root/drivers/mmc/host/dw_mmc-hi3798mv200.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Modified from dw_mmc-hi3798cv200.c
 *
 * Copyright (c) 2024 Yang Xiwen <forbidden405@outlook.com>
 * Copyright (c) 2018 HiSilicon Technologies Co., Ltd.
 */

#include <linux/clk.h>
#include <linux/mfd/syscon.h>
#include <linux/mmc/host.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>

#include "dw_mmc.h"
#include "dw_mmc-pltfm.h"

#define SDMMC_TUNING_CTRL       0x118
#define SDMMC_TUNING_FIND_EDGE  BIT(5)

#define ALL_INT_CLR             0x1ffff

/* DLL ctrl reg */
#define SAP_DLL_CTRL_DLLMODE    BIT(16)

struct dw_mci_hi3798mv200_priv {
        struct clk *sample_clk;
        struct clk *drive_clk;
        struct regmap *crg_reg;
        u32 sap_dll_offset;
        struct mmc_clk_phase_map phase_map;
};

static void dw_mci_hi3798mv200_set_ios(struct dw_mci *host, struct mmc_ios *ios)
{
        struct dw_mci_hi3798mv200_priv *priv = host->priv;
        struct mmc_clk_phase phase = priv->phase_map.phase[ios->timing];
        u32 val;

        val = mci_readl(host, ENABLE_SHIFT);
        if (ios->timing == MMC_TIMING_MMC_DDR52
            || ios->timing == MMC_TIMING_UHS_DDR50)
                val |= SDMMC_ENABLE_PHASE;
        else
                val &= ~SDMMC_ENABLE_PHASE;
        mci_writel(host, ENABLE_SHIFT, val);

        val = mci_readl(host, DDR_REG);
        if (ios->timing == MMC_TIMING_MMC_HS400)
                val |= SDMMC_DDR_HS400;
        else
                val &= ~SDMMC_DDR_HS400;
        mci_writel(host, DDR_REG, val);

        if (clk_set_rate(host->ciu_clk, ios->clock))
                dev_warn(host->dev, "Failed to set rate to %u\n", ios->clock);
        else
                /*
                 * CLK_MUX_ROUND_NEAREST is enabled for this clock
                 * The actual clock rate is not what we set, but a rounded value
                 * so we should get the rate once again
                 */
                host->bus_hz = clk_get_rate(host->ciu_clk);

        if (phase.valid) {
                clk_set_phase(priv->drive_clk, phase.out_deg);
                clk_set_phase(priv->sample_clk, phase.in_deg);
        } else {
                dev_warn(host->dev,
                         "The phase entry for timing mode %d is missing in device tree.\n",
                         ios->timing);
        }
}

static inline int dw_mci_hi3798mv200_enable_tuning(struct dw_mci_slot *slot)
{
        struct dw_mci_hi3798mv200_priv *priv = slot->host->priv;

        return regmap_clear_bits(priv->crg_reg, priv->sap_dll_offset, SAP_DLL_CTRL_DLLMODE);
}

static inline int dw_mci_hi3798mv200_disable_tuning(struct dw_mci_slot *slot)
{
        struct dw_mci_hi3798mv200_priv *priv = slot->host->priv;

        return regmap_set_bits(priv->crg_reg, priv->sap_dll_offset, SAP_DLL_CTRL_DLLMODE);
}

static int dw_mci_hi3798mv200_execute_tuning_mix_mode(struct dw_mci_slot *slot,
                                             u32 opcode)
{
        static const int degrees[] = { 0, 45, 90, 135, 180, 225, 270, 315 };
        struct dw_mci *host = slot->host;
        struct dw_mci_hi3798mv200_priv *priv = host->priv;
        int raise_point = -1, fall_point = -1, mid;
        int err, prev_err = -1;
        int found = 0;
        int regval;
        int i;
        int ret;

        ret = dw_mci_hi3798mv200_enable_tuning(slot);
        if (ret < 0)
                return ret;

        for (i = 0; i < ARRAY_SIZE(degrees); i++) {
                clk_set_phase(priv->sample_clk, degrees[i]);
                mci_writel(host, RINTSTS, ALL_INT_CLR);

                /*
                 * HiSilicon implemented a tuning mechanism.
                 * It needs special interaction with the DLL.
                 *
                 * Treat edge(flip) found as an error too.
                 */
                err = mmc_send_tuning(slot->mmc, opcode, NULL);
                regval = mci_readl(host, TUNING_CTRL);
                if (err || (regval & SDMMC_TUNING_FIND_EDGE))
                        err = 1;
                else
                        found = 1;

                if (i > 0) {
                        if (err && !prev_err)
                                fall_point = i - 1;
                        if (!err && prev_err)
                                raise_point = i;
                }

                if (raise_point != -1 && fall_point != -1)
                        goto tuning_out;

                prev_err = err;
        }

tuning_out:
        ret = dw_mci_hi3798mv200_disable_tuning(slot);
        if (ret < 0)
                return ret;

        if (found) {
                if (raise_point == -1)
                        raise_point = 0;
                if (fall_point == -1)
                        fall_point = ARRAY_SIZE(degrees) - 1;
                if (fall_point < raise_point) {
                        if ((raise_point + fall_point) >
                            (ARRAY_SIZE(degrees) - 1))
                                mid = fall_point / 2;
                        else
                                mid = (raise_point + ARRAY_SIZE(degrees) - 1) / 2;
                } else {
                        mid = (raise_point + fall_point) / 2;
                }

                /*
                 * We don't care what timing we are tuning for,
                 * simply use the same phase for all timing needs tuning.
                 */
                priv->phase_map.phase[MMC_TIMING_MMC_HS200].in_deg = degrees[mid];
                priv->phase_map.phase[MMC_TIMING_MMC_HS400].in_deg = degrees[mid];
                priv->phase_map.phase[MMC_TIMING_UHS_SDR104].in_deg = degrees[mid];

                clk_set_phase(priv->sample_clk, degrees[mid]);
                dev_dbg(host->dev, "Tuning clk_sample[%d, %d], set[%d]\n",
                        raise_point, fall_point, degrees[mid]);
                ret = 0;
        } else {
                dev_err(host->dev, "No valid clk_sample shift!\n");
                ret = -EINVAL;
        }

        mci_writel(host, RINTSTS, ALL_INT_CLR);

        return ret;
}

static int dw_mci_hi3798mv200_init(struct dw_mci *host)
{
        struct dw_mci_hi3798mv200_priv *priv;
        struct device_node *np = host->dev->of_node;

        priv = devm_kzalloc(host->dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        mmc_of_parse_clk_phase(host->dev, &priv->phase_map);

        priv->sample_clk = devm_clk_get_enabled(host->dev, "ciu-sample");
        if (IS_ERR(priv->sample_clk))
                return dev_err_probe(host->dev, PTR_ERR(priv->sample_clk),
                                     "failed to get enabled ciu-sample clock\n");

        priv->drive_clk = devm_clk_get_enabled(host->dev, "ciu-drive");
        if (IS_ERR(priv->drive_clk))
                return dev_err_probe(host->dev, PTR_ERR(priv->drive_clk),
                                     "failed to get enabled ciu-drive clock\n");

        priv->crg_reg = syscon_regmap_lookup_by_phandle_args(np, "hisilicon,sap-dll-reg",
                                                             1, &priv->sap_dll_offset);
        if (IS_ERR(priv->crg_reg))
                return dev_err_probe(host->dev, PTR_ERR(priv->crg_reg),
                                     "failed to get CRG reg\n");

        host->priv = priv;
        return 0;
}

static const struct dw_mci_drv_data hi3798mv200_data = {
        .common_caps = MMC_CAP_CMD23,
        .init = dw_mci_hi3798mv200_init,
        .set_ios = dw_mci_hi3798mv200_set_ios,
        .execute_tuning = dw_mci_hi3798mv200_execute_tuning_mix_mode,
};

static const struct of_device_id dw_mci_hi3798mv200_match[] = {
        { .compatible = "hisilicon,hi3798mv200-dw-mshc" },
        {},
};

static int dw_mci_hi3798mv200_probe(struct platform_device *pdev)
{
        return dw_mci_pltfm_register(pdev, &hi3798mv200_data);
}

static void dw_mci_hi3798mv200_remove(struct platform_device *pdev)
{
        dw_mci_pltfm_remove(pdev);
}

MODULE_DEVICE_TABLE(of, dw_mci_hi3798mv200_match);
static struct platform_driver dw_mci_hi3798mv200_driver = {
        .probe = dw_mci_hi3798mv200_probe,
        .remove = dw_mci_hi3798mv200_remove,
        .driver = {
                .name = "dwmmc_hi3798mv200",
                .probe_type = PROBE_PREFER_ASYNCHRONOUS,
                .of_match_table = dw_mci_hi3798mv200_match,
        },
};
module_platform_driver(dw_mci_hi3798mv200_driver);

MODULE_DESCRIPTION("HiSilicon Hi3798MV200 Specific DW-MSHC Driver Extension");
MODULE_LICENSE("GPL");