// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2019 Spreadtrum Communications Inc.

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/hwspinlock.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/nvmem-provider.h>
#include <linux/of.h>
#include <linux/platform_device.h>

#define SPRD_EFUSE_ENABLE               0x20
#define SPRD_EFUSE_ERR_FLAG             0x24
#define SPRD_EFUSE_ERR_CLR              0x28
#define SPRD_EFUSE_MAGIC_NUM            0x2c
#define SPRD_EFUSE_FW_CFG               0x50
#define SPRD_EFUSE_PW_SWT               0x54
#define SPRD_EFUSE_MEM(val)             (0x1000 + ((val) << 2))

#define SPRD_EFUSE_VDD_EN               BIT(0)
#define SPRD_EFUSE_AUTO_CHECK_EN        BIT(1)
#define SPRD_EFUSE_DOUBLE_EN            BIT(2)
#define SPRD_EFUSE_MARGIN_RD_EN         BIT(3)
#define SPRD_EFUSE_LOCK_WR_EN           BIT(4)

#define SPRD_EFUSE_ERR_CLR_MASK         GENMASK(13, 0)

#define SPRD_EFUSE_ENK1_ON              BIT(0)
#define SPRD_EFUSE_ENK2_ON              BIT(1)
#define SPRD_EFUSE_PROG_EN              BIT(2)

#define SPRD_EFUSE_MAGIC_NUMBER         0x8810

/* Block width (bytes) definitions */
#define SPRD_EFUSE_BLOCK_WIDTH          4

/*
 * The Spreadtrum AP efuse contains 2 parts: normal efuse and secure efuse,
 * and we can only access the normal efuse in kernel. So define the normal
 * block offset index and normal block numbers.
 */
#define SPRD_EFUSE_NORMAL_BLOCK_NUMS    24
#define SPRD_EFUSE_NORMAL_BLOCK_OFFSET  72

/* Timeout (ms) for the trylock of hardware spinlocks */
#define SPRD_EFUSE_HWLOCK_TIMEOUT       5000

/*
 * Since different Spreadtrum SoC chip can have different normal block numbers
 * and offset. And some SoC can support block double feature, which means
 * when reading or writing data to efuse memory, the controller can save double
 * data in case one data become incorrect after a long period.
 *
 * Thus we should save them in the device data structure.
 */
struct sprd_efuse_variant_data {
        u32 blk_nums;
        u32 blk_offset;
        bool blk_double;
};

struct sprd_efuse {
        struct device *dev;
        struct clk *clk;
        struct hwspinlock *hwlock;
        struct mutex mutex;
        void __iomem *base;
        const struct sprd_efuse_variant_data *data;
};

static const struct sprd_efuse_variant_data ums312_data = {
        .blk_nums = SPRD_EFUSE_NORMAL_BLOCK_NUMS,
        .blk_offset = SPRD_EFUSE_NORMAL_BLOCK_OFFSET,
        .blk_double = false,
};

/*
 * On Spreadtrum platform, we have multi-subsystems will access the unique
 * efuse controller, so we need one hardware spinlock to synchronize between
 * the multiple subsystems.
 */
static int sprd_efuse_lock(struct sprd_efuse *efuse)
{
        int ret;

        mutex_lock(&efuse->mutex);

        ret = hwspin_lock_timeout_raw(efuse->hwlock,
                                      SPRD_EFUSE_HWLOCK_TIMEOUT);
        if (ret) {
                dev_err(efuse->dev, "timeout get the hwspinlock\n");
                mutex_unlock(&efuse->mutex);
                return ret;
        }

        return 0;
}

static void sprd_efuse_unlock(struct sprd_efuse *efuse)
{
        hwspin_unlock_raw(efuse->hwlock);
        mutex_unlock(&efuse->mutex);
}

static void sprd_efuse_set_prog_power(struct sprd_efuse *efuse, bool en)
{
        u32 val = readl(efuse->base + SPRD_EFUSE_PW_SWT);

        if (en)
                val &= ~SPRD_EFUSE_ENK2_ON;
        else
                val &= ~SPRD_EFUSE_ENK1_ON;

        writel(val, efuse->base + SPRD_EFUSE_PW_SWT);

        /* Open or close efuse power need wait 1000us to make power stable. */
        usleep_range(1000, 1200);

        if (en)
                val |= SPRD_EFUSE_ENK1_ON;
        else
                val |= SPRD_EFUSE_ENK2_ON;

        writel(val, efuse->base + SPRD_EFUSE_PW_SWT);

        /* Open or close efuse power need wait 1000us to make power stable. */
        usleep_range(1000, 1200);
}

static void sprd_efuse_set_read_power(struct sprd_efuse *efuse, bool en)
{
        u32 val = readl(efuse->base + SPRD_EFUSE_ENABLE);

        if (en)
                val |= SPRD_EFUSE_VDD_EN;
        else
                val &= ~SPRD_EFUSE_VDD_EN;

        writel(val, efuse->base + SPRD_EFUSE_ENABLE);

        /* Open or close efuse power need wait 1000us to make power stable. */
        usleep_range(1000, 1200);
}

static void sprd_efuse_set_prog_lock(struct sprd_efuse *efuse, bool en)
{
        u32 val = readl(efuse->base + SPRD_EFUSE_ENABLE);

        if (en)
                val |= SPRD_EFUSE_LOCK_WR_EN;
        else
                val &= ~SPRD_EFUSE_LOCK_WR_EN;

        writel(val, efuse->base + SPRD_EFUSE_ENABLE);
}

static void sprd_efuse_set_auto_check(struct sprd_efuse *efuse, bool en)
{
        u32 val = readl(efuse->base + SPRD_EFUSE_ENABLE);

        if (en)
                val |= SPRD_EFUSE_AUTO_CHECK_EN;
        else
                val &= ~SPRD_EFUSE_AUTO_CHECK_EN;

        writel(val, efuse->base + SPRD_EFUSE_ENABLE);
}

static void sprd_efuse_set_data_double(struct sprd_efuse *efuse, bool en)
{
        u32 val = readl(efuse->base + SPRD_EFUSE_ENABLE);

        if (en)
                val |= SPRD_EFUSE_DOUBLE_EN;
        else
                val &= ~SPRD_EFUSE_DOUBLE_EN;

        writel(val, efuse->base + SPRD_EFUSE_ENABLE);
}

static void sprd_efuse_set_prog_en(struct sprd_efuse *efuse, bool en)
{
        u32 val = readl(efuse->base + SPRD_EFUSE_PW_SWT);

        if (en)
                val |= SPRD_EFUSE_PROG_EN;
        else
                val &= ~SPRD_EFUSE_PROG_EN;

        writel(val, efuse->base + SPRD_EFUSE_PW_SWT);
}

static int sprd_efuse_raw_prog(struct sprd_efuse *efuse, u32 blk, bool doub,
                               bool lock, u32 *data)
{
        u32 status;
        int ret = 0;

        /*
         * We need set the correct magic number before writing the efuse to
         * allow programming, and block other programming until we clear the
         * magic number.
         */
        writel(SPRD_EFUSE_MAGIC_NUMBER,
               efuse->base + SPRD_EFUSE_MAGIC_NUM);

        /*
         * Power on the efuse, enable programme and enable double data
         * if asked.
         */
        sprd_efuse_set_prog_power(efuse, true);
        sprd_efuse_set_prog_en(efuse, true);
        sprd_efuse_set_data_double(efuse, doub);

        /*
         * Enable the auto-check function to validate if the programming is
         * successful.
         */
        if (lock)
                sprd_efuse_set_auto_check(efuse, true);

        writel(*data, efuse->base + SPRD_EFUSE_MEM(blk));

        /* Disable auto-check and data double after programming */
        if (lock)
                sprd_efuse_set_auto_check(efuse, false);
        sprd_efuse_set_data_double(efuse, false);

        /*
         * Check the efuse error status, if the programming is successful,
         * we should lock this efuse block to avoid programming again.
         */
        status = readl(efuse->base + SPRD_EFUSE_ERR_FLAG);
        if (status) {
                dev_err(efuse->dev,
                        "write error status %u of block %d\n", status, blk);

                writel(SPRD_EFUSE_ERR_CLR_MASK,
                       efuse->base + SPRD_EFUSE_ERR_CLR);
                ret = -EBUSY;
        } else if (lock) {
                sprd_efuse_set_prog_lock(efuse, lock);
                writel(0, efuse->base + SPRD_EFUSE_MEM(blk));
                sprd_efuse_set_prog_lock(efuse, false);
        }

        sprd_efuse_set_prog_power(efuse, false);
        writel(0, efuse->base + SPRD_EFUSE_MAGIC_NUM);

        return ret;
}

static int sprd_efuse_raw_read(struct sprd_efuse *efuse, int blk, u32 *val,
                               bool doub)
{
        u32 status;

        /*
         * Need power on the efuse before reading data from efuse, and will
         * power off the efuse after reading process.
         */
        sprd_efuse_set_read_power(efuse, true);

        /* Enable double data if asked */
        sprd_efuse_set_data_double(efuse, doub);

        /* Start to read data from efuse block */
        *val = readl(efuse->base + SPRD_EFUSE_MEM(blk));

        /* Disable double data */
        sprd_efuse_set_data_double(efuse, false);

        /* Power off the efuse */
        sprd_efuse_set_read_power(efuse, false);

        /*
         * Check the efuse error status and clear them if there are some
         * errors occurred.
         */
        status = readl(efuse->base + SPRD_EFUSE_ERR_FLAG);
        if (status) {
                dev_err(efuse->dev,
                        "read error status %d of block %d\n", status, blk);

                writel(SPRD_EFUSE_ERR_CLR_MASK,
                       efuse->base + SPRD_EFUSE_ERR_CLR);
                return -EBUSY;
        }

        return 0;
}

static int sprd_efuse_read(void *context, u32 offset, void *val, size_t bytes)
{
        struct sprd_efuse *efuse = context;
        bool blk_double = efuse->data->blk_double;
        u32 index = offset / SPRD_EFUSE_BLOCK_WIDTH + efuse->data->blk_offset;
        u32 blk_offset = (offset % SPRD_EFUSE_BLOCK_WIDTH) * BITS_PER_BYTE;
        u32 data;
        int ret;

        ret = sprd_efuse_lock(efuse);
        if (ret)
                return ret;

        ret = clk_prepare_enable(efuse->clk);
        if (ret)
                goto unlock;

        ret = sprd_efuse_raw_read(efuse, index, &data, blk_double);
        if (!ret) {
                data >>= blk_offset;
                memcpy(val, &data, bytes);
        }

        clk_disable_unprepare(efuse->clk);

unlock:
        sprd_efuse_unlock(efuse);
        return ret;
}

static int sprd_efuse_write(void *context, u32 offset, void *val, size_t bytes)
{
        struct sprd_efuse *efuse = context;
        bool blk_double = efuse->data->blk_double;
        bool lock;
        int ret;

        ret = sprd_efuse_lock(efuse);
        if (ret)
                return ret;

        ret = clk_prepare_enable(efuse->clk);
        if (ret)
                goto unlock;

        /*
         * If the writing bytes are equal with the block width, which means the
         * whole block will be programmed. For this case, we should not allow
         * this block to be programmed again by locking this block.
         *
         * If the block was programmed partially, we should allow this block to
         * be programmed again.
         */
        if (bytes < SPRD_EFUSE_BLOCK_WIDTH)
                lock = false;
        else
                lock = true;

        ret = sprd_efuse_raw_prog(efuse, offset, blk_double, lock, val);

        clk_disable_unprepare(efuse->clk);

unlock:
        sprd_efuse_unlock(efuse);
        return ret;
}

static int sprd_efuse_probe(struct platform_device *pdev)
{
        struct device_node *np = pdev->dev.of_node;
        struct nvmem_device *nvmem;
        struct nvmem_config econfig = { };
        struct sprd_efuse *efuse;
        const struct sprd_efuse_variant_data *pdata;
        int ret;

        pdata = of_device_get_match_data(&pdev->dev);
        if (!pdata) {
                dev_err(&pdev->dev, "No matching driver data found\n");
                return -EINVAL;
        }

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

        efuse->base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(efuse->base))
                return PTR_ERR(efuse->base);

        ret = of_hwspin_lock_get_id(np, 0);
        if (ret < 0) {
                dev_err(&pdev->dev, "failed to get hwlock id\n");
                return ret;
        }

        efuse->hwlock = devm_hwspin_lock_request_specific(&pdev->dev, ret);
        if (!efuse->hwlock) {
                dev_err(&pdev->dev, "failed to request hwlock\n");
                return -ENXIO;
        }

        efuse->clk = devm_clk_get(&pdev->dev, "enable");
        if (IS_ERR(efuse->clk)) {
                dev_err(&pdev->dev, "failed to get enable clock\n");
                return PTR_ERR(efuse->clk);
        }

        mutex_init(&efuse->mutex);
        efuse->dev = &pdev->dev;
        efuse->data = pdata;

        econfig.stride = 1;
        econfig.word_size = 1;
        econfig.read_only = false;
        econfig.name = "sprd-efuse";
        econfig.size = efuse->data->blk_nums * SPRD_EFUSE_BLOCK_WIDTH;
        econfig.add_legacy_fixed_of_cells = true;
        econfig.reg_read = sprd_efuse_read;
        econfig.reg_write = sprd_efuse_write;
        econfig.priv = efuse;
        econfig.dev = &pdev->dev;
        nvmem = devm_nvmem_register(&pdev->dev, &econfig);
        if (IS_ERR(nvmem)) {
                dev_err(&pdev->dev, "failed to register nvmem\n");
                return PTR_ERR(nvmem);
        }

        return 0;
}

static const struct of_device_id sprd_efuse_of_match[] = {
        { .compatible = "sprd,ums312-efuse", .data = &ums312_data },
        { }
};
MODULE_DEVICE_TABLE(of, sprd_efuse_of_match);

static struct platform_driver sprd_efuse_driver = {
        .probe = sprd_efuse_probe,
        .driver = {
                .name = "sprd-efuse",
                .of_match_table = sprd_efuse_of_match,
        },
};

module_platform_driver(sprd_efuse_driver);

MODULE_AUTHOR("Freeman Liu <freeman.liu@spreadtrum.com>");
MODULE_DESCRIPTION("Spreadtrum AP efuse driver");
MODULE_LICENSE("GPL v2");