root/drivers/nvmem/rockchip-otp.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Rockchip OTP Driver
 *
 * Copyright (c) 2018 Rockchip Electronics Co. Ltd.
 * Author: Finley Xiao <finley.xiao@rock-chips.com>
 */

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

/* OTP Register Offsets */
#define OTPC_SBPI_CTRL                  0x0020
#define OTPC_SBPI_CMD_VALID_PRE         0x0024
#define OTPC_SBPI_CS_VALID_PRE          0x0028
#define OTPC_SBPI_STATUS                0x002C
#define OTPC_USER_CTRL                  0x0100
#define OTPC_USER_ADDR                  0x0104
#define OTPC_USER_ENABLE                0x0108
#define OTPC_USER_Q                     0x0124
#define OTPC_INT_STATUS                 0x0304
#define OTPC_SBPI_CMD0_OFFSET           0x1000
#define OTPC_SBPI_CMD1_OFFSET           0x1004

/* OTP Register bits and masks */
#define OTPC_USER_ADDR_MASK             GENMASK(31, 16)
#define OTPC_USE_USER                   BIT(0)
#define OTPC_USE_USER_MASK              GENMASK(16, 16)
#define OTPC_USER_FSM_ENABLE            BIT(0)
#define OTPC_USER_FSM_ENABLE_MASK       GENMASK(16, 16)
#define OTPC_SBPI_DONE                  BIT(1)
#define OTPC_USER_DONE                  BIT(2)

#define SBPI_DAP_ADDR                   0x02
#define SBPI_DAP_ADDR_SHIFT             8
#define SBPI_DAP_ADDR_MASK              GENMASK(31, 24)
#define SBPI_CMD_VALID_MASK             GENMASK(31, 16)
#define SBPI_DAP_CMD_WRF                0xC0
#define SBPI_DAP_REG_ECC                0x3A
#define SBPI_ECC_ENABLE                 0x00
#define SBPI_ECC_DISABLE                0x09
#define SBPI_ENABLE                     BIT(0)
#define SBPI_ENABLE_MASK                GENMASK(16, 16)

#define OTPC_TIMEOUT                    10000

/* RK3588 Register */
#define RK3588_OTPC_AUTO_CTRL           0x04
#define RK3588_OTPC_AUTO_EN             0x08
#define RK3588_OTPC_INT_ST              0x84
#define RK3588_OTPC_DOUT0               0x20
#define RK3588_NBYTES                   4
#define RK3588_BURST_NUM                1
#define RK3588_BURST_SHIFT              8
#define RK3588_ADDR_SHIFT               16
#define RK3588_AUTO_EN                  BIT(0)
#define RK3588_RD_DONE                  BIT(1)

struct rockchip_data {
        int size;
        int read_offset;
        const char * const *clks;
        int num_clks;
        nvmem_reg_read_t reg_read;
};

struct rockchip_otp {
        struct device *dev;
        void __iomem *base;
        struct clk_bulk_data *clks;
        struct reset_control *rst;
        const struct rockchip_data *data;
};

static int rockchip_otp_reset(struct rockchip_otp *otp)
{
        int ret;

        ret = reset_control_assert(otp->rst);
        if (ret) {
                dev_err(otp->dev, "failed to assert otp phy %d\n", ret);
                return ret;
        }

        udelay(2);

        ret = reset_control_deassert(otp->rst);
        if (ret) {
                dev_err(otp->dev, "failed to deassert otp phy %d\n", ret);
                return ret;
        }

        return 0;
}

static int rockchip_otp_wait_status(struct rockchip_otp *otp,
                                    unsigned int reg, u32 flag)
{
        u32 status = 0;
        int ret;

        ret = readl_poll_timeout_atomic(otp->base + reg, status,
                                        (status & flag), 1, OTPC_TIMEOUT);
        if (ret)
                return ret;

        /* clean int status */
        writel(flag, otp->base + reg);

        return 0;
}

static int rockchip_otp_ecc_enable(struct rockchip_otp *otp, bool enable)
{
        int ret = 0;

        writel(SBPI_DAP_ADDR_MASK | (SBPI_DAP_ADDR << SBPI_DAP_ADDR_SHIFT),
               otp->base + OTPC_SBPI_CTRL);

        writel(SBPI_CMD_VALID_MASK | 0x1, otp->base + OTPC_SBPI_CMD_VALID_PRE);
        writel(SBPI_DAP_CMD_WRF | SBPI_DAP_REG_ECC,
               otp->base + OTPC_SBPI_CMD0_OFFSET);
        if (enable)
                writel(SBPI_ECC_ENABLE, otp->base + OTPC_SBPI_CMD1_OFFSET);
        else
                writel(SBPI_ECC_DISABLE, otp->base + OTPC_SBPI_CMD1_OFFSET);

        writel(SBPI_ENABLE_MASK | SBPI_ENABLE, otp->base + OTPC_SBPI_CTRL);

        ret = rockchip_otp_wait_status(otp, OTPC_INT_STATUS, OTPC_SBPI_DONE);
        if (ret < 0)
                dev_err(otp->dev, "timeout during ecc_enable\n");

        return ret;
}

static int px30_otp_read(void *context, unsigned int offset,
                         void *val, size_t bytes)
{
        struct rockchip_otp *otp = context;
        u8 *buf = val;
        int ret;

        ret = rockchip_otp_reset(otp);
        if (ret) {
                dev_err(otp->dev, "failed to reset otp phy\n");
                return ret;
        }

        ret = rockchip_otp_ecc_enable(otp, false);
        if (ret < 0) {
                dev_err(otp->dev, "rockchip_otp_ecc_enable err\n");
                return ret;
        }

        writel(OTPC_USE_USER | OTPC_USE_USER_MASK, otp->base + OTPC_USER_CTRL);
        udelay(5);
        while (bytes--) {
                writel(offset++ | OTPC_USER_ADDR_MASK,
                       otp->base + OTPC_USER_ADDR);
                writel(OTPC_USER_FSM_ENABLE | OTPC_USER_FSM_ENABLE_MASK,
                       otp->base + OTPC_USER_ENABLE);
                ret = rockchip_otp_wait_status(otp, OTPC_INT_STATUS, OTPC_USER_DONE);
                if (ret < 0) {
                        dev_err(otp->dev, "timeout during read setup\n");
                        goto read_end;
                }
                *buf++ = readb(otp->base + OTPC_USER_Q);
        }

read_end:
        writel(0x0 | OTPC_USE_USER_MASK, otp->base + OTPC_USER_CTRL);

        return ret;
}

static int rk3588_otp_read(void *context, unsigned int offset,
                           void *val, size_t bytes)
{
        struct rockchip_otp *otp = context;
        unsigned int addr_start, addr_end, addr_len;
        int ret, i = 0;
        u32 data;
        u8 *buf;

        addr_start = round_down(offset, RK3588_NBYTES) / RK3588_NBYTES;
        addr_end = round_up(offset + bytes, RK3588_NBYTES) / RK3588_NBYTES;
        addr_len = addr_end - addr_start;
        addr_start += otp->data->read_offset / RK3588_NBYTES;

        buf = kzalloc(array_size(addr_len, RK3588_NBYTES), GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        while (addr_len--) {
                writel((addr_start << RK3588_ADDR_SHIFT) |
                       (RK3588_BURST_NUM << RK3588_BURST_SHIFT),
                       otp->base + RK3588_OTPC_AUTO_CTRL);
                writel(RK3588_AUTO_EN, otp->base + RK3588_OTPC_AUTO_EN);

                ret = rockchip_otp_wait_status(otp, RK3588_OTPC_INT_ST,
                                               RK3588_RD_DONE);
                if (ret < 0) {
                        dev_err(otp->dev, "timeout during read setup\n");
                        goto read_end;
                }

                data = readl(otp->base + RK3588_OTPC_DOUT0);
                memcpy(&buf[i], &data, RK3588_NBYTES);

                i += RK3588_NBYTES;
                addr_start++;
        }

        memcpy(val, buf + offset % RK3588_NBYTES, bytes);

read_end:
        kfree(buf);

        return ret;
}

static int rockchip_otp_read(void *context, unsigned int offset,
                             void *val, size_t bytes)
{
        struct rockchip_otp *otp = context;
        int ret;

        if (!otp->data || !otp->data->reg_read)
                return -EINVAL;

        ret = clk_bulk_prepare_enable(otp->data->num_clks, otp->clks);
        if (ret < 0) {
                dev_err(otp->dev, "failed to prepare/enable clks\n");
                return ret;
        }

        ret = otp->data->reg_read(context, offset, val, bytes);

        clk_bulk_disable_unprepare(otp->data->num_clks, otp->clks);

        return ret;
}

static struct nvmem_config otp_config = {
        .name = "rockchip-otp",
        .owner = THIS_MODULE,
        .add_legacy_fixed_of_cells = true,
        .type = NVMEM_TYPE_OTP,
        .read_only = true,
        .stride = 1,
        .word_size = 1,
        .reg_read = rockchip_otp_read,
};

static const char * const px30_otp_clocks[] = {
        "otp", "apb_pclk", "phy",
};

static const struct rockchip_data px30_data = {
        .size = 0x40,
        .clks = px30_otp_clocks,
        .num_clks = ARRAY_SIZE(px30_otp_clocks),
        .reg_read = px30_otp_read,
};

static const struct rockchip_data rk3576_data = {
        .size = 0x100,
        .read_offset = 0x700,
        .clks = px30_otp_clocks,
        .num_clks = ARRAY_SIZE(px30_otp_clocks),
        .reg_read = rk3588_otp_read,
};

static const char * const rk3588_otp_clocks[] = {
        "otp", "apb_pclk", "phy", "arb",
};

static const struct rockchip_data rk3588_data = {
        .size = 0x400,
        .read_offset = 0xc00,
        .clks = rk3588_otp_clocks,
        .num_clks = ARRAY_SIZE(rk3588_otp_clocks),
        .reg_read = rk3588_otp_read,
};

static const struct of_device_id rockchip_otp_match[] = {
        {
                .compatible = "rockchip,px30-otp",
                .data = &px30_data,
        },
        {
                .compatible = "rockchip,rk3308-otp",
                .data = &px30_data,
        },
        {
                .compatible = "rockchip,rk3576-otp",
                .data = &rk3576_data,
        },
        {
                .compatible = "rockchip,rk3588-otp",
                .data = &rk3588_data,
        },
        { /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, rockchip_otp_match);

static int rockchip_otp_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct rockchip_otp *otp;
        const struct rockchip_data *data;
        struct nvmem_device *nvmem;
        int ret, i;

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

        otp = devm_kzalloc(&pdev->dev, sizeof(struct rockchip_otp),
                           GFP_KERNEL);
        if (!otp)
                return -ENOMEM;

        otp->data = data;
        otp->dev = dev;
        otp->base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(otp->base))
                return dev_err_probe(dev, PTR_ERR(otp->base),
                                     "failed to ioremap resource\n");

        otp->clks = devm_kcalloc(dev, data->num_clks, sizeof(*otp->clks),
                                 GFP_KERNEL);
        if (!otp->clks)
                return -ENOMEM;

        for (i = 0; i < data->num_clks; ++i)
                otp->clks[i].id = data->clks[i];

        ret = devm_clk_bulk_get(dev, data->num_clks, otp->clks);
        if (ret)
                return dev_err_probe(dev, ret, "failed to get clocks\n");

        otp->rst = devm_reset_control_array_get_exclusive(dev);
        if (IS_ERR(otp->rst))
                return dev_err_probe(dev, PTR_ERR(otp->rst),
                                     "failed to get resets\n");

        otp_config.size = data->size;
        otp_config.priv = otp;
        otp_config.dev = dev;

        nvmem = devm_nvmem_register(dev, &otp_config);
        if (IS_ERR(nvmem))
                return dev_err_probe(dev, PTR_ERR(nvmem),
                                     "failed to register nvmem device\n");
        return 0;
}

static struct platform_driver rockchip_otp_driver = {
        .probe = rockchip_otp_probe,
        .driver = {
                .name = "rockchip-otp",
                .of_match_table = rockchip_otp_match,
        },
};

module_platform_driver(rockchip_otp_driver);
MODULE_DESCRIPTION("Rockchip OTP driver");
MODULE_LICENSE("GPL v2");