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commit d5f674d96740cd581bf3e062d8ec4a864089f062
Author: Filipe Cavalcanti <filipe.cavalca...@espressif.com>
AuthorDate: Wed Jul 16 12:05:51 2025 -0300
arch/xtensa: add common driver for E-Fuse on Espressif devices
Adds a common E-Fuse driver to be used by Espressif Xtensa devices.
Signed-off-by: Filipe Cavalcanti <filipe.cavalca...@espressif.com>
---
arch/xtensa/src/common/espressif/Kconfig | 44 ++++
arch/xtensa/src/common/espressif/Make.defs | 5 +
arch/xtensa/src/common/espressif/esp_efuse.c | 308 +++++++++++++++++++++++++++
arch/xtensa/src/common/espressif/esp_efuse.h | 142 ++++++++++++
4 files changed, 499 insertions(+)
diff --git a/arch/xtensa/src/common/espressif/Kconfig
b/arch/xtensa/src/common/espressif/Kconfig
index 3f8768777d8..0640638c68f 100644
--- a/arch/xtensa/src/common/espressif/Kconfig
+++ b/arch/xtensa/src/common/espressif/Kconfig
@@ -41,6 +41,50 @@ config ESPRESSIF_ADC_2
endif # ESPRESSIF_ADC
+config ESPRESSIF_EFUSE
+ bool "EFUSE support"
+ default n
+ select EFUSE
+ ---help---
+ Enable efuse support.
+
+config ESPRESSIF_EFUSE_VIRTUAL
+ bool "Virtual EFUSE support"
+ depends on ESPRESSIF_EFUSE
+ default n
+ ---help---
+ Enable virtual efuse support to simulate eFuse operations in
RAM, changes will be reverted each reboot
+
+config ESPRESSIF_EFUSE_VIRTUAL_KEEP_IN_FLASH
+ bool "Keep E-Fuses in flash"
+ depends on ESPRESSIF_EFUSE_VIRTUAL
+ ---help---
+ In addition to the "Virtual E-Fuses support" option, this
option just adds
+ a feature to keep E-Fuses after reboots in flash memory.
+
+ During startup, the E-Fuses are copied from flash or,
+ in case if flash is empty, from real E-Fuse to RAM and then
update flash.
+ This mode is useful when need to keep changes after reboot
(testing secure_boot,
+ flash_encryption or using MCUBoot + encryption).
+
+if ESPRESSIF_EFUSE_VIRTUAL_KEEP_IN_FLASH
+
+config ESPRESSIF_EFUSE_VIRTUAL_KEEP_IN_FLASH_OFFSET
+ hex "E-Fuses offset in flash"
+ depends on ESPRESSIF_EFUSE_VIRTUAL_KEEP_IN_FLASH
+ default 0x250000
+ ---help---
+ Offset in flash where the E-Fuses will be stored when using the
"E-Fuses size to keep in flash" option.
+
+config ESPRESSIF_EFUSE_VIRTUAL_KEEP_IN_FLASH_SIZE
+ hex "E-Fuses size to keep in flash"
+ depends on ESPRESSIF_EFUSE_VIRTUAL_KEEP_IN_FLASH
+ default 0x2000
+ ---help---
+ Size of E-Fuse region to keep in flash.
+
+endif # ESPRESSIF_EFUSE_VIRTUAL_KEEP_IN_FLASH
+
config ESPRESSIF_TEMP
bool "Internal Temperature Sensor"
default n
diff --git a/arch/xtensa/src/common/espressif/Make.defs
b/arch/xtensa/src/common/espressif/Make.defs
index e18aeb711a1..03582f9a821 100644
--- a/arch/xtensa/src/common/espressif/Make.defs
+++ b/arch/xtensa/src/common/espressif/Make.defs
@@ -111,6 +111,11 @@ ifeq ($(CONFIG_ESPRESSIF_ADC),y)
CHIP_CSRCS += esp_adc.c
endif
+ifeq ($(CONFIG_ESPRESSIF_EFUSE),y)
+CHIP_CSRCS += esp_efuse.c
+LDFLAGS += -u esp_efuse_startup_include_func
+endif
+
ifeq ($(CONFIG_ESPRESSIF_WIRELESS),y)
include common$(DELIM)espressif$(DELIM)Wireless.mk
endif
diff --git a/arch/xtensa/src/common/espressif/esp_efuse.c
b/arch/xtensa/src/common/espressif/esp_efuse.c
new file mode 100644
index 00000000000..e7066e07460
--- /dev/null
+++ b/arch/xtensa/src/common/espressif/esp_efuse.c
@@ -0,0 +1,308 @@
+/****************************************************************************
+ * arch/xtensa/src/common/espressif/esp_efuse.c
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership. The
+ * ASF licenses this file to you 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.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <stdlib.h>
+#include <debug.h>
+#include <errno.h>
+#include <assert.h>
+#include <string.h>
+#include <sys/param.h>
+#include <nuttx/irq.h>
+#include <nuttx/efuse/efuse.h>
+
+#include "espressif/esp_efuse.h"
+
+#include "esp_efuse.h"
+#include "esp_efuse_utility.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#define EFUSE_MAX_BLK_LEN 256 /* Max length of efuse block. */
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+struct esp_efuse_lowerhalf_s
+{
+ const struct efuse_ops_s *ops; /* Lower half operations */
+ void *upper; /* Pointer to efuse_upperhalf_s */
+};
+
+/****************************************************************************
+ * Private Functions Prototypes
+ ****************************************************************************/
+
+/* "Lower half" driver methods */
+
+static int esp_efuse_lowerhalf_read(struct efuse_lowerhalf_s *lower,
+ const efuse_desc_t *field[],
+ uint8_t *data, size_t bits_len);
+static int esp_efuse_lowerhalf_write(struct efuse_lowerhalf_s *lower,
+ const efuse_desc_t *field[],
+ const uint8_t *data,
+ size_t bits_len);
+static int esp_efuse_lowerhalf_ioctl(struct efuse_lowerhalf_s *lower,
+ int cmd, unsigned long arg);
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/* "Lower half" driver methods */
+
+static const struct efuse_ops_s g_esp_efuse_ops =
+{
+ .read_field = esp_efuse_lowerhalf_read,
+ .write_field = esp_efuse_lowerhalf_write,
+ .ioctl = esp_efuse_lowerhalf_ioctl,
+};
+
+/* EFUSE lower-half */
+
+static struct esp_efuse_lowerhalf_s g_esp_efuse_lowerhalf =
+{
+ .ops = &g_esp_efuse_ops,
+ .upper = NULL,
+};
+
+/****************************************************************************
+ * Private functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: esp_efuse_lowerhalf_read
+ *
+ * Description:
+ * Read value from EFUSE, writing it into an array.
+ * The field[0]->bit_offset received from the upper half represents
+ * the bit offset taking into consideration that each block is 256 bits.
+ * This is necessary as we have multiple blocks of 256 bits.
+ *
+ * Example: To read data from USER_DATA (EFUSE_BLK3), from bit 16 onwards,
+ * then bit_offset should be 3*256 + 16.
+ *
+ * Input Parameters:
+ * lower - A pointer the publicly visible representation of
+ * the "lower-half" driver state structure
+ * field - A pointer to describing the fields of efuse
+ * data - A pointer to array that contains the data for reading
+ * bits_len - The number of bits required to read
+ *
+ * Returned Value:
+ * Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+static int esp_efuse_lowerhalf_read(struct efuse_lowerhalf_s *lower,
+ const efuse_desc_t *field[],
+ uint8_t *data, size_t bits_len)
+{
+ int ret = OK;
+ uint8_t blk_num = field[0]->bit_offset / EFUSE_MAX_BLK_LEN;
+
+ esp_efuse_desc_t recv =
+ {
+ .efuse_block = blk_num,
+ .bit_start = field[0]->bit_offset - blk_num * EFUSE_MAX_BLK_LEN,
+ .bit_count = field[0]->bit_count
+ };
+
+ const esp_efuse_desc_t *desc[] =
+ {
+ &recv,
+ NULL
+ };
+
+ minfo("read from blk_num: %d, bit_start: %d, bit_count: %d\n",
+ blk_num, recv.bit_start, recv.bit_count);
+
+ /* Read the requested field */
+
+ ret = esp_efuse_read_field_blob((const esp_efuse_desc_t**)&desc,
+ data,
+ bits_len);
+
+ return ret;
+}
+
+/****************************************************************************
+ * Name: esp_efuse_lowerhalf_write
+ *
+ * Description:
+ * Write array to EFUSE.
+ *
+ * The field[0]->bit_offset received from the upper half represents
+ * the bit offset taking into consideration that each block is 256 bits.
+ * This is necessary as we have multiple blocks of 256 bits.
+ *
+ * Example: To write data to USER_DATA (EFUSE_BLK3), from bit 16 onwards,
+ * then bit_offset should be 3*256 + 16.
+ *
+ * Input Parameters:
+ * lower - A pointer the publicly visible representation of
+ * the "lower-half" driver state structure
+ * field - A pointer to describing the fields of efuse
+ * data - A pointer to array that contains the data for writing
+ * bits_len - The number of bits required to write
+ *
+ * Returned Value:
+ * Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+static int esp_efuse_lowerhalf_write(struct efuse_lowerhalf_s *lower,
+ const efuse_desc_t *field[],
+ const uint8_t *data,
+ size_t bits_len)
+{
+ irqstate_t flags;
+ int ret = OK;
+ uint8_t blk_num = field[0]->bit_offset / EFUSE_MAX_BLK_LEN;
+ esp_efuse_desc_t recv =
+ {
+ .efuse_block = blk_num,
+ .bit_start = field[0]->bit_offset - blk_num * EFUSE_MAX_BLK_LEN,
+ .bit_count = field[0]->bit_count
+ };
+
+ const esp_efuse_desc_t *desc[] =
+ {
+ &recv,
+ NULL
+ };
+
+ minfo("write to blk_num: %d, bit_start: %d, bit_count: %d\n",
+ blk_num, recv.bit_start, recv.bit_count);
+
+ flags = enter_critical_section();
+
+ ret = esp_efuse_write_field_blob((const esp_efuse_desc_t**)&desc,
+ data,
+ bits_len);
+
+ leave_critical_section(flags);
+
+ if (ret != OK)
+ {
+ return ERROR;
+ }
+
+ return ret;
+}
+
+/****************************************************************************
+ * Name: esp_efuse_lowerhalf_ioctl
+ *
+ * Description:
+ * Any ioctl commands that are not recognized by the "upper-half"
+ * driver are forwarded to the lower half driver through this method.
+ *
+ * Input Parameters:
+ * lower - A pointer the publicly visible representation of the
+ * "lower-half" driver state structure.
+ * cmd - The ioctl command value
+ * arg - The optional argument that accompanies the ioctl command.
+ *
+ * Returned Value:
+ * Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+static int esp_efuse_lowerhalf_ioctl(struct efuse_lowerhalf_s *lower,
+ int cmd, unsigned long arg)
+{
+ int ret = OK;
+
+ switch (cmd)
+ {
+ /* We don't have proprietary EFUSE ioctls */
+
+ default:
+ {
+ minfo("Unrecognized cmd: %d\n", cmd);
+ ret = -ENOTTY;
+ }
+ break;
+ }
+
+ return ret;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: esp_efuse_initialize
+ *
+ * Description:
+ * Initialize the efuse driver. The efuse is initialized
+ * and registered as 'devpath'
+ *
+ * Input Parameters:
+ * devpath - The full path to the efuse device.
+ * This should be of the form /dev/efuse
+ *
+ * Returned Value:
+ * Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+int esp_efuse_initialize(const char *devpath)
+{
+ struct esp_efuse_lowerhalf_s *lower = NULL;
+ int ret = OK;
+
+ DEBUGASSERT(devpath != NULL);
+
+ lower = &g_esp_efuse_lowerhalf;
+
+ /* Register the efuse upper driver */
+
+ lower->upper = efuse_register(devpath,
+ (struct efuse_lowerhalf_s *)lower);
+
+ if (lower->upper == NULL)
+ {
+ /* The actual cause of the failure may have been a failure to allocate
+ * perhaps a failure to register the efuse driver (such as if the
+ * 'devpath' were not unique). We know here but we return EEXIST to
+ * indicate the failure (implying the non-unique devpath).
+ */
+
+ ret = -EEXIST;
+ }
+
+#ifdef CONFIG_ESPRESSIF_EFUSE_VIRTUAL
+ mwarn("Virtual E-Fuses are enabled\n");
+ esp_efuse_utility_update_virt_blocks();
+#endif
+
+ return ret;
+}
diff --git a/arch/xtensa/src/common/espressif/esp_efuse.h
b/arch/xtensa/src/common/espressif/esp_efuse.h
new file mode 100644
index 00000000000..4d00ae1ac5e
--- /dev/null
+++ b/arch/xtensa/src/common/espressif/esp_efuse.h
@@ -0,0 +1,142 @@
+/****************************************************************************
+ * arch/xtensa/src/common/espressif/esp_efuse.h
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership. The
+ * ASF licenses this file to you 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.
+ *
+ ****************************************************************************/
+
+#ifndef __ARCH_XTENSA_SRC_COMMON_ESPRESSIF_ESP_EFUSE_H
+#define __ARCH_XTENSA_SRC_COMMON_ESPRESSIF_ESP_EFUSE_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/efuse/efuse.h>
+
+#ifndef __ASSEMBLY__
+
+#undef EXTERN
+#if defined(__cplusplus)
+#define EXTERN extern "C"
+extern "C"
+{
+#else
+#define EXTERN extern
+#endif
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#define ESP_EFUSE_BLK_LEN 256
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+/* E-Fuse block and bit definitions can be found on the Technical Reference
+ * Manual or on the ESP-IDF documentation.
+ */
+
+#ifdef CONFIG_ARCH_CHIP_ESP32
+typedef enum
+{
+ ESP_EFUSE_BLK0 = 0,
+
+ ESP_EFUSE_BLK1 = 1,
+ ESP_EFUSE_BLK_KEY0 = 1,
+ ESP_EFUSE_BLK_ENCRYPT_FLASH = 1,
+
+ ESP_EFUSE_BLK2 = 2,
+ ESP_EFUSE_BLK_KEY1 = 2,
+ ESP_EFUSE_BLK_SECURE_BOOT = 2,
+
+ ESP_EFUSE_BLK3 = 3,
+ ESP_EFUSE_BLK_KEY2 = 3,
+ ESP_EFUSE_BLK_KEY_MAX = 4,
+
+ ESP_EFUSE_BLK_MAX = 4,
+} esp_efuse_blk_num_t;
+#else
+typedef enum
+{
+ ESP_EFUSE_BLK0 = 0,
+ ESP_EFUSE_BLK1 = 1,
+
+ ESP_EFUSE_BLK2 = 2,
+ ESP_EFUSE_BLK_SYS_DATA_PART1 = 2,
+
+ ESP_EFUSE_BLK3 = 3,
+ ESP_EFUSE_BLK_USER_DATA = 3,
+
+ ESP_EFUSE_BLK4 = 4,
+ ESP_EFUSE_BLK_KEY0 = 4,
+
+ ESP_EFUSE_BLK5 = 5,
+ ESP_EFUSE_BLK_KEY1 = 5,
+
+ ESP_EFUSE_BLK6 = 6,
+ ESP_EFUSE_BLK_KEY2 = 6,
+
+ ESP_EFUSE_BLK7 = 7,
+ ESP_EFUSE_BLK_KEY3 = 7,
+
+ ESP_EFUSE_BLK8 = 8,
+ ESP_EFUSE_BLK_KEY4 = 8,
+
+ ESP_EFUSE_BLK9 = 9,
+ ESP_EFUSE_BLK_KEY5 = 9,
+ ESP_EFUSE_BLK_KEY_MAX = 10,
+
+ ESP_EFUSE_BLK10 = 10,
+ ESP_EFUSE_BLK_SYS_DATA_PART2 = 10,
+
+ ESP_EFUSE_BLK_MAX
+} esp_efuse_blk_num_t;
+#endif
+
+/****************************************************************************
+ * Public Functions Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: esp_efuse_initialize
+ *
+ * Description:
+ * Initialize the efuse driver. The efuse is initialized
+ * and registered as 'devpath'
+ *
+ * Input Parameters:
+ * devpath - The full path to the efuse device.
+ * This should be of the form /dev/efuse
+ *
+ * Returned Value:
+ * Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+int esp_efuse_initialize(const char *devpath);
+
+#undef EXTERN
+#if defined(__cplusplus)
+}
+#endif
+
+#endif /* __ASSEMBLY__ */
+#endif /* __ARCH_XTENSA_SRC_COMMON_ESPRESSIF_ESP_EFUSE_H */
