/*
 * atmel-pcm.c  --  ALSA PCM interface for the Atmel atmel SoC.
 *
 *  Copyright (C) 2005 SAN People
 *  Copyright (C) 2008 Atmel
 *
 * Authors: Sedji Gaouaou <sedji.gaouaou@atmel.com>
 *
 * Based on at91-pcm. by:
 * Frank Mandarino <fmandarino@endrelia.com>
 * 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"


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_SSC_DMABUF_SIZE;

        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: alloc dma buffer: area=%p, addr=%p, size=%zu\n",
                        (void *)buf->area, (void *)(long)buf->addr, size);

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

        buf->bytes = size;
        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 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;

        ret = dma_coerce_mask_and_coherent(card->dev, DMA_BIT_MASK(32));
        if (ret)
                return ret;

        if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream) {
                pr_debug("atmel-pcm: allocating PCM playback DMA buffer\n");
                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(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;
        }
}

/*--------------------------------------------------------------------------*\
 * 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,
        .period_bytes_min       = 32,
        .period_bytes_max       = 8192,
        .periods_min            = 2,
        .periods_max            = 1024,
        .buffer_bytes_max       = ATMEL_SSC_DMABUF_SIZE,
};


/*--------------------------------------------------------------------------*\
 * 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 */
};

/*--------------------------------------------------------------------------*\
 * 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_warn("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=%zu, period_size=%zu)\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 = %zu\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 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,
};

static struct snd_soc_platform_driver atmel_soc_platform = {
        .ops            = &atmel_pcm_ops,
        .pcm_new        = atmel_pcm_new,
        .pcm_free       = atmel_pcm_free,
};

int atmel_pcm_pdc_platform_register(struct device *dev)
{
        return snd_soc_register_platform(dev, &atmel_soc_platform);
}
EXPORT_SYMBOL(atmel_pcm_pdc_platform_register);

void atmel_pcm_pdc_platform_unregister(struct device *dev)
{
        snd_soc_unregister_platform(dev);
}
EXPORT_SYMBOL(atmel_pcm_pdc_platform_unregister);

MODULE_AUTHOR("Sedji Gaouaou <sedji.gaouaou@atmel.com>");
MODULE_DESCRIPTION("Atmel PCM module");
MODULE_LICENSE("GPL");