spear_pcm.c

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/*
 * ALSA PCM interface for ST SPEAr Processors
 *
 * sound/soc/spear/spear_pcm.c
 *
 * Copyright (C) 2012 ST Microelectronics
 * Rajeev Kumar<[email protected]>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/module.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>
#include <sound/core.h>
#include <sound/dmaengine_pcm.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>
#include <sound/spear_dma.h>

struct snd_pcm_hardware spear_pcm_hardware = {
    .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER |
         SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID |
         SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME),
    .buffer_bytes_max = 16 * 1024, /* max buffer size */
    .period_bytes_min = 2 * 1024, /* 1 msec data minimum period size */
    .period_bytes_max = 2 * 1024, /* maximum period size */
    .periods_min = 1, /* min # periods */
    .periods_max = 8, /* max # of periods */
    .fifo_size = 0, /* fifo size in bytes */
};

static int spear_pcm_hw_params(struct snd_pcm_substream *substream,
        struct snd_pcm_hw_params *params)
{
    snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);

    return 0;
}

static int spear_pcm_hw_free(struct snd_pcm_substream *substream)
{
    snd_pcm_set_runtime_buffer(substream, NULL);

    return 0;
}

static int spear_pcm_open(struct snd_pcm_substream *substream)
{
    struct snd_soc_pcm_runtime *rtd = substream->private_data;

    struct spear_dma_data *dma_data = (struct spear_dma_data *)
        snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
    int ret;

    ret = snd_soc_set_runtime_hwparams(substream, &spear_pcm_hardware);
    if (ret)
        return ret;

    ret = snd_dmaengine_pcm_open(substream, dma_data->filter, dma_data);
    if (ret)
        return ret;

    snd_dmaengine_pcm_set_data(substream, dma_data);

    return 0;
}

static int spear_pcm_close(struct snd_pcm_substream *substream)
{

    snd_dmaengine_pcm_close(substream);

    return 0;
}

static int spear_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 spear_pcm_ops = {
    .open       = spear_pcm_open,
    .close      = spear_pcm_close,
    .ioctl      = snd_pcm_lib_ioctl,
    .hw_params  = spear_pcm_hw_params,
    .hw_free    = spear_pcm_hw_free,
    .trigger    = snd_dmaengine_pcm_trigger,
    .pointer    = snd_dmaengine_pcm_pointer,
    .mmap       = spear_pcm_mmap,
};

static int
spear_pcm_preallocate_dma_buffer(struct snd_pcm *pcm, int stream,
        size_t size)
{
    struct snd_pcm_substream *substream = pcm->streams[stream].substream;
    struct snd_dma_buffer *buf = &substream->dma_buffer;

    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;

    dev_info(buf->dev.dev,
            " preallocate_dma_buffer: area=%p, addr=%p, size=%d\n",
            (void *)buf->area, (void *)buf->addr, size);

    buf->bytes = size;
    return 0;
}

static void spear_pcm_free(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 || !buf->area)
            continue;

        dma_free_writecombine(pcm->card->dev, buf->bytes,
                buf->area, buf->addr);
        buf->area = NULL;
    }
}

static u64 spear_pcm_dmamask = DMA_BIT_MASK(32);

static int spear_pcm_new(struct snd_card *card,
        struct snd_soc_dai *dai, struct snd_pcm *pcm)
{
    int ret;

    if (!card->dev->dma_mask)
        card->dev->dma_mask = &spear_pcm_dmamask;
    if (!card->dev->coherent_dma_mask)
        card->dev->coherent_dma_mask = DMA_BIT_MASK(32);

    if (dai->driver->playback.channels_min) {
        ret = spear_pcm_preallocate_dma_buffer(pcm,
                SNDRV_PCM_STREAM_PLAYBACK,
                spear_pcm_hardware.buffer_bytes_max);
        if (ret)
            return ret;
    }

    if (dai->driver->capture.channels_min) {
        ret = spear_pcm_preallocate_dma_buffer(pcm,
                SNDRV_PCM_STREAM_CAPTURE,
                spear_pcm_hardware.buffer_bytes_max);
        if (ret)
            return ret;
    }

    return 0;
}

struct snd_soc_platform_driver spear_soc_platform = {
    .ops        =   &spear_pcm_ops,
    .pcm_new    =   spear_pcm_new,
    .pcm_free   =   spear_pcm_free,
};

static int __devinit spear_soc_platform_probe(struct platform_device *pdev)
{
    return snd_soc_register_platform(&pdev->dev, &spear_soc_platform);
}

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

    return 0;
}

static struct platform_driver spear_pcm_driver = {
    .driver = {
        .name = "spear-pcm-audio",
        .owner = THIS_MODULE,
    },

    .probe = spear_soc_platform_probe,
    .remove = __devexit_p(spear_soc_platform_remove),
};

module_platform_driver(spear_pcm_driver);

MODULE_AUTHOR("Rajeev Kumar <[email protected]>");
MODULE_DESCRIPTION("SPEAr PCM DMA module");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:spear-pcm-audio");