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pxa2xx-pcm.c

/*
 * linux/sound/arm/pxa2xx-pcm.c -- ALSA PCM interface for the Intel PXA2xx chip
 *
 * 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 <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>

#include <asm/dma.h>
#include <asm/hardware.h>
#include <asm/arch/pxa-regs.h>
#include <asm/arch/audio.h>

#include "pxa2xx-pcm.h"

static const struct snd_pcm_hardware pxa2xx_pcm_hardware = {
      .info             = SNDRV_PCM_INFO_MMAP |
                          SNDRV_PCM_INFO_MMAP_VALID |
                          SNDRV_PCM_INFO_INTERLEAVED |
                          SNDRV_PCM_INFO_PAUSE |
                          SNDRV_PCM_INFO_RESUME,
      .formats          = SNDRV_PCM_FMTBIT_S16_LE |
                              SNDRV_PCM_FMTBIT_S24_LE |
                              SNDRV_PCM_FMTBIT_S32_LE,
      .period_bytes_min = 32,
      .period_bytes_max = 8192 - 32,
      .periods_min            = 1,
      .periods_max            = PAGE_SIZE/sizeof(pxa_dma_desc),
      .buffer_bytes_max = 128 * 1024,
      .fifo_size        = 32,
};

struct pxa2xx_runtime_data {
      int dma_ch;
      struct pxa2xx_pcm_dma_params *params;
      pxa_dma_desc *dma_desc_array;
      dma_addr_t dma_desc_array_phys;
};

static void pxa2xx_pcm_dma_irq(int dma_ch, void *dev_id)
{
      struct snd_pcm_substream *substream = dev_id;
      struct pxa2xx_runtime_data *prtd = substream->runtime->private_data;
      int dcsr;

      dcsr = DCSR(dma_ch);
      DCSR(dma_ch) = dcsr & ~DCSR_STOPIRQEN;

      if (dcsr & DCSR_ENDINTR) {
            snd_pcm_period_elapsed(substream);
      } else {
            printk(KERN_ERR "%s: DMA error on channel %d (DCSR=%#x)\n",
                  prtd->params->name, dma_ch, dcsr);
      }
}

static int pxa2xx_pcm_hw_params(struct snd_pcm_substream *substream,
      struct snd_pcm_hw_params *params)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct pxa2xx_runtime_data *prtd = runtime->private_data;
      struct snd_soc_pcm_runtime *rtd = substream->private_data;
      struct pxa2xx_pcm_dma_params *dma = rtd->dai->cpu_dai->dma_data;
      size_t totsize = params_buffer_bytes(params);
      size_t period = params_period_bytes(params);
      pxa_dma_desc *dma_desc;
      dma_addr_t dma_buff_phys, next_desc_phys;
      int ret;

      /* 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 */
      if (prtd->params == NULL) {
            prtd->params = dma;
            ret = pxa_request_dma(prtd->params->name, DMA_PRIO_LOW,
                        pxa2xx_pcm_dma_irq, substream);
            if (ret < 0)
                  return ret;
            prtd->dma_ch = ret;
      } else if (prtd->params != dma) {
            pxa_free_dma(prtd->dma_ch);
            prtd->params = dma;
            ret = pxa_request_dma(prtd->params->name, DMA_PRIO_LOW,
                        pxa2xx_pcm_dma_irq, substream);
            if (ret < 0)
                  return ret;
            prtd->dma_ch = ret;
      }

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

      dma_desc = prtd->dma_desc_array;
      next_desc_phys = prtd->dma_desc_array_phys;
      dma_buff_phys = runtime->dma_addr;
      do {
            next_desc_phys += sizeof(pxa_dma_desc);
            dma_desc->ddadr = next_desc_phys;
            if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
                  dma_desc->dsadr = dma_buff_phys;
                  dma_desc->dtadr = prtd->params->dev_addr;
            } else {
                  dma_desc->dsadr = prtd->params->dev_addr;
                  dma_desc->dtadr = dma_buff_phys;
            }
            if (period > totsize)
                  period = totsize;
            dma_desc->dcmd = prtd->params->dcmd | period | DCMD_ENDIRQEN;
            dma_desc++;
            dma_buff_phys += period;
      } while (totsize -= period);
      dma_desc[-1].ddadr = prtd->dma_desc_array_phys;

      return 0;
}

static int pxa2xx_pcm_hw_free(struct snd_pcm_substream *substream)
{
      struct pxa2xx_runtime_data *prtd = substream->runtime->private_data;

      if (prtd && prtd->params)
            *prtd->params->drcmr = 0;

      if (prtd->dma_ch) {
            snd_pcm_set_runtime_buffer(substream, NULL);
            pxa_free_dma(prtd->dma_ch);
            prtd->dma_ch = 0;
      }

      return 0;
}

static int pxa2xx_pcm_prepare(struct snd_pcm_substream *substream)
{
      struct pxa2xx_runtime_data *prtd = substream->runtime->private_data;

      DCSR(prtd->dma_ch) &= ~DCSR_RUN;
      DCSR(prtd->dma_ch) = 0;
      DCMD(prtd->dma_ch) = 0;
      *prtd->params->drcmr = prtd->dma_ch | DRCMR_MAPVLD;

      return 0;
}

static int pxa2xx_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
      struct pxa2xx_runtime_data *prtd = substream->runtime->private_data;
      int ret = 0;

      switch (cmd) {
      case SNDRV_PCM_TRIGGER_START:
            DDADR(prtd->dma_ch) = prtd->dma_desc_array_phys;
            DCSR(prtd->dma_ch) = DCSR_RUN;
            break;

      case SNDRV_PCM_TRIGGER_STOP:
      case SNDRV_PCM_TRIGGER_SUSPEND:
      case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
            DCSR(prtd->dma_ch) &= ~DCSR_RUN;
            break;

      case SNDRV_PCM_TRIGGER_RESUME:
            DCSR(prtd->dma_ch) |= DCSR_RUN;
            break;
      case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
            DDADR(prtd->dma_ch) = prtd->dma_desc_array_phys;
            DCSR(prtd->dma_ch) |= DCSR_RUN;
            break;

      default:
            ret = -EINVAL;
      }

      return ret;
}

static snd_pcm_uframes_t
pxa2xx_pcm_pointer(struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct pxa2xx_runtime_data *prtd = runtime->private_data;

      dma_addr_t ptr = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) ?
                   DSADR(prtd->dma_ch) : DTADR(prtd->dma_ch);
      snd_pcm_uframes_t x = bytes_to_frames(runtime, ptr - runtime->dma_addr);

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

static int pxa2xx_pcm_open(struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct pxa2xx_runtime_data *prtd;
      int ret;

      snd_soc_set_runtime_hwparams(substream, &pxa2xx_pcm_hardware);

      /*
       * For mysterious reasons (and despite what the manual says)
       * playback samples are lost if the DMA count is not a multiple
       * of the DMA burst size.  Let's add a rule to enforce that.
       */
      ret = snd_pcm_hw_constraint_step(runtime, 0,
            SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 32);
      if (ret)
            goto out;

      ret = snd_pcm_hw_constraint_step(runtime, 0,
            SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 32);
      if (ret)
            goto out;

      ret = snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
      if (ret < 0)
            goto out;

      prtd = kzalloc(sizeof(struct pxa2xx_runtime_data), GFP_KERNEL);
      if (prtd == NULL) {
            ret = -ENOMEM;
            goto out;
      }

      prtd->dma_desc_array =
            dma_alloc_writecombine(substream->pcm->card->dev, PAGE_SIZE,
                               &prtd->dma_desc_array_phys, GFP_KERNEL);
      if (!prtd->dma_desc_array) {
            ret = -ENOMEM;
            goto err1;
      }

      runtime->private_data = prtd;
      return 0;

 err1:
      kfree(prtd);
 out:
      return ret;
}

static int pxa2xx_pcm_close(struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct pxa2xx_runtime_data *prtd = runtime->private_data;

      dma_free_writecombine(substream->pcm->card->dev, PAGE_SIZE,
                        prtd->dma_desc_array, prtd->dma_desc_array_phys);
      kfree(prtd);
      return 0;
}

static int pxa2xx_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 pxa2xx_pcm_ops = {
      .open       = pxa2xx_pcm_open,
      .close            = pxa2xx_pcm_close,
      .ioctl            = snd_pcm_lib_ioctl,
      .hw_params  = pxa2xx_pcm_hw_params,
      .hw_free    = pxa2xx_pcm_hw_free,
      .prepare    = pxa2xx_pcm_prepare,
      .trigger    = pxa2xx_pcm_trigger,
      .pointer    = pxa2xx_pcm_pointer,
      .mmap       = pxa2xx_pcm_mmap,
};

static int pxa2xx_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 = pxa2xx_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);
      if (!buf->area)
            return -ENOMEM;
      buf->bytes = size;
      return 0;
}

static void pxa2xx_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;
      }
}

static u64 pxa2xx_pcm_dmamask = DMA_32BIT_MASK;

int pxa2xx_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 = &pxa2xx_pcm_dmamask;
      if (!card->dev->coherent_dma_mask)
            card->dev->coherent_dma_mask = DMA_32BIT_MASK;

      if (dai->playback.channels_min) {
            ret = pxa2xx_pcm_preallocate_dma_buffer(pcm,
                  SNDRV_PCM_STREAM_PLAYBACK);
            if (ret)
                  goto out;
      }

      if (dai->capture.channels_min) {
            ret = pxa2xx_pcm_preallocate_dma_buffer(pcm,
                  SNDRV_PCM_STREAM_CAPTURE);
            if (ret)
                  goto out;
      }
 out:
      return ret;
}

struct snd_soc_platform pxa2xx_soc_platform = {
      .name       = "pxa2xx-audio",
      .pcm_ops    = &pxa2xx_pcm_ops,
      .pcm_new    = pxa2xx_pcm_new,
      .pcm_free   = pxa2xx_pcm_free_dma_buffers,
};
EXPORT_SYMBOL_GPL(pxa2xx_soc_platform);

MODULE_AUTHOR("Nicolas Pitre");
MODULE_DESCRIPTION("Intel PXA2xx PCM DMA module");
MODULE_LICENSE("GPL");

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