linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 * STM32 Factory-programmed memory read access driver

 *

 * Copyright (C) 2017, STMicroelectronics - All Rights Reserved

 * Author: Fabrice Gasnier <fabrice.gasnier@st.com> for STMicroelectronics.

 */

​

#include <linux/arm-smccc.h>

#include <linux/io.h>

#include <linux/module.h>

#include <linux/nvmem-provider.h>

#include <linux/of_device.h>

​

/* BSEC secure service access from non-secure */

#define STM32_SMC_BSEC          0x82001003

#define STM32_SMC_READ_SHADOW       0x01

#define STM32_SMC_PROG_OTP      0x02

#define STM32_SMC_WRITE_SHADOW      0x03

#define STM32_SMC_READ_OTP      0x04

​

/* shadow registers offest */

#define STM32MP15_BSEC_DATA0        0x200

​

/* 32 (x 32-bits) lower shadow registers */

#define STM32MP15_BSEC_NUM_LOWER    32

​

struct stm32_romem_cfg {

    int size;

};

​

struct stm32_romem_priv {

    void __iomem *base;

    struct nvmem_config cfg;

};

​

static int stm32_romem_read(void *context, unsigned int offset, void *buf,

                size_t bytes)

{

    struct stm32_romem_priv *priv = context;

    u8 *buf8 = buf;

    int i;

​

    for (i = offset; i < offset + bytes; i++)

        *buf8++ = readb_relaxed(priv->base + i);

​

    return 0;

}

​

static int stm32_bsec_smc(u8 op, u32 otp, u32 data, u32 *result)

{

#if IS_ENABLED(CONFIG_HAVE_ARM_SMCCC)

    struct arm_smccc_res res;

​

    arm_smccc_smc(STM32_SMC_BSEC, op, otp, data, 0, 0, 0, 0, &res);

    if (res.a0)

        return -EIO;

​

    if (result)

        *result = (u32)res.a1;

​

    return 0;

#else

    return -ENXIO;

#endif

}

​

static int stm32_bsec_read(void *context, unsigned int offset, void *buf,

               size_t bytes)

{

    struct stm32_romem_priv *priv = context;

    struct device *dev = priv->cfg.dev;

    u32 roffset, rbytes, val;

    u8 *buf8 = buf, *val8 = (u8 *)&val;

    int i, j = 0, ret, skip_bytes, size;

​

    /* Round unaligned access to 32-bits */

    roffset = rounddown(offset, 4);

    skip_bytes = offset & 0x3;

    rbytes = roundup(bytes + skip_bytes, 4);

​

    if (roffset + rbytes > priv->cfg.size)

        return -EINVAL;

​

    for (i = roffset; (i < roffset + rbytes); i += 4) {

        u32 otp = i >> 2;

​

        if (otp < STM32MP15_BSEC_NUM_LOWER) {

            /* read lower data from shadow registers */

            val = readl_relaxed(

                priv->base + STM32MP15_BSEC_DATA0 + i);

        } else {