/*
   * sh_dac_audio.c - SuperH DAC audio driver for ALSA
   *
   * Copyright (c) 2009 by Rafael Ignacio Zurita <rizurita@yahoo.com>
   *
   *
   * Based on sh_dac_audio.c (Copyright (C) 2004, 2005 by Andriy Skulysh)
   *
   *   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, write to the Free Software
   *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
   *
   */
  
  #include <linux/hrtimer.h>
  #include <linux/interrupt.h>
  #include <linux/io.h>
  #include <linux/platform_device.h>

  #include <linux/slab.h>

  #include <linux/module.h>

  #include <sound/core.h>
  #include <sound/initval.h>
  #include <sound/pcm.h>
  #include <sound/sh_dac_audio.h>
  #include <asm/clock.h>
  #include <asm/hd64461.h>
  #include <mach/hp6xx.h>
  #include <cpu/dac.h>
  
  MODULE_AUTHOR("Rafael Ignacio Zurita <rizurita@yahoo.com>");
  MODULE_DESCRIPTION("SuperH DAC audio driver");
  MODULE_LICENSE("GPL");
  MODULE_SUPPORTED_DEVICE("{{SuperH DAC audio support}}");
  
  /* Module Parameters */
  static int index = SNDRV_DEFAULT_IDX1;
  static char *id = SNDRV_DEFAULT_STR1;
  module_param(index, int, 0444);
  MODULE_PARM_DESC(index, "Index value for SuperH DAC audio.");
  module_param(id, charp, 0444);
  MODULE_PARM_DESC(id, "ID string for SuperH DAC audio.");
  
  /* main struct */
  struct snd_sh_dac {
  	struct snd_card *card;
  	struct snd_pcm_substream *substream;
  	struct hrtimer hrtimer;
  	ktime_t wakeups_per_second;
  
  	int rate;
  	int empty;
  	char *data_buffer, *buffer_begin, *buffer_end;
  	int processed; /* bytes proccesed, to compare with period_size */
  	int buffer_size;
  	struct dac_audio_pdata *pdata;
  };
  
  
  static void dac_audio_start_timer(struct snd_sh_dac *chip)
  {
  	hrtimer_start(&chip->hrtimer, chip->wakeups_per_second,
  		      HRTIMER_MODE_REL);
  }
  
  static void dac_audio_stop_timer(struct snd_sh_dac *chip)
  {
  	hrtimer_cancel(&chip->hrtimer);
  }
  
  static void dac_audio_reset(struct snd_sh_dac *chip)
  {
  	dac_audio_stop_timer(chip);
  	chip->buffer_begin = chip->buffer_end = chip->data_buffer;
  	chip->processed = 0;
  	chip->empty = 1;
  }
  
  static void dac_audio_set_rate(struct snd_sh_dac *chip)
  {

  	chip->wakeups_per_second = 1000000000 / chip->rate;

  }
  
  
  /* PCM INTERFACE */

  static const struct snd_pcm_hardware snd_sh_dac_pcm_hw = {

  	.info			= (SNDRV_PCM_INFO_MMAP |
  					SNDRV_PCM_INFO_MMAP_VALID |
  					SNDRV_PCM_INFO_INTERLEAVED |
  					SNDRV_PCM_INFO_HALF_DUPLEX),
  	.formats		= SNDRV_PCM_FMTBIT_U8,
  	.rates			= SNDRV_PCM_RATE_8000,
  	.rate_min		= 8000,
  	.rate_max		= 8000,
  	.channels_min		= 1,
  	.channels_max		= 1,
  	.buffer_bytes_max	= (48*1024),
  	.period_bytes_min	= 1,
  	.period_bytes_max	= (48*1024),
  	.periods_min		= 1,
  	.periods_max		= 1024,
  };
  
  static int snd_sh_dac_pcm_open(struct snd_pcm_substream *substream)
  {
  	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
  	struct snd_pcm_runtime *runtime = substream->runtime;
  
  	runtime->hw = snd_sh_dac_pcm_hw;
  
  	chip->substream = substream;
  	chip->buffer_begin = chip->buffer_end = chip->data_buffer;
  	chip->processed = 0;
  	chip->empty = 1;
  
  	chip->pdata->start(chip->pdata);
  
  	return 0;
  }
  
  static int snd_sh_dac_pcm_close(struct snd_pcm_substream *substream)
  {
  	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
  
  	chip->substream = NULL;
  
  	dac_audio_stop_timer(chip);
  	chip->pdata->stop(chip->pdata);
  
  	return 0;
  }
  
  static int snd_sh_dac_pcm_hw_params(struct snd_pcm_substream *substream,
  				struct snd_pcm_hw_params *hw_params)
  {
  	return snd_pcm_lib_malloc_pages(substream,
  			params_buffer_bytes(hw_params));
  }
  
  static int snd_sh_dac_pcm_hw_free(struct snd_pcm_substream *substream)
  {
  	return snd_pcm_lib_free_pages(substream);
  }
  
  static int snd_sh_dac_pcm_prepare(struct snd_pcm_substream *substream)
  {
  	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
  	struct snd_pcm_runtime *runtime = chip->substream->runtime;
  
  	chip->buffer_size = runtime->buffer_size;
  	memset(chip->data_buffer, 0, chip->pdata->buffer_size);
  
  	return 0;
  }
  
  static int snd_sh_dac_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
  {
  	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
  
  	switch (cmd) {
  	case SNDRV_PCM_TRIGGER_START:
  		dac_audio_start_timer(chip);
  		break;
  	case SNDRV_PCM_TRIGGER_STOP:
  		chip->buffer_begin = chip->buffer_end = chip->data_buffer;
  		chip->processed = 0;
  		chip->empty = 1;
  		dac_audio_stop_timer(chip);
  		break;
  	default:
  		 return -EINVAL;
  	}
  
  	return 0;
  }

  static int snd_sh_dac_pcm_copy(struct snd_pcm_substream *substream,
  			       int channel, unsigned long pos,
  			       void __user *src, unsigned long count)

  {
  	/* channel is not used (interleaved data) */
  	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
  	struct snd_pcm_runtime *runtime = substream->runtime;

  	if (copy_from_user_toio(chip->data_buffer + pos, src, count))
  		return -EFAULT;
  	chip->buffer_end = chip->data_buffer + pos + count;

  	if (chip->empty) {
  		chip->empty = 0;
  		dac_audio_start_timer(chip);
  	}
  
  	return 0;
  }

  static int snd_sh_dac_pcm_copy_kernel(struct snd_pcm_substream *substream,
  				      int channel, unsigned long pos,
  				      void *src, unsigned long count)
  {
  	/* channel is not used (interleaved data) */
  	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
  	struct snd_pcm_runtime *runtime = substream->runtime;
  
  	memcpy_toio(chip->data_buffer + pos, src, count);
  	chip->buffer_end = chip->data_buffer + pos + count;

  
  	if (chip->empty) {
  		chip->empty = 0;
  		dac_audio_start_timer(chip);
  	}
  
  	return 0;
  }
  
  static int snd_sh_dac_pcm_silence(struct snd_pcm_substream *substream,

  				  int channel, unsigned long pos,
  				  unsigned long count)

  {
  	/* channel is not used (interleaved data) */
  	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
  	struct snd_pcm_runtime *runtime = substream->runtime;

  	memset_io(chip->data_buffer + pos, 0, count);
  	chip->buffer_end = chip->data_buffer + pos + count;

  
  	if (chip->empty) {
  		chip->empty = 0;
  		dac_audio_start_timer(chip);
  	}
  
  	return 0;
  }
  
  static
  snd_pcm_uframes_t snd_sh_dac_pcm_pointer(struct snd_pcm_substream *substream)
  {
  	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
  	int pointer = chip->buffer_begin - chip->data_buffer;
  
  	return pointer;
  }
  
  /* pcm ops */

  static const struct snd_pcm_ops snd_sh_dac_pcm_ops = {

  	.open		= snd_sh_dac_pcm_open,
  	.close		= snd_sh_dac_pcm_close,
  	.ioctl		= snd_pcm_lib_ioctl,
  	.hw_params	= snd_sh_dac_pcm_hw_params,
  	.hw_free	= snd_sh_dac_pcm_hw_free,
  	.prepare	= snd_sh_dac_pcm_prepare,
  	.trigger	= snd_sh_dac_pcm_trigger,
  	.pointer	= snd_sh_dac_pcm_pointer,

  	.copy_user	= snd_sh_dac_pcm_copy,
  	.copy_kernel	= snd_sh_dac_pcm_copy_kernel,
  	.fill_silence	= snd_sh_dac_pcm_silence,

  	.mmap		= snd_pcm_lib_mmap_iomem,
  };

  static int snd_sh_dac_pcm(struct snd_sh_dac *chip, int device)

  {
  	int err;
  	struct snd_pcm *pcm;
  
  	/* device should be always 0 for us */
  	err = snd_pcm_new(chip->card, "SH_DAC PCM", device, 1, 0, &pcm);
  	if (err < 0)
  		return err;
  
  	pcm->private_data = chip;
  	strcpy(pcm->name, "SH_DAC PCM");
  	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &snd_sh_dac_pcm_ops);
  
  	/* buffer size=48K */
  	snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
  					  snd_dma_continuous_data(GFP_KERNEL),
  							48 * 1024,
  							48 * 1024);
  
  	return 0;
  }
  /* END OF PCM INTERFACE */
  
  
  /* driver .remove  --  destructor */
  static int snd_sh_dac_remove(struct platform_device *devptr)
  {
  	snd_card_free(platform_get_drvdata(devptr));

  	return 0;
  }
  
  /* free -- it has been defined by create */
  static int snd_sh_dac_free(struct snd_sh_dac *chip)
  {
  	/* release the data */
  	kfree(chip->data_buffer);
  	kfree(chip);
  
  	return 0;
  }
  
  static int snd_sh_dac_dev_free(struct snd_device *device)
  {
  	struct snd_sh_dac *chip = device->device_data;
  
  	return snd_sh_dac_free(chip);
  }
  
  static enum hrtimer_restart sh_dac_audio_timer(struct hrtimer *handle)
  {
  	struct snd_sh_dac *chip = container_of(handle, struct snd_sh_dac,
  					       hrtimer);
  	struct snd_pcm_runtime *runtime = chip->substream->runtime;
  	ssize_t b_ps = frames_to_bytes(runtime, runtime->period_size);
  
  	if (!chip->empty) {
  		sh_dac_output(*chip->buffer_begin, chip->pdata->channel);
  		chip->buffer_begin++;
  
  		chip->processed++;
  		if (chip->processed >= b_ps) {
  			chip->processed -= b_ps;
  			snd_pcm_period_elapsed(chip->substream);
  		}
  
  		if (chip->buffer_begin == (chip->data_buffer +
  					   chip->buffer_size - 1))
  			chip->buffer_begin = chip->data_buffer;
  
  		if (chip->buffer_begin == chip->buffer_end)
  			chip->empty = 1;
  
  	}
  
  	if (!chip->empty)
  		hrtimer_start(&chip->hrtimer, chip->wakeups_per_second,
  			      HRTIMER_MODE_REL);
  
  	return HRTIMER_NORESTART;
  }
  
  /* create  --  chip-specific constructor for the cards components */

  static int snd_sh_dac_create(struct snd_card *card,
  			     struct platform_device *devptr,
  			     struct snd_sh_dac **rchip)

  {
  	struct snd_sh_dac *chip;
  	int err;
  
  	static struct snd_device_ops ops = {
  		   .dev_free = snd_sh_dac_dev_free,
  	};
  
  	*rchip = NULL;
  
  	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
  	if (chip == NULL)
  		return -ENOMEM;
  
  	chip->card = card;
  
  	hrtimer_init(&chip->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
  	chip->hrtimer.function = sh_dac_audio_timer;
  
  	dac_audio_reset(chip);
  	chip->rate = 8000;
  	dac_audio_set_rate(chip);
  
  	chip->pdata = devptr->dev.platform_data;
  
  	chip->data_buffer = kmalloc(chip->pdata->buffer_size, GFP_KERNEL);
  	if (chip->data_buffer == NULL) {
  		kfree(chip);
  		return -ENOMEM;
  	}
  
  	err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops);
  	if (err < 0) {
  		snd_sh_dac_free(chip);
  		return err;
  	}
  
  	*rchip = chip;
  
  	return 0;
  }
  
  /* driver .probe  --  constructor */

  static int snd_sh_dac_probe(struct platform_device *devptr)

  {
  	struct snd_sh_dac *chip;
  	struct snd_card *card;
  	int err;

  	err = snd_card_new(&devptr->dev, index, id, THIS_MODULE, 0, &card);

  	if (err < 0) {
  			snd_printk(KERN_ERR "cannot allocate the card
  ");
  			return err;
  	}
  
  	err = snd_sh_dac_create(card, devptr, &chip);
  	if (err < 0)
  		goto probe_error;
  
  	err = snd_sh_dac_pcm(chip, 0);
  	if (err < 0)
  		goto probe_error;
  
  	strcpy(card->driver, "snd_sh_dac");
  	strcpy(card->shortname, "SuperH DAC audio driver");
  	printk(KERN_INFO "%s %s", card->longname, card->shortname);
  
  	err = snd_card_register(card);
  	if (err < 0)
  		goto probe_error;

  	snd_printk(KERN_INFO "ALSA driver for SuperH DAC audio");

  
  	platform_set_drvdata(devptr, card);
  	return 0;
  
  probe_error:
  	snd_card_free(card);
  	return err;
  }
  
  /*
   * "driver" definition
   */

  static struct platform_driver sh_dac_driver = {

  	.probe	= snd_sh_dac_probe,
  	.remove = snd_sh_dac_remove,
  	.driver = {
  		.name = "dac_audio",
  	},
  };

  module_platform_driver(sh_dac_driver);