sh_dac_audio.c

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/*
 * sh_dac_audio.c - SuperH DAC audio driver for ALSA
 *
 * Copyright (c) 2009 by Rafael Ignacio Zurita <[email protected]>
 *
 *
 * Based on sh_dac_audio.c (Copyright (C) 2004, 2005 by Andriy Skulysh)
 *
 *   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.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

#include <linux/hrtimer.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <sound/core.h>
#include <sound/initval.h>
#include <sound/pcm.h>
#include <sound/sh_dac_audio.h>
#include <asm/clock.h>
#include <asm/hd64461.h>
#include <mach/hp6xx.h>
#include <cpu/dac.h>

MODULE_AUTHOR("Rafael Ignacio Zurita <[email protected]>");
MODULE_DESCRIPTION("SuperH DAC audio driver");
MODULE_LICENSE("GPL");
MODULE_SUPPORTED_DEVICE("{{SuperH DAC audio support}}");

/* Module Parameters */
static int index = SNDRV_DEFAULT_IDX1;
static char *id = SNDRV_DEFAULT_STR1;
module_param(index, int, 0444);
MODULE_PARM_DESC(index, "Index value for SuperH DAC audio.");
module_param(id, charp, 0444);
MODULE_PARM_DESC(id, "ID string for SuperH DAC audio.");

/* main struct */
struct snd_sh_dac {
    struct snd_card *card;
    struct snd_pcm_substream *substream;
    struct hrtimer hrtimer;
    ktime_t wakeups_per_second;

    int rate;
    int empty;
    char *data_buffer, *buffer_begin, *buffer_end;
    int processed; /* bytes proccesed, to compare with period_size */
    int buffer_size;
    struct dac_audio_pdata *pdata;
};


static void dac_audio_start_timer(struct snd_sh_dac *chip)
{
    hrtimer_start(&chip->hrtimer, chip->wakeups_per_second,
              HRTIMER_MODE_REL);
}

static void dac_audio_stop_timer(struct snd_sh_dac *chip)
{
    hrtimer_cancel(&chip->hrtimer);
}

static void dac_audio_reset(struct snd_sh_dac *chip)
{
    dac_audio_stop_timer(chip);
    chip->buffer_begin = chip->buffer_end = chip->data_buffer;
    chip->processed = 0;
    chip->empty = 1;
}

static void dac_audio_set_rate(struct snd_sh_dac *chip)
{
    chip->wakeups_per_second = ktime_set(0, 1000000000 / chip->rate);
}


/* PCM INTERFACE */

static struct snd_pcm_hardware snd_sh_dac_pcm_hw = {
    .info           = (SNDRV_PCM_INFO_MMAP |
                    SNDRV_PCM_INFO_MMAP_VALID |
                    SNDRV_PCM_INFO_INTERLEAVED |
                    SNDRV_PCM_INFO_HALF_DUPLEX),
    .formats        = SNDRV_PCM_FMTBIT_U8,
    .rates          = SNDRV_PCM_RATE_8000,
    .rate_min       = 8000,
    .rate_max       = 8000,
    .channels_min       = 1,
    .channels_max       = 1,
    .buffer_bytes_max   = (48*1024),
    .period_bytes_min   = 1,
    .period_bytes_max   = (48*1024),
    .periods_min        = 1,
    .periods_max        = 1024,
};

static int snd_sh_dac_pcm_open(struct snd_pcm_substream *substream)
{
    struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
    struct snd_pcm_runtime *runtime = substream->runtime;

    runtime->hw = snd_sh_dac_pcm_hw;

    chip->substream = substream;
    chip->buffer_begin = chip->buffer_end = chip->data_buffer;
    chip->processed = 0;
    chip->empty = 1;

    chip->pdata->start(chip->pdata);

    return 0;
}

static int snd_sh_dac_pcm_close(struct snd_pcm_substream *substream)
{
    struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);

    chip->substream = NULL;

    dac_audio_stop_timer(chip);
    chip->pdata->stop(chip->pdata);

    return 0;
}

static int snd_sh_dac_pcm_hw_params(struct snd_pcm_substream *substream,
                struct snd_pcm_hw_params *hw_params)
{
    return snd_pcm_lib_malloc_pages(substream,
            params_buffer_bytes(hw_params));
}

static int snd_sh_dac_pcm_hw_free(struct snd_pcm_substream *substream)
{
    return snd_pcm_lib_free_pages(substream);
}

static int snd_sh_dac_pcm_prepare(struct snd_pcm_substream *substream)
{
    struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
    struct snd_pcm_runtime *runtime = chip->substream->runtime;

    chip->buffer_size = runtime->buffer_size;
    memset(chip->data_buffer, 0, chip->pdata->buffer_size);

    return 0;
}

static int snd_sh_dac_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
    struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);

    switch (cmd) {
    case SNDRV_PCM_TRIGGER_START:
        dac_audio_start_timer(chip);
        break;
    case SNDRV_PCM_TRIGGER_STOP:
        chip->buffer_begin = chip->buffer_end = chip->data_buffer;
        chip->processed = 0;
        chip->empty = 1;
        dac_audio_stop_timer(chip);
        break;
    default:
         return -EINVAL;
    }

    return 0;
}

static int snd_sh_dac_pcm_copy(struct snd_pcm_substream *substream, int channel,
    snd_pcm_uframes_t pos, void __user *src, snd_pcm_uframes_t count)
{
    /* channel is not used (interleaved data) */
    struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
    struct snd_pcm_runtime *runtime = substream->runtime;
    ssize_t b_count = frames_to_bytes(runtime , count);
    ssize_t b_pos = frames_to_bytes(runtime , pos);

    if (count < 0)
        return -EINVAL;

    if (!count)
        return 0;

    memcpy_toio(chip->data_buffer + b_pos, src, b_count);
    chip->buffer_end = chip->data_buffer + b_pos + b_count;

    if (chip->empty) {
        chip->empty = 0;
        dac_audio_start_timer(chip);
    }

    return 0;
}

static int snd_sh_dac_pcm_silence(struct snd_pcm_substream *substream,
                  int channel, snd_pcm_uframes_t pos,
                  snd_pcm_uframes_t count)
{
    /* channel is not used (interleaved data) */
    struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
    struct snd_pcm_runtime *runtime = substream->runtime;
    ssize_t b_count = frames_to_bytes(runtime , count);
    ssize_t b_pos = frames_to_bytes(runtime , pos);

    if (count < 0)
        return -EINVAL;

    if (!count)
        return 0;

    memset_io(chip->data_buffer + b_pos, 0, b_count);
    chip->buffer_end = chip->data_buffer + b_pos + b_count;

    if (chip->empty) {
        chip->empty = 0;
        dac_audio_start_timer(chip);
    }

    return 0;
}

static
snd_pcm_uframes_t snd_sh_dac_pcm_pointer(struct snd_pcm_substream *substream)
{
    struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
    int pointer = chip->buffer_begin - chip->data_buffer;

    return pointer;
}

/* pcm ops */
static struct snd_pcm_ops snd_sh_dac_pcm_ops = {
    .open       = snd_sh_dac_pcm_open,
    .close      = snd_sh_dac_pcm_close,
    .ioctl      = snd_pcm_lib_ioctl,
    .hw_params  = snd_sh_dac_pcm_hw_params,
    .hw_free    = snd_sh_dac_pcm_hw_free,
    .prepare    = snd_sh_dac_pcm_prepare,
    .trigger    = snd_sh_dac_pcm_trigger,
    .pointer    = snd_sh_dac_pcm_pointer,
    .copy       = snd_sh_dac_pcm_copy,
    .silence    = snd_sh_dac_pcm_silence,
    .mmap       = snd_pcm_lib_mmap_iomem,
};

static int __devinit snd_sh_dac_pcm(struct snd_sh_dac *chip, int device)
{
    int err;
    struct snd_pcm *pcm;

    /* device should be always 0 for us */
    err = snd_pcm_new(chip->card, "SH_DAC PCM", device, 1, 0, &pcm);
    if (err < 0)
        return err;

    pcm->private_data = chip;
    strcpy(pcm->name, "SH_DAC PCM");
    snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &snd_sh_dac_pcm_ops);

    /* buffer size=48K */
    snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
                      snd_dma_continuous_data(GFP_KERNEL),
                            48 * 1024,
                            48 * 1024);

    return 0;
}
/* END OF PCM INTERFACE */


/* driver .remove  --  destructor */
static int snd_sh_dac_remove(struct platform_device *devptr)
{
    snd_card_free(platform_get_drvdata(devptr));
    platform_set_drvdata(devptr, NULL);

    return 0;
}

/* free -- it has been defined by create */
static int snd_sh_dac_free(struct snd_sh_dac *chip)
{
    /* release the data */
    kfree(chip->data_buffer);
    kfree(chip);

    return 0;
}

static int snd_sh_dac_dev_free(struct snd_device *device)
{
    struct snd_sh_dac *chip = device->device_data;

    return snd_sh_dac_free(chip);
}

static enum hrtimer_restart sh_dac_audio_timer(struct hrtimer *handle)
{
    struct snd_sh_dac *chip = container_of(handle, struct snd_sh_dac,
                           hrtimer);
    struct snd_pcm_runtime *runtime = chip->substream->runtime;
    ssize_t b_ps = frames_to_bytes(runtime, runtime->period_size);

    if (!chip->empty) {
        sh_dac_output(*chip->buffer_begin, chip->pdata->channel);
        chip->buffer_begin++;

        chip->processed++;
        if (chip->processed >= b_ps) {
            chip->processed -= b_ps;
            snd_pcm_period_elapsed(chip->substream);
        }

        if (chip->buffer_begin == (chip->data_buffer +
                       chip->buffer_size - 1))
            chip->buffer_begin = chip->data_buffer;

        if (chip->buffer_begin == chip->buffer_end)
            chip->empty = 1;

    }

    if (!chip->empty)
        hrtimer_start(&chip->hrtimer, chip->wakeups_per_second,
                  HRTIMER_MODE_REL);

    return HRTIMER_NORESTART;
}

/* create  --  chip-specific constructor for the cards components */
static int __devinit snd_sh_dac_create(struct snd_card *card,
                       struct platform_device *devptr,
                       struct snd_sh_dac **rchip)
{
    struct snd_sh_dac *chip;
    int err;

    static struct snd_device_ops ops = {
           .dev_free = snd_sh_dac_dev_free,
    };

    *rchip = NULL;

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

    chip->card = card;

    hrtimer_init(&chip->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
    chip->hrtimer.function = sh_dac_audio_timer;

    dac_audio_reset(chip);
    chip->rate = 8000;
    dac_audio_set_rate(chip);

    chip->pdata = devptr->dev.platform_data;

    chip->data_buffer = kmalloc(chip->pdata->buffer_size, GFP_KERNEL);
    if (chip->data_buffer == NULL) {
        kfree(chip);
        return -ENOMEM;
    }

    err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops);
    if (err < 0) {
        snd_sh_dac_free(chip);
        return err;
    }

    *rchip = chip;

    return 0;
}

/* driver .probe  --  constructor */
static int __devinit snd_sh_dac_probe(struct platform_device *devptr)
{
    struct snd_sh_dac *chip;
    struct snd_card *card;
    int err;

    err = snd_card_create(index, id, THIS_MODULE, 0, &card);
    if (err < 0) {
            snd_printk(KERN_ERR "cannot allocate the card\n");
            return err;
    }

    err = snd_sh_dac_create(card, devptr, &chip);
    if (err < 0)
        goto probe_error;

    err = snd_sh_dac_pcm(chip, 0);
    if (err < 0)
        goto probe_error;

    strcpy(card->driver, "snd_sh_dac");
    strcpy(card->shortname, "SuperH DAC audio driver");
    printk(KERN_INFO "%s %s", card->longname, card->shortname);

    err = snd_card_register(card);
    if (err < 0)
        goto probe_error;

    snd_printk("ALSA driver for SuperH DAC audio");

    platform_set_drvdata(devptr, card);
    return 0;

probe_error:
    snd_card_free(card);
    return err;
}

/*
 * "driver" definition
 */
static struct platform_driver sh_dac_driver = {
    .probe  = snd_sh_dac_probe,
    .remove = snd_sh_dac_remove,
    .driver = {
        .name = "dac_audio",
        .owner  = THIS_MODULE,
    },
};

module_platform_driver(sh_dac_driver);