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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/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 <asm/dma.h>
#include <asm/hardware.h>
#include <asm/arch/pxa-regs.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,
      .formats          = SNDRV_PCM_FMTBIT_S16_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 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 *rtd = runtime->private_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;

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

      dma_desc = rtd->dma_desc_array;
      next_desc_phys = rtd->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 = rtd->params->dev_addr;
            } else {
                  dma_desc->dsadr = rtd->params->dev_addr;
                  dma_desc->dtadr = dma_buff_phys;
            }
            if (period > totsize)
                  period = totsize;
            dma_desc->dcmd = rtd->params->dcmd | period | DCMD_ENDIRQEN;
            dma_desc++;
            dma_buff_phys += period;
      } while (totsize -= period);
      dma_desc[-1].ddadr = rtd->dma_desc_array_phys;

      return 0;
}

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

      *rtd->params->drcmr = 0;
      snd_pcm_set_runtime_buffer(substream, NULL);
      return 0;
}

static int pxa2xx_pcm_prepare(struct snd_pcm_substream *substream)
{
      struct pxa2xx_pcm_client *client = substream->private_data;
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct pxa2xx_runtime_data *rtd = runtime->private_data;

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

      return client->prepare(substream);
}

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

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

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

      case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
            DCSR(rtd->dma_ch) |= DCSR_RUN;
            break;

      default:
            ret = -EINVAL;
      }

      return ret;
}

static void pxa2xx_pcm_dma_irq(int dma_ch, void *dev_id)
{
      struct snd_pcm_substream *substream = dev_id;
      struct pxa2xx_runtime_data *rtd = 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",
                  rtd->params->name, dma_ch, dcsr );
            snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
      }
}

static snd_pcm_uframes_t pxa2xx_pcm_pointer(struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct pxa2xx_runtime_data *rtd = runtime->private_data;
      dma_addr_t ptr = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) ?
                   DSADR(rtd->dma_ch) : DTADR(rtd->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_hw_rule_mult32(struct snd_pcm_hw_params *params, struct snd_pcm_hw_rule *rule)
{
      struct snd_interval *i = hw_param_interval(params, rule->var);
      int changed = 0;

      if (i->min & 31) {
            i->min = (i->min & ~31) + 32;
            i->openmin = 0;
            changed = 1;
      }

      if (i->max & 31) {
            i->max &= ~31;
            i->openmax = 0;
            changed = 1;
      }

      return changed;
}

static int pxa2xx_pcm_open(struct snd_pcm_substream *substream)
{
      struct pxa2xx_pcm_client *client = substream->private_data;
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct pxa2xx_runtime_data *rtd;
      int ret;

      runtime->hw = 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_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
                          pxa2xx_pcm_hw_rule_mult32, NULL,
                          SNDRV_PCM_HW_PARAM_PERIOD_BYTES, -1);
      if (ret)
            goto out;
      ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_BYTES,
                          pxa2xx_pcm_hw_rule_mult32, NULL,
                          SNDRV_PCM_HW_PARAM_BUFFER_BYTES, -1);
      if (ret)
            goto out;

      ret = -ENOMEM;
      rtd = kmalloc(sizeof(*rtd), GFP_KERNEL);
      if (!rtd)
            goto out;
      rtd->dma_desc_array =
            dma_alloc_writecombine(substream->pcm->card->dev, PAGE_SIZE,
                               &rtd->dma_desc_array_phys, GFP_KERNEL);
      if (!rtd->dma_desc_array)
            goto err1;

      rtd->params = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) ?
                  client->playback_params : client->capture_params;
      ret = pxa_request_dma(rtd->params->name, DMA_PRIO_LOW,
                        pxa2xx_pcm_dma_irq, substream);
      if (ret < 0)
            goto err2;
      rtd->dma_ch = ret;

      runtime->private_data = rtd;
      ret = client->startup(substream);
      if (!ret)
            goto out;

      pxa_free_dma(rtd->dma_ch);
 err2:
      dma_free_writecombine(substream->pcm->card->dev, PAGE_SIZE,
                        rtd->dma_desc_array, rtd->dma_desc_array_phys);
 err1:
      kfree(rtd);
 out:
      return ret;
}

static int pxa2xx_pcm_close(struct snd_pcm_substream *substream)
{
      struct pxa2xx_pcm_client *client = substream->private_data;
      struct pxa2xx_runtime_data *rtd = substream->runtime->private_data;

      pxa_free_dma(rtd->dma_ch);
      client->shutdown(substream);
      dma_free_writecombine(substream->pcm->card->dev, PAGE_SIZE,
                        rtd->dma_desc_array, rtd->dma_desc_array_phys);
      kfree(rtd);
      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);
}

static 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 = 0xffffffff;

int pxa2xx_pcm_new(struct snd_card *card, struct pxa2xx_pcm_client *client,
               struct snd_pcm **rpcm)
{
      struct snd_pcm *pcm;
      int play = client->playback_params ? 1 : 0;
      int capt = client->capture_params ? 1 : 0;
      int ret;

      ret = snd_pcm_new(card, "PXA2xx-PCM", 0, play, capt, &pcm);
      if (ret)
            goto out;

      pcm->private_data = client;
      pcm->private_free = pxa2xx_pcm_free_dma_buffers;

      if (!card->dev->dma_mask)
            card->dev->dma_mask = &pxa2xx_pcm_dmamask;
      if (!card->dev->coherent_dma_mask)
            card->dev->coherent_dma_mask = 0xffffffff;

      if (play) {
            int stream = SNDRV_PCM_STREAM_PLAYBACK;
            snd_pcm_set_ops(pcm, stream, &pxa2xx_pcm_ops);
            ret = pxa2xx_pcm_preallocate_dma_buffer(pcm, stream);
            if (ret)
                  goto out;
      }
      if (capt) {
            int stream = SNDRV_PCM_STREAM_CAPTURE;
            snd_pcm_set_ops(pcm, stream, &pxa2xx_pcm_ops);
            ret = pxa2xx_pcm_preallocate_dma_buffer(pcm, stream);
            if (ret)
                  goto out;
      }

      if (rpcm)
            *rpcm = pcm;
      ret = 0;

 out:
      return ret;
}

EXPORT_SYMBOL(pxa2xx_pcm_new);

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

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