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s3c24xx-pcm.c

/*
 * s3c24xx-pcm.c  --  ALSA Soc Audio Layer
 *
 * (c) 2006 Wolfson Microelectronics PLC.
 * Graeme Gregory graeme.gregory@wolfsonmicro.com or linux@wolfsonmicro.com
 *
 * Copyright 2004-2005 Simtec Electronics
 *    http://armlinux.simtec.co.uk/
 *    Ben Dooks <ben@simtec.co.uk>
 *
 *  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/module.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>

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

#include <asm/dma.h>
#include <mach/hardware.h>
#include <mach/dma.h>
#include <plat/audio.h>

#include "s3c24xx-pcm.h"

static const struct snd_pcm_hardware s3c24xx_pcm_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 |
                            SNDRV_PCM_FMTBIT_U16_LE |
                            SNDRV_PCM_FMTBIT_U8 |
                            SNDRV_PCM_FMTBIT_S8,
      .channels_min           = 2,
      .channels_max           = 2,
      .buffer_bytes_max = 128*1024,
      .period_bytes_min = PAGE_SIZE,
      .period_bytes_max = PAGE_SIZE*2,
      .periods_min            = 2,
      .periods_max            = 128,
      .fifo_size        = 32,
};

struct s3c24xx_runtime_data {
      spinlock_t lock;
      int state;
      unsigned int dma_loaded;
      unsigned int dma_limit;
      unsigned int dma_period;
      dma_addr_t dma_start;
      dma_addr_t dma_pos;
      dma_addr_t dma_end;
      struct s3c24xx_pcm_dma_params *params;
};

/* s3c24xx_pcm_enqueue
 *
 * place a dma buffer onto the queue for the dma system
 * to handle.
*/
static void s3c24xx_pcm_enqueue(struct snd_pcm_substream *substream)
{
      struct s3c24xx_runtime_data *prtd = substream->runtime->private_data;
      dma_addr_t pos = prtd->dma_pos;
      int ret;

      pr_debug("Entered %s\n", __func__);

      while (prtd->dma_loaded < prtd->dma_limit) {
            unsigned long len = prtd->dma_period;

            pr_debug("dma_loaded: %d\n", prtd->dma_loaded);

            if ((pos + len) > prtd->dma_end) {
                  len  = prtd->dma_end - pos;
                  pr_debug(KERN_DEBUG "%s: corrected dma len %ld\n",
                         __func__, len);
            }

            ret = s3c2410_dma_enqueue(prtd->params->channel,
                  substream, pos, len);

            if (ret == 0) {
                  prtd->dma_loaded++;
                  pos += prtd->dma_period;
                  if (pos >= prtd->dma_end)
                        pos = prtd->dma_start;
            } else
                  break;
      }

      prtd->dma_pos = pos;
}

static void s3c24xx_audio_buffdone(struct s3c2410_dma_chan *channel,
                        void *dev_id, int size,
                        enum s3c2410_dma_buffresult result)
{
      struct snd_pcm_substream *substream = dev_id;
      struct s3c24xx_runtime_data *prtd;

      pr_debug("Entered %s\n", __func__);

      if (result == S3C2410_RES_ABORT || result == S3C2410_RES_ERR)
            return;

      prtd = substream->runtime->private_data;

      if (substream)
            snd_pcm_period_elapsed(substream);

      spin_lock(&prtd->lock);
      if (prtd->state & ST_RUNNING) {
            prtd->dma_loaded--;
            s3c24xx_pcm_enqueue(substream);
      }

      spin_unlock(&prtd->lock);
}

static int s3c24xx_pcm_hw_params(struct snd_pcm_substream *substream,
      struct snd_pcm_hw_params *params)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct s3c24xx_runtime_data *prtd = runtime->private_data;
      struct snd_soc_pcm_runtime *rtd = substream->private_data;
      struct s3c24xx_pcm_dma_params *dma = rtd->dai->cpu_dai->dma_data;
      unsigned long totbytes = params_buffer_bytes(params);
      int ret = 0;

      pr_debug("Entered %s\n", __func__);

      /* return if this is a bufferless transfer e.g.
       * codec <--> BT codec or GSM modem -- lg FIXME */
      if (!dma)
            return 0;

      /* this may get called several times by oss emulation
       * with different params -HW */
      if (prtd->params == NULL) {
            /* prepare DMA */
            prtd->params = dma;

            pr_debug("params %p, client %p, channel %d\n", prtd->params,
                  prtd->params->client, prtd->params->channel);

            ret = s3c2410_dma_request(prtd->params->channel,
                                prtd->params->client, NULL);

            if (ret < 0) {
                  printk(KERN_ERR "failed to get dma channel\n");
                  return ret;
            }
      }

      s3c2410_dma_set_buffdone_fn(prtd->params->channel,
                            s3c24xx_audio_buffdone);

      snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);

      runtime->dma_bytes = totbytes;

      spin_lock_irq(&prtd->lock);
      prtd->dma_loaded = 0;
      prtd->dma_limit = runtime->hw.periods_min;
      prtd->dma_period = params_period_bytes(params);
      prtd->dma_start = runtime->dma_addr;
      prtd->dma_pos = prtd->dma_start;
      prtd->dma_end = prtd->dma_start + totbytes;
      spin_unlock_irq(&prtd->lock);

      return 0;
}

static int s3c24xx_pcm_hw_free(struct snd_pcm_substream *substream)
{
      struct s3c24xx_runtime_data *prtd = substream->runtime->private_data;

      pr_debug("Entered %s\n", __func__);

      /* TODO - do we need to ensure DMA flushed */
      snd_pcm_set_runtime_buffer(substream, NULL);

      if (prtd->params) {
            s3c2410_dma_free(prtd->params->channel, prtd->params->client);
            prtd->params = NULL;
      }

      return 0;
}

static int s3c24xx_pcm_prepare(struct snd_pcm_substream *substream)
{
      struct s3c24xx_runtime_data *prtd = substream->runtime->private_data;
      int ret = 0;

      pr_debug("Entered %s\n", __func__);

      /* return if this is a bufferless transfer e.g.
       * codec <--> BT codec or GSM modem -- lg FIXME */
      if (!prtd->params)
            return 0;

      /* channel needs configuring for mem=>device, increment memory addr,
       * sync to pclk, half-word transfers to the IIS-FIFO. */
      if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
            s3c2410_dma_devconfig(prtd->params->channel,
                              S3C2410_DMASRC_MEM,
                              prtd->params->dma_addr);
      } else {
            s3c2410_dma_devconfig(prtd->params->channel,
                              S3C2410_DMASRC_HW,
                              prtd->params->dma_addr);
      }

      s3c2410_dma_config(prtd->params->channel,
                     prtd->params->dma_size);

      /* flush the DMA channel */
      s3c2410_dma_ctrl(prtd->params->channel, S3C2410_DMAOP_FLUSH);
      prtd->dma_loaded = 0;
      prtd->dma_pos = prtd->dma_start;

      /* enqueue dma buffers */
      s3c24xx_pcm_enqueue(substream);

      return ret;
}

static int s3c24xx_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
      struct s3c24xx_runtime_data *prtd = substream->runtime->private_data;
      int ret = 0;

      pr_debug("Entered %s\n", __func__);

      spin_lock(&prtd->lock);

      switch (cmd) {
      case SNDRV_PCM_TRIGGER_START:
      case SNDRV_PCM_TRIGGER_RESUME:
      case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
            prtd->state |= ST_RUNNING;
            s3c2410_dma_ctrl(prtd->params->channel, S3C2410_DMAOP_START);
            break;

      case SNDRV_PCM_TRIGGER_STOP:
      case SNDRV_PCM_TRIGGER_SUSPEND:
      case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
            prtd->state &= ~ST_RUNNING;
            s3c2410_dma_ctrl(prtd->params->channel, S3C2410_DMAOP_STOP);
            break;

      default:
            ret = -EINVAL;
            break;
      }

      spin_unlock(&prtd->lock);

      return ret;
}

static snd_pcm_uframes_t
s3c24xx_pcm_pointer(struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct s3c24xx_runtime_data *prtd = runtime->private_data;
      unsigned long res;
      dma_addr_t src, dst;

      pr_debug("Entered %s\n", __func__);

      spin_lock(&prtd->lock);
      s3c2410_dma_getposition(prtd->params->channel, &src, &dst);

      if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
            res = dst - prtd->dma_start;
      else
            res = src - prtd->dma_start;

      spin_unlock(&prtd->lock);

      pr_debug("Pointer %x %x\n", src, dst);

      /* we seem to be getting the odd error from the pcm library due
       * to out-of-bounds pointers. this is maybe due to the dma engine
       * not having loaded the new values for the channel before being
       * callled... (todo - fix )
       */

      if (res >= snd_pcm_lib_buffer_bytes(substream)) {
            if (res == snd_pcm_lib_buffer_bytes(substream))
                  res = 0;
      }

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

static int s3c24xx_pcm_open(struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct s3c24xx_runtime_data *prtd;

      pr_debug("Entered %s\n", __func__);

      snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
      snd_soc_set_runtime_hwparams(substream, &s3c24xx_pcm_hardware);

      prtd = kzalloc(sizeof(struct s3c24xx_runtime_data), GFP_KERNEL);
      if (prtd == NULL)
            return -ENOMEM;

      spin_lock_init(&prtd->lock);

      runtime->private_data = prtd;
      return 0;
}

static int s3c24xx_pcm_close(struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct s3c24xx_runtime_data *prtd = runtime->private_data;

      pr_debug("Entered %s\n", __func__);

      if (!prtd)
            pr_debug("s3c24xx_pcm_close called with prtd == NULL\n");

      kfree(prtd);

      return 0;
}

static int s3c24xx_pcm_mmap(struct snd_pcm_substream *substream,
      struct vm_area_struct *vma)
{
      struct snd_pcm_runtime *runtime = substream->runtime;

      pr_debug("Entered %s\n", __func__);

      return dma_mmap_writecombine(substream->pcm->card->dev, vma,
                             runtime->dma_area,
                             runtime->dma_addr,
                             runtime->dma_bytes);
}

static struct snd_pcm_ops s3c24xx_pcm_ops = {
      .open       = s3c24xx_pcm_open,
      .close            = s3c24xx_pcm_close,
      .ioctl            = snd_pcm_lib_ioctl,
      .hw_params  = s3c24xx_pcm_hw_params,
      .hw_free    = s3c24xx_pcm_hw_free,
      .prepare    = s3c24xx_pcm_prepare,
      .trigger    = s3c24xx_pcm_trigger,
      .pointer    = s3c24xx_pcm_pointer,
      .mmap       = s3c24xx_pcm_mmap,
};

static int s3c24xx_pcm_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 = s3c24xx_pcm_hardware.buffer_bytes_max;

      pr_debug("Entered %s\n", __func__);

      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);
      if (!buf->area)
            return -ENOMEM;
      buf->bytes = size;
      return 0;
}

static void s3c24xx_pcm_free_dma_buffers(struct snd_pcm *pcm)
{
      struct snd_pcm_substream *substream;
      struct snd_dma_buffer *buf;
      int stream;

      pr_debug("Entered %s\n", __func__);

      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 u64 s3c24xx_pcm_dmamask = DMA_BIT_MASK(32);

static int s3c24xx_pcm_new(struct snd_card *card,
      struct snd_soc_dai *dai, struct snd_pcm *pcm)
{
      int ret = 0;

      pr_debug("Entered %s\n", __func__);

      if (!card->dev->dma_mask)
            card->dev->dma_mask = &s3c24xx_pcm_dmamask;
      if (!card->dev->coherent_dma_mask)
            card->dev->coherent_dma_mask = 0xffffffff;

      if (dai->playback.channels_min) {
            ret = s3c24xx_pcm_preallocate_dma_buffer(pcm,
                  SNDRV_PCM_STREAM_PLAYBACK);
            if (ret)
                  goto out;
      }

      if (dai->capture.channels_min) {
            ret = s3c24xx_pcm_preallocate_dma_buffer(pcm,
                  SNDRV_PCM_STREAM_CAPTURE);
            if (ret)
                  goto out;
      }
 out:
      return ret;
}

struct snd_soc_platform s3c24xx_soc_platform = {
      .name       = "s3c24xx-audio",
      .pcm_ops    = &s3c24xx_pcm_ops,
      .pcm_new    = s3c24xx_pcm_new,
      .pcm_free   = s3c24xx_pcm_free_dma_buffers,
};
EXPORT_SYMBOL_GPL(s3c24xx_soc_platform);

static int __init s3c24xx_soc_platform_init(void)
{
      return snd_soc_register_platform(&s3c24xx_soc_platform);
}
module_init(s3c24xx_soc_platform_init);

static void __exit s3c24xx_soc_platform_exit(void)
{
      snd_soc_unregister_platform(&s3c24xx_soc_platform);
}
module_exit(s3c24xx_soc_platform_exit);

MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
MODULE_DESCRIPTION("Samsung S3C24XX PCM DMA module");
MODULE_LICENSE("GPL");

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