/*
   * kirkwood-dma.c
   *
   * (c) 2010 Arnaud Patard <apatard@mandriva.com>

   * (c) 2010 Arnaud Patard <arnaud.patard@rtp-net.org>

   *
   *  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/init.h>
  #include <linux/module.h>
  #include <linux/device.h>
  #include <linux/io.h>
  #include <linux/slab.h>
  #include <linux/interrupt.h>
  #include <linux/dma-mapping.h>
  #include <linux/mbus.h>
  #include <sound/soc.h>

  #include "kirkwood.h"
  
  #define KIRKWOOD_RATES \
  	(SNDRV_PCM_RATE_44100 | \
  	 SNDRV_PCM_RATE_48000 | SNDRV_PCM_RATE_96000)
  #define KIRKWOOD_FORMATS \
  	(SNDRV_PCM_FMTBIT_S16_LE | \
  	 SNDRV_PCM_FMTBIT_S24_LE | \
  	 SNDRV_PCM_FMTBIT_S32_LE)
  
  struct kirkwood_dma_priv {
  	struct snd_pcm_substream *play_stream;
  	struct snd_pcm_substream *rec_stream;
  	struct kirkwood_dma_data *data;
  };
  
  static struct snd_pcm_hardware kirkwood_dma_snd_hw = {
  	.info = (SNDRV_PCM_INFO_INTERLEAVED |
  		 SNDRV_PCM_INFO_MMAP |
  		 SNDRV_PCM_INFO_MMAP_VALID |
  		 SNDRV_PCM_INFO_BLOCK_TRANSFER |
  		 SNDRV_PCM_INFO_PAUSE),
  	.formats		= KIRKWOOD_FORMATS,
  	.rates			= KIRKWOOD_RATES,
  	.rate_min		= 44100,
  	.rate_max		= 96000,
  	.channels_min		= 1,
  	.channels_max		= 2,
  	.buffer_bytes_max	= KIRKWOOD_SND_MAX_PERIOD_BYTES * KIRKWOOD_SND_MAX_PERIODS,
  	.period_bytes_min	= KIRKWOOD_SND_MIN_PERIOD_BYTES,
  	.period_bytes_max	= KIRKWOOD_SND_MAX_PERIOD_BYTES,
  	.periods_min		= KIRKWOOD_SND_MIN_PERIODS,
  	.periods_max		= KIRKWOOD_SND_MAX_PERIODS,
  	.fifo_size		= 0,
  };
  
  static u64 kirkwood_dma_dmamask = 0xFFFFFFFFUL;
  
  static irqreturn_t kirkwood_dma_irq(int irq, void *dev_id)
  {
  	struct kirkwood_dma_priv *prdata = dev_id;
  	struct kirkwood_dma_data *priv = prdata->data;
  	unsigned long mask, status, cause;
  
  	mask = readl(priv->io + KIRKWOOD_INT_MASK);
  	status = readl(priv->io + KIRKWOOD_INT_CAUSE) & mask;
  
  	cause = readl(priv->io + KIRKWOOD_ERR_CAUSE);
  	if (unlikely(cause)) {
  		printk(KERN_WARNING "%s: got err interrupt 0x%lx
  ",
  				__func__, cause);
  		writel(cause, priv->io + KIRKWOOD_ERR_CAUSE);
  		return IRQ_HANDLED;
  	}
  
  	/* we've enabled only bytes interrupts ... */
  	if (status & ~(KIRKWOOD_INT_CAUSE_PLAY_BYTES | \
  			KIRKWOOD_INT_CAUSE_REC_BYTES)) {
  		printk(KERN_WARNING "%s: unexpected interrupt %lx
  ",
  			__func__, status);
  		return IRQ_NONE;
  	}
  
  	/* ack int */
  	writel(status, priv->io + KIRKWOOD_INT_CAUSE);
  
  	if (status & KIRKWOOD_INT_CAUSE_PLAY_BYTES)
  		snd_pcm_period_elapsed(prdata->play_stream);
  
  	if (status & KIRKWOOD_INT_CAUSE_REC_BYTES)
  		snd_pcm_period_elapsed(prdata->rec_stream);
  
  	return IRQ_HANDLED;
  }

  static void
  kirkwood_dma_conf_mbus_windows(void __iomem *base, int win,
  			       unsigned long dma,
  			       const struct mbus_dram_target_info *dram)

  {
  	int i;
  
  	/* First disable and clear windows */
  	writel(0, base + KIRKWOOD_AUDIO_WIN_CTRL_REG(win));
  	writel(0, base + KIRKWOOD_AUDIO_WIN_BASE_REG(win));
  
  	/* try to find matching cs for current dma address */
  	for (i = 0; i < dram->num_cs; i++) {

  		const struct mbus_dram_window *cs = dram->cs + i;

  		if ((cs->base & 0xffff0000) < (dma & 0xffff0000)) {
  			writel(cs->base & 0xffff0000,
  				base + KIRKWOOD_AUDIO_WIN_BASE_REG(win));
  			writel(((cs->size - 1) & 0xffff0000) |
  				(cs->mbus_attr << 8) |
  				(dram->mbus_dram_target_id << 4) | 1,
  				base + KIRKWOOD_AUDIO_WIN_CTRL_REG(win));
  		}
  	}
  }
  
  static int kirkwood_dma_open(struct snd_pcm_substream *substream)
  {
  	int err;
  	struct snd_pcm_runtime *runtime = substream->runtime;
  	struct snd_soc_pcm_runtime *soc_runtime = substream->private_data;

  	struct snd_soc_platform *platform = soc_runtime->platform;
  	struct snd_soc_dai *cpu_dai = soc_runtime->cpu_dai;

  	struct kirkwood_dma_data *priv;

  	struct kirkwood_dma_priv *prdata = snd_soc_platform_get_drvdata(platform);

  	const struct mbus_dram_target_info *dram;

  	unsigned long addr;
  
  	priv = snd_soc_dai_get_dma_data(cpu_dai, substream);
  	snd_soc_set_runtime_hwparams(substream, &kirkwood_dma_snd_hw);

  	/* Ensure that all constraints linked to dma burst are fulfilled */

  	err = snd_pcm_hw_constraint_minmax(runtime,
  			SNDRV_PCM_HW_PARAM_BUFFER_BYTES,
  			priv->burst * 2,
  			KIRKWOOD_AUDIO_BUF_MAX-1);
  	if (err < 0)
  		return err;
  
  	err = snd_pcm_hw_constraint_step(runtime, 0,
  			SNDRV_PCM_HW_PARAM_BUFFER_BYTES,
  			priv->burst);
  	if (err < 0)
  		return err;
  
  	err = snd_pcm_hw_constraint_step(substream->runtime, 0,
  			 SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
  			 priv->burst);
  	if (err < 0)
  		return err;

  	if (prdata == NULL) {

  		prdata = kzalloc(sizeof(struct kirkwood_dma_priv), GFP_KERNEL);
  		if (prdata == NULL)
  			return -ENOMEM;
  
  		prdata->data = priv;
  
  		err = request_irq(priv->irq, kirkwood_dma_irq, IRQF_SHARED,
  				  "kirkwood-i2s", prdata);
  		if (err) {
  			kfree(prdata);
  			return -EBUSY;
  		}

  		snd_soc_platform_set_drvdata(platform, prdata);

  
  		/*
  		 * Enable Error interrupts. We're only ack'ing them but

  		 * it's useful for diagnostics

  		 */
  		writel((unsigned long)-1, priv->io + KIRKWOOD_ERR_MASK);
  	}

  	dram = mv_mbus_dram_info();

  	addr = virt_to_phys(substream->dma_buffer.area);
  	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
  		prdata->play_stream = substream;
  		kirkwood_dma_conf_mbus_windows(priv->io,

  			KIRKWOOD_PLAYBACK_WIN, addr, dram);

  	} else {
  		prdata->rec_stream = substream;
  		kirkwood_dma_conf_mbus_windows(priv->io,

  			KIRKWOOD_RECORD_WIN, addr, dram);

  	}
  
  	return 0;
  }
  
  static int kirkwood_dma_close(struct snd_pcm_substream *substream)
  {
  	struct snd_soc_pcm_runtime *soc_runtime = substream->private_data;

  	struct snd_soc_dai *cpu_dai = soc_runtime->cpu_dai;
  	struct snd_soc_platform *platform = soc_runtime->platform;
  	struct kirkwood_dma_priv *prdata = snd_soc_platform_get_drvdata(platform);

  	struct kirkwood_dma_data *priv;
  
  	priv = snd_soc_dai_get_dma_data(cpu_dai, substream);
  
  	if (!prdata || !priv)
  		return 0;
  
  	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
  		prdata->play_stream = NULL;
  	else
  		prdata->rec_stream = NULL;
  
  	if (!prdata->play_stream && !prdata->rec_stream) {
  		writel(0, priv->io + KIRKWOOD_ERR_MASK);
  		free_irq(priv->irq, prdata);
  		kfree(prdata);

  		snd_soc_platform_set_drvdata(platform, NULL);

  	}
  
  	return 0;
  }
  
  static int kirkwood_dma_hw_params(struct snd_pcm_substream *substream,
  				struct snd_pcm_hw_params *params)
  {
  	struct snd_pcm_runtime *runtime = substream->runtime;
  
  	snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
  	runtime->dma_bytes = params_buffer_bytes(params);
  
  	return 0;
  }
  
  static int kirkwood_dma_hw_free(struct snd_pcm_substream *substream)
  {
  	snd_pcm_set_runtime_buffer(substream, NULL);
  	return 0;
  }
  
  static int kirkwood_dma_prepare(struct snd_pcm_substream *substream)
  {
  	struct snd_pcm_runtime *runtime = substream->runtime;
  	struct snd_soc_pcm_runtime *soc_runtime = substream->private_data;

  	struct snd_soc_dai *cpu_dai = soc_runtime->cpu_dai;

  	struct kirkwood_dma_data *priv;
  	unsigned long size, count;
  
  	priv = snd_soc_dai_get_dma_data(cpu_dai, substream);
  
  	/* compute buffer size in term of "words" as requested in specs */
  	size = frames_to_bytes(runtime, runtime->buffer_size);
  	size = (size>>2)-1;
  	count = snd_pcm_lib_period_bytes(substream);
  
  	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
  		writel(count, priv->io + KIRKWOOD_PLAY_BYTE_INT_COUNT);
  		writel(runtime->dma_addr, priv->io + KIRKWOOD_PLAY_BUF_ADDR);
  		writel(size, priv->io + KIRKWOOD_PLAY_BUF_SIZE);
  	} else {
  		writel(count, priv->io + KIRKWOOD_REC_BYTE_INT_COUNT);
  		writel(runtime->dma_addr, priv->io + KIRKWOOD_REC_BUF_ADDR);
  		writel(size, priv->io + KIRKWOOD_REC_BUF_SIZE);
  	}
  
  
  	return 0;
  }
  
  static snd_pcm_uframes_t kirkwood_dma_pointer(struct snd_pcm_substream
  						*substream)
  {
  	struct snd_soc_pcm_runtime *soc_runtime = substream->private_data;

  	struct snd_soc_dai *cpu_dai = soc_runtime->cpu_dai;

  	struct kirkwood_dma_data *priv;
  	snd_pcm_uframes_t count;
  
  	priv = snd_soc_dai_get_dma_data(cpu_dai, substream);
  
  	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
  		count = bytes_to_frames(substream->runtime,
  			readl(priv->io + KIRKWOOD_PLAY_BYTE_COUNT));
  	else
  		count = bytes_to_frames(substream->runtime,
  			readl(priv->io + KIRKWOOD_REC_BYTE_COUNT));
  
  	return count;
  }
  
  struct snd_pcm_ops kirkwood_dma_ops = {
  	.open =		kirkwood_dma_open,
  	.close =        kirkwood_dma_close,
  	.ioctl =	snd_pcm_lib_ioctl,
  	.hw_params =	kirkwood_dma_hw_params,
  	.hw_free =      kirkwood_dma_hw_free,
  	.prepare =      kirkwood_dma_prepare,
  	.pointer =	kirkwood_dma_pointer,
  };
  
  static int kirkwood_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 = kirkwood_dma_snd_hw.buffer_bytes_max;
  
  	buf->dev.type = SNDRV_DMA_TYPE_DEV;
  	buf->dev.dev = pcm->card->dev;
  	buf->area = dma_alloc_coherent(pcm->card->dev, size,
  			&buf->addr, GFP_KERNEL);
  	if (!buf->area)
  		return -ENOMEM;
  	buf->bytes = size;
  	buf->private_data = NULL;
  
  	return 0;
  }

  static int kirkwood_dma_new(struct snd_soc_pcm_runtime *rtd)

  {

  	struct snd_card *card = rtd->card->snd_card;

  	struct snd_pcm *pcm = rtd->pcm;

  	int ret;
  
  	if (!card->dev->dma_mask)
  		card->dev->dma_mask = &kirkwood_dma_dmamask;
  	if (!card->dev->coherent_dma_mask)
  		card->dev->coherent_dma_mask = 0xffffffff;

  	if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream) {

  		ret = kirkwood_dma_preallocate_dma_buffer(pcm,
  				SNDRV_PCM_STREAM_PLAYBACK);
  		if (ret)
  			return ret;
  	}

  	if (pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream) {

  		ret = kirkwood_dma_preallocate_dma_buffer(pcm,
  				SNDRV_PCM_STREAM_CAPTURE);
  		if (ret)
  			return ret;
  	}
  
  	return 0;
  }
  
  static void kirkwood_dma_free_dma_buffers(struct snd_pcm *pcm)
  {
  	struct snd_pcm_substream *substream;
  	struct snd_dma_buffer *buf;
  	int stream;
  
  	for (stream = 0; stream < 2; stream++) {
  		substream = pcm->streams[stream].substream;
  		if (!substream)
  			continue;
  		buf = &substream->dma_buffer;
  		if (!buf->area)
  			continue;
  
  		dma_free_coherent(pcm->card->dev, buf->bytes,
  				buf->area, buf->addr);
  		buf->area = NULL;
  	}
  }

  static struct snd_soc_platform_driver kirkwood_soc_platform = {
  	.ops		= &kirkwood_dma_ops,

  	.pcm_new	= kirkwood_dma_new,
  	.pcm_free	= kirkwood_dma_free_dma_buffers,
  };

  static int __devinit kirkwood_soc_platform_probe(struct platform_device *pdev)

  {

  	return snd_soc_register_platform(&pdev->dev, &kirkwood_soc_platform);

  }

  static int __devexit kirkwood_soc_platform_remove(struct platform_device *pdev)

  {

  	snd_soc_unregister_platform(&pdev->dev);
  	return 0;
  }
  
  static struct platform_driver kirkwood_pcm_driver = {
  	.driver = {
  			.name = "kirkwood-pcm-audio",
  			.owner = THIS_MODULE,
  	},
  
  	.probe = kirkwood_soc_platform_probe,
  	.remove = __devexit_p(kirkwood_soc_platform_remove),
  };

  module_platform_driver(kirkwood_pcm_driver);

  MODULE_AUTHOR("Arnaud Patard <arnaud.patard@rtp-net.org>");

  MODULE_DESCRIPTION("Marvell Kirkwood Audio DMA module");
  MODULE_LICENSE("GPL");

  MODULE_ALIAS("platform:kirkwood-pcm-audio");