dma.c

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/*
 * dma.c  --  ALSA Soc Audio Layer
 *
 * (c) 2006 Wolfson Microelectronics PLC.
 * Graeme Gregory [email protected] or [email protected]
 *
 * Copyright 2004-2005 Simtec Electronics
 *  http://armlinux.simtec.co.uk/
 *  Ben Dooks <[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.
 */

#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <linux/module.h>

#include <sound/soc.h>
#include <sound/pcm_params.h>

#include <asm/dma.h>
#include <mach/hardware.h>
#include <mach/dma.h>

#include "dma.h"

#define ST_RUNNING      (1<<0)
#define ST_OPENED       (1<<1)

static const struct snd_pcm_hardware dma_hardware = {
    .info           = SNDRV_PCM_INFO_INTERLEAVED |
                    SNDRV_PCM_INFO_BLOCK_TRANSFER |
                    SNDRV_PCM_INFO_MMAP |
                    SNDRV_PCM_INFO_MMAP_VALID,
    .formats        = SNDRV_PCM_FMTBIT_S16_LE |
                    SNDRV_PCM_FMTBIT_U16_LE |
                    SNDRV_PCM_FMTBIT_U8 |
                    SNDRV_PCM_FMTBIT_S8,
    .channels_min       = 2,
    .channels_max       = 2,
    .buffer_bytes_max   = 128*1024,
    .period_bytes_min   = PAGE_SIZE,
    .period_bytes_max   = PAGE_SIZE*2,
    .periods_min        = 2,
    .periods_max        = 128,
    .fifo_size      = 32,
};

struct runtime_data {
    spinlock_t lock;
    int state;
    unsigned int dma_loaded;
    unsigned int dma_period;
    dma_addr_t dma_start;
    dma_addr_t dma_pos;
    dma_addr_t dma_end;
    struct s3c_dma_params *params;
};

static void audio_buffdone(void *data);

/* dma_enqueue
 *
 * place a dma buffer onto the queue for the dma system
 * to handle.
 */
static void dma_enqueue(struct snd_pcm_substream *substream)
{
    struct runtime_data *prtd = substream->runtime->private_data;
    dma_addr_t pos = prtd->dma_pos;
    unsigned int limit;
    struct samsung_dma_prep dma_info;

    pr_debug("Entered %s\n", __func__);

    limit = (prtd->dma_end - prtd->dma_start) / prtd->dma_period;

    pr_debug("%s: loaded %d, limit %d\n",
                __func__, prtd->dma_loaded, limit);

    dma_info.cap = (samsung_dma_has_circular() ? DMA_CYCLIC : DMA_SLAVE);
    dma_info.direction =
        (substream->stream == SNDRV_PCM_STREAM_PLAYBACK
        ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM);
    dma_info.fp = audio_buffdone;
    dma_info.fp_param = substream;
    dma_info.period = prtd->dma_period;
    dma_info.len = prtd->dma_period*limit;

    while (prtd->dma_loaded < limit) {
        pr_debug("dma_loaded: %d\n", prtd->dma_loaded);

        if ((pos + dma_info.period) > prtd->dma_end) {
            dma_info.period  = prtd->dma_end - pos;
            pr_debug("%s: corrected dma len %ld\n",
                    __func__, dma_info.period);
        }

        dma_info.buf = pos;
        prtd->params->ops->prepare(prtd->params->ch, &dma_info);

        prtd->dma_loaded++;
        pos += prtd->dma_period;
        if (pos >= prtd->dma_end)
            pos = prtd->dma_start;
    }

    prtd->dma_pos = pos;
}

static void audio_buffdone(void *data)
{
    struct snd_pcm_substream *substream = data;
    struct runtime_data *prtd = substream->runtime->private_data;

    pr_debug("Entered %s\n", __func__);

    if (prtd->state & ST_RUNNING) {
        prtd->dma_pos += prtd->dma_period;
        if (prtd->dma_pos >= prtd->dma_end)
            prtd->dma_pos = prtd->dma_start;

        if (substream)
            snd_pcm_period_elapsed(substream);

        spin_lock(&prtd->lock);
        if (!samsung_dma_has_circular()) {
            prtd->dma_loaded--;
            dma_enqueue(substream);
        }
        spin_unlock(&prtd->lock);
    }
}

static int dma_hw_params(struct snd_pcm_substream *substream,
    struct snd_pcm_hw_params *params)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct runtime_data *prtd = runtime->private_data;
    struct snd_soc_pcm_runtime *rtd = substream->private_data;
    unsigned long totbytes = params_buffer_bytes(params);
    struct s3c_dma_params *dma =
        snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
    struct samsung_dma_req req;
    struct samsung_dma_config config;

    pr_debug("Entered %s\n", __func__);

    /* return if this is a bufferless transfer e.g.
     * codec <--> BT codec or GSM modem -- lg FIXME */
    if (!dma)
        return 0;

    /* this may get called several times by oss emulation
     * with different params -HW */
    if (prtd->params == NULL) {
        /* prepare DMA */
        prtd->params = dma;

        pr_debug("params %p, client %p, channel %d\n", prtd->params,
            prtd->params->client, prtd->params->channel);

        prtd->params->ops = samsung_dma_get_ops();

        req.cap = (samsung_dma_has_circular() ?
            DMA_CYCLIC : DMA_SLAVE);
        req.client = prtd->params->client;
        config.direction =
            (substream->stream == SNDRV_PCM_STREAM_PLAYBACK
            ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM);
        config.width = prtd->params->dma_size;
        config.fifo = prtd->params->dma_addr;
        prtd->params->ch = prtd->params->ops->request(
                prtd->params->channel, &req);
        prtd->params->ops->config(prtd->params->ch, &config);
    }

    snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);

    runtime->dma_bytes = totbytes;

    spin_lock_irq(&prtd->lock);
    prtd->dma_loaded = 0;
    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 + totbytes;
    spin_unlock_irq(&prtd->lock);

    return 0;
}

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

    pr_debug("Entered %s\n", __func__);

    snd_pcm_set_runtime_buffer(substream, NULL);

    if (prtd->params) {
        prtd->params->ops->flush(prtd->params->ch);
        prtd->params->ops->release(prtd->params->ch,
                    prtd->params->client);
        prtd->params = NULL;
    }

    return 0;
}

static int dma_prepare(struct snd_pcm_substream *substream)
{
    struct runtime_data *prtd = substream->runtime->private_data;
    int ret = 0;

    pr_debug("Entered %s\n", __func__);

    /* return if this is a bufferless transfer e.g.
     * codec <--> BT codec or GSM modem -- lg FIXME */
    if (!prtd->params)
        return 0;

    /* flush the DMA channel */
    prtd->params->ops->flush(prtd->params->ch);

    prtd->dma_loaded = 0;
    prtd->dma_pos = prtd->dma_start;

    /* enqueue dma buffers */
    dma_enqueue(substream);

    return ret;
}

static int dma_trigger(struct snd_pcm_substream *substream, int cmd)
{
    struct runtime_data *prtd = substream->runtime->private_data;
    int ret = 0;

    pr_debug("Entered %s\n", __func__);

    spin_lock(&prtd->lock);

    switch (cmd) {
    case SNDRV_PCM_TRIGGER_START:
        prtd->state |= ST_RUNNING;
        prtd->params->ops->trigger(prtd->params->ch);
        break;

    case SNDRV_PCM_TRIGGER_STOP:
        prtd->state &= ~ST_RUNNING;
        prtd->params->ops->stop(prtd->params->ch);
        break;

    default:
        ret = -EINVAL;
        break;
    }

    spin_unlock(&prtd->lock);

    return ret;
}

static snd_pcm_uframes_t
dma_pointer(struct snd_pcm_substream *substream)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct runtime_data *prtd = runtime->private_data;
    unsigned long res;

    pr_debug("Entered %s\n", __func__);

    res = prtd->dma_pos - prtd->dma_start;

    pr_debug("Pointer offset: %lu\n", res);

    /* we seem to be getting the odd error from the pcm library due
     * to out-of-bounds pointers. this is maybe due to the dma engine
     * not having loaded the new values for the channel before being
     * called... (todo - fix )
     */

    if (res >= snd_pcm_lib_buffer_bytes(substream)) {
        if (res == snd_pcm_lib_buffer_bytes(substream))
            res = 0;
    }

    return bytes_to_frames(substream->runtime, res);
}

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

    pr_debug("Entered %s\n", __func__);

    snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
    snd_soc_set_runtime_hwparams(substream, &dma_hardware);

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

    spin_lock_init(&prtd->lock);

    runtime->private_data = prtd;
    return 0;
}

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

    pr_debug("Entered %s\n", __func__);

    if (!prtd)
        pr_debug("dma_close called with prtd == NULL\n");

    kfree(prtd);

    return 0;
}

static int dma_mmap(struct snd_pcm_substream *substream,
    struct vm_area_struct *vma)
{
    struct snd_pcm_runtime *runtime = substream->runtime;

    pr_debug("Entered %s\n", __func__);

    return dma_mmap_writecombine(substream->pcm->card->dev, vma,
                     runtime->dma_area,
                     runtime->dma_addr,
                     runtime->dma_bytes);
}

static struct snd_pcm_ops dma_ops = {
    .open       = dma_open,
    .close      = dma_close,
    .ioctl      = snd_pcm_lib_ioctl,
    .hw_params  = dma_hw_params,
    .hw_free    = dma_hw_free,
    .prepare    = dma_prepare,
    .trigger    = dma_trigger,
    .pointer    = dma_pointer,
    .mmap       = dma_mmap,
};

static int 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 = dma_hardware.buffer_bytes_max;

    pr_debug("Entered %s\n", __func__);

    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;
    buf->bytes = size;
    return 0;
}

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

    pr_debug("Entered %s\n", __func__);

    for (stream = 0; stream < 2; stream++) {
        substream = pcm->streams[stream].substream;
        if (!substream)
            continue;

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

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

static u64 dma_mask = DMA_BIT_MASK(32);

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

    pr_debug("Entered %s\n", __func__);

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

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

    if (pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream) {
        ret = preallocate_dma_buffer(pcm,
            SNDRV_PCM_STREAM_CAPTURE);
        if (ret)
            goto out;
    }
out:
    return ret;
}

static struct snd_soc_platform_driver samsung_asoc_platform = {
    .ops        = &dma_ops,
    .pcm_new    = dma_new,
    .pcm_free   = dma_free_dma_buffers,
};

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

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

static struct platform_driver asoc_dma_driver = {
    .driver = {
        .name = "samsung-audio",
        .owner = THIS_MODULE,
    },

    .probe = samsung_asoc_platform_probe,
    .remove = __devexit_p(samsung_asoc_platform_remove),
};

module_platform_driver(asoc_dma_driver);

MODULE_AUTHOR("Ben Dooks, <[email protected]>");
MODULE_DESCRIPTION("Samsung ASoC DMA Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:samsung-audio");