boards: arm: Enable MPS3 Corstone310 for userspace

What is the change?
 - MPS3 Corstone310 can now be used with userspace application.
   This is done by dividing flash into ITCM+ISRAM and using a
   bigger SRAM.

Why do we need this change?
 - ITCM and DTCM for MPS3 Corstone310 are small (32KB) to build
   with userspace. So we need bigger flash and sram.
   We can use the bigger ISRAM as flash but, Cortex-M expects
   vector table to be in 1st few bytes of ITCM.
   So to build for userspace we distribute FLASH between ITCM and
   ISRAM while using SRAM as sram.

Signed-off-by: Sudan Landge <[email protected]>

Author: wearyzen

boards/arm/mps3/Kconfig.defconfig

@@ -1,5 +1,5 @@
 # Copyright (c) 2018-2021 Linaro Limited
-# Copyright 2024 Arm Limited and/or its affiliates <[email protected]>
+# Copyright 2024-2025 Arm Limited and/or its affiliates <[email protected]>
 # SPDX-License-Identifier: Apache-2.0
 
 if BOARD_MPS3_CORSTONE300_AN547 || BOARD_MPS3_CORSTONE300_AN552 || BOARD_MPS3_CORSTONE300_FVP || BOARD_MPS3_CORSTONE310_AN555 || BOARD_MPS3_CORSTONE310_FVP
@@ -19,4 +19,14 @@ config UART_INTERRUPT_DRIVEN
 
 endif # SERIAL
 
+if ROMSTART_RELOCATION_ROM && (BOARD_MPS3_CORSTONE310_AN555 || BOARD_MPS3_CORSTONE310_FVP)
+
+config ROMSTART_REGION_ADDRESS
+	default $(dt_nodelabel_reg_addr_hex,itcm)
+
+config ROMSTART_REGION_SIZE
+	default $(dt_nodelabel_reg_size_hex,itcm,0,k)
+
+endif
+
 endif

boards/arm/mps3/board.cmake

@@ -37,6 +37,10 @@ elseif(CONFIG_BOARD_MPS3_CORSTONE310_FVP OR CONFIG_BOARD_MPS3_CORSTONE310_FVP_NS
     set(ARMFVP_FLAGS
       # default is '0x11000000' but should match cpu<i>.INITSVTOR which is 0.
       -C mps3_board.sse300.iotss3_systemcontrol.INITSVTOR_RST=0
+      # default is 0x8, this change is needed since we split flash into itcm
+      # and sram and it reduces the number of available mpu regions causing a
+      # few MPU tests to fail.
+      -C cpu0.MPU_S=16
     )
   endif()
 endif()

boards/arm/mps3/mps3_corstone310_an555.dts

@@ -1,5 +1,5 @@
 /*
- * Copyright 2024 Arm Limited and/or its affiliates <[email protected]>
+ * Copyright 2024-2025 Arm Limited and/or its affiliates <[email protected]>
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -20,8 +20,8 @@
 	chosen {
 		zephyr,console = &uart0;
 		zephyr,shell-uart = &uart0;
-		zephyr,sram = &dtcm;
-		zephyr,flash = &itcm;
+		zephyr,sram = &sram;
+		zephyr,flash = &isram;
 	};
 
 	cpus {

boards/arm/mps3/mps3_corstone310_an555_defconfig

@@ -1,4 +1,4 @@
-# Copyright 2024 Arm Limited and/or its affiliates <[email protected]>
+# Copyright 2024-2025 Arm Limited and/or its affiliates <[email protected]>
 # SPDX-License-Identifier: Apache-2.0
 
 CONFIG_RUNTIME_NMI=y
@@ -15,3 +15,5 @@ CONFIG_SERIAL=y
 
 # Build a Secure firmware image
 CONFIG_TRUSTED_EXECUTION_SECURE=y
+# ROMSTART_REGION address and size are defined in Kconfig.defconfig
+CONFIG_ROMSTART_RELOCATION_ROM=y

boards/arm/mps3/mps3_corstone310_fvp.dts

@@ -1,5 +1,5 @@
 /*
- * Copyright 2024 Arm Limited and/or its affiliates <[email protected]>
+ * Copyright 2024-2025 Arm Limited and/or its affiliates <[email protected]>
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -20,8 +20,8 @@
 	chosen {
 		zephyr,console = &uart0;
 		zephyr,shell-uart = &uart0;
-		zephyr,sram = &dtcm;
-		zephyr,flash = &itcm;
+		zephyr,sram = &sram;
+		zephyr,flash = &isram;
 	};
 
 	cpus {

boards/arm/mps3/mps3_corstone310_fvp_defconfig

@@ -1,4 +1,4 @@
-# Copyright 2024 Arm Limited and/or its affiliates <[email protected]>
+# Copyright 2024-2025 Arm Limited and/or its affiliates <[email protected]>
 # SPDX-License-Identifier: Apache-2.0
 
 CONFIG_RUNTIME_NMI=y
@@ -15,3 +15,5 @@ CONFIG_SERIAL=y
 
 # Build a Secure firmware image
 CONFIG_TRUSTED_EXECUTION_SECURE=y
+# ROMSTART_REGION address and size are defined in Kconfig.defconfig
+CONFIG_ROMSTART_RELOCATION_ROM=y