[LTD fromlist] arm: soc: nxp k6x: Add Allow write on Flash

This patch adds the allow flash write CONFIG option to the NXP MPU
configuration in privileged mode.

Signed-off-by: Vincenzo Frascino <vincenzo.frascino@linaro.org>
Signed-off-by: Marti Bolivar <marti.bolivar@linaro.org>
LTD: some conflict resolution on top of what was posted to the list.

Author: Vincenzo Frascino

arch/arm/core/cortex_m/mpu/Kconfig

@@ -38,3 +38,10 @@ config NXP_MPU
 	default n
 	help
 	  MCU has NXP MPU
+
+config MPU_ALLOW_FLASH_WRITE
+	bool "Add MPU access to write to flash"
+	depends on NXP_MPU
+	default n
+	help
+	  Enable this to allow MPU RWX access to flash memory

include/arch/arm/cortex_m/mpu/nxp_mpu.h

@@ -62,13 +62,29 @@
 #define ENDADDR_ROUND(x) (x - 0x1F)
 
 /* Some helper defines for common regions */
+#if defined(CONFIG_MPU_ALLOW_FLASH_WRITE)
+/*
+ * This config option enables the possibility to write in flash and to execute
+ * from RAM since it is required to initialize the flash driver.
+ */
+#define REGION_RAM_ATTR	  (MPU_REGION_READ | \
+			   MPU_REGION_WRITE | \
+			   MPU_REGION_EXEC | \
+			   MPU_REGION_SU)
+
+#define REGION_FLASH_ATTR (MPU_REGION_READ | \
+			   MPU_REGION_WRITE | \
+			   MPU_REGION_EXEC | \
+			   MPU_REGION_SU)
+#else
 #define REGION_RAM_ATTR	  (MPU_REGION_READ | \
 			   MPU_REGION_WRITE | \
 			   MPU_REGION_SU)
 
 #define REGION_FLASH_ATTR (MPU_REGION_READ | \
 			   MPU_REGION_EXEC | \
 			   MPU_REGION_SU)
+#endif
 
 #define REGION_IO_ATTR	  (MPU_REGION_READ | \
 			   MPU_REGION_WRITE | \