/*
 * imx-pcm-fiq.c  --  ALSA Soc Audio Layer
 *
 * Copyright 2009 Sascha Hauer <s.hauer@pengutronix.de>
 *
 * This code is based on code copyrighted by Freescale,
 * Liam Girdwood, Javier Martin and probably others.
 *
 *  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/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#include <sound/core.h>
#include <sound/initval.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>

#include <asm/fiq.h>

#include <mach/ssi.h>

#include "imx-ssi.h"

struct imx_pcm_runtime_data {
	int period;
	int periods;
	unsigned long offset;
	unsigned long last_offset;
	unsigned long size;
	struct hrtimer hrt;
	int poll_time_ns;
	struct snd_pcm_substream *substream;
	atomic_t running;
};

static enum hrtimer_restart snd_hrtimer_callback(struct hrtimer *hrt)
{
	struct imx_pcm_runtime_data *iprtd =
		container_of(hrt, struct imx_pcm_runtime_data, hrt);
	struct snd_pcm_substream *substream = iprtd->substream;
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct pt_regs regs;
	unsigned long delta;

	if (!atomic_read(&iprtd->running))
		return HRTIMER_NORESTART;

	get_fiq_regs(&regs);

	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
		iprtd->offset = regs.ARM_r8 & 0xffff;
	else
		iprtd->offset = regs.ARM_r9 & 0xffff;

	/* How much data have we transferred since the last period report? */
	if (iprtd->offset >= iprtd->last_offset)
		delta = iprtd->offset - iprtd->last_offset;
	else
		delta = runtime->buffer_size + iprtd->offset
			- iprtd->last_offset;

	/* If we've transferred at least a period then report it and
	 * reset our poll time */
	if (delta >= iprtd->period) {
		snd_pcm_period_elapsed(substream);
		iprtd->last_offset = iprtd->offset;
	}

	hrtimer_forward_now(hrt, ns_to_ktime(iprtd->poll_time_ns));

	return HRTIMER_RESTART;
}

static struct fiq_handler fh = {
	.name		= DRV_NAME,
};

static int snd_imx_pcm_hw_params(struct snd_pcm_substream *substream,
				struct snd_pcm_hw_params *params)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct imx_pcm_runtime_data *iprtd = runtime->private_data;

	iprtd->size = params_buffer_bytes(params);
	iprtd->periods = params_periods(params);
	iprtd->period = params_period_bytes(params) ;
	iprtd->offset = 0;
	iprtd->last_offset = 0;
	iprtd->poll_time_ns = 1000000000 / params_rate(params) *
				params_period_size(params);
	snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);

	return 0;
}

static int snd_imx_pcm_prepare(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct imx_pcm_runtime_data *iprtd = runtime->private_data;
	struct pt_regs regs;

	get_fiq_regs(&regs);
	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
		regs.ARM_r8 = (iprtd->period * iprtd->periods - 1) << 16;
	else
		regs.ARM_r9 = (iprtd->period * iprtd->periods - 1) << 16;

	set_fiq_regs(&regs);

	return 0;
}

static int fiq_enable;
static int imx_pcm_fiq;

static int snd_imx_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct imx_pcm_runtime_data *iprtd = runtime->private_data;

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
	case SNDRV_PCM_TRIGGER_RESUME:
	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
		atomic_set(&iprtd->running, 1);
		hrtimer_start(&iprtd->hrt, ns_to_ktime(iprtd->poll_time_ns),
		      HRTIMER_MODE_REL);
		if (++fiq_enable == 1)
			enable_fiq(imx_pcm_fiq);

		break;

	case SNDRV_PCM_TRIGGER_STOP:
	case SNDRV_PCM_TRIGGER_SUSPEND:
	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
		atomic_set(&iprtd->running, 0);

		if (--fiq_enable == 0)
			disable_fiq(imx_pcm_fiq);

		break;
	default:
		return -EINVAL;
	}

	return 0;
}

static snd_pcm_uframes_t snd_imx_pcm_pointer(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct imx_pcm_runtime_data *iprtd = runtime->private_data;

	return bytes_to_frames(substream->runtime, iprtd->offset);
}

static struct snd_pcm_hardware snd_imx_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,
	.formats = SNDRV_PCM_FMTBIT_S16_LE,
	.rate_min = 8000,
	.channels_min = 2,
	.channels_max = 2,
	.buffer_bytes_max = IMX_SSI_DMABUF_SIZE,
	.period_bytes_min = 128,
	.period_bytes_max = 16 * 1024,
	.periods_min = 4,
	.periods_max = 255,
	.fifo_size = 0,
};

static int snd_imx_open(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct imx_pcm_runtime_data *iprtd;
	int ret;

	iprtd = kzalloc(sizeof(*iprtd), GFP_KERNEL);
	if (iprtd == NULL)
		return -ENOMEM;
	runtime->private_data = iprtd;

	iprtd->substream = substream;

	atomic_set(&iprtd->running, 0);
	hrtimer_init(&iprtd->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	iprtd->hrt.function = snd_hrtimer_callback;

	ret = snd_pcm_hw_constraint_integer(substream->runtime,
			SNDRV_PCM_HW_PARAM_PERIODS);
	if (ret < 0) {
		kfree(iprtd);
		return ret;
	}

	snd_soc_set_runtime_hwparams(substream, &snd_imx_hardware);
	return 0;
}

static int snd_imx_close(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct imx_pcm_runtime_data *iprtd = runtime->private_data;

	hrtimer_cancel(&iprtd->hrt);

	kfree(iprtd);

	return 0;
}

static struct snd_pcm_ops imx_pcm_ops = {
	.open		= snd_imx_open,
	.close		= snd_imx_close,
	.ioctl		= snd_pcm_lib_ioctl,
	.hw_params	= snd_imx_pcm_hw_params,
	.prepare	= snd_imx_pcm_prepare,
	.trigger	= snd_imx_pcm_trigger,
	.pointer	= snd_imx_pcm_pointer,
	.mmap		= snd_imx_pcm_mmap,
};

static int ssi_irq = 0;

static int imx_pcm_fiq_new(struct snd_soc_pcm_runtime *rtd)
{
	struct snd_pcm *pcm = rtd->pcm;
	struct snd_pcm_substream *substream;
	int ret;

	ret = imx_pcm_new(rtd);
	if (ret)
		return ret;

	substream = pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream;
	if (substream) {
		struct snd_dma_buffer *buf = &substream->dma_buffer;

		imx_ssi_fiq_tx_buffer = (unsigned long)buf->area;
	}

	substream = pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream;
	if (substream) {
		struct snd_dma_buffer *buf = &substream->dma_buffer;

		imx_ssi_fiq_rx_buffer = (unsigned long)buf->area;
	}

	set_fiq_handler(&imx_ssi_fiq_start,
		&imx_ssi_fiq_end - &imx_ssi_fiq_start);

	return 0;
}

static void imx_pcm_fiq_free(struct snd_pcm *pcm)
{
	mxc_set_irq_fiq(ssi_irq, 0);
	release_fiq(&fh);
	imx_pcm_free(pcm);
}

static struct snd_soc_platform_driver imx_soc_platform_fiq = {
	.ops		= &imx_pcm_ops,
	.pcm_new	= imx_pcm_fiq_new,
	.pcm_free	= imx_pcm_fiq_free,
};

static int __devinit imx_soc_platform_probe(struct platform_device *pdev)
{
	struct imx_ssi *ssi = platform_get_drvdata(pdev);
	int ret;

	ret = claim_fiq(&fh);
	if (ret) {
		dev_err(&pdev->dev, "failed to claim fiq: %d", ret);
		return ret;
	}

	mxc_set_irq_fiq(ssi->irq, 1);
	ssi_irq = ssi->irq;

	imx_pcm_fiq = ssi->irq;

	imx_ssi_fiq_base = (unsigned long)ssi->base;

	ssi->dma_params_tx.burstsize = 4;
	ssi->dma_params_rx.burstsize = 6;

	ret = snd_soc_register_platform(&pdev->dev, &imx_soc_platform_fiq);
	if (ret)
		goto failed_register;

	return 0;

failed_register:
	mxc_set_irq_fiq(ssi_irq, 0);
	release_fiq(&fh);

	return ret;
}

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

static struct platform_driver imx_pcm_driver = {
	.driver = {
			.name = "imx-fiq-pcm-audio",
			.owner = THIS_MODULE,
	},

	.probe = imx_soc_platform_probe,
	.remove = __devexit_p(imx_soc_platform_remove),
};

module_platform_driver(imx_pcm_driver);

MODULE_LICENSE("GPL");
