[nrf fromtree] soc: nordic: add option for forcing RAM power on reboot

soc/nordic/common/CMakeLists.txt

@@ -11,6 +11,11 @@ if(CONFIG_ARM)
   zephyr_linker_sources(SECTIONS arm_platform_init.ld)
 endif()
 
+# TF-M provides its own reboot sequence
+if(NOT CONFIG_TFM_PARTITION_PLATFORM)
+  zephyr_library_sources_ifdef(CONFIG_ARM reboot.c)
+endif()
+
 zephyr_library_sources_ifdef(CONFIG_POWEROFF poweroff.c)
 if(CONFIG_ARM)
   zephyr_library_sources_ifdef(CONFIG_NRF_PLATFORM_HALTIUM soc_lrcconf.c)

soc/nordic/common/Kconfig

@@ -7,6 +7,16 @@ config HAS_NORDIC_DMM
 config HAS_NORDIC_RAM_CTRL
 	bool
 
+config NRF_FORCE_RAM_ON_REBOOT
+	bool "Force all RAM blocks to be powered on before rebooting"
+	depends on HAS_NORDIC_RAM_CTRL
+	help
+	  RAM power configuration is preserved through soft reset,
+	  meaning that there is a risk of accessing powered off RAM blocks
+	  when booting in different application (i.e. bootloader).
+	  Force all RAM blocks to be powered on before triggering soft reset
+	  to prevent this from happening.
+
 config NRF_SYS_EVENT
 	bool "nRF system event support"
 	select NRFX_POWER if !NRF_PLATFORM_HALTIUM

soc/nordic/common/reboot.c

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/kernel.h>
+#include <zephyr/sys/reboot.h>
+#if defined(CONFIG_HAS_NORDIC_RAM_CTRL)
+#include <helpers/nrfx_ram_ctrl.h>
+#endif
+
+void sys_arch_reboot(int type)
+{
+	ARG_UNUSED(type);
+
+#ifdef CONFIG_NRF_FORCE_RAM_ON_REBOOT
+	uint8_t *ram_start;
+	size_t ram_size;
+
+#if defined(NRF_MEMORY_RAM_BASE)
+	ram_start = (uint8_t *)NRF_MEMORY_RAM_BASE;
+#else
+	ram_start = (uint8_t *)NRF_MEMORY_RAM0_BASE;
+#endif
+
+	ram_size = 0;
+#if defined(NRF_MEMORY_RAM_SIZE)
+	ram_size += NRF_MEMORY_RAM_SIZE;
+#endif
+#if defined(NRF_MEMORY_RAM0_SIZE)
+	ram_size += NRF_MEMORY_RAM0_SIZE;
+#endif
+#if defined(NRF_MEMORY_RAM1_SIZE)
+	ram_size += NRF_MEMORY_RAM1_SIZE;
+#endif
+#if defined(NRF_MEMORY_RAM2_SIZE)
+	ram_size += NRF_MEMORY_RAM2_SIZE;
+#endif
+
+	/* Power on all RAM blocks */
+	nrfx_ram_ctrl_power_enable_set(ram_start, ram_size, true);
+#endif
+
+	NVIC_SystemReset();
+}