root/drivers/mmc/host/sdhci-of-k1.c
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2023-2025 SpacemiT (Hangzhou) Technology Co. Ltd
 * Copyright (c) 2025 Yixun Lan <dlan@gentoo.org>
 */

#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/iopoll.h>
#include <linux/init.h>
#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
#include <linux/mmc/mmc.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>

#include "sdhci.h"
#include "sdhci-pltfm.h"

#define SPACEMIT_SDHC_MMC_CTRL_REG      0x114
#define  SDHC_MISC_INT_EN               BIT(1)
#define  SDHC_MISC_INT                  BIT(2)
#define  SDHC_ENHANCE_STROBE_EN         BIT(8)
#define  SDHC_MMC_HS400                 BIT(9)
#define  SDHC_MMC_HS200                 BIT(10)
#define  SDHC_MMC_CARD_MODE             BIT(12)

#define SPACEMIT_SDHC_TX_CFG_REG        0x11C
#define  SDHC_TX_INT_CLK_SEL            BIT(30)
#define  SDHC_TX_MUX_SEL                BIT(31)

#define SPACEMIT_SDHC_PHY_CTRL_REG      0x160
#define  SDHC_PHY_FUNC_EN               BIT(0)
#define  SDHC_PHY_PLL_LOCK              BIT(1)
#define  SDHC_HOST_LEGACY_MODE          BIT(31)

#define SPACEMIT_SDHC_PHY_FUNC_REG      0x164
#define  SDHC_PHY_TEST_EN               BIT(7)
#define  SDHC_HS200_USE_RFIFO           BIT(15)

#define SPACEMIT_SDHC_PHY_DLLCFG        0x168
#define  SDHC_DLL_PREDLY_NUM            GENMASK(3, 2)
#define  SDHC_DLL_FULLDLY_RANGE         GENMASK(5, 4)
#define  SDHC_DLL_VREG_CTRL             GENMASK(7, 6)
#define  SDHC_DLL_ENABLE                BIT(31)

#define SPACEMIT_SDHC_PHY_DLLCFG1       0x16C
#define  SDHC_DLL_REG1_CTRL             GENMASK(7, 0)
#define  SDHC_DLL_REG2_CTRL             GENMASK(15, 8)
#define  SDHC_DLL_REG3_CTRL             GENMASK(23, 16)
#define  SDHC_DLL_REG4_CTRL             GENMASK(31, 24)

#define SPACEMIT_SDHC_PHY_DLLSTS        0x170
#define  SDHC_DLL_LOCK_STATE            BIT(0)

#define SPACEMIT_SDHC_PHY_PADCFG_REG    0x178
#define  SDHC_PHY_DRIVE_SEL             GENMASK(2, 0)
#define  SDHC_RX_BIAS_CTRL              BIT(5)

struct spacemit_sdhci_host {
        struct clk *clk_core;
        struct clk *clk_io;
};

/* All helper functions will update clr/set while preserve rest bits */
static inline void spacemit_sdhci_setbits(struct sdhci_host *host, u32 val, int reg)
{
        sdhci_writel(host, sdhci_readl(host, reg) | val, reg);
}

static inline void spacemit_sdhci_clrbits(struct sdhci_host *host, u32 val, int reg)
{
        sdhci_writel(host, sdhci_readl(host, reg) & ~val, reg);
}

static inline void spacemit_sdhci_clrsetbits(struct sdhci_host *host, u32 clr, u32 set, int reg)
{
        u32 val = sdhci_readl(host, reg);

        val = (val & ~clr) | set;
        sdhci_writel(host, val, reg);
}

static void spacemit_sdhci_reset(struct sdhci_host *host, u8 mask)
{
        sdhci_reset(host, mask);

        if (mask != SDHCI_RESET_ALL)
                return;

        spacemit_sdhci_setbits(host, SDHC_PHY_FUNC_EN | SDHC_PHY_PLL_LOCK,
                               SPACEMIT_SDHC_PHY_CTRL_REG);

        spacemit_sdhci_clrsetbits(host, SDHC_PHY_DRIVE_SEL,
                                  SDHC_RX_BIAS_CTRL | FIELD_PREP(SDHC_PHY_DRIVE_SEL, 4),
                                  SPACEMIT_SDHC_PHY_PADCFG_REG);

        if (!(host->mmc->caps2 & MMC_CAP2_NO_MMC))
                spacemit_sdhci_setbits(host, SDHC_MMC_CARD_MODE, SPACEMIT_SDHC_MMC_CTRL_REG);
}

static void spacemit_sdhci_set_uhs_signaling(struct sdhci_host *host, unsigned int timing)
{
        if (timing == MMC_TIMING_MMC_HS200)
                spacemit_sdhci_setbits(host, SDHC_MMC_HS200, SPACEMIT_SDHC_MMC_CTRL_REG);

        if (timing == MMC_TIMING_MMC_HS400)
                spacemit_sdhci_setbits(host, SDHC_MMC_HS400, SPACEMIT_SDHC_MMC_CTRL_REG);

        sdhci_set_uhs_signaling(host, timing);

        if (!(host->mmc->caps2 & MMC_CAP2_NO_SDIO))
                spacemit_sdhci_setbits(host, SDHCI_CTRL_VDD_180, SDHCI_HOST_CONTROL2);
}

static void spacemit_sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
{
        struct mmc_host *mmc = host->mmc;

        if (mmc->ios.timing <= MMC_TIMING_UHS_SDR50)
                spacemit_sdhci_setbits(host, SDHC_TX_INT_CLK_SEL, SPACEMIT_SDHC_TX_CFG_REG);
        else
                spacemit_sdhci_clrbits(host, SDHC_TX_INT_CLK_SEL, SPACEMIT_SDHC_TX_CFG_REG);

        sdhci_set_clock(host, clock);
};

static void spacemit_sdhci_phy_dll_init(struct sdhci_host *host)
{
        u32 state;
        int ret;

        spacemit_sdhci_clrsetbits(host, SDHC_DLL_PREDLY_NUM |
                                  SDHC_DLL_FULLDLY_RANGE |
                                  SDHC_DLL_VREG_CTRL,
                                  FIELD_PREP(SDHC_DLL_PREDLY_NUM, 1) |
                                  FIELD_PREP(SDHC_DLL_FULLDLY_RANGE, 1) |
                                  FIELD_PREP(SDHC_DLL_VREG_CTRL, 1),
                                  SPACEMIT_SDHC_PHY_DLLCFG);

        spacemit_sdhci_clrsetbits(host, SDHC_DLL_REG1_CTRL,
                                  FIELD_PREP(SDHC_DLL_REG1_CTRL, 0x92),
                                  SPACEMIT_SDHC_PHY_DLLCFG1);

        spacemit_sdhci_setbits(host, SDHC_DLL_ENABLE, SPACEMIT_SDHC_PHY_DLLCFG);

        ret = readl_poll_timeout(host->ioaddr + SPACEMIT_SDHC_PHY_DLLSTS, state,
                                 state & SDHC_DLL_LOCK_STATE, 2, 100);
        if (ret == -ETIMEDOUT)
                dev_warn(mmc_dev(host->mmc), "fail to lock phy dll in 100us!\n");
}

static void spacemit_sdhci_hs400_enhanced_strobe(struct mmc_host *mmc, struct mmc_ios *ios)
{
        struct sdhci_host *host = mmc_priv(mmc);

        if (!ios->enhanced_strobe) {
                spacemit_sdhci_clrbits(host, SDHC_ENHANCE_STROBE_EN, SPACEMIT_SDHC_MMC_CTRL_REG);
                return;
        }

        spacemit_sdhci_setbits(host, SDHC_ENHANCE_STROBE_EN, SPACEMIT_SDHC_MMC_CTRL_REG);
        spacemit_sdhci_phy_dll_init(host);
}

static unsigned int spacemit_sdhci_clk_get_max_clock(struct sdhci_host *host)
{
        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);

        return clk_get_rate(pltfm_host->clk);
}

static int spacemit_sdhci_pre_select_hs400(struct mmc_host *mmc)
{
        struct sdhci_host *host = mmc_priv(mmc);

        spacemit_sdhci_setbits(host, SDHC_MMC_HS400, SPACEMIT_SDHC_MMC_CTRL_REG);

        return 0;
}

static void spacemit_sdhci_post_select_hs400(struct mmc_host *mmc)
{
        struct sdhci_host *host = mmc_priv(mmc);

        spacemit_sdhci_phy_dll_init(host);
}

static void spacemit_sdhci_pre_hs400_to_hs200(struct mmc_host *mmc)
{
        struct sdhci_host *host = mmc_priv(mmc);

        spacemit_sdhci_clrbits(host, SDHC_PHY_FUNC_EN | SDHC_PHY_PLL_LOCK,
                               SPACEMIT_SDHC_PHY_CTRL_REG);
        spacemit_sdhci_clrbits(host, SDHC_MMC_HS400 | SDHC_MMC_HS200 | SDHC_ENHANCE_STROBE_EN,
                               SPACEMIT_SDHC_MMC_CTRL_REG);
        spacemit_sdhci_clrbits(host, SDHC_HS200_USE_RFIFO, SPACEMIT_SDHC_PHY_FUNC_REG);

        udelay(5);

        spacemit_sdhci_setbits(host, SDHC_PHY_FUNC_EN | SDHC_PHY_PLL_LOCK,
                               SPACEMIT_SDHC_PHY_CTRL_REG);
}

static inline int spacemit_sdhci_get_clocks(struct device *dev,
                                            struct sdhci_pltfm_host *pltfm_host)
{
        struct spacemit_sdhci_host *sdhst = sdhci_pltfm_priv(pltfm_host);

        sdhst->clk_core = devm_clk_get_enabled(dev, "core");
        if (IS_ERR(sdhst->clk_core))
                return -EINVAL;

        sdhst->clk_io = devm_clk_get_enabled(dev, "io");
        if (IS_ERR(sdhst->clk_io))
                return -EINVAL;

        pltfm_host->clk = sdhst->clk_io;

        return 0;
}

static const struct sdhci_ops spacemit_sdhci_ops = {
        .get_max_clock          = spacemit_sdhci_clk_get_max_clock,
        .reset                  = spacemit_sdhci_reset,
        .set_bus_width          = sdhci_set_bus_width,
        .set_clock              = spacemit_sdhci_set_clock,
        .set_uhs_signaling      = spacemit_sdhci_set_uhs_signaling,
};

static const struct sdhci_pltfm_data spacemit_sdhci_k1_pdata = {
        .ops = &spacemit_sdhci_ops,
        .quirks = SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK |
                  SDHCI_QUIRK_NO_ENDATTR_IN_NOPDESC |
                  SDHCI_QUIRK_32BIT_ADMA_SIZE |
                  SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN |
                  SDHCI_QUIRK_BROKEN_CARD_DETECTION |
                  SDHCI_QUIRK_BROKEN_TIMEOUT_VAL,
        .quirks2 = SDHCI_QUIRK2_BROKEN_64_BIT_DMA |
                   SDHCI_QUIRK2_PRESET_VALUE_BROKEN,
};

static const struct of_device_id spacemit_sdhci_of_match[] = {
        { .compatible = "spacemit,k1-sdhci" },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, spacemit_sdhci_of_match);

static int spacemit_sdhci_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct spacemit_sdhci_host *sdhst;
        struct sdhci_pltfm_host *pltfm_host;
        struct sdhci_host *host;
        struct mmc_host_ops *mops;
        int ret;

        host = sdhci_pltfm_init(pdev, &spacemit_sdhci_k1_pdata, sizeof(*sdhst));
        if (IS_ERR(host))
                return PTR_ERR(host);

        pltfm_host = sdhci_priv(host);

        ret = mmc_of_parse(host->mmc);
        if (ret)
                goto err_pltfm;

        sdhci_get_of_property(pdev);

        if (!(host->mmc->caps2 & MMC_CAP2_NO_MMC)) {
                mops = &host->mmc_host_ops;
                mops->hs400_prepare_ddr = spacemit_sdhci_pre_select_hs400;
                mops->hs400_complete    = spacemit_sdhci_post_select_hs400;
                mops->hs400_downgrade   = spacemit_sdhci_pre_hs400_to_hs200;
                mops->hs400_enhanced_strobe = spacemit_sdhci_hs400_enhanced_strobe;
        }

        host->mmc->caps |= MMC_CAP_NEED_RSP_BUSY;

        ret = spacemit_sdhci_get_clocks(dev, pltfm_host);
        if (ret)
                goto err_pltfm;

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

        return 0;

err_pltfm:
        return ret;
}

static struct platform_driver spacemit_sdhci_driver = {
        .driver         = {
                .name   = "sdhci-spacemit",
                .of_match_table = spacemit_sdhci_of_match,
        },
        .probe          = spacemit_sdhci_probe,
        .remove         = sdhci_pltfm_remove,
};
module_platform_driver(spacemit_sdhci_driver);

MODULE_DESCRIPTION("SpacemiT SDHCI platform driver");
MODULE_LICENSE("GPL");