// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * atmel-pcm-dma.c  --  ALSA PCM DMA support for the Atmel SoC.
 *
 *  Copyright (C) 2012 Atmel
 *
 * Author: Bo Shen <voice.shen@atmel.com>
 *
 * Based on atmel-pcm by:
 * Sedji Gaouaou <sedji.gaouaou@atmel.com>
 * Copyright 2008 Atmel
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/atmel-ssc.h>

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

#include "atmel-pcm.h"

/*--------------------------------------------------------------------------*\
 * Hardware definition
\*--------------------------------------------------------------------------*/
static const struct snd_pcm_hardware atmel_pcm_dma_hardware = {
        .info                   = SNDRV_PCM_INFO_MMAP |
                                  SNDRV_PCM_INFO_MMAP_VALID |
                                  SNDRV_PCM_INFO_INTERLEAVED |
                                  SNDRV_PCM_INFO_RESUME |
                                  SNDRV_PCM_INFO_PAUSE,
        .period_bytes_min       = 256,          /* lighting DMA overhead */
        .period_bytes_max       = 2 * 0xffff,   /* if 2 bytes format */
        .periods_min            = 8,
        .periods_max            = 1024,         /* no limit */
        .buffer_bytes_max       = 512 * 1024,
};

/*
 * atmel_pcm_dma_irq: SSC interrupt handler for DMAENGINE enabled SSC
 *
 * We use DMAENGINE to send/receive data to/from SSC so this ISR is only to
 * check if any overrun occured.
 */
static void atmel_pcm_dma_irq(u32 ssc_sr,
        struct snd_pcm_substream *substream)
{
        struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
        struct atmel_pcm_dma_params *prtd;

        prtd = snd_soc_dai_get_dma_data(snd_soc_rtd_to_cpu(rtd, 0), substream);

        if (ssc_sr & prtd->mask->ssc_error) {
                if (snd_pcm_running(substream))
                        pr_warn("atmel-pcm: buffer %s on %s (SSC_SR=%#x)\n",
                                substream->stream == SNDRV_PCM_STREAM_PLAYBACK
                                ? "underrun" : "overrun", prtd->name,
                                ssc_sr);

                /* stop RX and capture: will be enabled again at restart */
                ssc_writex(prtd->ssc->regs, SSC_CR, prtd->mask->ssc_disable);
                snd_pcm_stop_xrun(substream);

                /* now drain RHR and read status to remove xrun condition */
                ssc_readx(prtd->ssc->regs, SSC_RHR);
                ssc_readx(prtd->ssc->regs, SSC_SR);
        }
}

static int atmel_pcm_configure_dma(struct snd_pcm_substream *substream,
        struct snd_pcm_hw_params *params, struct dma_slave_config *slave_config)
{
        struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
        struct atmel_pcm_dma_params *prtd;
        struct ssc_device *ssc;
        int ret;

        prtd = snd_soc_dai_get_dma_data(snd_soc_rtd_to_cpu(rtd, 0), substream);
        ssc = prtd->ssc;

        ret = snd_hwparams_to_dma_slave_config(substream, params, slave_config);
        if (ret) {
                pr_err("atmel-pcm: hwparams to dma slave configure failed\n");
                return ret;
        }

        slave_config->dst_addr = ssc->phybase + SSC_THR;
        slave_config->dst_maxburst = 1;

        slave_config->src_addr = ssc->phybase + SSC_RHR;
        slave_config->src_maxburst = 1;

        prtd->dma_intr_handler = atmel_pcm_dma_irq;

        return 0;
}

static const struct snd_dmaengine_pcm_config atmel_dmaengine_pcm_config = {
        .prepare_slave_config = atmel_pcm_configure_dma,
        .pcm_hardware = &atmel_pcm_dma_hardware,
        .prealloc_buffer_size = 64 * 1024,
};

int atmel_pcm_dma_platform_register(struct device *dev)
{
        return devm_snd_dmaengine_pcm_register(dev,
                                        &atmel_dmaengine_pcm_config, 0);
}
EXPORT_SYMBOL(atmel_pcm_dma_platform_register);

MODULE_AUTHOR("Bo Shen <voice.shen@atmel.com>");
MODULE_DESCRIPTION("Atmel DMA based PCM module");
MODULE_LICENSE("GPL");