// SPDX-License-Identifier: GPL-2.0-only
/*
 * Au12x0/Au1550 PSC ALSA ASoC audio support.
 *
 * (c) 2007-2009 MSC Vertriebsges.m.b.H.,
 *      Manuel Lauss <manuel.lauss@gmail.com>
 *
 * Au1xxx-PSC AC97 glue.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/suspend.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/initval.h>
#include <sound/soc.h>
#include <asm/mach-au1x00/au1000.h>
#include <asm/mach-au1x00/au1xxx_psc.h>

#include "psc.h"

/* how often to retry failed codec register reads/writes */
#define AC97_RW_RETRIES 5

#define AC97_DIR        \
        (SND_SOC_DAIDIR_PLAYBACK | SND_SOC_DAIDIR_CAPTURE)

#define AC97_RATES      \
        SNDRV_PCM_RATE_8000_48000

#define AC97_FMTS       \
        (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S20_3BE)

#define AC97PCR_START(stype)    \
        ((stype) == SNDRV_PCM_STREAM_PLAYBACK ? PSC_AC97PCR_TS : PSC_AC97PCR_RS)
#define AC97PCR_STOP(stype)     \
        ((stype) == SNDRV_PCM_STREAM_PLAYBACK ? PSC_AC97PCR_TP : PSC_AC97PCR_RP)
#define AC97PCR_CLRFIFO(stype)  \
        ((stype) == SNDRV_PCM_STREAM_PLAYBACK ? PSC_AC97PCR_TC : PSC_AC97PCR_RC)

#define AC97STAT_BUSY(stype)    \
        ((stype) == SNDRV_PCM_STREAM_PLAYBACK ? PSC_AC97STAT_TB : PSC_AC97STAT_RB)

/* instance data. There can be only one, MacLeod!!!! */
static struct au1xpsc_audio_data *au1xpsc_ac97_workdata;

#if 0

/* this could theoretically work, but ac97->bus->card->private_data can be NULL
 * when snd_ac97_mixer() is called; I don't know if the rest further down the
 * chain are always valid either.
 */
static inline struct au1xpsc_audio_data *ac97_to_pscdata(struct snd_ac97 *x)
{
        struct snd_soc_card *c = x->bus->card->private_data;
        return snd_soc_dai_get_drvdata(c->snd_soc_rtd_to_cpu(rtd, 0));
}

#else

#define ac97_to_pscdata(x)      au1xpsc_ac97_workdata

#endif

/* AC97 controller reads codec register */
static unsigned short au1xpsc_ac97_read(struct snd_ac97 *ac97,
                                        unsigned short reg)
{
        struct au1xpsc_audio_data *pscdata = ac97_to_pscdata(ac97);
        unsigned short retry, tmo;
        unsigned long data;

        __raw_writel(PSC_AC97EVNT_CD, AC97_EVNT(pscdata));
        wmb(); /* drain writebuffer */

        retry = AC97_RW_RETRIES;
        do {
                mutex_lock(&pscdata->lock);

                __raw_writel(PSC_AC97CDC_RD | PSC_AC97CDC_INDX(reg),
                          AC97_CDC(pscdata));
                wmb(); /* drain writebuffer */

                tmo = 20;
                do {
                        udelay(21);
                        if (__raw_readl(AC97_EVNT(pscdata)) & PSC_AC97EVNT_CD)
                                break;
                } while (--tmo);

                data = __raw_readl(AC97_CDC(pscdata));

                __raw_writel(PSC_AC97EVNT_CD, AC97_EVNT(pscdata));
                wmb(); /* drain writebuffer */

                mutex_unlock(&pscdata->lock);

                if (reg != ((data >> 16) & 0x7f))
                        tmo = 1;        /* wrong register, try again */

        } while (--retry && !tmo);

        return retry ? data & 0xffff : 0xffff;
}

/* AC97 controller writes to codec register */
static void au1xpsc_ac97_write(struct snd_ac97 *ac97, unsigned short reg,
                                unsigned short val)
{
        struct au1xpsc_audio_data *pscdata = ac97_to_pscdata(ac97);
        unsigned int tmo, retry;

        __raw_writel(PSC_AC97EVNT_CD, AC97_EVNT(pscdata));
        wmb(); /* drain writebuffer */

        retry = AC97_RW_RETRIES;
        do {
                mutex_lock(&pscdata->lock);

                __raw_writel(PSC_AC97CDC_INDX(reg) | (val & 0xffff),
                          AC97_CDC(pscdata));
                wmb(); /* drain writebuffer */

                tmo = 20;
                do {
                        udelay(21);
                        if (__raw_readl(AC97_EVNT(pscdata)) & PSC_AC97EVNT_CD)
                                break;
                } while (--tmo);

                __raw_writel(PSC_AC97EVNT_CD, AC97_EVNT(pscdata));
                wmb(); /* drain writebuffer */

                mutex_unlock(&pscdata->lock);
        } while (--retry && !tmo);
}

/* AC97 controller asserts a warm reset */
static void au1xpsc_ac97_warm_reset(struct snd_ac97 *ac97)
{
        struct au1xpsc_audio_data *pscdata = ac97_to_pscdata(ac97);

        __raw_writel(PSC_AC97RST_SNC, AC97_RST(pscdata));
        wmb(); /* drain writebuffer */
        msleep(10);
        __raw_writel(0, AC97_RST(pscdata));
        wmb(); /* drain writebuffer */
}

static void au1xpsc_ac97_cold_reset(struct snd_ac97 *ac97)
{
        struct au1xpsc_audio_data *pscdata = ac97_to_pscdata(ac97);
        int i;

        /* disable PSC during cold reset */
        __raw_writel(0, AC97_CFG(au1xpsc_ac97_workdata));
        wmb(); /* drain writebuffer */
        __raw_writel(PSC_CTRL_DISABLE, PSC_CTRL(pscdata));
        wmb(); /* drain writebuffer */

        /* issue cold reset */
        __raw_writel(PSC_AC97RST_RST, AC97_RST(pscdata));
        wmb(); /* drain writebuffer */
        msleep(500);
        __raw_writel(0, AC97_RST(pscdata));
        wmb(); /* drain writebuffer */

        /* enable PSC */
        __raw_writel(PSC_CTRL_ENABLE, PSC_CTRL(pscdata));
        wmb(); /* drain writebuffer */

        /* wait for PSC to indicate it's ready */
        i = 1000;
        while (!((__raw_readl(AC97_STAT(pscdata)) & PSC_AC97STAT_SR)) && (--i))
                msleep(1);

        if (i == 0) {
                printk(KERN_ERR "au1xpsc-ac97: PSC not ready!\n");
                return;
        }

        /* enable the ac97 function */
        __raw_writel(pscdata->cfg | PSC_AC97CFG_DE_ENABLE, AC97_CFG(pscdata));
        wmb(); /* drain writebuffer */

        /* wait for AC97 core to become ready */
        i = 1000;
        while (!((__raw_readl(AC97_STAT(pscdata)) & PSC_AC97STAT_DR)) && (--i))
                msleep(1);
        if (i == 0)
                printk(KERN_ERR "au1xpsc-ac97: AC97 ctrl not ready\n");
}

/* AC97 controller operations */
static struct snd_ac97_bus_ops psc_ac97_ops = {
        .read           = au1xpsc_ac97_read,
        .write          = au1xpsc_ac97_write,
        .reset          = au1xpsc_ac97_cold_reset,
        .warm_reset     = au1xpsc_ac97_warm_reset,
};

static int au1xpsc_ac97_hw_params(struct snd_pcm_substream *substream,
                                  struct snd_pcm_hw_params *params,
                                  struct snd_soc_dai *dai)
{
        struct au1xpsc_audio_data *pscdata = snd_soc_dai_get_drvdata(dai);
        unsigned long r, ro, stat;
        int chans, t, stype = substream->stream;

        chans = params_channels(params);

        r = ro = __raw_readl(AC97_CFG(pscdata));
        stat = __raw_readl(AC97_STAT(pscdata));

        /* already active? */
        if (stat & (PSC_AC97STAT_TB | PSC_AC97STAT_RB)) {
                /* reject parameters not currently set up */
                if ((PSC_AC97CFG_GET_LEN(r) != params->msbits) ||
                    (pscdata->rate != params_rate(params)))
                        return -EINVAL;
        } else {

                /* set sample bitdepth: REG[24:21]=(BITS-2)/2 */
                r &= ~PSC_AC97CFG_LEN_MASK;
                r |= PSC_AC97CFG_SET_LEN(params->msbits);

                /* channels: enable slots for front L/R channel */
                if (stype == SNDRV_PCM_STREAM_PLAYBACK) {
                        r &= ~PSC_AC97CFG_TXSLOT_MASK;
                        r |= PSC_AC97CFG_TXSLOT_ENA(3);
                        r |= PSC_AC97CFG_TXSLOT_ENA(4);
                } else {
                        r &= ~PSC_AC97CFG_RXSLOT_MASK;
                        r |= PSC_AC97CFG_RXSLOT_ENA(3);
                        r |= PSC_AC97CFG_RXSLOT_ENA(4);
                }

                /* do we need to poke the hardware? */
                if (!(r ^ ro))
                        goto out;

                /* ac97 engine is about to be disabled */
                mutex_lock(&pscdata->lock);

                /* disable AC97 device controller first... */
                __raw_writel(r & ~PSC_AC97CFG_DE_ENABLE, AC97_CFG(pscdata));
                wmb(); /* drain writebuffer */

                /* ...wait for it... */
                t = 100;
                while ((__raw_readl(AC97_STAT(pscdata)) & PSC_AC97STAT_DR) && --t)
                        msleep(1);

                if (!t)
                        printk(KERN_ERR "PSC-AC97: can't disable!\n");

                /* ...write config... */
                __raw_writel(r, AC97_CFG(pscdata));
                wmb(); /* drain writebuffer */

                /* ...enable the AC97 controller again... */
                __raw_writel(r | PSC_AC97CFG_DE_ENABLE, AC97_CFG(pscdata));
                wmb(); /* drain writebuffer */

                /* ...and wait for ready bit */
                t = 100;
                while ((!(__raw_readl(AC97_STAT(pscdata)) & PSC_AC97STAT_DR)) && --t)
                        msleep(1);

                if (!t)
                        printk(KERN_ERR "PSC-AC97: can't enable!\n");

                mutex_unlock(&pscdata->lock);

                pscdata->cfg = r;
                pscdata->rate = params_rate(params);
        }

out:
        return 0;
}

static int au1xpsc_ac97_trigger(struct snd_pcm_substream *substream,
                                int cmd, struct snd_soc_dai *dai)
{
        struct au1xpsc_audio_data *pscdata = snd_soc_dai_get_drvdata(dai);
        int ret, stype = substream->stream;

        ret = 0;

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
        case SNDRV_PCM_TRIGGER_RESUME:
                __raw_writel(AC97PCR_CLRFIFO(stype), AC97_PCR(pscdata));
                wmb(); /* drain writebuffer */
                __raw_writel(AC97PCR_START(stype), AC97_PCR(pscdata));
                wmb(); /* drain writebuffer */
                break;
        case SNDRV_PCM_TRIGGER_STOP:
        case SNDRV_PCM_TRIGGER_SUSPEND:
                __raw_writel(AC97PCR_STOP(stype), AC97_PCR(pscdata));
                wmb(); /* drain writebuffer */

                while (__raw_readl(AC97_STAT(pscdata)) & AC97STAT_BUSY(stype))
                        asm volatile ("nop");

                __raw_writel(AC97PCR_CLRFIFO(stype), AC97_PCR(pscdata));
                wmb(); /* drain writebuffer */

                break;
        default:
                ret = -EINVAL;
        }
        return ret;
}

static int au1xpsc_ac97_startup(struct snd_pcm_substream *substream,
                                struct snd_soc_dai *dai)
{
        struct au1xpsc_audio_data *pscdata = snd_soc_dai_get_drvdata(dai);
        snd_soc_dai_set_dma_data(dai, substream, &pscdata->dmaids[0]);
        return 0;
}

static int au1xpsc_ac97_probe(struct snd_soc_dai *dai)
{
        return au1xpsc_ac97_workdata ? 0 : -ENODEV;
}

static const struct snd_soc_dai_ops au1xpsc_ac97_dai_ops = {
        .probe          = au1xpsc_ac97_probe,
        .startup        = au1xpsc_ac97_startup,
        .trigger        = au1xpsc_ac97_trigger,
        .hw_params      = au1xpsc_ac97_hw_params,
};

static const struct snd_soc_dai_driver au1xpsc_ac97_dai_template = {
        .playback = {
                .rates          = AC97_RATES,
                .formats        = AC97_FMTS,
                .channels_min   = 2,
                .channels_max   = 2,
        },
        .capture = {
                .rates          = AC97_RATES,
                .formats        = AC97_FMTS,
                .channels_min   = 2,
                .channels_max   = 2,
        },
        .ops = &au1xpsc_ac97_dai_ops,
};

static const struct snd_soc_component_driver au1xpsc_ac97_component = {
        .name                   = "au1xpsc-ac97",
        .legacy_dai_naming      = 1,
};

static int au1xpsc_ac97_drvprobe(struct platform_device *pdev)
{
        int ret;
        struct resource *dmares;
        unsigned long sel;
        struct au1xpsc_audio_data *wd;

        wd = devm_kzalloc(&pdev->dev, sizeof(struct au1xpsc_audio_data),
                          GFP_KERNEL);
        if (!wd)
                return -ENOMEM;

        mutex_init(&wd->lock);

        wd->mmio = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(wd->mmio))
                return PTR_ERR(wd->mmio);

        dmares = platform_get_resource(pdev, IORESOURCE_DMA, 0);
        if (!dmares)
                return -EBUSY;
        wd->dmaids[SNDRV_PCM_STREAM_PLAYBACK] = dmares->start;

        dmares = platform_get_resource(pdev, IORESOURCE_DMA, 1);
        if (!dmares)
                return -EBUSY;
        wd->dmaids[SNDRV_PCM_STREAM_CAPTURE] = dmares->start;

        /* configuration: max dma trigger threshold, enable ac97 */
        wd->cfg = PSC_AC97CFG_RT_FIFO8 | PSC_AC97CFG_TT_FIFO8 |
                  PSC_AC97CFG_DE_ENABLE;

        /* preserve PSC clock source set up by platform  */
        sel = __raw_readl(PSC_SEL(wd)) & PSC_SEL_CLK_MASK;
        __raw_writel(PSC_CTRL_DISABLE, PSC_CTRL(wd));
        wmb(); /* drain writebuffer */
        __raw_writel(0, PSC_SEL(wd));
        wmb(); /* drain writebuffer */
        __raw_writel(PSC_SEL_PS_AC97MODE | sel, PSC_SEL(wd));
        wmb(); /* drain writebuffer */

        /* name the DAI like this device instance ("au1xpsc-ac97.PSCINDEX") */
        memcpy(&wd->dai_drv, &au1xpsc_ac97_dai_template,
               sizeof(struct snd_soc_dai_driver));
        wd->dai_drv.name = dev_name(&pdev->dev);

        platform_set_drvdata(pdev, wd);

        ret = snd_soc_set_ac97_ops(&psc_ac97_ops);
        if (ret)
                return ret;

        ret = snd_soc_register_component(&pdev->dev, &au1xpsc_ac97_component,
                                         &wd->dai_drv, 1);
        if (ret)
                return ret;

        au1xpsc_ac97_workdata = wd;
        return 0;
}

static void au1xpsc_ac97_drvremove(struct platform_device *pdev)
{
        struct au1xpsc_audio_data *wd = platform_get_drvdata(pdev);

        snd_soc_unregister_component(&pdev->dev);

        /* disable PSC completely */
        __raw_writel(0, AC97_CFG(wd));
        wmb(); /* drain writebuffer */
        __raw_writel(PSC_CTRL_DISABLE, PSC_CTRL(wd));
        wmb(); /* drain writebuffer */

        au1xpsc_ac97_workdata = NULL;   /* MDEV */
}

static int au1xpsc_ac97_drvsuspend(struct device *dev)
{
        struct au1xpsc_audio_data *wd = dev_get_drvdata(dev);

        /* save interesting registers and disable PSC */
        wd->pm[0] = __raw_readl(PSC_SEL(wd));

        __raw_writel(0, AC97_CFG(wd));
        wmb(); /* drain writebuffer */
        __raw_writel(PSC_CTRL_DISABLE, PSC_CTRL(wd));
        wmb(); /* drain writebuffer */

        return 0;
}

static int au1xpsc_ac97_drvresume(struct device *dev)
{
        struct au1xpsc_audio_data *wd = dev_get_drvdata(dev);

        /* restore PSC clock config */
        __raw_writel(wd->pm[0] | PSC_SEL_PS_AC97MODE, PSC_SEL(wd));
        wmb(); /* drain writebuffer */

        /* after this point the ac97 core will cold-reset the codec.
         * During cold-reset the PSC is reinitialized and the last
         * configuration set up in hw_params() is restored.
         */
        return 0;
}

static DEFINE_SIMPLE_DEV_PM_OPS(au1xpscac97_pmops, au1xpsc_ac97_drvsuspend,
                                au1xpsc_ac97_drvresume);

static struct platform_driver au1xpsc_ac97_driver = {
        .driver = {
                .name   = "au1xpsc_ac97",
                .pm     = pm_ptr(&au1xpscac97_pmops),
        },
        .probe          = au1xpsc_ac97_drvprobe,
        .remove         = au1xpsc_ac97_drvremove,
};

module_platform_driver(au1xpsc_ac97_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Au12x0/Au1550 PSC AC97 ALSA ASoC audio driver");
MODULE_AUTHOR("Manuel Lauss");