// SPDX-License-Identifier: GPL-2.0-only
/*
 * Support for SDHCI on STMicroelectronics SoCs
 *
 * Copyright (C) 2014 STMicroelectronics Ltd
 * Author: Giuseppe Cavallaro <peppe.cavallaro@st.com>
 * Contributors: Peter Griffin <peter.griffin@linaro.org>
 *
 * Based on sdhci-cns3xxx.c
 */

#include <linux/io.h>
#include <linux/of.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/mmc/host.h>
#include <linux/reset.h>
#include "sdhci-pltfm.h"

struct st_mmc_platform_data {
        struct  reset_control *rstc;
        struct  clk *icnclk;
        void __iomem *top_ioaddr;
};

/* MMCSS glue logic to setup the HC on some ST SoCs (e.g. STiH407 family) */

#define ST_MMC_CCONFIG_REG_1            0x400
#define ST_MMC_CCONFIG_TIMEOUT_CLK_UNIT BIT(24)
#define ST_MMC_CCONFIG_TIMEOUT_CLK_FREQ BIT(12)
#define ST_MMC_CCONFIG_TUNING_COUNT_DEFAULT     BIT(8)
#define ST_MMC_CCONFIG_ASYNC_WAKEUP     BIT(0)
#define ST_MMC_CCONFIG_1_DEFAULT        \
                                ((ST_MMC_CCONFIG_TIMEOUT_CLK_UNIT) | \
                                 (ST_MMC_CCONFIG_TIMEOUT_CLK_FREQ) | \
                                 (ST_MMC_CCONFIG_TUNING_COUNT_DEFAULT))

#define ST_MMC_CCONFIG_REG_2            0x404
#define ST_MMC_CCONFIG_HIGH_SPEED       BIT(28)
#define ST_MMC_CCONFIG_ADMA2            BIT(24)
#define ST_MMC_CCONFIG_8BIT             BIT(20)
#define ST_MMC_CCONFIG_MAX_BLK_LEN      16
#define  MAX_BLK_LEN_1024               1
#define  MAX_BLK_LEN_2048               2
#define BASE_CLK_FREQ_200               0xc8
#define BASE_CLK_FREQ_100               0x64
#define BASE_CLK_FREQ_50                0x32
#define ST_MMC_CCONFIG_2_DEFAULT \
        (ST_MMC_CCONFIG_HIGH_SPEED | ST_MMC_CCONFIG_ADMA2 | \
         ST_MMC_CCONFIG_8BIT | \
         (MAX_BLK_LEN_1024 << ST_MMC_CCONFIG_MAX_BLK_LEN))

#define ST_MMC_CCONFIG_REG_3                    0x408
#define ST_MMC_CCONFIG_EMMC_SLOT_TYPE           BIT(28)
#define ST_MMC_CCONFIG_64BIT                    BIT(24)
#define ST_MMC_CCONFIG_ASYNCH_INTR_SUPPORT      BIT(20)
#define ST_MMC_CCONFIG_1P8_VOLT                 BIT(16)
#define ST_MMC_CCONFIG_3P0_VOLT                 BIT(12)
#define ST_MMC_CCONFIG_3P3_VOLT                 BIT(8)
#define ST_MMC_CCONFIG_SUSP_RES_SUPPORT         BIT(4)
#define ST_MMC_CCONFIG_SDMA                     BIT(0)
#define ST_MMC_CCONFIG_3_DEFAULT        \
                         (ST_MMC_CCONFIG_ASYNCH_INTR_SUPPORT    | \
                          ST_MMC_CCONFIG_3P3_VOLT               | \
                          ST_MMC_CCONFIG_SUSP_RES_SUPPORT       | \
                          ST_MMC_CCONFIG_SDMA)

#define ST_MMC_CCONFIG_REG_4    0x40c
#define ST_MMC_CCONFIG_D_DRIVER BIT(20)
#define ST_MMC_CCONFIG_C_DRIVER BIT(16)
#define ST_MMC_CCONFIG_A_DRIVER BIT(12)
#define ST_MMC_CCONFIG_DDR50    BIT(8)
#define ST_MMC_CCONFIG_SDR104   BIT(4)
#define ST_MMC_CCONFIG_SDR50    BIT(0)
#define ST_MMC_CCONFIG_4_DEFAULT        0

#define ST_MMC_CCONFIG_REG_5            0x410
#define ST_MMC_CCONFIG_TUNING_FOR_SDR50 BIT(8)
#define RETUNING_TIMER_CNT_MAX          0xf
#define ST_MMC_CCONFIG_5_DEFAULT        0

/* I/O configuration for Arasan IP */
#define ST_MMC_GP_OUTPUT        0x450
#define ST_MMC_GP_OUTPUT_CD     BIT(12)

#define ST_MMC_STATUS_R         0x460

#define ST_TOP_MMC_DLY_FIX_OFF(x)       (x - 0x8)

/* TOP config registers to manage static and dynamic delay */
#define ST_TOP_MMC_TX_CLK_DLY                   ST_TOP_MMC_DLY_FIX_OFF(0x8)
#define ST_TOP_MMC_RX_CLK_DLY                   ST_TOP_MMC_DLY_FIX_OFF(0xc)
/* MMC delay control register */
#define ST_TOP_MMC_DLY_CTRL                     ST_TOP_MMC_DLY_FIX_OFF(0x18)
#define ST_TOP_MMC_DLY_CTRL_DLL_BYPASS_CMD      BIT(0)
#define ST_TOP_MMC_DLY_CTRL_DLL_BYPASS_PH_SEL   BIT(1)
#define ST_TOP_MMC_DLY_CTRL_TX_DLL_ENABLE       BIT(8)
#define ST_TOP_MMC_DLY_CTRL_RX_DLL_ENABLE       BIT(9)
#define ST_TOP_MMC_DLY_CTRL_ATUNE_NOT_CFG_DLY   BIT(10)
#define ST_TOP_MMC_START_DLL_LOCK               BIT(11)

/* register to provide the phase-shift value for DLL */
#define ST_TOP_MMC_TX_DLL_STEP_DLY              ST_TOP_MMC_DLY_FIX_OFF(0x1c)
#define ST_TOP_MMC_RX_DLL_STEP_DLY              ST_TOP_MMC_DLY_FIX_OFF(0x20)
#define ST_TOP_MMC_RX_CMD_STEP_DLY              ST_TOP_MMC_DLY_FIX_OFF(0x24)

/* phase shift delay on the tx clk 2.188ns */
#define ST_TOP_MMC_TX_DLL_STEP_DLY_VALID        0x6

#define ST_TOP_MMC_DLY_MAX                      0xf

#define ST_TOP_MMC_DYN_DLY_CONF \
                (ST_TOP_MMC_DLY_CTRL_TX_DLL_ENABLE | \
                 ST_TOP_MMC_DLY_CTRL_ATUNE_NOT_CFG_DLY | \
                 ST_TOP_MMC_START_DLL_LOCK)

/*
 * For clock speeds greater than 90MHz, we need to check that the
 * DLL procedure has finished before switching to ultra-speed modes.
 */
#define CLK_TO_CHECK_DLL_LOCK   90000000

static inline void st_mmcss_set_static_delay(void __iomem *ioaddr)
{
        if (!ioaddr)
                return;

        writel_relaxed(0x0, ioaddr + ST_TOP_MMC_DLY_CTRL);
        writel_relaxed(ST_TOP_MMC_DLY_MAX,
                        ioaddr + ST_TOP_MMC_TX_CLK_DLY);
}

/**
 * st_mmcss_cconfig: configure the Arasan HC inside the flashSS.
 * @np: dt device node.
 * @host: sdhci host
 * Description: this function is to configure the Arasan host controller.
 * On some ST SoCs, i.e. STiH407 family, the MMC devices inside a dedicated
 * flashSS sub-system which needs to be configured to be compliant to eMMC 4.5
 * or eMMC4.3.  This has to be done before registering the sdhci host.
 */
static void st_mmcss_cconfig(struct device_node *np, struct sdhci_host *host)
{
        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
        struct mmc_host *mhost = host->mmc;
        u32 cconf2, cconf3, cconf4, cconf5;

        if (!of_device_is_compatible(np, "st,sdhci-stih407"))
                return;

        cconf2 = ST_MMC_CCONFIG_2_DEFAULT;
        cconf3 = ST_MMC_CCONFIG_3_DEFAULT;
        cconf4 = ST_MMC_CCONFIG_4_DEFAULT;
        cconf5 = ST_MMC_CCONFIG_5_DEFAULT;

        writel_relaxed(ST_MMC_CCONFIG_1_DEFAULT,
                        host->ioaddr + ST_MMC_CCONFIG_REG_1);

        /* Set clock frequency, default to 50MHz if max-frequency is not
         * provided */

        switch (mhost->f_max) {
        case 200000000:
                clk_set_rate(pltfm_host->clk, mhost->f_max);
                cconf2 |= BASE_CLK_FREQ_200;
                break;
        case 100000000:
                clk_set_rate(pltfm_host->clk, mhost->f_max);
                cconf2 |= BASE_CLK_FREQ_100;
                break;
        default:
                clk_set_rate(pltfm_host->clk, 50000000);
                cconf2 |= BASE_CLK_FREQ_50;
        }

        writel_relaxed(cconf2, host->ioaddr + ST_MMC_CCONFIG_REG_2);

        if (!mmc_card_is_removable(mhost))
                cconf3 |= ST_MMC_CCONFIG_EMMC_SLOT_TYPE;
        else
                /* CARD _D ET_CTRL */
                writel_relaxed(ST_MMC_GP_OUTPUT_CD,
                                host->ioaddr + ST_MMC_GP_OUTPUT);

        if (mhost->caps & MMC_CAP_UHS_SDR50) {
                /* use 1.8V */
                cconf3 |= ST_MMC_CCONFIG_1P8_VOLT;
                cconf4 |= ST_MMC_CCONFIG_SDR50;
                /* Use tuning */
                cconf5 |= ST_MMC_CCONFIG_TUNING_FOR_SDR50;
                /* Max timeout for retuning */
                cconf5 |= RETUNING_TIMER_CNT_MAX;
        }

        if (mhost->caps & MMC_CAP_UHS_SDR104) {
                /*
                 * SDR104 implies the HC can support HS200 mode, so
                 * it's mandatory to use 1.8V
                 */
                cconf3 |= ST_MMC_CCONFIG_1P8_VOLT;
                cconf4 |= ST_MMC_CCONFIG_SDR104;
                /* Max timeout for retuning */
                cconf5 |= RETUNING_TIMER_CNT_MAX;
        }

        if (mhost->caps & MMC_CAP_UHS_DDR50)
                cconf4 |= ST_MMC_CCONFIG_DDR50;

        writel_relaxed(cconf3, host->ioaddr + ST_MMC_CCONFIG_REG_3);
        writel_relaxed(cconf4, host->ioaddr + ST_MMC_CCONFIG_REG_4);
        writel_relaxed(cconf5, host->ioaddr + ST_MMC_CCONFIG_REG_5);
}

static inline void st_mmcss_set_dll(void __iomem *ioaddr)
{
        if (!ioaddr)
                return;

        writel_relaxed(ST_TOP_MMC_DYN_DLY_CONF, ioaddr + ST_TOP_MMC_DLY_CTRL);
        writel_relaxed(ST_TOP_MMC_TX_DLL_STEP_DLY_VALID,
                        ioaddr + ST_TOP_MMC_TX_DLL_STEP_DLY);
}

static int st_mmcss_lock_dll(void __iomem *ioaddr)
{
        unsigned long curr, value;
        unsigned long finish = jiffies + HZ;

        /* Checks if the DLL procedure is finished */
        do {
                curr = jiffies;
                value = readl(ioaddr + ST_MMC_STATUS_R);
                if (value & 0x1)
                        return 0;

                cpu_relax();
        } while (!time_after_eq(curr, finish));

        return -EBUSY;
}

static int sdhci_st_set_dll_for_clock(struct sdhci_host *host)
{
        int ret = 0;
        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
        struct st_mmc_platform_data *pdata = sdhci_pltfm_priv(pltfm_host);

        if (host->clock > CLK_TO_CHECK_DLL_LOCK) {
                st_mmcss_set_dll(pdata->top_ioaddr);
                ret = st_mmcss_lock_dll(host->ioaddr);
        }

        return ret;
}

static void sdhci_st_set_uhs_signaling(struct sdhci_host *host,
                                        unsigned int uhs)
{
        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
        struct st_mmc_platform_data *pdata = sdhci_pltfm_priv(pltfm_host);
        u16 ctrl_2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
        int ret = 0;

        /* Select Bus Speed Mode for host */
        ctrl_2 &= ~SDHCI_CTRL_UHS_MASK;
        switch (uhs) {
        /*
         * Set V18_EN -- UHS modes do not work without this.
         * does not change signaling voltage
         */

        case MMC_TIMING_UHS_SDR12:
                st_mmcss_set_static_delay(pdata->top_ioaddr);
                ctrl_2 |= SDHCI_CTRL_UHS_SDR12 | SDHCI_CTRL_VDD_180;
                break;
        case MMC_TIMING_UHS_SDR25:
                st_mmcss_set_static_delay(pdata->top_ioaddr);
                ctrl_2 |= SDHCI_CTRL_UHS_SDR25 | SDHCI_CTRL_VDD_180;
                break;
        case MMC_TIMING_UHS_SDR50:
                st_mmcss_set_static_delay(pdata->top_ioaddr);
                ctrl_2 |= SDHCI_CTRL_UHS_SDR50 | SDHCI_CTRL_VDD_180;
                ret = sdhci_st_set_dll_for_clock(host);
                break;
        case MMC_TIMING_UHS_SDR104:
        case MMC_TIMING_MMC_HS200:
                st_mmcss_set_static_delay(pdata->top_ioaddr);
                ctrl_2 |= SDHCI_CTRL_UHS_SDR104 | SDHCI_CTRL_VDD_180;
                ret =  sdhci_st_set_dll_for_clock(host);
                break;
        case MMC_TIMING_UHS_DDR50:
        case MMC_TIMING_MMC_DDR52:
                st_mmcss_set_static_delay(pdata->top_ioaddr);
                ctrl_2 |= SDHCI_CTRL_UHS_DDR50 | SDHCI_CTRL_VDD_180;
                break;
        }

        if (ret)
                dev_warn(mmc_dev(host->mmc), "Error setting dll for clock "
                                                "(uhs %d)\n", uhs);

        dev_dbg(mmc_dev(host->mmc), "uhs %d, ctrl_2 %04X\n", uhs, ctrl_2);

        sdhci_writew(host, ctrl_2, SDHCI_HOST_CONTROL2);
}

static u32 sdhci_st_readl(struct sdhci_host *host, int reg)
{
        u32 ret;

        switch (reg) {
        case SDHCI_CAPABILITIES:
                ret = readl_relaxed(host->ioaddr + reg);
                /* Support 3.3V and 1.8V */
                ret &= ~SDHCI_CAN_VDD_300;
                break;
        default:
                ret = readl_relaxed(host->ioaddr + reg);
        }
        return ret;
}

static const struct sdhci_ops sdhci_st_ops = {
        .get_max_clock = sdhci_pltfm_clk_get_max_clock,
        .set_clock = sdhci_set_clock,
        .set_bus_width = sdhci_set_bus_width,
        .read_l = sdhci_st_readl,
        .reset = sdhci_reset,
        .set_uhs_signaling = sdhci_st_set_uhs_signaling,
};

static const struct sdhci_pltfm_data sdhci_st_pdata = {
        .ops = &sdhci_st_ops,
        .quirks = SDHCI_QUIRK_NO_ENDATTR_IN_NOPDESC |
                SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN |
                SDHCI_QUIRK_NO_HISPD_BIT,
        .quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN |
                SDHCI_QUIRK2_STOP_WITH_TC,
};


static int sdhci_st_probe(struct platform_device *pdev)
{
        struct device_node *np = pdev->dev.of_node;
        struct sdhci_host *host;
        struct st_mmc_platform_data *pdata;
        struct sdhci_pltfm_host *pltfm_host;
        struct clk *clk, *icnclk;
        int ret = 0;
        u16 host_version;
        struct reset_control *rstc;

        clk =  devm_clk_get(&pdev->dev, "mmc");
        if (IS_ERR(clk)) {
                dev_err(&pdev->dev, "Peripheral clk not found\n");
                return PTR_ERR(clk);
        }

        /* ICN clock isn't compulsory, but use it if it's provided. */
        icnclk = devm_clk_get(&pdev->dev, "icn");
        if (IS_ERR(icnclk))
                icnclk = NULL;

        rstc = devm_reset_control_get_optional_exclusive(&pdev->dev, NULL);
        if (IS_ERR(rstc))
                return PTR_ERR(rstc);
        reset_control_deassert(rstc);

        host = sdhci_pltfm_init(pdev, &sdhci_st_pdata, sizeof(*pdata));
        if (IS_ERR(host)) {
                dev_err(&pdev->dev, "Failed sdhci_pltfm_init\n");
                ret = PTR_ERR(host);
                goto err_pltfm_init;
        }

        pltfm_host = sdhci_priv(host);
        pdata = sdhci_pltfm_priv(pltfm_host);
        pdata->rstc = rstc;

        ret = mmc_of_parse(host->mmc);
        if (ret) {
                dev_err(&pdev->dev, "Failed mmc_of_parse\n");
                goto err_pltfm_init;
        }

        ret = clk_prepare_enable(clk);
        if (ret) {
                dev_err(&pdev->dev, "Failed to prepare clock\n");
                goto err_pltfm_init;
        }

        ret = clk_prepare_enable(icnclk);
        if (ret) {
                dev_err(&pdev->dev, "Failed to prepare icn clock\n");
                goto err_icnclk;
        }

        /* Configure the FlashSS Top registers for setting eMMC TX/RX delay */
        pdata->top_ioaddr = devm_platform_ioremap_resource_byname(pdev, "top-mmc-delay");
        if (IS_ERR(pdata->top_ioaddr))
                pdata->top_ioaddr = NULL;

        pltfm_host->clk = clk;
        pdata->icnclk = icnclk;

        /* Configure the Arasan HC inside the flashSS */
        st_mmcss_cconfig(np, host);

        ret = sdhci_add_host(host);
        if (ret)
                goto err_out;

        host_version = readw_relaxed((host->ioaddr + SDHCI_HOST_VERSION));

        dev_info(&pdev->dev, "SDHCI ST Initialised: Host Version: 0x%x Vendor Version 0x%x\n",
                ((host_version & SDHCI_SPEC_VER_MASK) >> SDHCI_SPEC_VER_SHIFT),
                ((host_version & SDHCI_VENDOR_VER_MASK) >>
                SDHCI_VENDOR_VER_SHIFT));

        return 0;

err_out:
        clk_disable_unprepare(icnclk);
err_icnclk:
        clk_disable_unprepare(clk);
err_pltfm_init:
        reset_control_assert(rstc);

        return ret;
}

static void sdhci_st_remove(struct platform_device *pdev)
{
        struct sdhci_host *host = platform_get_drvdata(pdev);
        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
        struct st_mmc_platform_data *pdata = sdhci_pltfm_priv(pltfm_host);
        struct reset_control *rstc = pdata->rstc;
        struct clk *clk = pltfm_host->clk;

        sdhci_pltfm_remove(pdev);

        clk_disable_unprepare(pdata->icnclk);
        clk_disable_unprepare(clk);

        reset_control_assert(rstc);
}

static int sdhci_st_suspend(struct device *dev)
{
        struct sdhci_host *host = dev_get_drvdata(dev);
        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
        struct st_mmc_platform_data *pdata = sdhci_pltfm_priv(pltfm_host);
        int ret;

        if (host->tuning_mode != SDHCI_TUNING_MODE_3)
                mmc_retune_needed(host->mmc);

        ret = sdhci_suspend_host(host);
        if (ret)
                goto out;

        reset_control_assert(pdata->rstc);

        clk_disable_unprepare(pdata->icnclk);
        clk_disable_unprepare(pltfm_host->clk);
out:
        return ret;
}

static int sdhci_st_resume(struct device *dev)
{
        struct sdhci_host *host = dev_get_drvdata(dev);
        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
        struct st_mmc_platform_data *pdata = sdhci_pltfm_priv(pltfm_host);
        struct device_node *np = dev->of_node;
        int ret;

        ret = clk_prepare_enable(pltfm_host->clk);
        if (ret)
                return ret;

        ret = clk_prepare_enable(pdata->icnclk);
        if (ret) {
                clk_disable_unprepare(pltfm_host->clk);
                return ret;
        }

        reset_control_deassert(pdata->rstc);

        st_mmcss_cconfig(np, host);

        return sdhci_resume_host(host);
}

static DEFINE_SIMPLE_DEV_PM_OPS(sdhci_st_pmops, sdhci_st_suspend, sdhci_st_resume);

static const struct of_device_id st_sdhci_match[] = {
        { .compatible = "st,sdhci" },
        {},
};

MODULE_DEVICE_TABLE(of, st_sdhci_match);

static struct platform_driver sdhci_st_driver = {
        .probe = sdhci_st_probe,
        .remove = sdhci_st_remove,
        .driver = {
                   .name = "sdhci-st",
                   .probe_type = PROBE_PREFER_ASYNCHRONOUS,
                   .pm = pm_sleep_ptr(&sdhci_st_pmops),
                   .of_match_table = st_sdhci_match,
                  },
};

module_platform_driver(sdhci_st_driver);

MODULE_DESCRIPTION("SDHCI driver for STMicroelectronics SoCs");
MODULE_AUTHOR("Giuseppe Cavallaro <peppe.cavallaro@st.com>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:sdhci-st");