/**
 * Copyright (c) 2016 - 2018, Nordic Semiconductor ASA
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form, except as embedded into a Nordic
 *    Semiconductor ASA integrated circuit in a product or a software update for
 *    such product, must reproduce the above copyright notice, this list of
 *    conditions and the following disclaimer in the documentation and/or other
 *    materials provided with the distribution.
 *
 * 3. Neither the name of Nordic Semiconductor ASA nor the names of its
 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
 * 4. This software, with or without modification, must only be used with a
 *    Nordic Semiconductor ASA integrated circuit.
 *
 * 5. Any software provided in binary form under this license must not be reverse
 *    engineered, decompiled, modified and/or disassembled.
 *
 * THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include "nrf_dfu_settings.h"
#include <stddef.h>
#include <string.h>
#include "nrf_dfu_flash.h"
#include "nrf_soc.h"
#include "crc32.h"
#include "nrf_nvmc.h"
#include "sdk_config.h"

#define DFU_SETTINGS_INIT_COMMAND_OFFSET        offsetof(nrf_dfu_settings_t, init_command)          //<! Offset in the settings struct where the InitCommand is located.

#define NRF_LOG_MODULE_NAME nrf_dfu_settings
#include "nrf_log.h"
NRF_LOG_MODULE_REGISTER();


/**@brief   This variable reserves a page in flash for bootloader settings
 *          to ensure the linker doesn't place any code or variables at this location.
 */
#if defined (__CC_ARM )

    uint8_t m_dfu_settings_buffer[BOOTLOADER_SETTINGS_PAGE_SIZE]
        __attribute__((at(BOOTLOADER_SETTINGS_ADDRESS)))
        __attribute__((used));

#elif defined ( __GNUC__ ) || defined ( __SES_ARM )

    uint8_t m_dfu_settings_buffer[BOOTLOADER_SETTINGS_PAGE_SIZE]
        __attribute__((section(".bootloader_settings_page")))
        __attribute__((used));

#elif defined ( __ICCARM__ )

    __no_init __root uint8_t m_dfu_settings_buffer[BOOTLOADER_SETTINGS_PAGE_SIZE]
        @ BOOTLOADER_SETTINGS_ADDRESS;

#else

    #error Not a valid compiler/linker for m_dfu_settings placement.

#endif // Compiler specific

#ifndef BL_SETTINGS_ACCESS_ONLY
#if defined(NRF52_SERIES)

/**@brief   This variable reserves a page in flash for MBR parameters
 *          to ensure the linker doesn't place any code or variables at this location.
 */
#if defined ( __CC_ARM )

    uint8_t m_mbr_params_page[NRF_MBR_PARAMS_PAGE_SIZE]
        __attribute__((at(NRF_MBR_PARAMS_PAGE_ADDRESS)))
        __attribute__((used));

#elif defined ( __GNUC__ ) || defined ( __SES_ARM )

    uint8_t m_mbr_params_page[NRF_MBR_PARAMS_PAGE_SIZE]
        __attribute__((section(".mbr_params_page")))
        __attribute__((used));

#elif defined ( __ICCARM__ )

    __no_init uint8_t m_mbr_params_page[NRF_MBR_PARAMS_PAGE_SIZE]
        @ NRF_MBR_PARAMS_PAGE_ADDRESS;

#else

    #error Not a valid compiler/linker for m_mbr_params_page placement.

#endif // Compiler specific

uint8_t * mp_dfu_settings_backup_buffer = &m_mbr_params_page[0];


/**@brief   This variable has the linker write the MBR parameters page address to the
 *          UICR register. This value will be written in the HEX file and thus to the
 *          UICR when the bootloader is flashed into the chip.
 */
#if defined ( __CC_ARM )

    uint32_t const m_uicr_mbr_params_page_address
        __attribute__((at(NRF_UICR_MBR_PARAMS_PAGE_ADDRESS))) = NRF_MBR_PARAMS_PAGE_ADDRESS;

#elif defined ( __GNUC__ ) || defined ( __SES_ARM )

    uint32_t const m_uicr_mbr_params_page_address
        __attribute__ ((section(".uicr_mbr_params_page")))
        __attribute__ ((used)) = NRF_MBR_PARAMS_PAGE_ADDRESS;

#elif defined ( __ICCARM__ )

    __root uint32_t const m_uicr_mbr_params_page_address
        @ NRF_UICR_MBR_PARAMS_PAGE_ADDRESS = NRF_MBR_PARAMS_PAGE_ADDRESS;

#else

    #error Not a valid compiler/linker for m_mbr_params_page placement.

#endif // Compiler specific
#endif // #if defined( NRF52_SERIES )
#endif // #ifndef BL_SETTINGS_ACCESS_ONLY


#ifndef NRF_DFU_SETTINGS_IN_APP
#define NRF_DFU_SETTINGS_IN_APP 0
#endif

nrf_dfu_settings_t s_dfu_settings;

static uint32_t settings_crc_get(nrf_dfu_settings_t const * p_settings)
{
    ASSERT(offsetof(nrf_dfu_settings_t, crc) == 0);
    // The crc is calculated from the s_dfu_settings struct, except the crc itself and the init command
    return crc32_compute((uint8_t*)(p_settings) + 4, DFU_SETTINGS_INIT_COMMAND_OFFSET  - 4, NULL);
}


static bool crc_ok(nrf_dfu_settings_t const * p_settings)
{
    if (p_settings->crc != 0xFFFFFFFF)
    {
        // CRC is set. Content must be valid
        uint32_t crc = settings_crc_get(p_settings);
        if (crc == p_settings->crc)
        {
            return true;
        }
    }
    return false;
}


static bool settings_crc_ok(void)
{
    nrf_dfu_settings_t const * p_settings = (nrf_dfu_settings_t const *)m_dfu_settings_buffer;
    return crc_ok(p_settings);
}


static bool settings_backup_crc_ok(void)
{
    nrf_dfu_settings_t const * p_settings = (nrf_dfu_settings_t const *)mp_dfu_settings_backup_buffer;
    return crc_ok(p_settings);
}


static bool settings_region_compare_to_backup(uint32_t  start_offset,
                                              uint32_t  end_offset,
                                              uint8_t * p_compare_addr)
{
    ASSERT(end_offset >= start_offset);
    return (0 == memcmp((uint8_t const *)(mp_dfu_settings_backup_buffer + start_offset),
                        (uint8_t const *)(p_compare_addr + start_offset),
                         end_offset - start_offset));
}

static bool settings_forbidden_parts_equal_to_backup(uint8_t * p_compare_addr)
{
    ASSERT(offsetof(nrf_dfu_settings_t, crc) == 0);

#if NRF_DFU_SETTINGS_ALLOW_UPDATE_FROM_APP
    return (settings_region_compare_to_backup(4, offsetof(nrf_dfu_settings_t, bank_1), p_compare_addr));
#else
    bool forbidden_region_1_equal = settings_region_compare_to_backup(
            4,
            offsetof(nrf_dfu_settings_t, enter_buttonless_dfu),
            p_compare_addr);

    bool forbidden_region_2_equal = settings_region_compare_to_backup(
            offsetof(nrf_dfu_settings_t, enter_buttonless_dfu) + 4,
            offsetof(nrf_dfu_settings_t, init_command) + INIT_COMMAND_MAX_SIZE,
            p_compare_addr);

    return (forbidden_region_1_equal && forbidden_region_2_equal);
#endif
}


ret_code_t nrf_dfu_settings_init(bool sd_irq_initialized)
{
    NRF_LOG_DEBUG("Calling nrf_dfu_settings_init()...");

    ret_code_t err_code = nrf_dfu_flash_init(sd_irq_initialized);
    if (err_code != NRF_SUCCESS)
    {
        NRF_LOG_ERROR("nrf_dfu_flash_init() failed with error: %x", err_code);
        return NRF_ERROR_INTERNAL;
    }

    bool settings_valid        = settings_crc_ok();
    bool settings_backup_valid = settings_backup_crc_ok();

    if (settings_valid &&
        settings_backup_valid &&
        !settings_forbidden_parts_equal_to_backup(m_dfu_settings_buffer))
    {
        NRF_LOG_WARNING("Restoring settings from backup since the app has tampered with the "
                        "off-limit parts of the settings page.");
        memcpy(&s_dfu_settings,
               mp_dfu_settings_backup_buffer,
               sizeof(nrf_dfu_settings_t));
    }
    else if (!settings_valid)
    {
        if (settings_backup_valid)
        {
            NRF_LOG_INFO("Restoring settings from backup since the settings page contents are "
                         "invalid (CRC error).");
            memcpy(&s_dfu_settings,
                   mp_dfu_settings_backup_buffer,
                   sizeof(nrf_dfu_settings_t));
        }
        else
        {
            NRF_LOG_WARNING("Resetting bootloader settings since neither the settings page nor the "
                            "backup are valid (CRC error).");
            memset(&s_dfu_settings, 0x00, sizeof(nrf_dfu_settings_t));
            s_dfu_settings.settings_version = NRF_DFU_SETTINGS_VERSION;
        }
    }
    else
    {
        NRF_LOG_DEBUG("Settings OK");
        memcpy(&s_dfu_settings, m_dfu_settings_buffer, sizeof(nrf_dfu_settings_t));
        return NRF_SUCCESS;
    }

    err_code = nrf_dfu_settings_write(NULL);

    if (err_code != NRF_SUCCESS)
    {
        NRF_LOG_ERROR("settings_write() failed with error: %x", err_code);
        return NRF_ERROR_INTERNAL;
    }

    return NRF_SUCCESS;
}


static ret_code_t settings_write(void                   * p_dst,
                                 void const             * p_src,
                                 nrf_dfu_flash_callback_t callback,
                                 nrf_dfu_settings_t     * p_dfu_settings_buffer)
{
    ret_code_t err_code;

    if (memcmp(p_dst, p_src, sizeof(nrf_dfu_settings_t)) == 0)
    {
        NRF_LOG_DEBUG("Destination settings are identical to source, write not needed. Skipping.");
        if (callback != NULL)
        {
            callback(NULL);
        }
        return NRF_SUCCESS;
    }

    if (NRF_DFU_SETTINGS_IN_APP && !settings_forbidden_parts_equal_to_backup((uint8_t *)&s_dfu_settings))
    {
        NRF_LOG_WARNING("Settings write aborted since it tries writing to forbidden settings.");
        // Assuming NRF_DFU_SETTINGS_ALLOW_UPDATE_FROM_APP is configured the same as in bootloader.
        return NRF_ERROR_FORBIDDEN;
    }

    NRF_LOG_DEBUG("Writing settings...");
    NRF_LOG_DEBUG("Erasing old settings at: 0x%08x", p_dst);

    // Not setting the callback function because ERASE is required before STORE
    // Only report completion on successful STORE.
    err_code = nrf_dfu_flash_erase((uint32_t)p_dst, 1, NULL);

    if (err_code != NRF_SUCCESS)
    {
        NRF_LOG_ERROR("Could not erase the settings page!");
        return NRF_ERROR_INTERNAL;
    }

    ASSERT(p_dfu_settings_buffer != NULL);
    memcpy(p_dfu_settings_buffer, p_src, sizeof(nrf_dfu_settings_t));

    err_code = nrf_dfu_flash_store((uint32_t)p_dst,
                                   p_dfu_settings_buffer,
                                   sizeof(nrf_dfu_settings_t),
                                   callback);

    if (err_code != NRF_SUCCESS)
    {
        NRF_LOG_ERROR("Could not write the DFU settings page!");
        return NRF_ERROR_INTERNAL;
    }

    return NRF_SUCCESS;
}


ret_code_t nrf_dfu_settings_write(nrf_dfu_flash_callback_t callback)
{
    static nrf_dfu_settings_t dfu_settings_buffer;
    s_dfu_settings.crc = settings_crc_get(&s_dfu_settings);
    return settings_write(m_dfu_settings_buffer,
                          &s_dfu_settings,
                          callback,
                          &dfu_settings_buffer);
}


void settings_backup(nrf_dfu_flash_callback_t callback, void * p_src)
{
#if NRF_DFU_SETTINGS_IN_APP
    NRF_LOG_INFO("Settings backup not available from app.");
#else
    static nrf_dfu_settings_t dfu_settings_buffer;
    NRF_LOG_INFO("Backing up settings page to address 0x%x.", mp_dfu_settings_backup_buffer);
    ASSERT(settings_crc_ok());
    ret_code_t err_code = settings_write(mp_dfu_settings_backup_buffer,
                                         p_src,
                                         callback,
                                         &dfu_settings_buffer);

    if (err_code != NRF_SUCCESS)
    {
        NRF_LOG_ERROR("Could not perform backup of bootloader settings! Error: 0x%x", err_code);
    }
#endif
}


void nrf_dfu_settings_backup(nrf_dfu_flash_callback_t callback)
{
    settings_backup(callback, m_dfu_settings_buffer);
}


ret_code_t nrf_dfu_settings_write_and_backup(nrf_dfu_flash_callback_t callback)
{
#if NRF_DFU_SETTINGS_IN_APP
    ret_code_t err_code = nrf_dfu_settings_write(callback);
#else
    ret_code_t err_code = nrf_dfu_settings_write(NULL);
    if (err_code == NRF_SUCCESS)
    {
        settings_backup(callback, &s_dfu_settings);
    }
#endif
    return err_code;
}


__WEAK ret_code_t nrf_dfu_settings_additional_erase(void)
{
    NRF_LOG_WARNING("No additional data erased");
    return NRF_SUCCESS;
}