boards: nordic: add 'iron' board variant for radio

This is needed for next generation Secure Domain firmware.

Signed-off-by: Sebastian Bøe <sebastian.boe@nordicsemi.no>
Signed-off-by: Jonathan Nilsen <jonathan.nilsen@nordicsemi.no>

Author: SebastianBoe

boards/nordic/nrf54h20dk/Kconfig.nrf54h20dk

@@ -4,9 +4,11 @@
 config BOARD_NRF54H20DK
 	select SOC_NRF54H20_CPUAPP if (BOARD_NRF54H20DK_NRF54H20_CPUAPP || \
 				       BOARD_NRF54H20DK_NRF54H20_CPUAPP_IRON)
-	select SOC_NRF54H20_CPURAD if BOARD_NRF54H20DK_NRF54H20_CPURAD
+	select SOC_NRF54H20_CPURAD if (BOARD_NRF54H20DK_NRF54H20_CPURAD || \
+				       BOARD_NRF54H20DK_NRF54H20_CPURAD_IRON)
 	select SOC_NRF54H20_CPUPPR if (BOARD_NRF54H20DK_NRF54H20_CPUPPR || \
 				       BOARD_NRF54H20DK_NRF54H20_CPUPPR_XIP)
 	select SOC_NRF54H20_CPUFLPR if (BOARD_NRF54H20DK_NRF54H20_CPUFLPR || \
 				        BOARD_NRF54H20DK_NRF54H20_CPUFLPR_XIP)
-	select SOC_NRF54H20_IRON if BOARD_NRF54H20DK_NRF54H20_CPUAPP_IRON
+	select SOC_NRF54H20_IRON if (BOARD_NRF54H20DK_NRF54H20_CPUAPP_IRON || \
+				       BOARD_NRF54H20DK_NRF54H20_CPURAD_IRON)

boards/nordic/nrf54h20dk/board.cmake

@@ -2,8 +2,10 @@
 
 include(${ZEPHYR_BASE}/boards/common/nrfutil.board.cmake)
 
-if(CONFIG_BOARD_NRF54H20DK_NRF54H20_CPUAPP OR CONFIG_BOARD_NRF54H20DK_NRF54H20_CPURAD
-    OR CONFIG_BOARD_NRF54H20DK_NRF54H20_CPUAPP_IRON)
+if(CONFIG_BOARD_NRF54H20DK_NRF54H20_CPUAPP OR
+   CONFIG_BOARD_NRF54H20DK_NRF54H20_CPURAD OR
+   CONFIG_BOARD_NRF54H20DK_NRF54H20_CPUAPP_IRON OR
+   CONFIG_BOARD_NRF54H20DK_NRF54H20_CPURAD_IRON)
   if(CONFIG_SOC_NRF54H20_CPUAPP)
     set(JLINKSCRIPTFILE ${CMAKE_CURRENT_LIST_DIR}/support/nrf54h20_cpuapp.JLinkScript)
   else()

boards/nordic/nrf54h20dk/board.yml

@@ -11,6 +11,8 @@ board:
       cpucluster: cpuflpr
     - name: iron
       cpucluster: cpuapp
+    - name: iron
+      cpucluster: cpurad
   revision:
     format: major.minor.patch
     default: "0.9.0"

boards/nordic/nrf54h20dk/nrf54h20dk_nrf54h20_cpurad_iron.dts

@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "nrf54h20dk_nrf54h20_cpurad.dts"
+#include "nrf54h20dk_nrf54h20-ipc_conf_iron.dtsi"
+#include "nrf54h20dk_nrf54h20-memory_map_iron.dtsi"
+
+/ {
+	chosen {
+		zephyr,code-partition = &cpurad_slot0_partition;
+		zephyr,uart-mcumgr = &uart135;
+	};
+};
+
+&cpusec_cpurad_ipc {
+	mbox-names = "tx", "rx";
+	status = "okay";
+};

boards/nordic/nrf54h20dk/nrf54h20dk_nrf54h20_cpurad_iron_0_9_0.yaml

@@ -0,0 +1,20 @@
+# Copyright (c) 2025 Nordic Semiconductor ASA
+# SPDX-License-Identifier: Apache-2.0
+
+identifier: nrf54h20dk/nrf54h20/cpurad/iron
+name: nRF54H20-DK-nRF54H20-Radio (IRONside SE compatible) (revision 0.9.0)
+type: mcu
+arch: arm
+toolchain:
+  - gnuarmemb
+  - xtools
+  - zephyr
+sysbuild: true
+ram: 192
+flash: 336
+supported:
+  - counter
+  - gpio
+  - pwm
+  - retained_mem
+  - spi

boards/nordic/nrf54h20dk/nrf54h20dk_nrf54h20_cpurad_iron_defconfig

@@ -0,0 +1,28 @@
+# Copyright (c) 2025 Nordic Semiconductor ASA
+# SPDX-License-Identifier: Apache-2.0
+
+# Enable UART driver
+CONFIG_SERIAL=y
+
+# Enable console
+CONFIG_CONSOLE=y
+CONFIG_UART_CONSOLE=y
+
+CONFIG_USE_DT_CODE_PARTITION=y
+
+# Enable MPU
+CONFIG_ARM_MPU=y
+
+# Enable hardware stack protection
+CONFIG_HW_STACK_PROTECTION=y
+
+# MPU-based null-pointer dereferencing detection cannot be applied
+# as the (0x0 - 0x400) region is unmapped for this target.
+CONFIG_NULL_POINTER_EXCEPTION_DETECTION_NONE=y
+
+# Enable cache
+CONFIG_CACHE_MANAGEMENT=y
+CONFIG_EXTERNAL_CACHE=y
+
+# UICR generation is not supported, and when reintroduced will not use nrf-regtool.
+CONFIG_NRF_REGTOOL_GENERATE_UICR=n