// SPDX-License-Identifier: GPL-2.0-only
/*
 * Au1000/Au1500/Au1100 AC97C controller driver for ASoC
 *
 * (c) 2011 Manuel Lauss <manuel.lauss@googlemail.com>
 *
 * based on the old ALSA driver originally written by
 *                      Charles Eidsness <charles@cooper-street.com>
 */

#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/platform_device.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 "psc.h"

/* register offsets and bits */
#define AC97_CONFIG     0x00
#define AC97_STATUS     0x04
#define AC97_DATA       0x08
#define AC97_CMDRESP    0x0c
#define AC97_ENABLE     0x10

#define CFG_RC(x)       (((x) & 0x3ff) << 13)   /* valid rx slots mask */
#define CFG_XS(x)       (((x) & 0x3ff) << 3)    /* valid tx slots mask */
#define CFG_SG          (1 << 2)        /* sync gate */
#define CFG_SN          (1 << 1)        /* sync control */
#define CFG_RS          (1 << 0)        /* acrst# control */
#define STAT_XU         (1 << 11)       /* tx underflow */
#define STAT_XO         (1 << 10)       /* tx overflow */
#define STAT_RU         (1 << 9)        /* rx underflow */
#define STAT_RO         (1 << 8)        /* rx overflow */
#define STAT_RD         (1 << 7)        /* codec ready */
#define STAT_CP         (1 << 6)        /* command pending */
#define STAT_TE         (1 << 4)        /* tx fifo empty */
#define STAT_TF         (1 << 3)        /* tx fifo full */
#define STAT_RE         (1 << 1)        /* rx fifo empty */
#define STAT_RF         (1 << 0)        /* rx fifo full */
#define CMD_SET_DATA(x) (((x) & 0xffff) << 16)
#define CMD_GET_DATA(x) ((x) & 0xffff)
#define CMD_READ        (1 << 7)
#define CMD_WRITE       (0 << 7)
#define CMD_IDX(x)      ((x) & 0x7f)
#define EN_D            (1 << 1)        /* DISable bit */
#define EN_CE           (1 << 0)        /* clock enable bit */

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

#define AC97_RATES      \
        SNDRV_PCM_RATE_CONTINUOUS

#define AC97_FMTS       \
        (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE)

/* instance data. There can be only one, MacLeod!!!!, fortunately there IS only
 * once AC97C on early Alchemy chips. The newer ones aren't so lucky.
 */
static struct au1xpsc_audio_data *ac97c_workdata;
#define ac97_to_ctx(x)          ac97c_workdata

static inline unsigned long RD(struct au1xpsc_audio_data *ctx, int reg)
{
        return __raw_readl(ctx->mmio + reg);
}

static inline void WR(struct au1xpsc_audio_data *ctx, int reg, unsigned long v)
{
        __raw_writel(v, ctx->mmio + reg);
        wmb();
}

static unsigned short au1xac97c_ac97_read(struct snd_ac97 *ac97,
                                          unsigned short r)
{
        struct au1xpsc_audio_data *ctx = ac97_to_ctx(ac97);
        unsigned int tmo, retry;
        unsigned long data;

        data = ~0;
        retry = AC97_RW_RETRIES;
        do {
                mutex_lock(&ctx->lock);

                tmo = 6;
                while ((RD(ctx, AC97_STATUS) & STAT_CP) && --tmo)
                        udelay(21);     /* wait an ac97 frame time */
                if (!tmo) {
                        pr_debug("ac97rd timeout #1\n");
                        goto next;
                }

                WR(ctx, AC97_CMDRESP, CMD_IDX(r) | CMD_READ);

                /* stupid errata: data is only valid for 21us, so
                 * poll, Forrest, poll...
                 */
                tmo = 0x10000;
                while ((RD(ctx, AC97_STATUS) & STAT_CP) && --tmo)
                        asm volatile ("nop");
                data = RD(ctx, AC97_CMDRESP);

                if (!tmo)
                        pr_debug("ac97rd timeout #2\n");

next:
                mutex_unlock(&ctx->lock);
        } while (--retry && !tmo);

        pr_debug("AC97RD %04x %04lx %d\n", r, data, retry);

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

static void au1xac97c_ac97_write(struct snd_ac97 *ac97, unsigned short r,
                                 unsigned short v)
{
        struct au1xpsc_audio_data *ctx = ac97_to_ctx(ac97);
        unsigned int tmo, retry;

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

                for (tmo = 5; (RD(ctx, AC97_STATUS) & STAT_CP) && tmo; tmo--)
                        udelay(21);
                if (!tmo) {
                        pr_debug("ac97wr timeout #1\n");
                        goto next;
                }

                WR(ctx, AC97_CMDRESP, CMD_WRITE | CMD_IDX(r) | CMD_SET_DATA(v));

                for (tmo = 10; (RD(ctx, AC97_STATUS) & STAT_CP) && tmo; tmo--)
                        udelay(21);
                if (!tmo)
                        pr_debug("ac97wr timeout #2\n");
next:
                mutex_unlock(&ctx->lock);
        } while (--retry && !tmo);

        pr_debug("AC97WR %04x %04x %d\n", r, v, retry);
}

static void au1xac97c_ac97_warm_reset(struct snd_ac97 *ac97)
{
        struct au1xpsc_audio_data *ctx = ac97_to_ctx(ac97);

        WR(ctx, AC97_CONFIG, ctx->cfg | CFG_SG | CFG_SN);
        msleep(20);
        WR(ctx, AC97_CONFIG, ctx->cfg | CFG_SG);
        WR(ctx, AC97_CONFIG, ctx->cfg);
}

static void au1xac97c_ac97_cold_reset(struct snd_ac97 *ac97)
{
        struct au1xpsc_audio_data *ctx = ac97_to_ctx(ac97);
        int i;

        WR(ctx, AC97_CONFIG, ctx->cfg | CFG_RS);
        msleep(500);
        WR(ctx, AC97_CONFIG, ctx->cfg);

        /* wait for codec ready */
        i = 50;
        while (((RD(ctx, AC97_STATUS) & STAT_RD) == 0) && --i)
                msleep(20);
        if (!i)
                printk(KERN_ERR "ac97c: codec not ready after cold reset\n");
}

/* AC97 controller operations */
static struct snd_ac97_bus_ops ac97c_bus_ops = {
        .read           = au1xac97c_ac97_read,
        .write          = au1xac97c_ac97_write,
        .reset          = au1xac97c_ac97_cold_reset,
        .warm_reset     = au1xac97c_ac97_warm_reset,
};

static int alchemy_ac97c_startup(struct snd_pcm_substream *substream,
                                 struct snd_soc_dai *dai)
{
        struct au1xpsc_audio_data *ctx = snd_soc_dai_get_drvdata(dai);
        snd_soc_dai_set_dma_data(dai, substream, &ctx->dmaids[0]);
        return 0;
}

static int au1xac97c_dai_probe(struct snd_soc_dai *dai)
{
        return ac97c_workdata ? 0 : -ENODEV;
}

static const struct snd_soc_dai_ops alchemy_ac97c_ops = {
        .probe                  = au1xac97c_dai_probe,
        .startup                = alchemy_ac97c_startup,
};

static struct snd_soc_dai_driver au1xac97c_dai_driver = {
        .name                   = "alchemy-ac97c",
        .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                    = &alchemy_ac97c_ops,
};

static const struct snd_soc_component_driver au1xac97c_component = {
        .name                   = "au1xac97c",
        .legacy_dai_naming      = 1,
};

static int au1xac97c_drvprobe(struct platform_device *pdev)
{
        int ret;
        struct resource *iores, *dmares;
        struct au1xpsc_audio_data *ctx;

        ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
        if (!ctx)
                return -ENOMEM;

        mutex_init(&ctx->lock);

        iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!iores)
                return -ENODEV;

        if (!devm_request_mem_region(&pdev->dev, iores->start,
                                     resource_size(iores),
                                     pdev->name))
                return -EBUSY;

        ctx->mmio = devm_ioremap(&pdev->dev, iores->start,
                                         resource_size(iores));
        if (!ctx->mmio)
                return -EBUSY;

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

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

        /* switch it on */
        WR(ctx, AC97_ENABLE, EN_D | EN_CE);
        WR(ctx, AC97_ENABLE, EN_CE);

        ctx->cfg = CFG_RC(3) | CFG_XS(3);
        WR(ctx, AC97_CONFIG, ctx->cfg);

        platform_set_drvdata(pdev, ctx);

        ret = snd_soc_set_ac97_ops(&ac97c_bus_ops);
        if (ret)
                return ret;

        ret = snd_soc_register_component(&pdev->dev, &au1xac97c_component,
                                         &au1xac97c_dai_driver, 1);
        if (ret)
                return ret;

        ac97c_workdata = ctx;
        return 0;
}

static void au1xac97c_drvremove(struct platform_device *pdev)
{
        struct au1xpsc_audio_data *ctx = platform_get_drvdata(pdev);

        snd_soc_unregister_component(&pdev->dev);

        WR(ctx, AC97_ENABLE, EN_D);     /* clock off, disable */

        ac97c_workdata = NULL;  /* MDEV */
}

#ifdef CONFIG_PM
static int au1xac97c_drvsuspend(struct device *dev)
{
        struct au1xpsc_audio_data *ctx = dev_get_drvdata(dev);

        WR(ctx, AC97_ENABLE, EN_D);     /* clock off, disable */

        return 0;
}

static int au1xac97c_drvresume(struct device *dev)
{
        struct au1xpsc_audio_data *ctx = dev_get_drvdata(dev);

        WR(ctx, AC97_ENABLE, EN_D | EN_CE);
        WR(ctx, AC97_ENABLE, EN_CE);
        WR(ctx, AC97_CONFIG, ctx->cfg);

        return 0;
}

static const struct dev_pm_ops au1xpscac97_pmops = {
        .suspend        = au1xac97c_drvsuspend,
        .resume         = au1xac97c_drvresume,
};

#define AU1XPSCAC97_PMOPS (&au1xpscac97_pmops)

#else

#define AU1XPSCAC97_PMOPS NULL

#endif

static struct platform_driver au1xac97c_driver = {
        .driver = {
                .name   = "alchemy-ac97c",
                .pm     = AU1XPSCAC97_PMOPS,
        },
        .probe          = au1xac97c_drvprobe,
        .remove         = au1xac97c_drvremove,
};

module_platform_driver(au1xac97c_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Au1000/1500/1100 AC97C ASoC driver");
MODULE_AUTHOR("Manuel Lauss");