imx-pcm-fiq.c

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/*
 * imx-pcm-fiq.c  --  ALSA Soc Audio Layer
 *
 * Copyright 2009 Sascha Hauer <[email protected]>
 *
 * This code is based on code copyrighted by Freescale,
 * Liam Girdwood, Javier Martin and probably others.
 *
 *  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/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#include <sound/core.h>
#include <sound/initval.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>

#include <asm/fiq.h>

#include <mach/irqs.h>
#include <linux/platform_data/asoc-imx-ssi.h>

#include "imx-ssi.h"

struct imx_pcm_runtime_data {
    int period;
    int periods;
    unsigned long offset;
    unsigned long last_offset;
    unsigned long size;
    struct hrtimer hrt;
    int poll_time_ns;
    struct snd_pcm_substream *substream;
    atomic_t running;
};

static enum hrtimer_restart snd_hrtimer_callback(struct hrtimer *hrt)
{
    struct imx_pcm_runtime_data *iprtd =
        container_of(hrt, struct imx_pcm_runtime_data, hrt);
    struct snd_pcm_substream *substream = iprtd->substream;
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct pt_regs regs;
    unsigned long delta;

    if (!atomic_read(&iprtd->running))
        return HRTIMER_NORESTART;

    get_fiq_regs(&regs);

    if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
        iprtd->offset = regs.ARM_r8 & 0xffff;
    else
        iprtd->offset = regs.ARM_r9 & 0xffff;

    /* How much data have we transferred since the last period report? */
    if (iprtd->offset >= iprtd->last_offset)
        delta = iprtd->offset - iprtd->last_offset;
    else
        delta = runtime->buffer_size + iprtd->offset
            - iprtd->last_offset;

    /* If we've transferred at least a period then report it and
     * reset our poll time */
    if (delta >= iprtd->period) {
        snd_pcm_period_elapsed(substream);
        iprtd->last_offset = iprtd->offset;
    }

    hrtimer_forward_now(hrt, ns_to_ktime(iprtd->poll_time_ns));

    return HRTIMER_RESTART;
}

static struct fiq_handler fh = {
    .name       = DRV_NAME,
};

static int snd_imx_pcm_hw_params(struct snd_pcm_substream *substream,
                struct snd_pcm_hw_params *params)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct imx_pcm_runtime_data *iprtd = runtime->private_data;

    iprtd->size = params_buffer_bytes(params);
    iprtd->periods = params_periods(params);
    iprtd->period = params_period_bytes(params) ;
    iprtd->offset = 0;
    iprtd->last_offset = 0;
    iprtd->poll_time_ns = 1000000000 / params_rate(params) *
                params_period_size(params);
    snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);

    return 0;
}

static int snd_imx_pcm_prepare(struct snd_pcm_substream *substream)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct imx_pcm_runtime_data *iprtd = runtime->private_data;
    struct pt_regs regs;

    get_fiq_regs(&regs);
    if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
        regs.ARM_r8 = (iprtd->period * iprtd->periods - 1) << 16;
    else
        regs.ARM_r9 = (iprtd->period * iprtd->periods - 1) << 16;

    set_fiq_regs(&regs);

    return 0;
}

static int fiq_enable;
static int imx_pcm_fiq;

static int snd_imx_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct imx_pcm_runtime_data *iprtd = runtime->private_data;

    switch (cmd) {
    case SNDRV_PCM_TRIGGER_START:
    case SNDRV_PCM_TRIGGER_RESUME:
    case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
        atomic_set(&iprtd->running, 1);
        hrtimer_start(&iprtd->hrt, ns_to_ktime(iprtd->poll_time_ns),
              HRTIMER_MODE_REL);
        if (++fiq_enable == 1)
            enable_fiq(imx_pcm_fiq);

        break;

    case SNDRV_PCM_TRIGGER_STOP:
    case SNDRV_PCM_TRIGGER_SUSPEND:
    case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
        atomic_set(&iprtd->running, 0);

        if (--fiq_enable == 0)
            disable_fiq(imx_pcm_fiq);

        break;
    default:
        return -EINVAL;
    }

    return 0;
}

static snd_pcm_uframes_t snd_imx_pcm_pointer(struct snd_pcm_substream *substream)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct imx_pcm_runtime_data *iprtd = runtime->private_data;

    return bytes_to_frames(substream->runtime, iprtd->offset);
}

static struct snd_pcm_hardware snd_imx_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,
    .formats = SNDRV_PCM_FMTBIT_S16_LE,
    .rate_min = 8000,
    .channels_min = 2,
    .channels_max = 2,
    .buffer_bytes_max = IMX_SSI_DMABUF_SIZE,
    .period_bytes_min = 128,
    .period_bytes_max = 16 * 1024,
    .periods_min = 4,
    .periods_max = 255,
    .fifo_size = 0,
};

static int snd_imx_open(struct snd_pcm_substream *substream)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct imx_pcm_runtime_data *iprtd;
    int ret;

    iprtd = kzalloc(sizeof(*iprtd), GFP_KERNEL);
    if (iprtd == NULL)
        return -ENOMEM;
    runtime->private_data = iprtd;

    iprtd->substream = substream;

    atomic_set(&iprtd->running, 0);
    hrtimer_init(&iprtd->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
    iprtd->hrt.function = snd_hrtimer_callback;

    ret = snd_pcm_hw_constraint_integer(substream->runtime,
            SNDRV_PCM_HW_PARAM_PERIODS);
    if (ret < 0) {
        kfree(iprtd);
        return ret;
    }

    snd_soc_set_runtime_hwparams(substream, &snd_imx_hardware);
    return 0;
}

static int snd_imx_close(struct snd_pcm_substream *substream)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct imx_pcm_runtime_data *iprtd = runtime->private_data;

    hrtimer_cancel(&iprtd->hrt);

    kfree(iprtd);

    return 0;
}

static struct snd_pcm_ops imx_pcm_ops = {
    .open       = snd_imx_open,
    .close      = snd_imx_close,
    .ioctl      = snd_pcm_lib_ioctl,
    .hw_params  = snd_imx_pcm_hw_params,
    .prepare    = snd_imx_pcm_prepare,
    .trigger    = snd_imx_pcm_trigger,
    .pointer    = snd_imx_pcm_pointer,
    .mmap       = snd_imx_pcm_mmap,
};

static int ssi_irq = 0;

static int imx_pcm_fiq_new(struct snd_soc_pcm_runtime *rtd)
{
    struct snd_pcm *pcm = rtd->pcm;
    struct snd_pcm_substream *substream;
    int ret;

    ret = imx_pcm_new(rtd);
    if (ret)
        return ret;

    substream = pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream;
    if (substream) {
        struct snd_dma_buffer *buf = &substream->dma_buffer;

        imx_ssi_fiq_tx_buffer = (unsigned long)buf->area;
    }

    substream = pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream;
    if (substream) {
        struct snd_dma_buffer *buf = &substream->dma_buffer;

        imx_ssi_fiq_rx_buffer = (unsigned long)buf->area;
    }

    set_fiq_handler(&imx_ssi_fiq_start,
        &imx_ssi_fiq_end - &imx_ssi_fiq_start);

    return 0;
}

static void imx_pcm_fiq_free(struct snd_pcm *pcm)
{
    mxc_set_irq_fiq(ssi_irq, 0);
    release_fiq(&fh);
    imx_pcm_free(pcm);
}

static struct snd_soc_platform_driver imx_soc_platform_fiq = {
    .ops        = &imx_pcm_ops,
    .pcm_new    = imx_pcm_fiq_new,
    .pcm_free   = imx_pcm_fiq_free,
};

static int __devinit imx_soc_platform_probe(struct platform_device *pdev)
{
    struct imx_ssi *ssi = platform_get_drvdata(pdev);
    int ret;

    ret = claim_fiq(&fh);
    if (ret) {
        dev_err(&pdev->dev, "failed to claim fiq: %d", ret);
        return ret;
    }

    mxc_set_irq_fiq(ssi->irq, 1);
    ssi_irq = ssi->irq;

    imx_pcm_fiq = ssi->irq;

    imx_ssi_fiq_base = (unsigned long)ssi->base;

    ssi->dma_params_tx.burstsize = 4;
    ssi->dma_params_rx.burstsize = 6;

    ret = snd_soc_register_platform(&pdev->dev, &imx_soc_platform_fiq);
    if (ret)
        goto failed_register;

    return 0;

failed_register:
    mxc_set_irq_fiq(ssi_irq, 0);
    release_fiq(&fh);

    return ret;
}

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

static struct platform_driver imx_pcm_driver = {
    .driver = {
            .name = "imx-fiq-pcm-audio",
            .owner = THIS_MODULE,
    },

    .probe = imx_soc_platform_probe,
    .remove = __devexit_p(imx_soc_platform_remove),
};

module_platform_driver(imx_pcm_driver);

MODULE_LICENSE("GPL");