efuse: Improve messages during burn operation

components/efuse/src/esp32/esp_efuse_utility.c

@@ -135,6 +135,7 @@ void esp_efuse_utility_clear_program_registers(void)
 // Burn values written to the efuse write registers
 esp_err_t esp_efuse_utility_burn_efuses(void)
 {
+    esp_err_t error = ESP_OK;
 #ifdef CONFIG_EFUSE_VIRTUAL
     ESP_LOGW(TAG, "Virtual efuses enabled: Not really burning eFuses");
     for (int num_block = EFUSE_BLK_MAX - 1; num_block >= EFUSE_BLK0; num_block--) {
@@ -151,8 +152,22 @@ esp_err_t esp_efuse_utility_burn_efuses(void)
         // It is necessary to process blocks in the order from MAX-> EFUSE_BLK0, because EFUSE_BLK0 has protection bits for other blocks.
         for (int num_block = EFUSE_BLK_MAX - 1; num_block >= EFUSE_BLK0; num_block--) {
             esp_efuse_coding_scheme_t scheme = esp_efuse_get_coding_scheme(num_block);
+            bool need_burn_block = false;
             for (uint32_t addr_wr_block = range_write_addr_blocks[num_block].start; addr_wr_block <= range_write_addr_blocks[num_block].end; addr_wr_block += 4) {
                 if (REG_READ(addr_wr_block) != 0) {
+                    need_burn_block = true;
+                    break;
+                }
+            }
+            if (!need_burn_block) {
+                continue;
+            }
+            if (error) {
+                // It is done for a use case: BLOCK2 (Flash encryption key) could have an error (incorrect written data)
+                // in this case we can not burn any data into BLOCK0 because it might set read/write protections of BLOCK2.
+                ESP_LOGE(TAG, "BLOCK%d can not be burned because a previous block got an error, skipped.", num_block);
+                continue;
+            }
             efuse_hal_clear_program_registers();
             unsigned w_data_len;
             unsigned r_data_len;
@@ -175,6 +190,9 @@ esp_err_t esp_efuse_utility_burn_efuses(void)
             int repeat_burn_op = 1;
             bool correct_written_data;
             bool coding_error_before = efuse_hal_is_coding_error_in_block(num_block);
+            if (coding_error_before) {
+                ESP_LOGW(TAG, "BLOCK%d already has a coding error", num_block);
+            }
             bool coding_error_occurred;
 
             do {
@@ -190,31 +208,29 @@ esp_err_t esp_efuse_utility_burn_efuses(void)
                 bool coding_error_after = efuse_hal_is_coding_error_in_block(num_block);
                 coding_error_occurred = (coding_error_before != coding_error_after) && coding_error_before == false;
                 if (coding_error_occurred) {
-                            ESP_LOGE(TAG, "BLOCK%d has an error", num_block);
+                    ESP_LOGW(TAG, "BLOCK%d got a coding error", num_block);
                 }
 
                 correct_written_data = esp_efuse_utility_is_correct_written_data(num_block, r_data_len);
                 if (!correct_written_data || coding_error_occurred) {
-                            ESP_LOGW(TAG, "BLOCK%d: next retry [%d/3]...", num_block, repeat_burn_op);
+                    ESP_LOGW(TAG, "BLOCK%d: next retry to fix an error [%d/3]...", num_block, repeat_burn_op);
                     memcpy((void *)start_write_addr[num_block], (void *)backup_write_data, w_data_len);
                 }
 
             } while ((!correct_written_data || coding_error_occurred) && repeat_burn_op++ < 3);
+
             if (coding_error_occurred) {
-                        ESP_LOGE(TAG, "Coding error occurred in block");
+                ESP_LOGW(TAG, "Coding error was not fixed");
             }
             if (!correct_written_data) {
                 ESP_LOGE(TAG, "Written data are incorrect");
-                        return ESP_FAIL;
+                error = ESP_FAIL;
-                    }
-                    break;
-                }
             }
         }
     }
 #endif // CONFIG_EFUSE_VIRTUAL
     esp_efuse_utility_reset();
-    return ESP_OK;
+    return error;
 }
 
 esp_err_t esp_efuse_utility_apply_34_encoding(const uint8_t *in_bytes, uint32_t *out_words, size_t in_bytes_len)

components/efuse/src/esp32s2/esp_efuse_utility.c

@@ -99,6 +99,7 @@ void esp_efuse_utility_clear_program_registers(void)
 // Burn values written to the efuse write registers
 esp_err_t esp_efuse_utility_burn_efuses(void)
 {
+    esp_err_t error = ESP_OK;
 #ifdef CONFIG_EFUSE_VIRTUAL
     ESP_LOGW(TAG, "Virtual efuses enabled: Not really burning eFuses");
     for (int num_block = EFUSE_BLK_MAX - 1; num_block >= EFUSE_BLK0; num_block--) {
@@ -114,8 +115,22 @@ esp_err_t esp_efuse_utility_burn_efuses(void)
         // Permanently update values written to the efuse write registers
         // It is necessary to process blocks in the order from MAX-> EFUSE_BLK0, because EFUSE_BLK0 has protection bits for other blocks.
         for (int num_block = EFUSE_BLK_MAX - 1; num_block >= EFUSE_BLK0; num_block--) {
+            bool need_burn_block = false;
             for (uint32_t addr_wr_block = range_write_addr_blocks[num_block].start; addr_wr_block <= range_write_addr_blocks[num_block].end; addr_wr_block += 4) {
                 if (REG_READ(addr_wr_block) != 0) {
+                    need_burn_block = true;
+                    break;
+                }
+            }
+            if (!need_burn_block) {
+                continue;
+            }
+            if (error) {
+                // It is done for a use case: BLOCK2 (Flash encryption key) could have an error (incorrect written data)
+                // in this case we can not burn any data into BLOCK0 because it might set read/write protections of BLOCK2.
+                ESP_LOGE(TAG, "BLOCK%d can not be burned because a previous block got an error, skipped.", num_block);
+                continue;
+            }
             ets_efuse_clear_program_registers();
             if (esp_efuse_get_coding_scheme(num_block) == EFUSE_CODING_SCHEME_RS) {
                 uint8_t block_rs[12];
@@ -131,6 +146,9 @@ esp_err_t esp_efuse_utility_burn_efuses(void)
             int repeat_burn_op = 1;
             bool correct_written_data;
             bool coding_error_before = efuse_hal_is_coding_error_in_block(num_block);
+            if (coding_error_before) {
+                ESP_LOGW(TAG, "BLOCK%d already has a coding error", num_block);
+            }
             bool coding_error_occurred;
 
             do {
@@ -147,31 +165,33 @@ esp_err_t esp_efuse_utility_burn_efuses(void)
                 }
                 coding_error_occurred = (coding_error_before != coding_error_after) && coding_error_before == false;
                 if (coding_error_occurred) {
-                            ESP_LOGE(TAG, "BLOCK%d has an error", num_block);
+                    ESP_LOGW(TAG, "BLOCK%d got a coding error", num_block);
                 }
 
                 correct_written_data = esp_efuse_utility_is_correct_written_data(num_block, r_data_len);
                 if (!correct_written_data || coding_error_occurred) {
-                            ESP_LOGW(TAG, "BLOCK%d: next retry [%d/3]...", num_block, repeat_burn_op);
+                    ESP_LOGW(TAG, "BLOCK%d: next retry to fix an error [%d/3]...", num_block, repeat_burn_op);
                     memcpy((void *)EFUSE_PGM_DATA0_REG, (void *)backup_write_data, sizeof(backup_write_data));
                 }
 
             } while ((!correct_written_data || coding_error_occurred) && repeat_burn_op++ < 3);
+
             if (coding_error_occurred) {
-                        ESP_LOGE(TAG, "Coding error occurred in block");
+                ESP_LOGW(TAG, "Coding error was not fixed");
+                if (num_block == 0) {
+                    ESP_LOGE(TAG, "BLOCK0 got a coding error, which might be critical for security");
+                    error = ESP_FAIL;
+                }
             }
             if (!correct_written_data) {
                 ESP_LOGE(TAG, "Written data are incorrect");
-                        return ESP_FAIL;
+                error = ESP_FAIL;
-                    }
-                    break;
-                }
             }
         }
     }
 #endif // CONFIG_EFUSE_VIRTUAL
     esp_efuse_utility_reset();
-    return ESP_OK;
+    return error;
 }
 
 // After esp_efuse_write.. functions EFUSE_BLKx_WDATAx_REG were filled is not coded values.

components/efuse/src/esp_efuse_utility.c

@@ -376,7 +376,7 @@ bool esp_efuse_utility_is_correct_written_data(esp_efuse_block_t block, unsigned
         }
     }
     if (!correct_written_data) {
-        ESP_LOGE(TAG, "BURN BLOCK%d - was not successful", block);
+        ESP_LOGE(TAG, "BURN BLOCK%d - ERROR (written bits != read bits)", block);
     }
     return correct_written_data;
 }