atmel-pcm.c

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/*
 * atmel-pcm.c  --  ALSA PCM interface for the Atmel atmel SoC.
 *
 *  Copyright (C) 2005 SAN People
 *  Copyright (C) 2008 Atmel
 *
 * Authors: Sedji Gaouaou <[email protected]>
 *
 * Based on at91-pcm. by:
 * Frank Mandarino <[email protected]>
 * Copyright 2006 Endrelia Technologies Inc.
 *
 * Based on pxa2xx-pcm.c by:
 *
 * Author:  Nicolas Pitre
 * Created: Nov 30, 2004
 * Copyright:   (C) 2004 MontaVista Software, Inc.
 *
 * 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/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <linux/atmel_pdc.h>
#include <linux/atmel-ssc.h>

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

#include "atmel-pcm.h"


/*--------------------------------------------------------------------------*\
 * Hardware definition
\*--------------------------------------------------------------------------*/
/* TODO: These values were taken from the AT91 platform driver, check
 *   them against real values for AT32
 */
static const struct snd_pcm_hardware atmel_pcm_hardware = {
    .info           = SNDRV_PCM_INFO_MMAP |
                  SNDRV_PCM_INFO_MMAP_VALID |
                  SNDRV_PCM_INFO_INTERLEAVED |
                  SNDRV_PCM_INFO_PAUSE,
    .formats        = SNDRV_PCM_FMTBIT_S16_LE,
    .period_bytes_min   = 32,
    .period_bytes_max   = 8192,
    .periods_min        = 2,
    .periods_max        = 1024,
    .buffer_bytes_max   = 32 * 1024,
};


/*--------------------------------------------------------------------------*\
 * Data types
\*--------------------------------------------------------------------------*/
struct atmel_runtime_data {
    struct atmel_pcm_dma_params *params;
    dma_addr_t dma_buffer;      /* physical address of dma buffer */
    dma_addr_t dma_buffer_end;  /* first address beyond DMA buffer */
    size_t period_size;

    dma_addr_t period_ptr;      /* physical address of next period */

    /* PDC register save */
    u32 pdc_xpr_save;
    u32 pdc_xcr_save;
    u32 pdc_xnpr_save;
    u32 pdc_xncr_save;
};


/*--------------------------------------------------------------------------*\
 * Helper functions
\*--------------------------------------------------------------------------*/
static int atmel_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 = atmel_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_coherent(pcm->card->dev, size,
                      &buf->addr, GFP_KERNEL);
    pr_debug("atmel-pcm:"
        "preallocate_dma_buffer: area=%p, addr=%p, size=%d\n",
        (void *) buf->area,
        (void *) buf->addr,
        size);

    if (!buf->area)
        return -ENOMEM;

    buf->bytes = size;
    return 0;
}
/*--------------------------------------------------------------------------*\
 * ISR
\*--------------------------------------------------------------------------*/
static void atmel_pcm_dma_irq(u32 ssc_sr,
    struct snd_pcm_substream *substream)
{
    struct atmel_runtime_data *prtd = substream->runtime->private_data;
    struct atmel_pcm_dma_params *params = prtd->params;
    static int count;

    count++;

    if (ssc_sr & params->mask->ssc_endbuf) {
        pr_warning("atmel-pcm: buffer %s on %s"
                " (SSC_SR=%#x, count=%d)\n",
                substream->stream == SNDRV_PCM_STREAM_PLAYBACK
                ? "underrun" : "overrun",
                params->name, ssc_sr, count);

        /* re-start the PDC */
        ssc_writex(params->ssc->regs, ATMEL_PDC_PTCR,
               params->mask->pdc_disable);
        prtd->period_ptr += prtd->period_size;
        if (prtd->period_ptr >= prtd->dma_buffer_end)
            prtd->period_ptr = prtd->dma_buffer;

        ssc_writex(params->ssc->regs, params->pdc->xpr,
               prtd->period_ptr);
        ssc_writex(params->ssc->regs, params->pdc->xcr,
               prtd->period_size / params->pdc_xfer_size);
        ssc_writex(params->ssc->regs, ATMEL_PDC_PTCR,
               params->mask->pdc_enable);
    }

    if (ssc_sr & params->mask->ssc_endx) {
        /* Load the PDC next pointer and counter registers */
        prtd->period_ptr += prtd->period_size;
        if (prtd->period_ptr >= prtd->dma_buffer_end)
            prtd->period_ptr = prtd->dma_buffer;

        ssc_writex(params->ssc->regs, params->pdc->xnpr,
               prtd->period_ptr);
        ssc_writex(params->ssc->regs, params->pdc->xncr,
               prtd->period_size / params->pdc_xfer_size);
    }

    snd_pcm_period_elapsed(substream);
}


/*--------------------------------------------------------------------------*\
 * PCM operations
\*--------------------------------------------------------------------------*/
static int atmel_pcm_hw_params(struct snd_pcm_substream *substream,
    struct snd_pcm_hw_params *params)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct atmel_runtime_data *prtd = runtime->private_data;
    struct snd_soc_pcm_runtime *rtd = substream->private_data;

    /* this may get called several times by oss emulation
     * with different params */

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

    prtd->params = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
    prtd->params->dma_intr_handler = atmel_pcm_dma_irq;

    prtd->dma_buffer = runtime->dma_addr;
    prtd->dma_buffer_end = runtime->dma_addr + runtime->dma_bytes;
    prtd->period_size = params_period_bytes(params);

    pr_debug("atmel-pcm: "
        "hw_params: DMA for %s initialized "
        "(dma_bytes=%u, period_size=%u)\n",
        prtd->params->name,
        runtime->dma_bytes,
        prtd->period_size);
    return 0;
}

static int atmel_pcm_hw_free(struct snd_pcm_substream *substream)
{
    struct atmel_runtime_data *prtd = substream->runtime->private_data;
    struct atmel_pcm_dma_params *params = prtd->params;

    if (params != NULL) {
        ssc_writex(params->ssc->regs, SSC_PDC_PTCR,
               params->mask->pdc_disable);
        prtd->params->dma_intr_handler = NULL;
    }

    return 0;
}

static int atmel_pcm_prepare(struct snd_pcm_substream *substream)
{
    struct atmel_runtime_data *prtd = substream->runtime->private_data;
    struct atmel_pcm_dma_params *params = prtd->params;

    ssc_writex(params->ssc->regs, SSC_IDR,
           params->mask->ssc_endx | params->mask->ssc_endbuf);
    ssc_writex(params->ssc->regs, ATMEL_PDC_PTCR,
           params->mask->pdc_disable);
    return 0;
}

static int atmel_pcm_trigger(struct snd_pcm_substream *substream,
    int cmd)
{
    struct snd_pcm_runtime *rtd = substream->runtime;
    struct atmel_runtime_data *prtd = rtd->private_data;
    struct atmel_pcm_dma_params *params = prtd->params;
    int ret = 0;

    pr_debug("atmel-pcm:buffer_size = %ld,"
        "dma_area = %p, dma_bytes = %u\n",
        rtd->buffer_size, rtd->dma_area, rtd->dma_bytes);

    switch (cmd) {
    case SNDRV_PCM_TRIGGER_START:
        prtd->period_ptr = prtd->dma_buffer;

        ssc_writex(params->ssc->regs, params->pdc->xpr,
               prtd->period_ptr);
        ssc_writex(params->ssc->regs, params->pdc->xcr,
               prtd->period_size / params->pdc_xfer_size);

        prtd->period_ptr += prtd->period_size;
        ssc_writex(params->ssc->regs, params->pdc->xnpr,
               prtd->period_ptr);
        ssc_writex(params->ssc->regs, params->pdc->xncr,
               prtd->period_size / params->pdc_xfer_size);

        pr_debug("atmel-pcm: trigger: "
            "period_ptr=%lx, xpr=%u, "
            "xcr=%u, xnpr=%u, xncr=%u\n",
            (unsigned long)prtd->period_ptr,
            ssc_readx(params->ssc->regs, params->pdc->xpr),
            ssc_readx(params->ssc->regs, params->pdc->xcr),
            ssc_readx(params->ssc->regs, params->pdc->xnpr),
            ssc_readx(params->ssc->regs, params->pdc->xncr));

        ssc_writex(params->ssc->regs, SSC_IER,
               params->mask->ssc_endx | params->mask->ssc_endbuf);
        ssc_writex(params->ssc->regs, SSC_PDC_PTCR,
               params->mask->pdc_enable);

        pr_debug("sr=%u imr=%u\n",
            ssc_readx(params->ssc->regs, SSC_SR),
            ssc_readx(params->ssc->regs, SSC_IER));
        break;      /* SNDRV_PCM_TRIGGER_START */

    case SNDRV_PCM_TRIGGER_STOP:
    case SNDRV_PCM_TRIGGER_SUSPEND:
    case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
        ssc_writex(params->ssc->regs, ATMEL_PDC_PTCR,
               params->mask->pdc_disable);
        break;

    case SNDRV_PCM_TRIGGER_RESUME:
    case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
        ssc_writex(params->ssc->regs, ATMEL_PDC_PTCR,
               params->mask->pdc_enable);
        break;

    default:
        ret = -EINVAL;
    }

    return ret;
}

static snd_pcm_uframes_t atmel_pcm_pointer(
    struct snd_pcm_substream *substream)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct atmel_runtime_data *prtd = runtime->private_data;
    struct atmel_pcm_dma_params *params = prtd->params;
    dma_addr_t ptr;
    snd_pcm_uframes_t x;

    ptr = (dma_addr_t) ssc_readx(params->ssc->regs, params->pdc->xpr);
    x = bytes_to_frames(runtime, ptr - prtd->dma_buffer);

    if (x == runtime->buffer_size)
        x = 0;

    return x;
}

static int atmel_pcm_open(struct snd_pcm_substream *substream)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct atmel_runtime_data *prtd;
    int ret = 0;

    snd_soc_set_runtime_hwparams(substream, &atmel_pcm_hardware);

    /* ensure that buffer size is a multiple of period size */
    ret = snd_pcm_hw_constraint_integer(runtime,
                        SNDRV_PCM_HW_PARAM_PERIODS);
    if (ret < 0)
        goto out;

    prtd = kzalloc(sizeof(struct atmel_runtime_data), GFP_KERNEL);
    if (prtd == NULL) {
        ret = -ENOMEM;
        goto out;
    }
    runtime->private_data = prtd;

 out:
    return ret;
}

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

    kfree(prtd);
    return 0;
}

static int atmel_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 atmel_pcm_ops = {
    .open       = atmel_pcm_open,
    .close      = atmel_pcm_close,
    .ioctl      = snd_pcm_lib_ioctl,
    .hw_params  = atmel_pcm_hw_params,
    .hw_free    = atmel_pcm_hw_free,
    .prepare    = atmel_pcm_prepare,
    .trigger    = atmel_pcm_trigger,
    .pointer    = atmel_pcm_pointer,
    .mmap       = atmel_pcm_mmap,
};


/*--------------------------------------------------------------------------*\
 * ASoC platform driver
\*--------------------------------------------------------------------------*/
static u64 atmel_pcm_dmamask = DMA_BIT_MASK(32);

static int atmel_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 = &atmel_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 = atmel_pcm_preallocate_dma_buffer(pcm,
            SNDRV_PCM_STREAM_PLAYBACK);
        if (ret)
            goto out;
    }

    if (pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream) {
        pr_debug("atmel-pcm:"
                "Allocating PCM capture DMA buffer\n");
        ret = atmel_pcm_preallocate_dma_buffer(pcm,
            SNDRV_PCM_STREAM_CAPTURE);
        if (ret)
            goto out;
    }
 out:
    return ret;
}

static void atmel_pcm_free_dma_buffers(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->area)
            continue;
        dma_free_coherent(pcm->card->dev, buf->bytes,
                  buf->area, buf->addr);
        buf->area = NULL;
    }
}

#ifdef CONFIG_PM
static int atmel_pcm_suspend(struct snd_soc_dai *dai)
{
    struct snd_pcm_runtime *runtime = dai->runtime;
    struct atmel_runtime_data *prtd;
    struct atmel_pcm_dma_params *params;

    if (!runtime)
        return 0;

    prtd = runtime->private_data;
    params = prtd->params;

    /* disable the PDC and save the PDC registers */

    ssc_writel(params->ssc->regs, PDC_PTCR, params->mask->pdc_disable);

    prtd->pdc_xpr_save = ssc_readx(params->ssc->regs, params->pdc->xpr);
    prtd->pdc_xcr_save = ssc_readx(params->ssc->regs, params->pdc->xcr);
    prtd->pdc_xnpr_save = ssc_readx(params->ssc->regs, params->pdc->xnpr);
    prtd->pdc_xncr_save = ssc_readx(params->ssc->regs, params->pdc->xncr);

    return 0;
}

static int atmel_pcm_resume(struct snd_soc_dai *dai)
{
    struct snd_pcm_runtime *runtime = dai->runtime;
    struct atmel_runtime_data *prtd;
    struct atmel_pcm_dma_params *params;

    if (!runtime)
        return 0;

    prtd = runtime->private_data;
    params = prtd->params;

    /* restore the PDC registers and enable the PDC */
    ssc_writex(params->ssc->regs, params->pdc->xpr, prtd->pdc_xpr_save);
    ssc_writex(params->ssc->regs, params->pdc->xcr, prtd->pdc_xcr_save);
    ssc_writex(params->ssc->regs, params->pdc->xnpr, prtd->pdc_xnpr_save);
    ssc_writex(params->ssc->regs, params->pdc->xncr, prtd->pdc_xncr_save);

    ssc_writel(params->ssc->regs, PDC_PTCR, params->mask->pdc_enable);
    return 0;
}
#else
#define atmel_pcm_suspend   NULL
#define atmel_pcm_resume    NULL
#endif

static struct snd_soc_platform_driver atmel_soc_platform = {
    .ops        = &atmel_pcm_ops,
    .pcm_new    = atmel_pcm_new,
    .pcm_free   = atmel_pcm_free_dma_buffers,
    .suspend    = atmel_pcm_suspend,
    .resume     = atmel_pcm_resume,
};

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

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

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

    .probe = atmel_soc_platform_probe,
    .remove = __devexit_p(atmel_soc_platform_remove),
};

module_platform_driver(atmel_pcm_driver);

MODULE_AUTHOR("Sedji Gaouaou <[email protected]>");
MODULE_DESCRIPTION("Atmel PCM module");
MODULE_LICENSE("GPL");