1  // Copyright 2015-2020 Espressif Systems (Shanghai) PTE LTD
  2  //
  3  // Licensed under the Apache License, Version 2.0 (the "License");
  4  // you may not use this file except in compliance with the License.
  5  // You may obtain a copy of the License at
  6  
  7  //     http://www.apache.org/licenses/LICENSE-2.0
  8  //
  9  // Unless required by applicable law or agreed to in writing, software
 10  // distributed under the License is distributed on an "AS IS" BASIS,
 11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 12  // See the License for the specific language governing permissions and
 13  // limitations under the License.
 14  
 15  #include <string.h>
 16  #include "esp32s2/rom/hmac.h"
 17  #include "esp_hmac.h"
 18  #include "esp_crypto_lock.h"
 19  #include "esp_efuse.h"
 20  #include "esp_efuse_table.h"
 21  #include "soc/hwcrypto_reg.h"
 22  #include "soc/system_reg.h"
 23  #include "esp_log.h"
 24  
 25  static const char *TAG = "esp_hmac";
 26  
 27  static ets_efuse_block_t convert_key_type(hmac_key_id_t key_id) {
 28      return ETS_EFUSE_BLOCK_KEY0 + (ets_efuse_block_t) key_id;
 29  }
 30  
 31  esp_err_t esp_hmac_calculate(hmac_key_id_t key_id,
 32          const void *message,
 33          size_t message_len,
 34          uint8_t *hmac)
 35  {
 36      int hmac_ret;
 37      if (!message || !hmac) return ESP_ERR_INVALID_ARG;
 38      if (key_id >= HMAC_KEY_MAX) return ESP_ERR_INVALID_ARG;
 39  
 40      esp_crypto_dma_lock_acquire();
 41  
 42      ets_hmac_enable();
 43      hmac_ret = ets_hmac_calculate_message(convert_key_type(key_id), message, message_len, hmac);
 44      ets_hmac_disable();
 45  
 46      esp_crypto_dma_lock_release();
 47  
 48      if (hmac_ret != 0) {
 49          return ESP_FAIL;
 50      } else {
 51          return ESP_OK;
 52      }
 53  
 54  }
 55  
 56  esp_err_t esp_hmac_jtag_enable(hmac_key_id_t key_id, const uint8_t *token)
 57  {
 58      esp_err_t err;
 59  
 60      if ((!token) || (key_id >= HMAC_KEY_MAX))
 61          return ESP_ERR_INVALID_ARG;
 62  
 63      /* Check if JTAG is permanently disabled by HW Disable eFuse */
 64      if (esp_efuse_read_field_bit(ESP_EFUSE_HARD_DIS_JTAG)) {
 65          ESP_LOGE(TAG, "JTAG disabled permanently.");
 66          return ESP_FAIL;
 67      }
 68  
 69      esp_crypto_dma_lock_acquire();
 70  
 71      ets_hmac_enable();
 72  
 73      /* Token updating into HMAC module. */
 74      for (int i = 0; i < 32; i += 4) {
 75          uint32_t key_word;
 76          memcpy(&key_word, &token[i], 4);
 77          REG_WRITE(DPORT_JTAG_CTRL_0_REG + i, __builtin_bswap32(key_word));
 78      }
 79  
 80      err = ets_hmac_calculate_downstream(convert_key_type(key_id), ETS_EFUSE_KEY_PURPOSE_HMAC_DOWN_JTAG);
 81      if (err != ETS_OK) {
 82          ESP_LOGE(TAG, "HMAC downstream JTAG enable mode setting failed.");
 83          return ESP_FAIL;
 84      }
 85  
 86      ESP_LOGD(TAG, "HMAC computation in downstream mode is completed.");
 87  
 88      ets_hmac_disable();
 89  
 90      esp_crypto_dma_lock_release();
 91  
 92      return ESP_OK;
 93  }
 94  
 95  esp_err_t esp_hmac_jtag_disable()
 96  {
 97      esp_crypto_dma_lock_acquire();
 98  
 99      REG_WRITE(HMAC_SET_INVALIDATE_JTAG_REG, 1);
100  
101      esp_crypto_dma_lock_release();
102  
103      ESP_LOGD(TAG, "Invalidate JTAG result register. JTAG disabled.");
104  
105      return ESP_OK;
106  }