/*
 * Au12x0/Au1550 PSC ALSA ASoC audio support.
 *
 * (c) 2007-2008 MSC Vertriebsges.m.b.H.,
 *      Manuel Lauss <manuel.lauss@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * DMA glue for Au1x-PSC audio.
 *
 */


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

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

#include <asm/mach-au1x00/au1000.h>
#include <asm/mach-au1x00/au1xxx_dbdma.h>
#include <asm/mach-au1x00/au1xxx_psc.h>

#include "psc.h"

/*#define PCM_DEBUG*/

#define MSG(x...)       printk(KERN_INFO "au1xpsc_pcm: " x)
#ifdef PCM_DEBUG
#define DBG             MSG
#else
#define DBG(x...)       do {} while (0)
#endif

struct au1xpsc_audio_dmadata {
        /* DDMA control data */
        unsigned int ddma_id;           /* DDMA direction ID for this PSC */
        u32 ddma_chan;                  /* DDMA context */

        /* PCM context (for irq handlers) */
        struct snd_pcm_substream *substream;
        unsigned long curr_period;      /* current segment DDMA is working on */
        unsigned long q_period;         /* queue period(s) */
        dma_addr_t dma_area;            /* address of queued DMA area */
        dma_addr_t dma_area_s;          /* start address of DMA area */
        unsigned long pos;              /* current byte position being played */
        unsigned long periods;          /* number of SG segments in total */
        unsigned long period_bytes;     /* size in bytes of one SG segment */

        /* runtime data */
        int msbits;
};

/*
 * These settings are somewhat okay, at least on my machine audio plays
 * almost skip-free. Especially the 64kB buffer seems to help a LOT.
 */
#define AU1XPSC_PERIOD_MIN_BYTES        1024
#define AU1XPSC_BUFFER_MIN_BYTES        65536

/* PCM hardware DMA capabilities - platform specific */
static const struct snd_pcm_hardware au1xpsc_pcm_hardware = {
        .info             = SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID |
                            SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BATCH,
        .period_bytes_min = AU1XPSC_PERIOD_MIN_BYTES,
        .period_bytes_max = 4096 * 1024 - 1,
        .periods_min      = 2,
        .periods_max      = 4096,       /* 2 to as-much-as-you-like */
        .buffer_bytes_max = 4096 * 1024 - 1,
        .fifo_size        = 16,         /* fifo entries of AC97/I2S PSC */
};

static void au1x_pcm_queue_tx(struct au1xpsc_audio_dmadata *cd)
{
        au1xxx_dbdma_put_source(cd->ddma_chan, cd->dma_area,
                                cd->period_bytes, DDMA_FLAGS_IE);

        /* update next-to-queue period */
        ++cd->q_period;
        cd->dma_area += cd->period_bytes;
        if (cd->q_period >= cd->periods) {
                cd->q_period = 0;
                cd->dma_area = cd->dma_area_s;
        }
}

static void au1x_pcm_queue_rx(struct au1xpsc_audio_dmadata *cd)
{
        au1xxx_dbdma_put_dest(cd->ddma_chan, cd->dma_area,
                              cd->period_bytes, DDMA_FLAGS_IE);

        /* update next-to-queue period */
        ++cd->q_period;
        cd->dma_area += cd->period_bytes;
        if (cd->q_period >= cd->periods) {
                cd->q_period = 0;
                cd->dma_area = cd->dma_area_s;
        }
}

static void au1x_pcm_dmatx_cb(int irq, void *dev_id)
{
        struct au1xpsc_audio_dmadata *cd = dev_id;

        cd->pos += cd->period_bytes;
        if (++cd->curr_period >= cd->periods) {
                cd->pos = 0;
                cd->curr_period = 0;
        }
        snd_pcm_period_elapsed(cd->substream);
        au1x_pcm_queue_tx(cd);
}

static void au1x_pcm_dmarx_cb(int irq, void *dev_id)
{
        struct au1xpsc_audio_dmadata *cd = dev_id;

        cd->pos += cd->period_bytes;
        if (++cd->curr_period >= cd->periods) {
                cd->pos = 0;
                cd->curr_period = 0;
        }
        snd_pcm_period_elapsed(cd->substream);
        au1x_pcm_queue_rx(cd);
}

static void au1x_pcm_dbdma_free(struct au1xpsc_audio_dmadata *pcd)
{
        if (pcd->ddma_chan) {
                au1xxx_dbdma_stop(pcd->ddma_chan);
                au1xxx_dbdma_reset(pcd->ddma_chan);
                au1xxx_dbdma_chan_free(pcd->ddma_chan);
                pcd->ddma_chan = 0;
                pcd->msbits = 0;
        }
}

/* in case of missing DMA ring or changed TX-source / RX-dest bit widths,
 * allocate (or reallocate) a 2-descriptor DMA ring with bit depth according
 * to ALSA-supplied sample depth.  This is due to limitations in the dbdma api
 * (cannot adjust source/dest widths of already allocated descriptor ring).
 */
static int au1x_pcm_dbdma_realloc(struct au1xpsc_audio_dmadata *pcd,
                                 int stype, int msbits)
{
        /* DMA only in 8/16/32 bit widths */
        if (msbits == 24)
                msbits = 32;

        /* check current config: correct bits and descriptors allocated? */
        if ((pcd->ddma_chan) && (msbits == pcd->msbits))
                goto out;       /* all ok! */

        au1x_pcm_dbdma_free(pcd);

        if (stype == SNDRV_PCM_STREAM_CAPTURE)
                pcd->ddma_chan = au1xxx_dbdma_chan_alloc(pcd->ddma_id,
                                        DSCR_CMD0_ALWAYS,
                                        au1x_pcm_dmarx_cb, (void *)pcd);
        else
                pcd->ddma_chan = au1xxx_dbdma_chan_alloc(DSCR_CMD0_ALWAYS,
                                        pcd->ddma_id,
                                        au1x_pcm_dmatx_cb, (void *)pcd);

        if (!pcd->ddma_chan)
                return -ENOMEM;

        au1xxx_dbdma_set_devwidth(pcd->ddma_chan, msbits);
        au1xxx_dbdma_ring_alloc(pcd->ddma_chan, 2);

        pcd->msbits = msbits;

        au1xxx_dbdma_stop(pcd->ddma_chan);
        au1xxx_dbdma_reset(pcd->ddma_chan);

out:
        return 0;
}

static inline struct au1xpsc_audio_dmadata *to_dmadata(struct snd_pcm_substream *ss)
{
        struct snd_soc_pcm_runtime *rtd = ss->private_data;
        struct au1xpsc_audio_dmadata *pcd =
                                snd_soc_platform_get_drvdata(rtd->platform);
        return &pcd[ss->stream];
}

static int au1xpsc_pcm_hw_params(struct snd_pcm_substream *substream,
                                 struct snd_pcm_hw_params *params)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct au1xpsc_audio_dmadata *pcd;
        int stype, ret;

        ret = snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params));
        if (ret < 0)
                goto out;

        stype = substream->stream;
        pcd = to_dmadata(substream);

        DBG("runtime->dma_area = 0x%08lx dma_addr_t = 0x%08lx dma_size = %zu "
            "runtime->min_align %lu\n",
                (unsigned long)runtime->dma_area,
                (unsigned long)runtime->dma_addr, runtime->dma_bytes,
                runtime->min_align);

        DBG("bits %d  frags %d  frag_bytes %d  is_rx %d\n", params->msbits,
                params_periods(params), params_period_bytes(params), stype);

        ret = au1x_pcm_dbdma_realloc(pcd, stype, params->msbits);
        if (ret) {
                MSG("DDMA channel (re)alloc failed!\n");
                goto out;
        }

        pcd->substream = substream;
        pcd->period_bytes = params_period_bytes(params);
        pcd->periods = params_periods(params);
        pcd->dma_area_s = pcd->dma_area = runtime->dma_addr;
        pcd->q_period = 0;
        pcd->curr_period = 0;
        pcd->pos = 0;

        ret = 0;
out:
        return ret;
}

static int au1xpsc_pcm_hw_free(struct snd_pcm_substream *substream)
{
        snd_pcm_lib_free_pages(substream);
        return 0;
}

static int au1xpsc_pcm_prepare(struct snd_pcm_substream *substream)
{
        struct au1xpsc_audio_dmadata *pcd = to_dmadata(substream);

        au1xxx_dbdma_reset(pcd->ddma_chan);

        if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
                au1x_pcm_queue_rx(pcd);
                au1x_pcm_queue_rx(pcd);
        } else {
                au1x_pcm_queue_tx(pcd);
                au1x_pcm_queue_tx(pcd);
        }

        return 0;
}

static int au1xpsc_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
        u32 c = to_dmadata(substream)->ddma_chan;

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
        case SNDRV_PCM_TRIGGER_RESUME:
                au1xxx_dbdma_start(c);
                break;
        case SNDRV_PCM_TRIGGER_STOP:
        case SNDRV_PCM_TRIGGER_SUSPEND:
                au1xxx_dbdma_stop(c);
                break;
        default:
                return -EINVAL;
        }
        return 0;
}

static snd_pcm_uframes_t
au1xpsc_pcm_pointer(struct snd_pcm_substream *substream)
{
        return bytes_to_frames(substream->runtime, to_dmadata(substream)->pos);
}

static int au1xpsc_pcm_open(struct snd_pcm_substream *substream)
{
        struct au1xpsc_audio_dmadata *pcd = to_dmadata(substream);
        struct snd_soc_pcm_runtime *rtd = substream->private_data;
        int stype = substream->stream, *dmaids;

        dmaids = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
        if (!dmaids)
                return -ENODEV; /* whoa, has ordering changed? */

        pcd->ddma_id = dmaids[stype];

        snd_soc_set_runtime_hwparams(substream, &au1xpsc_pcm_hardware);
        return 0;
}

static int au1xpsc_pcm_close(struct snd_pcm_substream *substream)
{
        au1x_pcm_dbdma_free(to_dmadata(substream));
        return 0;
}

static struct snd_pcm_ops au1xpsc_pcm_ops = {
        .open           = au1xpsc_pcm_open,
        .close          = au1xpsc_pcm_close,
        .ioctl          = snd_pcm_lib_ioctl,
        .hw_params      = au1xpsc_pcm_hw_params,
        .hw_free        = au1xpsc_pcm_hw_free,
        .prepare        = au1xpsc_pcm_prepare,
        .trigger        = au1xpsc_pcm_trigger,
        .pointer        = au1xpsc_pcm_pointer,
};

static int au1xpsc_pcm_new(struct snd_soc_pcm_runtime *rtd)
{
        struct snd_card *card = rtd->card->snd_card;
        struct snd_pcm *pcm = rtd->pcm;

        snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV,
                card->dev, AU1XPSC_BUFFER_MIN_BYTES, (4096 * 1024) - 1);

        return 0;
}

/* au1xpsc audio platform */
static struct snd_soc_platform_driver au1xpsc_soc_platform = {
        .ops            = &au1xpsc_pcm_ops,
        .pcm_new        = au1xpsc_pcm_new,
};

static int au1xpsc_pcm_drvprobe(struct platform_device *pdev)
{
        struct au1xpsc_audio_dmadata *dmadata;

        dmadata = devm_kzalloc(&pdev->dev,
                               2 * sizeof(struct au1xpsc_audio_dmadata),
                               GFP_KERNEL);
        if (!dmadata)
                return -ENOMEM;

        platform_set_drvdata(pdev, dmadata);

        return devm_snd_soc_register_platform(&pdev->dev,
                                              &au1xpsc_soc_platform);
}

static struct platform_driver au1xpsc_pcm_driver = {
        .driver = {
                .name   = "au1xpsc-pcm",
        },
        .probe          = au1xpsc_pcm_drvprobe,
};

module_platform_driver(au1xpsc_pcm_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Au12x0/Au1550 PSC Audio DMA driver");
MODULE_AUTHOR("Manuel Lauss");