dma.c

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/*
 * Au1000/Au1500/Au1100 Audio DMA support.
 *
 * (c) 2011 Manuel Lauss <[email protected]>
 *
 * copied almost verbatim from the old ALSA driver, written by
 *          Charles Eidsness <[email protected]>
 */

#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/au1000_dma.h>

#include "psc.h"

#define ALCHEMY_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)

struct pcm_period {
    u32 start;
    u32 relative_end;   /* relative to start of buffer */
    struct pcm_period *next;
};

struct audio_stream {
    struct snd_pcm_substream *substream;
    int dma;
    struct pcm_period *buffer;
    unsigned int period_size;
    unsigned int periods;
};

struct alchemy_pcm_ctx {
    struct audio_stream stream[2];  /* playback & capture */
};

static void au1000_release_dma_link(struct audio_stream *stream)
{
    struct pcm_period *pointer;
    struct pcm_period *pointer_next;

    stream->period_size = 0;
    stream->periods = 0;
    pointer = stream->buffer;
    if (!pointer)
        return;
    do {
        pointer_next = pointer->next;
        kfree(pointer);
        pointer = pointer_next;
    } while (pointer != stream->buffer);
    stream->buffer = NULL;
}

static int au1000_setup_dma_link(struct audio_stream *stream,
                 unsigned int period_bytes,
                 unsigned int periods)
{
    struct snd_pcm_substream *substream = stream->substream;
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct pcm_period *pointer;
    unsigned long dma_start;
    int i;

    dma_start = virt_to_phys(runtime->dma_area);

    if (stream->period_size == period_bytes &&
        stream->periods == periods)
        return 0; /* not changed */

    au1000_release_dma_link(stream);

    stream->period_size = period_bytes;
    stream->periods = periods;

    stream->buffer = kmalloc(sizeof(struct pcm_period), GFP_KERNEL);
    if (!stream->buffer)
        return -ENOMEM;
    pointer = stream->buffer;
    for (i = 0; i < periods; i++) {
        pointer->start = (u32)(dma_start + (i * period_bytes));
        pointer->relative_end = (u32) (((i+1) * period_bytes) - 0x1);
        if (i < periods - 1) {
            pointer->next = kmalloc(sizeof(struct pcm_period),
                        GFP_KERNEL);
            if (!pointer->next) {
                au1000_release_dma_link(stream);
                return -ENOMEM;
            }
            pointer = pointer->next;
        }
    }
    pointer->next = stream->buffer;
    return 0;
}

static void au1000_dma_stop(struct audio_stream *stream)
{
    if (stream->buffer)
        disable_dma(stream->dma);
}

static void au1000_dma_start(struct audio_stream *stream)
{
    if (!stream->buffer)
        return;

    init_dma(stream->dma);
    if (get_dma_active_buffer(stream->dma) == 0) {
        clear_dma_done0(stream->dma);
        set_dma_addr0(stream->dma, stream->buffer->start);
        set_dma_count0(stream->dma, stream->period_size >> 1);
        set_dma_addr1(stream->dma, stream->buffer->next->start);
        set_dma_count1(stream->dma, stream->period_size >> 1);
    } else {
        clear_dma_done1(stream->dma);
        set_dma_addr1(stream->dma, stream->buffer->start);
        set_dma_count1(stream->dma, stream->period_size >> 1);
        set_dma_addr0(stream->dma, stream->buffer->next->start);
        set_dma_count0(stream->dma, stream->period_size >> 1);
    }
    enable_dma_buffers(stream->dma);
    start_dma(stream->dma);
}

static irqreturn_t au1000_dma_interrupt(int irq, void *ptr)
{
    struct audio_stream *stream = (struct audio_stream *)ptr;
    struct snd_pcm_substream *substream = stream->substream;

    switch (get_dma_buffer_done(stream->dma)) {
    case DMA_D0:
        stream->buffer = stream->buffer->next;
        clear_dma_done0(stream->dma);
        set_dma_addr0(stream->dma, stream->buffer->next->start);
        set_dma_count0(stream->dma, stream->period_size >> 1);
        enable_dma_buffer0(stream->dma);
        break;
    case DMA_D1:
        stream->buffer = stream->buffer->next;
        clear_dma_done1(stream->dma);
        set_dma_addr1(stream->dma, stream->buffer->next->start);
        set_dma_count1(stream->dma, stream->period_size >> 1);
        enable_dma_buffer1(stream->dma);
        break;
    case (DMA_D0 | DMA_D1):
        pr_debug("DMA %d missed interrupt.\n", stream->dma);
        au1000_dma_stop(stream);
        au1000_dma_start(stream);
        break;
    case (~DMA_D0 & ~DMA_D1):
        pr_debug("DMA %d empty irq.\n", stream->dma);
    }
    snd_pcm_period_elapsed(substream);
    return IRQ_HANDLED;
}

static const struct snd_pcm_hardware alchemy_pcm_hardware = {
    .info         = SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID |
                SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BATCH,
    .formats      = ALCHEMY_PCM_FMTS,
    .rates        = SNDRV_PCM_RATE_8000_192000,
    .rate_min     = SNDRV_PCM_RATE_8000,
    .rate_max     = SNDRV_PCM_RATE_192000,
    .channels_min     = 2,
    .channels_max     = 2,
    .period_bytes_min = 1024,
    .period_bytes_max = 16 * 1024 - 1,
    .periods_min      = 4,
    .periods_max      = 255,
    .buffer_bytes_max = 128 * 1024,
    .fifo_size    = 16,
};

static inline struct alchemy_pcm_ctx *ss_to_ctx(struct snd_pcm_substream *ss)
{
    struct snd_soc_pcm_runtime *rtd = ss->private_data;
    return snd_soc_platform_get_drvdata(rtd->platform);
}

static inline struct audio_stream *ss_to_as(struct snd_pcm_substream *ss)
{
    struct alchemy_pcm_ctx *ctx = ss_to_ctx(ss);
    return &(ctx->stream[ss->stream]);
}

static int alchemy_pcm_open(struct snd_pcm_substream *substream)
{
    struct alchemy_pcm_ctx *ctx = ss_to_ctx(substream);
    struct snd_soc_pcm_runtime *rtd = substream->private_data;
    int *dmaids, s = substream->stream;
    char *name;

    dmaids = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
    if (!dmaids)
        return -ENODEV; /* whoa, has ordering changed? */

    /* DMA setup */
    name = (s == SNDRV_PCM_STREAM_PLAYBACK) ? "audio-tx" : "audio-rx";
    ctx->stream[s].dma = request_au1000_dma(dmaids[s], name,
                    au1000_dma_interrupt, 0,
                    &ctx->stream[s]);
    set_dma_mode(ctx->stream[s].dma,
             get_dma_mode(ctx->stream[s].dma) & ~DMA_NC);

    ctx->stream[s].substream = substream;
    ctx->stream[s].buffer = NULL;
    snd_soc_set_runtime_hwparams(substream, &alchemy_pcm_hardware);

    return 0;
}

static int alchemy_pcm_close(struct snd_pcm_substream *substream)
{
    struct alchemy_pcm_ctx *ctx = ss_to_ctx(substream);
    int stype = substream->stream;

    ctx->stream[stype].substream = NULL;
    free_au1000_dma(ctx->stream[stype].dma);

    return 0;
}

static int alchemy_pcm_hw_params(struct snd_pcm_substream *substream,
                 struct snd_pcm_hw_params *hw_params)
{
    struct audio_stream *stream = ss_to_as(substream);
    int err;

    err = snd_pcm_lib_malloc_pages(substream,
                       params_buffer_bytes(hw_params));
    if (err < 0)
        return err;
    err = au1000_setup_dma_link(stream,
                    params_period_bytes(hw_params),
                    params_periods(hw_params));
    if (err)
        snd_pcm_lib_free_pages(substream);

    return err;
}

static int alchemy_pcm_hw_free(struct snd_pcm_substream *substream)
{
    struct audio_stream *stream = ss_to_as(substream);
    au1000_release_dma_link(stream);
    return snd_pcm_lib_free_pages(substream);
}

static int alchemy_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
    struct audio_stream *stream = ss_to_as(substream);
    int err = 0;

    switch (cmd) {
    case SNDRV_PCM_TRIGGER_START:
        au1000_dma_start(stream);
        break;
    case SNDRV_PCM_TRIGGER_STOP:
        au1000_dma_stop(stream);
        break;
    default:
        err = -EINVAL;
        break;
    }
    return err;
}

static snd_pcm_uframes_t alchemy_pcm_pointer(struct snd_pcm_substream *ss)
{
    struct audio_stream *stream = ss_to_as(ss);
    long location;

    location = get_dma_residue(stream->dma);
    location = stream->buffer->relative_end - location;
    if (location == -1)
        location = 0;
    return bytes_to_frames(ss->runtime, location);
}

static struct snd_pcm_ops alchemy_pcm_ops = {
    .open           = alchemy_pcm_open,
    .close          = alchemy_pcm_close,
    .ioctl          = snd_pcm_lib_ioctl,
    .hw_params          = alchemy_pcm_hw_params,
    .hw_free            = alchemy_pcm_hw_free,
    .trigger        = alchemy_pcm_trigger,
    .pointer        = alchemy_pcm_pointer,
};

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

static int alchemy_pcm_new(struct snd_soc_pcm_runtime *rtd)
{
    struct snd_pcm *pcm = rtd->pcm;

    snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
        snd_dma_continuous_data(GFP_KERNEL), 65536, (4096 * 1024) - 1);

    return 0;
}

static struct snd_soc_platform_driver alchemy_pcm_soc_platform = {
    .ops        = &alchemy_pcm_ops,
    .pcm_new    = alchemy_pcm_new,
    .pcm_free   = alchemy_pcm_free_dma_buffers,
};

static int __devinit alchemy_pcm_drvprobe(struct platform_device *pdev)
{
    struct alchemy_pcm_ctx *ctx;

    ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
    if (!ctx)
        return -ENOMEM;

    platform_set_drvdata(pdev, ctx);

    return snd_soc_register_platform(&pdev->dev, &alchemy_pcm_soc_platform);
}

static int __devexit alchemy_pcm_drvremove(struct platform_device *pdev)
{
    snd_soc_unregister_platform(&pdev->dev);

    return 0;
}

static struct platform_driver alchemy_pcmdma_driver = {
    .driver = {
        .name   = "alchemy-pcm-dma",
        .owner  = THIS_MODULE,
    },
    .probe      = alchemy_pcm_drvprobe,
    .remove     = __devexit_p(alchemy_pcm_drvremove),
};

module_platform_driver(alchemy_pcmdma_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Au1000/Au1500/Au1100 Audio DMA driver");
MODULE_AUTHOR("Manuel Lauss");