driver: flash: stm32 option bytes reloaded when locking

do not force option byte reloading in the write function because RDP
byte cannot be reloaded that way: it needs a POR through Standby mode.
when FLASH_CR_OBL_LAUNCH is defined, use it to force-reload option bytes
directly in the locking function.

Signed-off-by: Cyril Fougeray <[email protected]>

Author: fouge

drivers/flash/flash_stm32_ex_op.c

@@ -24,6 +24,13 @@ int flash_stm32_option_bytes_lock(const struct device *dev, bool enable)
 {
 	FLASH_TypeDef *regs = FLASH_STM32_REGS(dev);
 
+#if defined(FLASH_CR_OBL_LAUNCH)
+	/* Force the option byte loading before locking */
+	if (enable) {
+		regs->CR |= FLASH_CR_OBL_LAUNCH;
+	}
+#endif
+
 #if defined(FLASH_OPTCR_OPTLOCK) /* F2, F4, F7 or H7 */
 	if (enable) {
 		regs->OPTCR |= FLASH_OPTCR_OPTLOCK;

drivers/flash/flash_stm32g4x.c

@@ -280,14 +280,6 @@ int flash_stm32_option_bytes_write(const struct device *dev, uint32_t mask,
 	/* Make sure previous write is completed. */
 	barrier_dsync_fence_full();
 
-	rc = flash_stm32_wait_flash_idle(dev);
-	if (rc < 0) {
-		return rc;
-	}
-
-	/* Force the option byte loading */
-	regs->CR |= FLASH_CR_OBL_LAUNCH;
-
 	return flash_stm32_wait_flash_idle(dev);
 }
 

drivers/flash/flash_stm32l4x.c

@@ -271,14 +271,6 @@ int flash_stm32_option_bytes_write(const struct device *dev, uint32_t mask,
 	/* Make sure previous write is completed. */
 	barrier_dsync_fence_full();
 
-	rc = flash_stm32_wait_flash_idle(dev);
-	if (rc < 0) {
-		return rc;
-	}
-
-	/* Force the option byte loading */
-	regs->CR |= FLASH_CR_OBL_LAUNCH;
-
 	return flash_stm32_wait_flash_idle(dev);
 }