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dbdma2.c

/*
 * Au12x0/Au1550 PSC ALSA ASoC audio support.
 *
 * (c) 2007-2008 MSC Vertriebsges.m.b.H.,
 *    Manuel Lauss <mano@roarinelk.homelinux.net>
 *
 * 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.
 *
 * DMA glue for Au1x-PSC audio.
 *
 * NOTE: all of these drivers can only work with a SINGLE instance
 *     of a PSC. Multiple independent audio devices are impossible
 *     with ASoC v1.
 */


#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/mach-au1x00/au1000.h>
#include <asm/mach-au1x00/au1xxx_dbdma.h>
#include <asm/mach-au1x00/au1xxx_psc.h>

#include "psc.h"

/*#define PCM_DEBUG*/

#define MSG(x...) printk(KERN_INFO "au1xpsc_pcm: " x)
#ifdef PCM_DEBUG
#define DBG       MSG
#else
#define DBG(x...) do {} while (0)
#endif

struct au1xpsc_audio_dmadata {
      /* DDMA control data */
      unsigned int ddma_id;         /* DDMA direction ID for this PSC */
      u32 ddma_chan;                /* DDMA context */

      /* PCM context (for irq handlers) */
      struct snd_pcm_substream *substream;
      unsigned long curr_period;    /* current segment DDMA is working on */
      unsigned long q_period;       /* queue period(s) */
      unsigned long dma_area;       /* address of queued DMA area */
      unsigned long dma_area_s;     /* start address of DMA area */
      unsigned long pos;            /* current byte position being played */
      unsigned long periods;        /* number of SG segments in total */
      unsigned long period_bytes;   /* size in bytes of one SG segment */

      /* runtime data */
      int msbits;
};

/* instance data. There can be only one, MacLeod!!!! */
static struct au1xpsc_audio_dmadata *au1xpsc_audio_pcmdma[2];

/*
 * These settings are somewhat okay, at least on my machine audio plays
 * almost skip-free. Especially the 64kB buffer seems to help a LOT.
 */
#define AU1XPSC_PERIOD_MIN_BYTES    1024
#define AU1XPSC_BUFFER_MIN_BYTES    65536

#define AU1XPSC_PCM_FMTS                              \
      (SNDRV_PCM_FMTBIT_S8     | SNDRV_PCM_FMTBIT_U8 |      \
       SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |  \
       SNDRV_PCM_FMTBIT_U16_LE | SNDRV_PCM_FMTBIT_U16_BE |  \
       SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |  \
       SNDRV_PCM_FMTBIT_U32_LE | SNDRV_PCM_FMTBIT_U32_BE |  \
       0)

/* PCM hardware DMA capabilities - platform specific */
static const struct snd_pcm_hardware au1xpsc_pcm_hardware = {
      .info         = SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID |
                      SNDRV_PCM_INFO_INTERLEAVED,
      .formats      = AU1XPSC_PCM_FMTS,
      .period_bytes_min = AU1XPSC_PERIOD_MIN_BYTES,
      .period_bytes_max = 4096 * 1024 - 1,
      .periods_min        = 2,
      .periods_max        = 4096,   /* 2 to as-much-as-you-like */
      .buffer_bytes_max = 4096 * 1024 - 1,
      .fifo_size    = 16,           /* fifo entries of AC97/I2S PSC */
};

static void au1x_pcm_queue_tx(struct au1xpsc_audio_dmadata *cd)
{
      au1xxx_dbdma_put_source_flags(cd->ddma_chan,
                        (void *)phys_to_virt(cd->dma_area),
                        cd->period_bytes, DDMA_FLAGS_IE);

      /* update next-to-queue period */
      ++cd->q_period;
      cd->dma_area += cd->period_bytes;
      if (cd->q_period >= cd->periods) {
            cd->q_period = 0;
            cd->dma_area = cd->dma_area_s;
      }
}

static void au1x_pcm_queue_rx(struct au1xpsc_audio_dmadata *cd)
{
      au1xxx_dbdma_put_dest_flags(cd->ddma_chan,
                        (void *)phys_to_virt(cd->dma_area),
                        cd->period_bytes, DDMA_FLAGS_IE);

      /* update next-to-queue period */
      ++cd->q_period;
      cd->dma_area += cd->period_bytes;
      if (cd->q_period >= cd->periods) {
            cd->q_period = 0;
            cd->dma_area = cd->dma_area_s;
      }
}

static void au1x_pcm_dmatx_cb(int irq, void *dev_id)
{
      struct au1xpsc_audio_dmadata *cd = dev_id;

      cd->pos += cd->period_bytes;
      if (++cd->curr_period >= cd->periods) {
            cd->pos = 0;
            cd->curr_period = 0;
      }
      snd_pcm_period_elapsed(cd->substream);
      au1x_pcm_queue_tx(cd);
}

static void au1x_pcm_dmarx_cb(int irq, void *dev_id)
{
      struct au1xpsc_audio_dmadata *cd = dev_id;

      cd->pos += cd->period_bytes;
      if (++cd->curr_period >= cd->periods) {
            cd->pos = 0;
            cd->curr_period = 0;
      }
      snd_pcm_period_elapsed(cd->substream);
      au1x_pcm_queue_rx(cd);
}

static void au1x_pcm_dbdma_free(struct au1xpsc_audio_dmadata *pcd)
{
      if (pcd->ddma_chan) {
            au1xxx_dbdma_stop(pcd->ddma_chan);
            au1xxx_dbdma_reset(pcd->ddma_chan);
            au1xxx_dbdma_chan_free(pcd->ddma_chan);
            pcd->ddma_chan = 0;
            pcd->msbits = 0;
      }
}

/* in case of missing DMA ring or changed TX-source / RX-dest bit widths,
 * allocate (or reallocate) a 2-descriptor DMA ring with bit depth according
 * to ALSA-supplied sample depth.  This is due to limitations in the dbdma api
 * (cannot adjust source/dest widths of already allocated descriptor ring).
 */
static int au1x_pcm_dbdma_realloc(struct au1xpsc_audio_dmadata *pcd,
                         int stype, int msbits)
{
      /* DMA only in 8/16/32 bit widths */
      if (msbits == 24)
            msbits = 32;

      /* check current config: correct bits and descriptors allocated? */
      if ((pcd->ddma_chan) && (msbits == pcd->msbits))
            goto out;   /* all ok! */

      au1x_pcm_dbdma_free(pcd);

      if (stype == PCM_RX)
            pcd->ddma_chan = au1xxx_dbdma_chan_alloc(pcd->ddma_id,
                              DSCR_CMD0_ALWAYS,
                              au1x_pcm_dmarx_cb, (void *)pcd);
      else
            pcd->ddma_chan = au1xxx_dbdma_chan_alloc(DSCR_CMD0_ALWAYS,
                              pcd->ddma_id,
                              au1x_pcm_dmatx_cb, (void *)pcd);

      if (!pcd->ddma_chan)
            return -ENOMEM;;

      au1xxx_dbdma_set_devwidth(pcd->ddma_chan, msbits);
      au1xxx_dbdma_ring_alloc(pcd->ddma_chan, 2);

      pcd->msbits = msbits;

      au1xxx_dbdma_stop(pcd->ddma_chan);
      au1xxx_dbdma_reset(pcd->ddma_chan);

out:
      return 0;
}

static int au1xpsc_pcm_hw_params(struct snd_pcm_substream *substream,
                         struct snd_pcm_hw_params *params)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct au1xpsc_audio_dmadata *pcd;
      int stype, ret;

      ret = snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params));
      if (ret < 0)
            goto out;

      stype = SUBSTREAM_TYPE(substream);
      pcd = au1xpsc_audio_pcmdma[stype];

      DBG("runtime->dma_area = 0x%08lx dma_addr_t = 0x%08lx dma_size = %d "
          "runtime->min_align %d\n",
            (unsigned long)runtime->dma_area,
            (unsigned long)runtime->dma_addr, runtime->dma_bytes,
            runtime->min_align);

      DBG("bits %d  frags %d  frag_bytes %d  is_rx %d\n", params->msbits,
            params_periods(params), params_period_bytes(params), stype);

      ret = au1x_pcm_dbdma_realloc(pcd, stype, params->msbits);
      if (ret) {
            MSG("DDMA channel (re)alloc failed!\n");
            goto out;
      }

      pcd->substream = substream;
      pcd->period_bytes = params_period_bytes(params);
      pcd->periods = params_periods(params);
      pcd->dma_area_s = pcd->dma_area = (unsigned long)runtime->dma_addr;
      pcd->q_period = 0;
      pcd->curr_period = 0;
      pcd->pos = 0;

      ret = 0;
out:
      return ret;
}

static int au1xpsc_pcm_hw_free(struct snd_pcm_substream *substream)
{
      snd_pcm_lib_free_pages(substream);
      return 0;
}

static int au1xpsc_pcm_prepare(struct snd_pcm_substream *substream)
{
      struct au1xpsc_audio_dmadata *pcd =
                  au1xpsc_audio_pcmdma[SUBSTREAM_TYPE(substream)];

      au1xxx_dbdma_reset(pcd->ddma_chan);

      if (SUBSTREAM_TYPE(substream) == PCM_RX) {
            au1x_pcm_queue_rx(pcd);
            au1x_pcm_queue_rx(pcd);
      } else {
            au1x_pcm_queue_tx(pcd);
            au1x_pcm_queue_tx(pcd);
      }

      return 0;
}

static int au1xpsc_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
      u32 c = au1xpsc_audio_pcmdma[SUBSTREAM_TYPE(substream)]->ddma_chan;

      switch (cmd) {
      case SNDRV_PCM_TRIGGER_START:
      case SNDRV_PCM_TRIGGER_RESUME:
            au1xxx_dbdma_start(c);
            break;
      case SNDRV_PCM_TRIGGER_STOP:
      case SNDRV_PCM_TRIGGER_SUSPEND:
            au1xxx_dbdma_stop(c);
            break;
      default:
            return -EINVAL;
      }
      return 0;
}

static snd_pcm_uframes_t
au1xpsc_pcm_pointer(struct snd_pcm_substream *substream)
{
      return bytes_to_frames(substream->runtime,
            au1xpsc_audio_pcmdma[SUBSTREAM_TYPE(substream)]->pos);
}

static int au1xpsc_pcm_open(struct snd_pcm_substream *substream)
{
      snd_soc_set_runtime_hwparams(substream, &au1xpsc_pcm_hardware);
      return 0;
}

static int au1xpsc_pcm_close(struct snd_pcm_substream *substream)
{
      au1x_pcm_dbdma_free(au1xpsc_audio_pcmdma[SUBSTREAM_TYPE(substream)]);
      return 0;
}

struct snd_pcm_ops au1xpsc_pcm_ops = {
      .open       = au1xpsc_pcm_open,
      .close            = au1xpsc_pcm_close,
      .ioctl            = snd_pcm_lib_ioctl,
      .hw_params  = au1xpsc_pcm_hw_params,
      .hw_free    = au1xpsc_pcm_hw_free,
      .prepare    = au1xpsc_pcm_prepare,
      .trigger    = au1xpsc_pcm_trigger,
      .pointer    = au1xpsc_pcm_pointer,
};

static void au1xpsc_pcm_free_dma_buffers(struct snd_pcm *pcm)
{
      snd_pcm_lib_preallocate_free_for_all(pcm);
}

static int au1xpsc_pcm_new(struct snd_card *card,
                     struct snd_soc_dai *dai,
                     struct snd_pcm *pcm)
{
      snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV,
            card->dev, AU1XPSC_BUFFER_MIN_BYTES, (4096 * 1024) - 1);

      return 0;
}

static int au1xpsc_pcm_probe(struct platform_device *pdev)
{
      struct resource *r;
      int ret;

      if (au1xpsc_audio_pcmdma[PCM_TX] || au1xpsc_audio_pcmdma[PCM_RX])
            return -EBUSY;

      /* TX DMA */
      au1xpsc_audio_pcmdma[PCM_TX]
            = kzalloc(sizeof(struct au1xpsc_audio_dmadata), GFP_KERNEL);
      if (!au1xpsc_audio_pcmdma[PCM_TX])
            return -ENOMEM;

      r = platform_get_resource(pdev, IORESOURCE_DMA, 0);
      if (!r) {
            ret = -ENODEV;
            goto out1;
      }
      (au1xpsc_audio_pcmdma[PCM_TX])->ddma_id = r->start;

      /* RX DMA */
      au1xpsc_audio_pcmdma[PCM_RX]
            = kzalloc(sizeof(struct au1xpsc_audio_dmadata), GFP_KERNEL);
      if (!au1xpsc_audio_pcmdma[PCM_RX])
            return -ENOMEM;

      r = platform_get_resource(pdev, IORESOURCE_DMA, 1);
      if (!r) {
            ret = -ENODEV;
            goto out2;
      }
      (au1xpsc_audio_pcmdma[PCM_RX])->ddma_id = r->start;

      return 0;

out2:
      kfree(au1xpsc_audio_pcmdma[PCM_RX]);
      au1xpsc_audio_pcmdma[PCM_RX] = NULL;
out1:
      kfree(au1xpsc_audio_pcmdma[PCM_TX]);
      au1xpsc_audio_pcmdma[PCM_TX] = NULL;
      return ret;
}

static int au1xpsc_pcm_remove(struct platform_device *pdev)
{
      int i;

      for (i = 0; i < 2; i++) {
            if (au1xpsc_audio_pcmdma[i]) {
                  au1x_pcm_dbdma_free(au1xpsc_audio_pcmdma[i]);
                  kfree(au1xpsc_audio_pcmdma[i]);
                  au1xpsc_audio_pcmdma[i] = NULL;
            }
      }

      return 0;
}

/* au1xpsc audio platform */
struct snd_soc_platform au1xpsc_soc_platform = {
      .name       = "au1xpsc-pcm-dbdma",
      .probe            = au1xpsc_pcm_probe,
      .remove           = au1xpsc_pcm_remove,
      .pcm_ops    = &au1xpsc_pcm_ops,
      .pcm_new    = au1xpsc_pcm_new,
      .pcm_free   = au1xpsc_pcm_free_dma_buffers,
};
EXPORT_SYMBOL_GPL(au1xpsc_soc_platform);

static int __init au1xpsc_audio_dbdma_init(void)
{
      au1xpsc_audio_pcmdma[PCM_TX] = NULL;
      au1xpsc_audio_pcmdma[PCM_RX] = NULL;
      return 0;
}

static void __exit au1xpsc_audio_dbdma_exit(void)
{
}

module_init(au1xpsc_audio_dbdma_init);
module_exit(au1xpsc_audio_dbdma_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Au12x0/Au1550 PSC Audio DMA driver");
MODULE_AUTHOR("Manuel Lauss <mano@roarinelk.homelinux.net>");

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