esp-idf/components/bootloader_support/src/flash_encrypt.c

// Copyright 2015-2019 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at

//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include <strings.h>
#include "esp_efuse.h"
#include "esp_efuse_table.h"
#include "esp_flash_encrypt.h"

void esp_flash_write_protect_crypt_cnt()
{
    uint8_t flash_crypt_cnt_wr_dis = 0;
    esp_efuse_read_field_blob(ESP_EFUSE_WR_DIS_FLASH_CRYPT_CNT, &flash_crypt_cnt_wr_dis, 1);
    if (!flash_crypt_cnt_wr_dis) {
        esp_efuse_write_field_cnt(ESP_EFUSE_WR_DIS_FLASH_CRYPT_CNT, 1);
    }
}

esp_flash_enc_mode_t esp_get_flash_encryption_mode()
{
    uint8_t efuse_flash_crypt_cnt_wr_protected = 0;
    uint8_t dis_dl_enc = 0, dis_dl_dec = 0, dis_dl_cache = 0;
    esp_flash_enc_mode_t mode = ESP_FLASH_ENC_MODE_DEVELOPMENT;

    if (esp_flash_encryption_enabled()) {
        /* Check if FLASH CRYPT CNT is write protected */
        esp_efuse_read_field_blob(ESP_EFUSE_WR_DIS_FLASH_CRYPT_CNT, &efuse_flash_crypt_cnt_wr_protected, 1);
        if (efuse_flash_crypt_cnt_wr_protected) {
            esp_efuse_read_field_blob(ESP_EFUSE_DISABLE_DL_CACHE, &dis_dl_cache, 1);
            esp_efuse_read_field_blob(ESP_EFUSE_DISABLE_DL_ENCRYPT, &dis_dl_enc, 1);
            esp_efuse_read_field_blob(ESP_EFUSE_DISABLE_DL_DECRYPT, &dis_dl_dec, 1);
            /* Check if DISABLE_DL_DECRYPT, DISABLE_DL_ENCRYPT & DISABLE_DL_CACHE are set */
            if ( dis_dl_cache && dis_dl_enc && dis_dl_dec ) {
                mode = ESP_FLASH_ENC_MODE_RELEASE;
            }
        }
    } else {
        mode = ESP_FLASH_ENC_MODE_DISABLED;
    }

    return mode;
}