arm: soc: nxp k6x: mpu: add Bus Master 3 User Mode access bits

Ethernet on K64F is connected via Logical Bus Master 3.
Section 19.3.8 of K64F reference manual establishes bits 20-18
(M3UM) on page 427 as "Bus Master 3 User Mode Access Control".

To fix RWX user mode access via Bus Master 3 when MPU is enabled,
we need to add these bits to the MPU region descriptors.

This fixes ETH0 on K64F when MPU is enabled.

Fix recommended by Maureen Helm <[email protected]>

Signed-off-by: Michael Scott <[email protected]>

Author: Michael Scott

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

@@ -21,6 +21,7 @@
 #define BM0_UM_SHIFT	0
 #define BM1_UM_SHIFT	6
 #define BM2_UM_SHIFT	12
+#define BM3_UM_SHIFT	18
 
 /* Bus Master Supervisor Mode Access */
 #define SM_RWX_ALLOW	0
@@ -36,17 +37,20 @@
 /* Read Attribute */
 #define MPU_REGION_READ  ((UM_READ << BM0_UM_SHIFT) | \
 			  (UM_READ << BM1_UM_SHIFT) | \
-			  (UM_READ << BM2_UM_SHIFT))
+			  (UM_READ << BM2_UM_SHIFT) | \
+			  (UM_READ << BM3_UM_SHIFT))
 
 /* Write Attribute */
 #define MPU_REGION_WRITE ((UM_WRITE << BM0_UM_SHIFT) | \
 			  (UM_WRITE << BM1_UM_SHIFT) | \
-			  (UM_WRITE << BM2_UM_SHIFT))
+			  (UM_WRITE << BM2_UM_SHIFT) | \
+			  (UM_WRITE << BM3_UM_SHIFT))
 
 /* Execute Attribute */
 #define MPU_REGION_EXEC  ((UM_EXEC << BM0_UM_SHIFT) | \
 			  (UM_EXEC << BM1_UM_SHIFT) | \
-			  (UM_EXEC << BM2_UM_SHIFT))
+			  (UM_EXEC << BM2_UM_SHIFT) | \
+			  (UM_EXEC << BM3_UM_SHIFT))
 
 /* Super User Attributes */
 #define MPU_REGION_SU	 ((SM_SAME_AS_UM << BM0_SM_SHIFT) | \