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at91-pcm.c

/*
 * at91-pcm.c -- ALSA PCM interface for the Atmel AT91 SoC
 *
 * Author:  Frank Mandarino <fmandarino@endrelia.com>
 *          Endrelia Technologies Inc.
 * Created: Mar 3, 2006
 *
 * Based on pxa2xx-pcm.c by:
 *
 * Author:  Nicolas Pitre
 * Created: Nov 30, 2004
 * Copyright:     (C) 2004 MontaVista Software, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <linux/atmel_pdc.h>

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

#include <mach/hardware.h>
#include <mach/at91_ssc.h>

#include "at91-pcm.h"

#if 0
#define     DBG(x...)   printk(KERN_INFO "at91-pcm: " x)
#else
#define     DBG(x...)
#endif

static const struct snd_pcm_hardware at91_pcm_hardware = {
      .info             = SNDRV_PCM_INFO_MMAP |
                          SNDRV_PCM_INFO_MMAP_VALID |
                          SNDRV_PCM_INFO_INTERLEAVED |
                          SNDRV_PCM_INFO_PAUSE,
      .formats          = SNDRV_PCM_FMTBIT_S16_LE,
      .period_bytes_min = 32,
      .period_bytes_max = 8192,
      .periods_min            = 2,
      .periods_max            = 1024,
      .buffer_bytes_max = 32 * 1024,
};

struct at91_runtime_data {
      struct at91_pcm_dma_params *params;
      dma_addr_t dma_buffer;              /* physical address of dma buffer */
      dma_addr_t dma_buffer_end;          /* first address beyond DMA buffer */
      size_t period_size;
      dma_addr_t period_ptr;              /* physical address of next period */
      u32 pdc_xpr_save;             /* PDC register save */
      u32 pdc_xcr_save;
      u32 pdc_xnpr_save;
      u32 pdc_xncr_save;
};

static void at91_pcm_dma_irq(u32 ssc_sr,
      struct snd_pcm_substream *substream)
{
      struct at91_runtime_data *prtd = substream->runtime->private_data;
      struct at91_pcm_dma_params *params = prtd->params;
      static int count = 0;

      count++;

      if (ssc_sr & params->mask->ssc_endbuf) {

            printk(KERN_WARNING
                  "at91-pcm: buffer %s on %s (SSC_SR=%#x, count=%d)\n",
                  substream->stream == SNDRV_PCM_STREAM_PLAYBACK
                        ? "underrun" : "overrun",
                  params->name, ssc_sr, count);

            /* re-start the PDC */
            at91_ssc_write(params->ssc_base + ATMEL_PDC_PTCR, params->mask->pdc_disable);

            prtd->period_ptr += prtd->period_size;
            if (prtd->period_ptr >= prtd->dma_buffer_end) {
                  prtd->period_ptr = prtd->dma_buffer;
            }

            at91_ssc_write(params->ssc_base + params->pdc->xpr, prtd->period_ptr);
            at91_ssc_write(params->ssc_base + params->pdc->xcr,
                        prtd->period_size / params->pdc_xfer_size);

            at91_ssc_write(params->ssc_base + ATMEL_PDC_PTCR, params->mask->pdc_enable);
      }

      if (ssc_sr & params->mask->ssc_endx) {

            /* Load the PDC next pointer and counter registers */
            prtd->period_ptr += prtd->period_size;
            if (prtd->period_ptr >= prtd->dma_buffer_end) {
                  prtd->period_ptr = prtd->dma_buffer;
            }
            at91_ssc_write(params->ssc_base + params->pdc->xnpr,
                         prtd->period_ptr);
            at91_ssc_write(params->ssc_base + params->pdc->xncr,
                        prtd->period_size / params->pdc_xfer_size);
      }

      snd_pcm_period_elapsed(substream);
}

static int at91_pcm_hw_params(struct snd_pcm_substream *substream,
      struct snd_pcm_hw_params *params)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct at91_runtime_data *prtd = runtime->private_data;
      struct snd_soc_pcm_runtime *rtd = substream->private_data;

      /* this may get called several times by oss emulation
       * with different params */

      snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
      runtime->dma_bytes = params_buffer_bytes(params);

      prtd->params = rtd->dai->cpu_dai->dma_data;
      prtd->params->dma_intr_handler = at91_pcm_dma_irq;

      prtd->dma_buffer = runtime->dma_addr;
      prtd->dma_buffer_end = runtime->dma_addr + runtime->dma_bytes;
      prtd->period_size = params_period_bytes(params);

      DBG("hw_params: DMA for %s initialized (dma_bytes=%d, period_size=%d)\n",
            prtd->params->name, runtime->dma_bytes, prtd->period_size);
      return 0;
}

static int at91_pcm_hw_free(struct snd_pcm_substream *substream)
{
      struct at91_runtime_data *prtd = substream->runtime->private_data;
      struct at91_pcm_dma_params *params = prtd->params;

      if (params != NULL) {
            at91_ssc_write(params->ssc_base + ATMEL_PDC_PTCR, params->mask->pdc_disable);
            prtd->params->dma_intr_handler = NULL;
      }

      return 0;
}

static int at91_pcm_prepare(struct snd_pcm_substream *substream)
{
      struct at91_runtime_data *prtd = substream->runtime->private_data;
      struct at91_pcm_dma_params *params = prtd->params;

      at91_ssc_write(params->ssc_base + AT91_SSC_IDR,
                  params->mask->ssc_endx | params->mask->ssc_endbuf);

      at91_ssc_write(params->ssc_base + ATMEL_PDC_PTCR, params->mask->pdc_disable);
      return 0;
}

static int at91_pcm_trigger(struct snd_pcm_substream *substream,
      int cmd)
{
      struct at91_runtime_data *prtd = substream->runtime->private_data;
      struct at91_pcm_dma_params *params = prtd->params;
      int ret = 0;

      switch (cmd) {
      case SNDRV_PCM_TRIGGER_START:
            prtd->period_ptr = prtd->dma_buffer;

            at91_ssc_write(params->ssc_base + params->pdc->xpr, prtd->period_ptr);
            at91_ssc_write(params->ssc_base + params->pdc->xcr,
                        prtd->period_size / params->pdc_xfer_size);

            prtd->period_ptr += prtd->period_size;
            at91_ssc_write(params->ssc_base + params->pdc->xnpr, prtd->period_ptr);
            at91_ssc_write(params->ssc_base + params->pdc->xncr,
                        prtd->period_size / params->pdc_xfer_size);

            DBG("trigger: period_ptr=%lx, xpr=%lx, xcr=%ld, xnpr=%lx, xncr=%ld\n",
                  (unsigned long) prtd->period_ptr,
                  at91_ssc_read(params->ssc_base + params->pdc->xpr),
                  at91_ssc_read(params->ssc_base + params->pdc->xcr),
                  at91_ssc_read(params->ssc_base + params->pdc->xnpr),
                  at91_ssc_read(params->ssc_base + params->pdc->xncr));

            at91_ssc_write(params->ssc_base + AT91_SSC_IER,
                  params->mask->ssc_endx | params->mask->ssc_endbuf);

            at91_ssc_write(params->ssc_base + ATMEL_PDC_PTCR,
                  params->mask->pdc_enable);

            DBG("sr=%lx imr=%lx\n",
                at91_ssc_read(params->ssc_base + AT91_SSC_SR),
                at91_ssc_read(params->ssc_base + AT91_SSC_IMR));
            break;

      case SNDRV_PCM_TRIGGER_STOP:
      case SNDRV_PCM_TRIGGER_SUSPEND:
      case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
            at91_ssc_write(params->ssc_base + ATMEL_PDC_PTCR, params->mask->pdc_disable);
            break;

      case SNDRV_PCM_TRIGGER_RESUME:
      case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
            at91_ssc_write(params->ssc_base + ATMEL_PDC_PTCR, params->mask->pdc_enable);
            break;

      default:
            ret = -EINVAL;
      }

      return ret;
}

static snd_pcm_uframes_t at91_pcm_pointer(
      struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct at91_runtime_data *prtd = runtime->private_data;
      struct at91_pcm_dma_params *params = prtd->params;
      dma_addr_t ptr;
      snd_pcm_uframes_t x;

      ptr = (dma_addr_t) at91_ssc_read(params->ssc_base + params->pdc->xpr);
      x = bytes_to_frames(runtime, ptr - prtd->dma_buffer);

      if (x == runtime->buffer_size)
            x = 0;
      return x;
}

static int at91_pcm_open(struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct at91_runtime_data *prtd;
      int ret = 0;

      snd_soc_set_runtime_hwparams(substream, &at91_pcm_hardware);

      /* ensure that buffer size is a multiple of period size */
      ret = snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
      if (ret < 0)
            goto out;

      prtd = kzalloc(sizeof(struct at91_runtime_data), GFP_KERNEL);
      if (prtd == NULL) {
            ret = -ENOMEM;
            goto out;
      }
      runtime->private_data = prtd;

 out:
      return ret;
}

static int at91_pcm_close(struct snd_pcm_substream *substream)
{
      struct at91_runtime_data *prtd = substream->runtime->private_data;

      kfree(prtd);
      return 0;
}

static int at91_pcm_mmap(struct snd_pcm_substream *substream,
      struct vm_area_struct *vma)
{
      struct snd_pcm_runtime *runtime = substream->runtime;

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

struct snd_pcm_ops at91_pcm_ops = {
      .open       = at91_pcm_open,
      .close            = at91_pcm_close,
      .ioctl            = snd_pcm_lib_ioctl,
      .hw_params  = at91_pcm_hw_params,
      .hw_free    = at91_pcm_hw_free,
      .prepare    = at91_pcm_prepare,
      .trigger    = at91_pcm_trigger,
      .pointer    = at91_pcm_pointer,
      .mmap       = at91_pcm_mmap,
};

static int at91_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 = at91_pcm_hardware.buffer_bytes_max;

      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);

      DBG("preallocate_dma_buffer: area=%p, addr=%p, size=%d\n",
            (void *) buf->area,
            (void *) buf->addr,
            size);

      if (!buf->area)
            return -ENOMEM;

      buf->bytes = size;
      return 0;
}

static u64 at91_pcm_dmamask = 0xffffffff;

static int at91_pcm_new(struct snd_card *card,
      struct snd_soc_dai *dai, struct snd_pcm *pcm)
{
      int ret = 0;

      if (!card->dev->dma_mask)
            card->dev->dma_mask = &at91_pcm_dmamask;
      if (!card->dev->coherent_dma_mask)
            card->dev->coherent_dma_mask = 0xffffffff;

      if (dai->playback.channels_min) {
            ret = at91_pcm_preallocate_dma_buffer(pcm,
                  SNDRV_PCM_STREAM_PLAYBACK);
            if (ret)
                  goto out;
      }

      if (dai->capture.channels_min) {
            ret = at91_pcm_preallocate_dma_buffer(pcm,
                  SNDRV_PCM_STREAM_CAPTURE);
            if (ret)
                  goto out;
      }
 out:
      return ret;
}

static void at91_pcm_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_writecombine(pcm->card->dev, buf->bytes,
                              buf->area, buf->addr);
            buf->area = NULL;
      }
}

#ifdef CONFIG_PM
static int at91_pcm_suspend(struct platform_device *pdev,
      struct snd_soc_dai *dai)
{
      struct snd_pcm_runtime *runtime = dai->runtime;
      struct at91_runtime_data *prtd;
      struct at91_pcm_dma_params *params;

      if (!runtime)
            return 0;

      prtd = runtime->private_data;
      params = prtd->params;

      /* disable the PDC and save the PDC registers */

      at91_ssc_write(params->ssc_base + ATMEL_PDC_PTCR, params->mask->pdc_disable);

      prtd->pdc_xpr_save  = at91_ssc_read(params->ssc_base + params->pdc->xpr);
      prtd->pdc_xcr_save  = at91_ssc_read(params->ssc_base + params->pdc->xcr);
      prtd->pdc_xnpr_save = at91_ssc_read(params->ssc_base + params->pdc->xnpr);
      prtd->pdc_xncr_save = at91_ssc_read(params->ssc_base + params->pdc->xncr);

      return 0;
}

static int at91_pcm_resume(struct platform_device *pdev,
      struct snd_soc_dai *dai)
{
      struct snd_pcm_runtime *runtime = dai->runtime;
      struct at91_runtime_data *prtd;
      struct at91_pcm_dma_params *params;

      if (!runtime)
            return 0;

      prtd = runtime->private_data;
      params = prtd->params;

      /* restore the PDC registers and enable the PDC */
      at91_ssc_write(params->ssc_base + params->pdc->xpr,  prtd->pdc_xpr_save);
      at91_ssc_write(params->ssc_base + params->pdc->xcr,  prtd->pdc_xcr_save);
      at91_ssc_write(params->ssc_base + params->pdc->xnpr, prtd->pdc_xnpr_save);
      at91_ssc_write(params->ssc_base + params->pdc->xncr, prtd->pdc_xncr_save);

      at91_ssc_write(params->ssc_base + ATMEL_PDC_PTCR, params->mask->pdc_enable);
      return 0;
}
#else
#define at91_pcm_suspend      NULL
#define at91_pcm_resume       NULL
#endif

struct snd_soc_platform at91_soc_platform = {
      .name       = "at91-audio",
      .pcm_ops    = &at91_pcm_ops,
      .pcm_new    = at91_pcm_new,
      .pcm_free   = at91_pcm_free_dma_buffers,
      .suspend    = at91_pcm_suspend,
      .resume           = at91_pcm_resume,
};

EXPORT_SYMBOL_GPL(at91_soc_platform);

MODULE_AUTHOR("Frank Mandarino <fmandarino@endrelia.com>");
MODULE_DESCRIPTION("Atmel AT91 PCM module");
MODULE_LICENSE("GPL");

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