// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
 */

#include <linux/clk.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/nvmem-provider.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/regulator/consumer.h>

/* Blow timer clock frequency in Mhz */
#define QFPROM_BLOW_TIMER_OFFSET 0x03c

/* Amount of time required to hold charge to blow fuse in micro-seconds */
#define QFPROM_FUSE_BLOW_POLL_US        100
#define QFPROM_FUSE_BLOW_TIMEOUT_US     1000

#define QFPROM_BLOW_STATUS_OFFSET       0x048
#define QFPROM_BLOW_STATUS_BUSY         0x1
#define QFPROM_BLOW_STATUS_READY        0x0

#define QFPROM_ACCEL_OFFSET             0x044

#define QFPROM_VERSION_OFFSET           0x0
#define QFPROM_MAJOR_VERSION_SHIFT      28
#define QFPROM_MAJOR_VERSION_MASK       GENMASK(31, QFPROM_MAJOR_VERSION_SHIFT)
#define QFPROM_MINOR_VERSION_SHIFT      16
#define QFPROM_MINOR_VERSION_MASK       GENMASK(27, QFPROM_MINOR_VERSION_SHIFT)

static bool read_raw_data;
module_param(read_raw_data, bool, 0644);
MODULE_PARM_DESC(read_raw_data, "Read raw instead of corrected data");

/**
 * struct qfprom_soc_data - config that varies from SoC to SoC.
 *
 * @accel_value:             Should contain qfprom accel value.
 * @qfprom_blow_timer_value: The timer value of qfprom when doing efuse blow.
 * @qfprom_blow_set_freq:    The frequency required to set when we start the
 *                           fuse blowing.
 */
struct qfprom_soc_data {
        u32 accel_value;
        u32 qfprom_blow_timer_value;
        u32 qfprom_blow_set_freq;
};

/**
 * struct qfprom_priv - structure holding qfprom attributes
 *
 * @qfpraw:       iomapped memory space for qfprom-efuse raw address space.
 * @qfpconf:      iomapped memory space for qfprom-efuse configuration address
 *                space.
 * @qfpcorrected: iomapped memory space for qfprom corrected address space.
 * @qfpsecurity:  iomapped memory space for qfprom security control space.
 * @dev:          qfprom device structure.
 * @secclk:       Clock supply.
 * @vcc:          Regulator supply.
 * @soc_data:     Data that for things that varies from SoC to SoC.
 */
struct qfprom_priv {
        void __iomem *qfpraw;
        void __iomem *qfpconf;
        void __iomem *qfpcorrected;
        void __iomem *qfpsecurity;
        struct device *dev;
        struct clk *secclk;
        struct regulator *vcc;
        const struct qfprom_soc_data *soc_data;
};

/**
 * struct qfprom_touched_values - saved values to restore after blowing
 *
 * @clk_rate: The rate the clock was at before blowing.
 * @accel_val: The value of the accel reg before blowing.
 * @timer_val: The value of the timer before blowing.
 */
struct qfprom_touched_values {
        unsigned long clk_rate;
        u32 accel_val;
        u32 timer_val;
};

/**
 * struct qfprom_soc_compatible_data - Data matched against the SoC
 * compatible string.
 *
 * @keepout: Array of keepout regions for this SoC.
 * @nkeepout: Number of elements in the keepout array.
 */
struct qfprom_soc_compatible_data {
        const struct nvmem_keepout *keepout;
        unsigned int nkeepout;
};

static const struct nvmem_keepout sc7180_qfprom_keepout[] = {
        {.start = 0x128, .end = 0x148},
        {.start = 0x220, .end = 0x228}
};

static const struct qfprom_soc_compatible_data sc7180_qfprom = {
        .keepout = sc7180_qfprom_keepout,
        .nkeepout = ARRAY_SIZE(sc7180_qfprom_keepout)
};

/**
 * qfprom_disable_fuse_blowing() - Undo enabling of fuse blowing.
 * @priv: Our driver data.
 * @old:  The data that was stashed from before fuse blowing.
 *
 * Resets the value of the blow timer, accel register and the clock
 * and voltage settings.
 *
 * Prints messages if there are errors but doesn't return an error code
 * since there's not much we can do upon failure.
 */
static void qfprom_disable_fuse_blowing(const struct qfprom_priv *priv,
                                        const struct qfprom_touched_values *old)
{
        int ret;

        ret = regulator_disable(priv->vcc);
        if (ret)
                dev_warn(priv->dev, "Failed to disable regulator (ignoring)\n");

        ret = clk_set_rate(priv->secclk, old->clk_rate);
        if (ret)
                dev_warn(priv->dev,
                         "Failed to set clock rate for disable (ignoring)\n");

        clk_disable_unprepare(priv->secclk);

        writel(old->timer_val, priv->qfpconf + QFPROM_BLOW_TIMER_OFFSET);
        writel(old->accel_val, priv->qfpconf + QFPROM_ACCEL_OFFSET);
}

/**
 * qfprom_enable_fuse_blowing() - Enable fuse blowing.
 * @priv: Our driver data.
 * @old:  We'll stash stuff here to use when disabling.
 *
 * Sets the value of the blow timer, accel register and the clock
 * and voltage settings.
 *
 * Prints messages if there are errors so caller doesn't need to.
 *
 * Return: 0 or -err.
 */
static int qfprom_enable_fuse_blowing(const struct qfprom_priv *priv,
                                      struct qfprom_touched_values *old)
{
        int ret;

        ret = clk_prepare_enable(priv->secclk);
        if (ret) {
                dev_err(priv->dev, "Failed to enable clock\n");
                return ret;
        }

        old->clk_rate = clk_get_rate(priv->secclk);
        ret = clk_set_rate(priv->secclk, priv->soc_data->qfprom_blow_set_freq);
        if (ret) {
                dev_err(priv->dev, "Failed to set clock rate for enable\n");
                goto err_clk_prepared;
        }

        ret = regulator_enable(priv->vcc);
        if (ret) {
                dev_err(priv->dev, "Failed to enable regulator\n");
                goto err_clk_rate_set;
        }

        old->timer_val = readl(priv->qfpconf + QFPROM_BLOW_TIMER_OFFSET);
        old->accel_val = readl(priv->qfpconf + QFPROM_ACCEL_OFFSET);
        writel(priv->soc_data->qfprom_blow_timer_value,
               priv->qfpconf + QFPROM_BLOW_TIMER_OFFSET);
        writel(priv->soc_data->accel_value,
               priv->qfpconf + QFPROM_ACCEL_OFFSET);

        return 0;

err_clk_rate_set:
        clk_set_rate(priv->secclk, old->clk_rate);
err_clk_prepared:
        clk_disable_unprepare(priv->secclk);
        return ret;
}

/**
 * qfprom_efuse_reg_write() - Write to fuses.
 * @context: Our driver data.
 * @reg:     The offset to write at.
 * @_val:    Pointer to data to write.
 * @bytes:   The number of bytes to write.
 *
 * Writes to fuses.  WARNING: THIS IS PERMANENT.
 *
 * Return: 0 or -err.
 */
static int qfprom_reg_write(void *context, unsigned int reg, void *_val,
                            size_t bytes)
{
        struct qfprom_priv *priv = context;
        struct qfprom_touched_values old;
        int words = bytes / 4;
        u32 *value = _val;
        u32 blow_status;
        int ret;
        int i;

        dev_dbg(priv->dev,
                "Writing to raw qfprom region : %#010x of size: %zu\n",
                reg, bytes);

        /*
         * The hardware only allows us to write word at a time, but we can
         * read byte at a time.  Until the nvmem framework allows a separate
         * word_size and stride for reading vs. writing, we'll enforce here.
         */
        if (bytes % 4) {
                dev_err(priv->dev,
                        "%zu is not an integral number of words\n", bytes);
                return -EINVAL;
        }
        if (reg % 4) {
                dev_err(priv->dev,
                        "Invalid offset: %#x.  Must be word aligned\n", reg);
                return -EINVAL;
        }

        ret = qfprom_enable_fuse_blowing(priv, &old);
        if (ret)
                return ret;

        ret = readl_relaxed_poll_timeout(
                priv->qfpconf + QFPROM_BLOW_STATUS_OFFSET,
                blow_status, blow_status == QFPROM_BLOW_STATUS_READY,
                QFPROM_FUSE_BLOW_POLL_US, QFPROM_FUSE_BLOW_TIMEOUT_US);

        if (ret) {
                dev_err(priv->dev,
                        "Timeout waiting for initial ready; aborting.\n");
                goto exit_enabled_fuse_blowing;
        }

        for (i = 0; i < words; i++)
                writel(value[i], priv->qfpraw + reg + (i * 4));

        ret = readl_relaxed_poll_timeout(
                priv->qfpconf + QFPROM_BLOW_STATUS_OFFSET,
                blow_status, blow_status == QFPROM_BLOW_STATUS_READY,
                QFPROM_FUSE_BLOW_POLL_US, QFPROM_FUSE_BLOW_TIMEOUT_US);

        /* Give an error, but not much we can do in this case */
        if (ret)
                dev_err(priv->dev, "Timeout waiting for finish.\n");

exit_enabled_fuse_blowing:
        qfprom_disable_fuse_blowing(priv, &old);

        return ret;
}

static int qfprom_reg_read(void *context,
                        unsigned int reg, void *_val, size_t bytes)
{
        struct qfprom_priv *priv = context;
        u8 *val = _val;
        int i = 0, words = bytes;
        void __iomem *base = priv->qfpcorrected;

        if (read_raw_data && priv->qfpraw)
                base = priv->qfpraw;

        while (words--)
                *val++ = readb(base + reg + i++);

        return 0;
}

static const struct qfprom_soc_data qfprom_7_8_data = {
        .accel_value = 0xD10,
        .qfprom_blow_timer_value = 25,
        .qfprom_blow_set_freq = 4800000,
};

static int qfprom_probe(struct platform_device *pdev)
{
        struct nvmem_config econfig = {
                .name = "qfprom",
                .stride = 1,
                .word_size = 1,
                .id = NVMEM_DEVID_AUTO,
                .reg_read = qfprom_reg_read,
        };
        struct device *dev = &pdev->dev;
        struct resource *res;
        struct nvmem_device *nvmem;
        const struct qfprom_soc_compatible_data *soc_data;
        struct qfprom_priv *priv;
        int ret;

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

        /* The corrected section is always provided */
        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        priv->qfpcorrected = devm_ioremap_resource(dev, res);
        if (IS_ERR(priv->qfpcorrected))
                return PTR_ERR(priv->qfpcorrected);

        econfig.size = resource_size(res);
        econfig.dev = dev;
        econfig.priv = priv;

        priv->dev = dev;
        soc_data = device_get_match_data(dev);
        if (soc_data) {
                econfig.keepout = soc_data->keepout;
                econfig.nkeepout = soc_data->nkeepout;
        }

        /*
         * If more than one region is provided then the OS has the ability
         * to write.
         */
        res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
        if (res) {
                u32 version;
                int major_version, minor_version;

                priv->qfpraw = devm_ioremap_resource(dev, res);
                if (IS_ERR(priv->qfpraw))
                        return PTR_ERR(priv->qfpraw);
                res = platform_get_resource(pdev, IORESOURCE_MEM, 2);
                priv->qfpconf = devm_ioremap_resource(dev, res);
                if (IS_ERR(priv->qfpconf))
                        return PTR_ERR(priv->qfpconf);
                res = platform_get_resource(pdev, IORESOURCE_MEM, 3);
                priv->qfpsecurity = devm_ioremap_resource(dev, res);
                if (IS_ERR(priv->qfpsecurity))
                        return PTR_ERR(priv->qfpsecurity);

                version = readl(priv->qfpsecurity + QFPROM_VERSION_OFFSET);
                major_version = (version & QFPROM_MAJOR_VERSION_MASK) >>
                                QFPROM_MAJOR_VERSION_SHIFT;
                minor_version = (version & QFPROM_MINOR_VERSION_MASK) >>
                                QFPROM_MINOR_VERSION_SHIFT;

                if (major_version == 7 && minor_version == 8)
                        priv->soc_data = &qfprom_7_8_data;

                priv->vcc = devm_regulator_get(&pdev->dev, "vcc");
                if (IS_ERR(priv->vcc))
                        return PTR_ERR(priv->vcc);

                priv->secclk = devm_clk_get(dev, "core");
                if (IS_ERR(priv->secclk)) {
                        ret = PTR_ERR(priv->secclk);
                        if (ret != -EPROBE_DEFER)
                                dev_err(dev, "Error getting clock: %d\n", ret);
                        return ret;
                }

                /* Only enable writing if we have SoC data. */
                if (priv->soc_data)
                        econfig.reg_write = qfprom_reg_write;
        }

        nvmem = devm_nvmem_register(dev, &econfig);

        return PTR_ERR_OR_ZERO(nvmem);
}

static const struct of_device_id qfprom_of_match[] = {
        { .compatible = "qcom,qfprom",},
        { .compatible = "qcom,sc7180-qfprom", .data = &sc7180_qfprom},
        {/* sentinel */},
};
MODULE_DEVICE_TABLE(of, qfprom_of_match);

static struct platform_driver qfprom_driver = {
        .probe = qfprom_probe,
        .driver = {
                .name = "qcom,qfprom",
                .of_match_table = qfprom_of_match,
        },
};
module_platform_driver(qfprom_driver);
MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org>");
MODULE_DESCRIPTION("Qualcomm QFPROM driver");
MODULE_LICENSE("GPL v2");