soc: esp32: virtual e-fuses support

Adds support for virtual e-fuses on esp32 socs

Signed-off-by: Marcio Ribeiro <[email protected]>

Author: wmrsouza

soc/espressif/common/Kconfig

@@ -62,6 +62,7 @@ endif
 
 rsource "Kconfig.amp"
 rsource "Kconfig.console"
+rsource "Kconfig.efuse"
 rsource "Kconfig.spiram"
 rsource "Kconfig.esptool"
 rsource "Kconfig.flash"

soc/espressif/common/Kconfig.efuse

@@ -0,0 +1,47 @@
+# Copyright (c) 2025 Espressif Systems (Shanghai) Co., Ltd.
+# SPDX-License-Identifier: Apache-2.0
+
+if SOC_FAMILY_ESPRESSIF_ESP32
+
+config ESP32_EFUSE_VIRTUAL
+	bool "Simulate eFuse operations in RAM"
+	help
+	  If "y" - The virtual mode is enabled and all eFuse operations (read and write) are redirected
+	  to RAM instead of eFuse registers, all permanent changes (via eFuse) are disabled.
+
+	  If it is "y", then SECURE_FLASH_ENCRYPTION_MODE_RELEASE cannot be used.
+	  Because the EFUSE VIRT mode is for testing only.
+
+	  During startup, the eFuses are copied into RAM. This mode is useful for fast tests.
+
+config ESP32_EFUSE_VIRTUAL_KEEP_IN_FLASH
+	bool "Keep eFuses in flash"
+	depends on ESP32_EFUSE_VIRTUAL
+	help
+	  In addition to the "Simulate eFuse operations in RAM" option, this option just adds
+	  a feature to keep eFuses after reboots in flash memory. To use this mode the partition_table
+	  should have the `sys_partition` partition.
+
+	  During startup, the eFuses are copied from flash or,
+	  in case if flash is empty, from real eFuse to RAM and then update flash.
+	  This mode is useful when need to keep changes after reboot
+	  (testing secure_boot and flash_encryption).
+
+config ESP32_EFUSE_VIRTUAL_OFFSET
+	hex
+	depends on ESP32_EFUSE_VIRTUAL_KEEP_IN_FLASH
+	default $(dt_nodelabel_reg_addr_hex,sys_partition) if $(dt_nodelabel_exists,sys_partition)
+	default 0x0
+
+config ESP32_EFUSE_VIRTUAL_SIZE
+	hex
+	depends on ESP32_EFUSE_VIRTUAL_KEEP_IN_FLASH
+	default 0x2000 if $(dt_nodelabel_exists,sys_partition)
+	default 0x0
+
+config ESP32_EFUSE_MAX_BLK_LEN
+	int
+	default 192 if SOC_SERIES_ESP32
+	default 256
+
+endif # SOC_FAMILY_ESPRESSIF_ESP32

soc/espressif/common/include/efuse_virtual.h

@@ -0,0 +1,20 @@
+/*
+ * Copyright (c) 2025 Espressif Systems (Shanghai) Co., Ltd.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#pragma once
+
+#include <esp_efuse.h>
+
+static inline void esp_efuse_init_virtual(void)
+{
+#if CONFIG_ESP32_EFUSE_VIRTUAL
+#if CONFIG_ESP32_EFUSE_VIRTUAL_KEEP_IN_FLASH
+	esp_efuse_init_virtual_mode_in_flash(CONFIG_ESP32_EFUSE_VIRTUAL_OFFSET,
+					     CONFIG_ESP32_EFUSE_VIRTUAL_SIZE);
+#else
+	esp_efuse_init_virtual_mode_in_ram();
+#endif
+#endif
+}

soc/espressif/esp32/soc.c

@@ -11,6 +11,7 @@
 #include <esp_private/cache_utils.h>
 #include <esp_private/system_internal.h>
 #include <esp_timer.h>
+#include <efuse_virtual.h>
 #include <psram.h>
 #include <zephyr/drivers/interrupt_controller/intc_esp32.h>
 #include <zephyr/sys/printk.h>
@@ -26,6 +27,8 @@ void IRAM_ATTR __esp_platform_app_start(void)
 
 	esp_flash_config();
 
+	esp_efuse_init_virtual();
+
 #if CONFIG_ESP_SPIRAM
 	esp_init_psram();
 

soc/espressif/esp32c2/soc.c

@@ -10,6 +10,7 @@
 #include <esp_private/cache_utils.h>
 #include <esp_private/system_internal.h>
 #include <esp_timer.h>
+#include <efuse_virtual.h>
 #include <zephyr/drivers/interrupt_controller/intc_esp32.h>
 #include <zephyr/kernel_structs.h>
 #include <kernel_internal.h>
@@ -24,6 +25,8 @@ void IRAM_ATTR __esp_platform_app_start(void)
 
 	esp_flash_config();
 
+	esp_efuse_init_virtual();
+
 	/* Start Zephyr */
 	z_cstart();
 

soc/espressif/esp32c3/soc.c

@@ -11,6 +11,7 @@
 #include <esp_private/cache_utils.h>
 #include <esp_private/system_internal.h>
 #include <esp_timer.h>
+#include <efuse_virtual.h>
 #include <zephyr/drivers/interrupt_controller/intc_esp32.h>
 #include <zephyr/kernel_structs.h>
 #include <kernel_internal.h>
@@ -25,6 +26,8 @@ void IRAM_ATTR __esp_platform_app_start(void)
 
 	esp_flash_config();
 
+	esp_efuse_init_virtual();
+
 	/* Start Zephyr */
 	z_cstart();
 

soc/espressif/esp32c6/soc.c

@@ -10,6 +10,7 @@
 #include <esp_private/cache_utils.h>
 #include <esp_private/system_internal.h>
 #include <esp_timer.h>
+#include <efuse_virtual.h>
 #include <zephyr/drivers/interrupt_controller/intc_esp32.h>
 #include <zephyr/kernel_structs.h>
 #include <kernel_internal.h>
@@ -24,6 +25,8 @@ void IRAM_ATTR __esp_platform_app_start(void)
 
 	esp_flash_config();
 
+	esp_efuse_init_virtual();
+
 	/* Start Zephyr */
 	z_cstart();
 

soc/espressif/esp32s2/soc.c

@@ -10,6 +10,7 @@
 #include <esp_private/cache_utils.h>
 #include <esp_private/system_internal.h>
 #include <esp_timer.h>
+#include <efuse_virtual.h>
 #include <psram.h>
 #include <zephyr/drivers/interrupt_controller/intc_esp32.h>
 #include <zephyr/sys/printk.h>
@@ -41,6 +42,8 @@ void IRAM_ATTR __esp_platform_app_start(void)
 
 	esp_flash_config();
 
+	esp_efuse_init_virtual();
+
 #if CONFIG_ESP_SPIRAM
 	esp_init_psram();
 

soc/espressif/esp32s3/soc.c

@@ -11,6 +11,7 @@
 #include <esp_private/cache_utils.h>
 #include <esp_private/system_internal.h>
 #include <esp_timer.h>
+#include <efuse_virtual.h>
 #include <psram.h>
 #include <zephyr/drivers/interrupt_controller/intc_esp32.h>
 #include <zephyr/sys/printk.h>
@@ -54,6 +55,8 @@ void IRAM_ATTR __esp_platform_app_start(void)
 
 	esp_flash_config();
 
+	esp_efuse_init_virtual();
+
 #if CONFIG_ESP_SPIRAM
 	esp_init_psram();