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atmel-pcm.c

/*
 * atmel-pcm.c  --  ALSA PCM interface for the Atmel atmel SoC.
 *
 *  Copyright (C) 2005 SAN People
 *  Copyright (C) 2008 Atmel
 *
 * Authors: Sedji Gaouaou <sedji.gaouaou@atmel.com>
 *
 * Based on at91-pcm. by:
 * Frank Mandarino <fmandarino@endrelia.com>
 * Copyright 2006 Endrelia Technologies Inc.
 *
 * 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 as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#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 <linux/atmel-ssc.h>

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

#include "atmel-pcm.h"


/*--------------------------------------------------------------------------*\
 * Hardware definition
\*--------------------------------------------------------------------------*/
/* TODO: These values were taken from the AT91 platform driver, check
 *     them against real values for AT32
 */
static const struct snd_pcm_hardware atmel_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,
};


/*--------------------------------------------------------------------------*\
 * Data types
\*--------------------------------------------------------------------------*/
struct atmel_runtime_data {
      struct atmel_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 */
      int periods;                  /* period index of period_ptr */

      /* PDC register save */
      u32 pdc_xpr_save;
      u32 pdc_xcr_save;
      u32 pdc_xnpr_save;
      u32 pdc_xncr_save;
};


/*--------------------------------------------------------------------------*\
 * Helper functions
\*--------------------------------------------------------------------------*/
static int atmel_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 = atmel_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_coherent(pcm->card->dev, size,
                                &buf->addr, GFP_KERNEL);
      pr_debug("atmel-pcm:"
            "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;
}
/*--------------------------------------------------------------------------*\
 * ISR
\*--------------------------------------------------------------------------*/
static void atmel_pcm_dma_irq(u32 ssc_sr,
      struct snd_pcm_substream *substream)
{
      struct atmel_runtime_data *prtd = substream->runtime->private_data;
      struct atmel_pcm_dma_params *params = prtd->params;
      static int count;

      count++;

      if (ssc_sr & params->mask->ssc_endbuf) {
            pr_warning("atmel-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 */
            ssc_writex(params->ssc->regs, 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;

            ssc_writex(params->ssc->regs, params->pdc->xpr,
                     prtd->period_ptr);
            ssc_writex(params->ssc->regs, params->pdc->xcr,
                     prtd->period_size / params->pdc_xfer_size);
            ssc_writex(params->ssc->regs, 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;

            ssc_writex(params->ssc->regs, params->pdc->xnpr,
                     prtd->period_ptr);
            ssc_writex(params->ssc->regs, params->pdc->xncr,
                     prtd->period_size / params->pdc_xfer_size);
      }

      snd_pcm_period_elapsed(substream);
}


/*--------------------------------------------------------------------------*\
 * PCM operations
\*--------------------------------------------------------------------------*/
static int atmel_pcm_hw_params(struct snd_pcm_substream *substream,
      struct snd_pcm_hw_params *params)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct atmel_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 = atmel_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);

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

static int atmel_pcm_hw_free(struct snd_pcm_substream *substream)
{
      struct atmel_runtime_data *prtd = substream->runtime->private_data;
      struct atmel_pcm_dma_params *params = prtd->params;

      if (params != NULL) {
            ssc_writex(params->ssc->regs, SSC_PDC_PTCR,
                     params->mask->pdc_disable);
            prtd->params->dma_intr_handler = NULL;
      }

      return 0;
}

static int atmel_pcm_prepare(struct snd_pcm_substream *substream)
{
      struct atmel_runtime_data *prtd = substream->runtime->private_data;
      struct atmel_pcm_dma_params *params = prtd->params;

      ssc_writex(params->ssc->regs, SSC_IDR,
               params->mask->ssc_endx | params->mask->ssc_endbuf);
      ssc_writex(params->ssc->regs, ATMEL_PDC_PTCR,
               params->mask->pdc_disable);
      return 0;
}

static int atmel_pcm_trigger(struct snd_pcm_substream *substream,
      int cmd)
{
      struct snd_pcm_runtime *rtd = substream->runtime;
      struct atmel_runtime_data *prtd = rtd->private_data;
      struct atmel_pcm_dma_params *params = prtd->params;
      int ret = 0;

      pr_debug("atmel-pcm:buffer_size = %ld,"
            "dma_area = %p, dma_bytes = %u\n",
            rtd->buffer_size, rtd->dma_area, rtd->dma_bytes);

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

            ssc_writex(params->ssc->regs, params->pdc->xpr,
                     prtd->period_ptr);
            ssc_writex(params->ssc->regs, params->pdc->xcr,
                     prtd->period_size / params->pdc_xfer_size);

            prtd->period_ptr += prtd->period_size;
            ssc_writex(params->ssc->regs, params->pdc->xnpr,
                     prtd->period_ptr);
            ssc_writex(params->ssc->regs, params->pdc->xncr,
                     prtd->period_size / params->pdc_xfer_size);

            pr_debug("atmel-pcm: trigger: "
                  "period_ptr=%lx, xpr=%u, "
                  "xcr=%u, xnpr=%u, xncr=%u\n",
                  (unsigned long)prtd->period_ptr,
                  ssc_readx(params->ssc->regs, params->pdc->xpr),
                  ssc_readx(params->ssc->regs, params->pdc->xcr),
                  ssc_readx(params->ssc->regs, params->pdc->xnpr),
                  ssc_readx(params->ssc->regs, params->pdc->xncr));

            ssc_writex(params->ssc->regs, SSC_IER,
                     params->mask->ssc_endx | params->mask->ssc_endbuf);
            ssc_writex(params->ssc->regs, SSC_PDC_PTCR,
                     params->mask->pdc_enable);

            pr_debug("sr=%u imr=%u\n",
                  ssc_readx(params->ssc->regs, SSC_SR),
                  ssc_readx(params->ssc->regs, SSC_IER));
            break;            /* SNDRV_PCM_TRIGGER_START */

      case SNDRV_PCM_TRIGGER_STOP:
      case SNDRV_PCM_TRIGGER_SUSPEND:
      case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
            ssc_writex(params->ssc->regs, ATMEL_PDC_PTCR,
                     params->mask->pdc_disable);
            break;

      case SNDRV_PCM_TRIGGER_RESUME:
      case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
            ssc_writex(params->ssc->regs, ATMEL_PDC_PTCR,
                     params->mask->pdc_enable);
            break;

      default:
            ret = -EINVAL;
      }

      return ret;
}

static snd_pcm_uframes_t atmel_pcm_pointer(
      struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct atmel_runtime_data *prtd = runtime->private_data;
      struct atmel_pcm_dma_params *params = prtd->params;
      dma_addr_t ptr;
      snd_pcm_uframes_t x;

      ptr = (dma_addr_t) ssc_readx(params->ssc->regs, params->pdc->xpr);
      x = bytes_to_frames(runtime, ptr - prtd->dma_buffer);

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

      return x;
}

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

      snd_soc_set_runtime_hwparams(substream, &atmel_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 atmel_runtime_data), GFP_KERNEL);
      if (prtd == NULL) {
            ret = -ENOMEM;
            goto out;
      }
      runtime->private_data = prtd;

 out:
      return ret;
}

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

      kfree(prtd);
      return 0;
}

static int atmel_pcm_mmap(struct snd_pcm_substream *substream,
      struct vm_area_struct *vma)
{
      return remap_pfn_range(vma, vma->vm_start,
                   substream->dma_buffer.addr >> PAGE_SHIFT,
                   vma->vm_end - vma->vm_start, vma->vm_page_prot);
}

static struct snd_pcm_ops atmel_pcm_ops = {
      .open       = atmel_pcm_open,
      .close            = atmel_pcm_close,
      .ioctl            = snd_pcm_lib_ioctl,
      .hw_params  = atmel_pcm_hw_params,
      .hw_free    = atmel_pcm_hw_free,
      .prepare    = atmel_pcm_prepare,
      .trigger    = atmel_pcm_trigger,
      .pointer    = atmel_pcm_pointer,
      .mmap       = atmel_pcm_mmap,
};


/*--------------------------------------------------------------------------*\
 * ASoC platform driver
\*--------------------------------------------------------------------------*/
static u64 atmel_pcm_dmamask = 0xffffffff;

static int atmel_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 = &atmel_pcm_dmamask;
      if (!card->dev->coherent_dma_mask)
            card->dev->coherent_dma_mask = 0xffffffff;

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

      if (dai->capture.channels_min) {
            pr_debug("at32-pcm:"
                        "Allocating PCM capture DMA buffer\n");
            ret = atmel_pcm_preallocate_dma_buffer(pcm,
                  SNDRV_PCM_STREAM_CAPTURE);
            if (ret)
                  goto out;
      }
 out:
      return ret;
}

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

#ifdef CONFIG_PM
static int atmel_pcm_suspend(struct snd_soc_dai *dai)
{
      struct snd_pcm_runtime *runtime = dai->runtime;
      struct atmel_runtime_data *prtd;
      struct atmel_pcm_dma_params *params;

      if (!runtime)
            return 0;

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

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

      ssc_writel(params->ssc->regs, PDC_PTCR, params->mask->pdc_disable);

      prtd->pdc_xpr_save = ssc_readx(params->ssc->regs, params->pdc->xpr);
      prtd->pdc_xcr_save = ssc_readx(params->ssc->regs, params->pdc->xcr);
      prtd->pdc_xnpr_save = ssc_readx(params->ssc->regs, params->pdc->xnpr);
      prtd->pdc_xncr_save = ssc_readx(params->ssc->regs, params->pdc->xncr);

      return 0;
}

static int atmel_pcm_resume(struct snd_soc_dai *dai)
{
      struct snd_pcm_runtime *runtime = dai->runtime;
      struct atmel_runtime_data *prtd;
      struct atmel_pcm_dma_params *params;

      if (!runtime)
            return 0;

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

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

      ssc_writel(params->ssc->regs, PDC_PTCR, params->mask->pdc_enable);
      return 0;
}
#else
#define atmel_pcm_suspend     NULL
#define atmel_pcm_resume      NULL
#endif

struct snd_soc_platform atmel_soc_platform = {
      .name       = "atmel-audio",
      .pcm_ops    = &atmel_pcm_ops,
      .pcm_new    = atmel_pcm_new,
      .pcm_free   = atmel_pcm_free_dma_buffers,
      .suspend    = atmel_pcm_suspend,
      .resume           = atmel_pcm_resume,
};
EXPORT_SYMBOL_GPL(atmel_soc_platform);

static int __init atmel_pcm_modinit(void)
{
      return snd_soc_register_platform(&atmel_soc_platform);
}
module_init(atmel_pcm_modinit);

static void __exit atmel_pcm_modexit(void)
{
      snd_soc_unregister_platform(&atmel_soc_platform);
}
module_exit(atmel_pcm_modexit);

MODULE_AUTHOR("Sedji Gaouaou <sedji.gaouaou@atmel.com>");
MODULE_DESCRIPTION("Atmel PCM module");
MODULE_LICENSE("GPL");

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