jz4740-pcm.c

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/*
 *  Copyright (C) 2010, Lars-Peter Clausen <[email protected]>
 *
 *  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.
 *
 *  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.,
 *  675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.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-jz4740/dma.h>
#include "jz4740-pcm.h"

struct jz4740_runtime_data {
    unsigned long dma_period;
    dma_addr_t dma_start;
    dma_addr_t dma_pos;
    dma_addr_t dma_end;

    struct jz4740_dma_chan *dma;

    dma_addr_t fifo_addr;
};

/* identify hardware playback capabilities */
static const struct snd_pcm_hardware jz4740_pcm_hardware = {
    .info = SNDRV_PCM_INFO_MMAP |
        SNDRV_PCM_INFO_MMAP_VALID |
        SNDRV_PCM_INFO_INTERLEAVED |
        SNDRV_PCM_INFO_BLOCK_TRANSFER,
    .formats = SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S8,

    .rates          = SNDRV_PCM_RATE_8000_48000,
    .channels_min       = 1,
    .channels_max       = 2,
    .period_bytes_min   = 16,
    .period_bytes_max   = 2 * PAGE_SIZE,
    .periods_min        = 2,
    .periods_max        = 128,
    .buffer_bytes_max   = 128 * 2 * PAGE_SIZE,
    .fifo_size      = 32,
};

static void jz4740_pcm_start_transfer(struct jz4740_runtime_data *prtd,
    struct snd_pcm_substream *substream)
{
    unsigned long count;

    if (prtd->dma_pos == prtd->dma_end)
        prtd->dma_pos = prtd->dma_start;

    if (prtd->dma_pos + prtd->dma_period > prtd->dma_end)
        count = prtd->dma_end - prtd->dma_pos;
    else
        count = prtd->dma_period;

    jz4740_dma_disable(prtd->dma);

    if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
        jz4740_dma_set_src_addr(prtd->dma, prtd->dma_pos);
        jz4740_dma_set_dst_addr(prtd->dma, prtd->fifo_addr);
    } else {
        jz4740_dma_set_src_addr(prtd->dma, prtd->fifo_addr);
        jz4740_dma_set_dst_addr(prtd->dma, prtd->dma_pos);
    }

    jz4740_dma_set_transfer_count(prtd->dma, count);

    prtd->dma_pos += count;

    jz4740_dma_enable(prtd->dma);
}

static void jz4740_pcm_dma_transfer_done(struct jz4740_dma_chan *dma, int err,
    void *dev_id)
{
    struct snd_pcm_substream *substream = dev_id;
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct jz4740_runtime_data *prtd = runtime->private_data;

    snd_pcm_period_elapsed(substream);

    jz4740_pcm_start_transfer(prtd, substream);
}

static int jz4740_pcm_hw_params(struct snd_pcm_substream *substream,
    struct snd_pcm_hw_params *params)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct jz4740_runtime_data *prtd = runtime->private_data;
    struct snd_soc_pcm_runtime *rtd = substream->private_data;
    struct jz4740_pcm_config *config;

    config = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);

    if (!config)
        return 0;

    if (!prtd->dma) {
        if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
            prtd->dma = jz4740_dma_request(substream, "PCM Capture");
        else
            prtd->dma = jz4740_dma_request(substream, "PCM Playback");
    }

    if (!prtd->dma)
        return -EBUSY;

    jz4740_dma_configure(prtd->dma, &config->dma_config);
    prtd->fifo_addr = config->fifo_addr;

    jz4740_dma_set_complete_cb(prtd->dma, jz4740_pcm_dma_transfer_done);

    snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
    runtime->dma_bytes = params_buffer_bytes(params);

    prtd->dma_period = params_period_bytes(params);
    prtd->dma_start = runtime->dma_addr;
    prtd->dma_pos = prtd->dma_start;
    prtd->dma_end = prtd->dma_start + runtime->dma_bytes;

    return 0;
}

static int jz4740_pcm_hw_free(struct snd_pcm_substream *substream)
{
    struct jz4740_runtime_data *prtd = substream->runtime->private_data;

    snd_pcm_set_runtime_buffer(substream, NULL);
    if (prtd->dma) {
        jz4740_dma_free(prtd->dma);
        prtd->dma = NULL;
    }

    return 0;
}

static int jz4740_pcm_prepare(struct snd_pcm_substream *substream)
{
    struct jz4740_runtime_data *prtd = substream->runtime->private_data;

    if (!prtd->dma)
        return -EBUSY;

    prtd->dma_pos = prtd->dma_start;

    return 0;
}

static int jz4740_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct jz4740_runtime_data *prtd = runtime->private_data;

    switch (cmd) {
    case SNDRV_PCM_TRIGGER_START:
    case SNDRV_PCM_TRIGGER_RESUME:
    case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
        jz4740_pcm_start_transfer(prtd, substream);
        break;
    case SNDRV_PCM_TRIGGER_STOP:
    case SNDRV_PCM_TRIGGER_SUSPEND:
    case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
        jz4740_dma_disable(prtd->dma);
        break;
    default:
        break;
    }

    return 0;
}

static snd_pcm_uframes_t jz4740_pcm_pointer(struct snd_pcm_substream *substream)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct jz4740_runtime_data *prtd = runtime->private_data;
    unsigned long byte_offset;
    snd_pcm_uframes_t offset;
    struct jz4740_dma_chan *dma = prtd->dma;

    /* prtd->dma_pos points to the end of the current transfer. So by
     * subtracting prdt->dma_start we get the offset to the end of the
     * current period in bytes. By subtracting the residue of the transfer
     * we get the current offset in bytes. */
    byte_offset = prtd->dma_pos - prtd->dma_start;
    byte_offset -= jz4740_dma_get_residue(dma);

    offset = bytes_to_frames(runtime, byte_offset);
    if (offset >= runtime->buffer_size)
        offset = 0;

    return offset;
}

static int jz4740_pcm_open(struct snd_pcm_substream *substream)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct jz4740_runtime_data *prtd;

    prtd = kzalloc(sizeof(*prtd), GFP_KERNEL);
    if (prtd == NULL)
        return -ENOMEM;

    snd_soc_set_runtime_hwparams(substream, &jz4740_pcm_hardware);

    runtime->private_data = prtd;

    return 0;
}

static int jz4740_pcm_close(struct snd_pcm_substream *substream)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct jz4740_runtime_data *prtd = runtime->private_data;

    kfree(prtd);

    return 0;
}

static int jz4740_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 jz4740_pcm_ops = {
    .open       = jz4740_pcm_open,
    .close      = jz4740_pcm_close,
    .ioctl      = snd_pcm_lib_ioctl,
    .hw_params  = jz4740_pcm_hw_params,
    .hw_free    = jz4740_pcm_hw_free,
    .prepare    = jz4740_pcm_prepare,
    .trigger    = jz4740_pcm_trigger,
    .pointer    = jz4740_pcm_pointer,
    .mmap       = jz4740_pcm_mmap,
};

static int jz4740_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 = jz4740_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_noncoherent(pcm->card->dev, size,
                      &buf->addr, GFP_KERNEL);
    if (!buf->area)
        return -ENOMEM;

    buf->bytes = size;

    return 0;
}

static void jz4740_pcm_free(struct snd_pcm *pcm)
{
    struct snd_pcm_substream *substream;
    struct snd_dma_buffer *buf;
    int stream;

    for (stream = 0; stream < SNDRV_PCM_STREAM_LAST; ++stream) {
        substream = pcm->streams[stream].substream;
        if (!substream)
            continue;

        buf = &substream->dma_buffer;
        if (!buf->area)
            continue;

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

static u64 jz4740_pcm_dmamask = DMA_BIT_MASK(32);

static int jz4740_pcm_new(struct snd_soc_pcm_runtime *rtd)
{
    struct snd_card *card = rtd->card->snd_card;
    struct snd_pcm *pcm = rtd->pcm;
    int ret = 0;

    if (!card->dev->dma_mask)
        card->dev->dma_mask = &jz4740_pcm_dmamask;

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

    if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream) {
        ret = jz4740_pcm_preallocate_dma_buffer(pcm,
            SNDRV_PCM_STREAM_PLAYBACK);
        if (ret)
            goto err;
    }

    if (pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream) {
        ret = jz4740_pcm_preallocate_dma_buffer(pcm,
            SNDRV_PCM_STREAM_CAPTURE);
        if (ret)
            goto err;
    }

err:
    return ret;
}

static struct snd_soc_platform_driver jz4740_soc_platform = {
        .ops        = &jz4740_pcm_ops,
        .pcm_new    = jz4740_pcm_new,
        .pcm_free   = jz4740_pcm_free,
};

static int __devinit jz4740_pcm_probe(struct platform_device *pdev)
{
    return snd_soc_register_platform(&pdev->dev, &jz4740_soc_platform);
}

static int __devexit jz4740_pcm_remove(struct platform_device *pdev)
{
    snd_soc_unregister_platform(&pdev->dev);
    return 0;
}

static struct platform_driver jz4740_pcm_driver = {
    .probe = jz4740_pcm_probe,
    .remove = __devexit_p(jz4740_pcm_remove),
    .driver = {
        .name = "jz4740-pcm-audio",
        .owner = THIS_MODULE,
    },
};

module_platform_driver(jz4740_pcm_driver);

MODULE_AUTHOR("Lars-Peter Clausen <[email protected]>");
MODULE_DESCRIPTION("Ingenic SoC JZ4740 PCM driver");
MODULE_LICENSE("GPL");