDRV_PCM_STREAM_CAPTURE);

	if (s->active) {
		wmt_resume_dma(s->dmach) ;
	}

	return 0;
}
#else
#define wmt_pcm_dma_suspend NULL
#define wmt_pcm_dma_resume  NULL
#endif

static struct snd_soc_platform_driver wmt_soc_platform = {
	.ops        = &wmt_pcm_dma_ops,
	.pcm_new    = wmt_pcm_dma_new,
	.pcm_free   = wmt_pcm_dma_free_dma_buffers,
	.suspend    = wmt_pcm_dma_suspend,
	.resume     = wmt_pcm_dma_resume,
};

static int __devinit wmt_pcm_dma_platform_probe(struct platform_device *pdev)
{
	DBG_DETAIL();
	return snd_soc_register_platform(&pdev->dev, &wmt_soc_platform);
}

static int __devexit wmt_pcm_dma_platform_remove(struct platform_device *pdev)
{
	DBG_DETAIL();
	snd_soc_unregister_platform(&pdev->dev);
	return 0;
}

static struct platform_driver wmt_pcm_dma_driver = {
	.driver = {
			.name = "wmt-pcm-dma",
			.owner = THIS_MODULE,
	},

	.probe = wmt_pcm_dma_platform_probe,
	.remove = __devexit_p(wmt_pcm_dma_platform_remove),
};

module_platform_driver(wmt_pcm_dma_driver);

MODULE_AUTHOR("WonderMedia Technologies, Inc.");
MODULE_DESCRIPTION("WMT [ALSA SoC/pcm dma] driver");
MODULE_LICENSE("GPL");