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diff --git a/chip/stm32/flash-regs.h b/chip/stm32/flash-regs.h
new file mode 100644
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+++ b/chip/stm32/flash-regs.h
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+/* Copyright 2021 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef __CROS_EC_STM32_FLASH_REGS_H
+#define __CROS_EC_STM32_FLASH_REGS_H
+
+#include <stdbool.h>
+
+/**
+ * Unlock the flash control register using the unlock sequence.
+ *
+ * If the flash control register has been disabled since the last reset when
+ * this function is called, a bus fault will be generated.
+ *
+ * See "3.5.1 Unlocking the Flash control register" in RM0402.
+ * See "4.9.2  FLASH key register for bank 1" in RM0433.
+ */
+void unlock_flash_control_register(void);
+
+/**
+ * Unlock the flash option bytes register using the unlock sequence.
+ *
+ * If the flash option bytes register has been disabled since the last reset
+ * when this function is called, a bus fault will be generated.
+ *
+ * See "3.6.2 Programming user option bytes" in RM0402.
+ * See "4.9.3 FLASH option key register" in RM0433.
+ */
+void unlock_flash_option_bytes(void);
+
+/**
+ * Lock the flash control register.
+ *
+ * If the flash control register has been disabled since the last reset when
+ * this function is called, a bus fault will be generated.
+ *
+ * See "3.5.1 Unlocking the Flash control register" in RM0402.
+ * See "4.9.4 Flash control register for bank 1" in RM0433.
+ */
+void lock_flash_control_register(void);
+
+/**
+ * Lock the flash option bytes register.
+ *
+ * If the flash option bytes register has been disabled since the last reset
+ * when this function is called, a bus fault will be generated.
+ *
+ * See "3.6.2 Programming user option bytes" in RM0402.
+ * See "4.9.7 FLASH option control register" in RM0433.
+ */
+void lock_flash_option_bytes(void);
+
+/**
+ * Disable the flash option bytes register.
+ *
+ * This function expects that bus faults have not already been ignored when
+ * called.
+ *
+ * Once this function is called any attempt at accessing the flash option
+ * bytes register will generate a bus fault until the next reset.
+ *
+ * See "3.6.2 Programming user option bytes" in RM0402.
+ * See "4.9.7 FLASH option control register" in RM0433.
+ */
+void disable_flash_option_bytes(void);
+
+/**
+ * Disable the flash control register.
+ *
+ * This function expects that bus faults have not already been ignored when
+ * called.
+ *
+ * Once this function is called any attempt at accessing the flash control
+ * register will generate a bus fault until the next reset.
+ *
+ * See "3.5.1 Unlocking the Flash control register" in RM0402.
+ * See "4.9.4 Flash control register for bank 1" in RM0433.
+ */
+void disable_flash_control_register(void);
+
+/**
+ * Check if the flash option bytes are locked.
+ *
+ * If the flash option bytes register has been disabled since the last reset
+ * when this function is called, a bus fault will be generated.
+
+ * See "3.6.2 Programming user option bytes" in RM0402.
+ * See "4.9.7 FLASH option control register" in RM0433.
+ *
+ * @return true if option bytes are locked, false otherwise
+ */
+bool flash_option_bytes_locked(void);
+
+/**
+ * Check if the flash control register is locked.
+ *
+ * If the flash control register has been disabled since the last reset
+ * when this function is called, a bus fault will be generated.
+ *
+ * See "3.5.1 Unlocking the Flash control register" in RM0402.
+ * See "4.9.4 Flash control register for bank 1" in RM0433.
+ *
+ * @return true if register is locked, false otherwise
+ */
+bool flash_control_register_locked(void);
+
+#endif /* __CROS_EC_STM32_FLASH_REGS_H */