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imx-pcm-fiq.c

/*
 * 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 timer_list timer;
      int poll_time;
};

static inline void imx_ssi_set_next_poll(struct imx_pcm_runtime_data *iprtd)
{
      iprtd->timer.expires = jiffies + iprtd->poll_time;
}

static void imx_ssi_timer_callback(unsigned long data)
{
      struct snd_pcm_substream *substream = (void *)data;
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct imx_pcm_runtime_data *iprtd = runtime->private_data;
      struct pt_regs regs;
      unsigned long delta;

      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 >= runtime->period_size) {
            snd_pcm_period_elapsed(substream);
            iprtd->last_offset = iprtd->offset;

            imx_ssi_set_next_poll(iprtd);
      }

      /* Restart the timer; if we didn't report we'll run on the next tick */
      add_timer(&iprtd->timer);

}

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 = HZ / (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:
            imx_ssi_set_next_poll(iprtd);
            add_timer(&iprtd->timer);
            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:
            del_timer(&iprtd->timer);
            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 = 2,
      .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);
      runtime->private_data = iprtd;

      init_timer(&iprtd->timer);
      iprtd->timer.data = (unsigned long)substream;
      iprtd->timer.function = imx_ssi_timer_callback;

      ret = snd_pcm_hw_constraint_integer(substream->runtime,
                  SNDRV_PCM_HW_PARAM_PERIODS);
      if (ret < 0)
            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;

      del_timer_sync(&iprtd->timer);
      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 imx_pcm_fiq_new(struct snd_card *card, struct snd_soc_dai *dai,
      struct snd_pcm *pcm)
{
      int ret;

      ret = imx_pcm_new(card, dai, pcm);
      if (ret)
            return ret;

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

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

      if (dai->capture.channels_min) {
            struct snd_pcm_substream *substream =
                  pcm->streams[SNDRV_PCM_STREAM_CAPTURE].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 struct snd_soc_platform imx_soc_platform_fiq = {
      .pcm_ops    = &imx_pcm_ops,
      .pcm_new    = imx_pcm_fiq_new,
      .pcm_free   = imx_pcm_free,
};

struct snd_soc_platform *imx_ssi_fiq_init(struct platform_device *pdev,
            struct imx_ssi *ssi)
{
      int ret = 0;

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

      mxc_set_irq_fiq(ssi->irq, 1);

      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;

      return &imx_soc_platform_fiq;
}

void imx_ssi_fiq_exit(struct platform_device *pdev,
            struct imx_ssi *ssi)
{
      mxc_set_irq_fiq(ssi->irq, 0);
      release_fiq(&fh);
}


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