root/drivers/nvmem/rockchip-efuse.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Rockchip eFuse Driver
 *
 * Copyright (c) 2015 Rockchip Electronics Co. Ltd.
 * Author: Caesar Wang <wxt@rock-chips.com>
 */

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

#define RK3288_A_SHIFT          6
#define RK3288_A_MASK           0x3ff
#define RK3288_PGENB            BIT(3)
#define RK3288_LOAD             BIT(2)
#define RK3288_STROBE           BIT(1)
#define RK3288_CSB              BIT(0)

#define RK3328_SECURE_SIZES     96
#define RK3328_INT_STATUS       0x0018
#define RK3328_DOUT             0x0020
#define RK3328_AUTO_CTRL        0x0024
#define RK3328_INT_FINISH       BIT(0)
#define RK3328_AUTO_ENB         BIT(0)
#define RK3328_AUTO_RD          BIT(1)

#define RK3399_A_SHIFT          16
#define RK3399_A_MASK           0x3ff
#define RK3399_NBYTES           4
#define RK3399_STROBSFTSEL      BIT(9)
#define RK3399_RSB              BIT(7)
#define RK3399_PD               BIT(5)
#define RK3399_PGENB            BIT(3)
#define RK3399_LOAD             BIT(2)
#define RK3399_STROBE           BIT(1)
#define RK3399_CSB              BIT(0)

#define REG_EFUSE_CTRL          0x0000
#define REG_EFUSE_DOUT          0x0004

struct rockchip_efuse_chip {
        struct device *dev;
        void __iomem *base;
        struct clk *clk;
};

static int rockchip_rk3288_efuse_read(void *context, unsigned int offset,
                                      void *val, size_t bytes)
{
        struct rockchip_efuse_chip *efuse = context;
        u8 *buf = val;
        int ret;

        ret = clk_prepare_enable(efuse->clk);
        if (ret < 0) {
                dev_err(efuse->dev, "failed to prepare/enable efuse clk\n");
                return ret;
        }

        writel(RK3288_LOAD | RK3288_PGENB, efuse->base + REG_EFUSE_CTRL);
        udelay(1);
        while (bytes--) {
                writel(readl(efuse->base + REG_EFUSE_CTRL) &
                             (~(RK3288_A_MASK << RK3288_A_SHIFT)),
                             efuse->base + REG_EFUSE_CTRL);
                writel(readl(efuse->base + REG_EFUSE_CTRL) |
                             ((offset++ & RK3288_A_MASK) << RK3288_A_SHIFT),
                             efuse->base + REG_EFUSE_CTRL);
                udelay(1);
                writel(readl(efuse->base + REG_EFUSE_CTRL) |
                             RK3288_STROBE, efuse->base + REG_EFUSE_CTRL);
                udelay(1);
                *buf++ = readb(efuse->base + REG_EFUSE_DOUT);
                writel(readl(efuse->base + REG_EFUSE_CTRL) &
                       (~RK3288_STROBE), efuse->base + REG_EFUSE_CTRL);
                udelay(1);
        }

        /* Switch to standby mode */
        writel(RK3288_PGENB | RK3288_CSB, efuse->base + REG_EFUSE_CTRL);

        clk_disable_unprepare(efuse->clk);

        return 0;
}

static int rockchip_rk3328_efuse_read(void *context, unsigned int offset,
                                      void *val, size_t bytes)
{
        struct rockchip_efuse_chip *efuse = context;
        unsigned int addr_start, addr_end, addr_offset, addr_len;
        u32 out_value, status;
        u8 *buf;
        int ret, i = 0;

        ret = clk_prepare_enable(efuse->clk);
        if (ret < 0) {
                dev_err(efuse->dev, "failed to prepare/enable efuse clk\n");
                return ret;
        }

        /* 128 Byte efuse, 96 Byte for secure, 32 Byte for non-secure */
        offset += RK3328_SECURE_SIZES;
        addr_start = rounddown(offset, RK3399_NBYTES) / RK3399_NBYTES;
        addr_end = roundup(offset + bytes, RK3399_NBYTES) / RK3399_NBYTES;
        addr_offset = offset % RK3399_NBYTES;
        addr_len = addr_end - addr_start;

        buf = kzalloc(array3_size(addr_len, RK3399_NBYTES, sizeof(*buf)),
                      GFP_KERNEL);
        if (!buf) {
                ret = -ENOMEM;
                goto nomem;
        }

        while (addr_len--) {
                writel(RK3328_AUTO_RD | RK3328_AUTO_ENB |
                       ((addr_start++ & RK3399_A_MASK) << RK3399_A_SHIFT),
                       efuse->base + RK3328_AUTO_CTRL);
                udelay(4);
                status = readl(efuse->base + RK3328_INT_STATUS);
                if (!(status & RK3328_INT_FINISH)) {
                        ret = -EIO;
                        goto err;
                }
                out_value = readl(efuse->base + RK3328_DOUT);
                writel(RK3328_INT_FINISH, efuse->base + RK3328_INT_STATUS);

                memcpy(&buf[i], &out_value, RK3399_NBYTES);
                i += RK3399_NBYTES;
        }

        memcpy(val, buf + addr_offset, bytes);
err:
        kfree(buf);
nomem:
        clk_disable_unprepare(efuse->clk);

        return ret;
}

static int rockchip_rk3399_efuse_read(void *context, unsigned int offset,
                                      void *val, size_t bytes)
{
        struct rockchip_efuse_chip *efuse = context;
        unsigned int addr_start, addr_end, addr_offset, addr_len;
        u32 out_value;
        u8 *buf;
        int ret, i = 0;

        ret = clk_prepare_enable(efuse->clk);
        if (ret < 0) {
                dev_err(efuse->dev, "failed to prepare/enable efuse clk\n");
                return ret;
        }

        addr_start = rounddown(offset, RK3399_NBYTES) / RK3399_NBYTES;
        addr_end = roundup(offset + bytes, RK3399_NBYTES) / RK3399_NBYTES;
        addr_offset = offset % RK3399_NBYTES;
        addr_len = addr_end - addr_start;

        buf = kzalloc(array3_size(addr_len, RK3399_NBYTES, sizeof(*buf)),
                      GFP_KERNEL);
        if (!buf) {
                clk_disable_unprepare(efuse->clk);
                return -ENOMEM;
        }

        writel(RK3399_LOAD | RK3399_PGENB | RK3399_STROBSFTSEL | RK3399_RSB,
               efuse->base + REG_EFUSE_CTRL);
        udelay(1);
        while (addr_len--) {
                writel(readl(efuse->base + REG_EFUSE_CTRL) | RK3399_STROBE |
                       ((addr_start++ & RK3399_A_MASK) << RK3399_A_SHIFT),
                       efuse->base + REG_EFUSE_CTRL);
                udelay(1);
                out_value = readl(efuse->base + REG_EFUSE_DOUT);
                writel(readl(efuse->base + REG_EFUSE_CTRL) & (~RK3399_STROBE),
                       efuse->base + REG_EFUSE_CTRL);
                udelay(1);

                memcpy(&buf[i], &out_value, RK3399_NBYTES);
                i += RK3399_NBYTES;
        }

        /* Switch to standby mode */
        writel(RK3399_PD | RK3399_CSB, efuse->base + REG_EFUSE_CTRL);

        memcpy(val, buf + addr_offset, bytes);

        kfree(buf);

        clk_disable_unprepare(efuse->clk);

        return 0;
}

static struct nvmem_config econfig = {
        .name = "rockchip-efuse",
        .add_legacy_fixed_of_cells = true,
        .type = NVMEM_TYPE_OTP,
        .stride = 1,
        .word_size = 1,
        .read_only = true,
};

static const struct of_device_id rockchip_efuse_match[] = {
        /* deprecated but kept around for dts binding compatibility */
        {
                .compatible = "rockchip,rockchip-efuse",
                .data = (void *)&rockchip_rk3288_efuse_read,
        },
        {
                .compatible = "rockchip,rk3066a-efuse",
                .data = (void *)&rockchip_rk3288_efuse_read,
        },
        {
                .compatible = "rockchip,rk3188-efuse",
                .data = (void *)&rockchip_rk3288_efuse_read,
        },
        {
                .compatible = "rockchip,rk3228-efuse",
                .data = (void *)&rockchip_rk3288_efuse_read,
        },
        {
                .compatible = "rockchip,rk3288-efuse",
                .data = (void *)&rockchip_rk3288_efuse_read,
        },
        {
                .compatible = "rockchip,rk3368-efuse",
                .data = (void *)&rockchip_rk3288_efuse_read,
        },
        {
                .compatible = "rockchip,rk3328-efuse",
                .data = (void *)&rockchip_rk3328_efuse_read,
        },
        {
                .compatible = "rockchip,rk3399-efuse",
                .data = (void *)&rockchip_rk3399_efuse_read,
        },
        { /* sentinel */},
};
MODULE_DEVICE_TABLE(of, rockchip_efuse_match);

static int rockchip_efuse_probe(struct platform_device *pdev)
{
        struct resource *res;
        struct nvmem_device *nvmem;
        struct rockchip_efuse_chip *efuse;
        const void *data;
        struct device *dev = &pdev->dev;

        data = of_device_get_match_data(dev);
        if (!data) {
                dev_err(dev, "failed to get match data\n");
                return -EINVAL;
        }

        efuse = devm_kzalloc(dev, sizeof(struct rockchip_efuse_chip),
                             GFP_KERNEL);
        if (!efuse)
                return -ENOMEM;

        efuse->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
        if (IS_ERR(efuse->base))
                return PTR_ERR(efuse->base);

        efuse->clk = devm_clk_get(dev, "pclk_efuse");
        if (IS_ERR(efuse->clk))
                return PTR_ERR(efuse->clk);

        efuse->dev = dev;
        if (of_property_read_u32(dev->of_node, "rockchip,efuse-size",
                                 &econfig.size))
                econfig.size = resource_size(res);
        econfig.reg_read = data;
        econfig.priv = efuse;
        econfig.dev = efuse->dev;
        nvmem = devm_nvmem_register(dev, &econfig);

        return PTR_ERR_OR_ZERO(nvmem);
}

static struct platform_driver rockchip_efuse_driver = {
        .probe = rockchip_efuse_probe,
        .driver = {
                .name = "rockchip-efuse",
                .of_match_table = rockchip_efuse_match,
        },
};

module_platform_driver(rockchip_efuse_driver);
MODULE_DESCRIPTION("rockchip_efuse driver");
MODULE_LICENSE("GPL v2");