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at32-pcm.c

/* sound/soc/at32/at32-pcm.c
 * ASoC PCM interface for Atmel AT32 SoC
 *
 * Copyright (C) 2008 Long Range Systems
 *    Geoffrey Wossum <gwossum@acm.org>
 *
 * 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.
 *
 * Note that this is basically a port of the sound/soc/at91-pcm.c to
 * the AVR32 kernel.  Thanks to Frank Mandarino for that code.
 */

#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 "at32-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 at32_pcm_hardware = {
      .info = (SNDRV_PCM_INFO_MMAP |
             SNDRV_PCM_INFO_MMAP_VALID |
             SNDRV_PCM_INFO_INTERLEAVED |
             SNDRV_PCM_INFO_BLOCK_TRANSFER |
             SNDRV_PCM_INFO_PAUSE),

      .formats = SNDRV_PCM_FMTBIT_S16,
      .period_bytes_min = 32,
      .period_bytes_max = 8192,     /* 512 frames * 16 bytes / frame */
      .periods_min = 2,
      .periods_max = 1024,
      .buffer_bytes_max = 32 * 1024,
};



/*--------------------------------------------------------------------------*\
 * Data types
\*--------------------------------------------------------------------------*/
struct at32_runtime_data {
      struct at32_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 */

      /* Save PDC registers (for power management) */
      u32 pdc_xpr_save;
      u32 pdc_xcr_save;
      u32 pdc_xnpr_save;
      u32 pdc_xncr_save;
};



/*--------------------------------------------------------------------------*\
 * Helper functions
\*--------------------------------------------------------------------------*/
static int at32_pcm_preallocate_dma_buffer(struct snd_pcm *pcm, int stream)
{
      struct snd_pcm_substream *substream = pcm->streams[stream].substream;
      struct snd_dma_buffer *dmabuf = &substream->dma_buffer;
      size_t size = at32_pcm_hardware.buffer_bytes_max;

      dmabuf->dev.type = SNDRV_DMA_TYPE_DEV;
      dmabuf->dev.dev = pcm->card->dev;
      dmabuf->private_data = NULL;
      dmabuf->area = dma_alloc_coherent(pcm->card->dev, size,
                                &dmabuf->addr, GFP_KERNEL);
      pr_debug("at32_pcm: preallocate_dma_buffer: "
             "area=%p, addr=%p, size=%ld\n",
             (void *)dmabuf->area, (void *)dmabuf->addr, size);

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

      dmabuf->bytes = size;
      return 0;
}



/*--------------------------------------------------------------------------*\
 * ISR
\*--------------------------------------------------------------------------*/
static void at32_pcm_dma_irq(u32 ssc_sr, struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *rtd = substream->runtime;
      struct at32_runtime_data *prtd = rtd->private_data;
      struct at32_pcm_dma_params *params = prtd->params;
      static int count;

      count++;
      if (ssc_sr & params->mask->ssc_endbuf) {
            pr_warning("at32-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 at32_pcm_hw_params(struct snd_pcm_substream *substream,
                        struct snd_pcm_hw_params *params)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct at32_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 = at32_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("hw_params: DMA for %s initialized "
             "(dma_bytes=%ld, period_size=%ld)\n",
             prtd->params->name, runtime->dma_bytes, prtd->period_size);

      return 0;
}



static int at32_pcm_hw_free(struct snd_pcm_substream *substream)
{
      struct at32_runtime_data *prtd = substream->runtime->private_data;
      struct at32_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 at32_pcm_prepare(struct snd_pcm_substream *substream)
{
      struct at32_runtime_data *prtd = substream->runtime->private_data;
      struct at32_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 at32_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
      struct snd_pcm_runtime *rtd = substream->runtime;
      struct at32_runtime_data *prtd = rtd->private_data;
      struct at32_pcm_dma_params *params = prtd->params;
      int ret = 0;

      pr_debug("at32_pcm_trigger: buffer_size = %ld, "
             "dma_area = %p, dma_bytes = %ld\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("trigger: period_ptr=%lx, xpr=%x, "
                   "xcr=%d, xnpr=%x, xncr=%d\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=%x, imr=%x\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 at32_pcm_pointer(struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct at32_runtime_data *prtd = runtime->private_data;
      struct at32_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 at32_pcm_open(struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct at32_runtime_data *prtd;
      int ret = 0;

      snd_soc_set_runtime_hwparams(substream, &at32_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(*prtd), GFP_KERNEL);
      if (prtd == NULL) {
            ret = -ENOMEM;
            goto out;
      }
      runtime->private_data = prtd;


out:
      return ret;
}



static int at32_pcm_close(struct snd_pcm_substream *substream)
{
      struct at32_runtime_data *prtd = substream->runtime->private_data;

      kfree(prtd);
      return 0;
}


static int at32_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 at32_pcm_ops = {
      .open = at32_pcm_open,
      .close = at32_pcm_close,
      .ioctl = snd_pcm_lib_ioctl,
      .hw_params = at32_pcm_hw_params,
      .hw_free = at32_pcm_hw_free,
      .prepare = at32_pcm_prepare,
      .trigger = at32_pcm_trigger,
      .pointer = at32_pcm_pointer,
      .mmap = at32_pcm_mmap,
};



/*--------------------------------------------------------------------------*\
 * ASoC platform driver
\*--------------------------------------------------------------------------*/
static u64 at32_pcm_dmamask = 0xffffffff;

static int at32_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 = &at32_pcm_dmamask;
      if (!card->dev->coherent_dma_mask)
            card->dev->coherent_dma_mask = 0xffffffff;

      if (dai->playback.channels_min) {
            ret = at32_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 = at32_pcm_preallocate_dma_buffer(
                    pcm, SNDRV_PCM_STREAM_CAPTURE);
            if (ret)
                  goto out;
      }


out:
      return ret;
}



static void at32_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 == NULL)
                  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 at32_pcm_suspend(struct platform_device *pdev,
                      struct snd_soc_dai *dai)
{
      struct snd_pcm_runtime *runtime = dai->runtime;
      struct at32_runtime_data *prtd;
      struct at32_pcm_dma_params *params;

      if (runtime == NULL)
            return 0;
      prtd = runtime->private_data;
      params = prtd->params;

      /* Disable the PDC and save the PDC registers */
      ssc_writex(params->ssc->regs, ATMEL_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 at32_pcm_resume(struct platform_device *pdev,
                     struct snd_soc_dai *dai)
{
      struct snd_pcm_runtime *runtime = dai->runtime;
      struct at32_runtime_data *prtd;
      struct at32_pcm_dma_params *params;

      if (runtime == NULL)
            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_writex(params->ssc->regs, ATMEL_PDC_PTCR, params->mask->pdc_enable);
      return 0;
}
#else /* CONFIG_PM */
#  define at32_pcm_suspend    NULL
#  define at32_pcm_resume     NULL
#endif /* CONFIG_PM */



struct snd_soc_platform at32_soc_platform = {
      .name = "at32-audio",
      .pcm_ops = &at32_pcm_ops,
      .pcm_new = at32_pcm_new,
      .pcm_free = at32_pcm_free_dma_buffers,
      .suspend = at32_pcm_suspend,
      .resume = at32_pcm_resume,
};
EXPORT_SYMBOL_GPL(at32_soc_platform);



MODULE_AUTHOR("Geoffrey Wossum <gwossum@acm.org>");
MODULE_DESCRIPTION("Atmel AT32 PCM module");
MODULE_LICENSE("GPL");

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