From b480fc3883ed6f515f57ad51a768130483329005 Mon Sep 17 00:00:00 2001
From: Andrzej Puzdrowski <andrzej.puzdrowski@nordicsemi.no>
Date: Thu, 18 Sep 2025 15:56:42 +0200
Subject: [PATCH 1/2] [nrf noup] boot/zephyr: improve S2RAM resume support
 using dedicated API

nrf-squash! [nrf noup] boot/zephyr: nRF54h20 resume from S2RAM (hardened)

CONFIG_ARM_SOC_START_HOOK=y allow to rework the
resume from S2RAM code to work without PM_S2RAM mocking.
It allows to implement only what really needed from
the MCUboot perspective.

Signed-off-by: Andrzej Puzdrowski <andrzej.puzdrowski@nordicsemi.no>
---
 boot/zephyr/CMakeLists.txt          |  3 +-
 boot/zephyr/nrf54h20_custom_s2ram.S | 43 +++++++++++++++++++++++++++++
 boot/zephyr/nrf54h20_custom_s2ram.c | 17 ++----------
 3 files changed, 47 insertions(+), 16 deletions(-)
 create mode 100644 boot/zephyr/nrf54h20_custom_s2ram.S

diff --git a/boot/zephyr/CMakeLists.txt b/boot/zephyr/CMakeLists.txt
index 6bd93f35a..b34824def 100644
--- a/boot/zephyr/CMakeLists.txt
+++ b/boot/zephyr/CMakeLists.txt
@@ -496,7 +496,8 @@ if(CONFIG_MCUBOOT_CLEANUP_ARM_CORE)
   )
 endif()
 
-if(CONFIG_SOC_NRF54H20_PM_S2RAM_OVERRIDE)
+if(CONFIG_SOC_EARLY_RESET_HOOK)
+  zephyr_library_sources(${BOOT_DIR}/zephyr/nrf54h20_custom_s2ram.S)
   zephyr_library_sources(${BOOT_DIR}/zephyr/nrf54h20_custom_s2ram.c)
 endif()
 
diff --git a/boot/zephyr/nrf54h20_custom_s2ram.S b/boot/zephyr/nrf54h20_custom_s2ram.S
new file mode 100644
index 000000000..1ffa17f42
--- /dev/null
+++ b/boot/zephyr/nrf54h20_custom_s2ram.S
@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2025, Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @file
+ * @brief ARM Cortex-M suspend-to-RAM resume intermediary code (S2RAM)
+ */
+
+
+
+/*
+ *             resume or
+ *              reboot                                                  reboot==T
+ *[S2RAM sleep]---------->[ boot (reset.S) ]---->[soc_early_reset_hook]---------->[regular boot]
+ *                                                       |
+ *                                                       |   resume==T
+ *                                                       \/
+ *                                                  [jump to well-known]
+ *                                                  [ App reset vector ]
+ */
+
+
+
+#include <zephyr/toolchain.h>
+#include <zephyr/arch/cpu.h>
+
+GTEXT(pm_s2ram_mark_check_and_mediate)
+
+GTEXT(soc_early_reset_hook)
+SECTION_FUNC(TEXT, soc_early_reset_hook)
+#if DT_NODE_EXISTS(DT_NODELABEL(pm_s2ram_stack)) &&\
+	DT_NODE_HAS_COMPAT(DT_NODELABEL(pm_s2ram_stack), zephyr_memory_region)
+     ldr r0, =DT_REG_ADDR(DT_NODELABEL(pm_s2ram_stack)) + DT_REG_SIZE(DT_NODELABEL(pm_s2ram_stack))
+#else
+#error "The support of bridge for S2RAM resume requires dedicated small stack"
+#endif
+     msr msp, r0
+     push {r0, lr}
+     bl pm_s2ram_mark_check_and_mediate
+     pop {r0, pc}
diff --git a/boot/zephyr/nrf54h20_custom_s2ram.c b/boot/zephyr/nrf54h20_custom_s2ram.c
index 51146e7b3..faa8d9b46 100644
--- a/boot/zephyr/nrf54h20_custom_s2ram.c
+++ b/boot/zephyr/nrf54h20_custom_s2ram.c
@@ -45,17 +45,6 @@ void s2ram_designate_slot(uint8_t slot)
 }
 #endif
 
-int soc_s2ram_suspend(pm_s2ram_system_off_fn_t system_off)
-{
-    (void)(system_off);
-    return -1;
-}
-
-void pm_s2ram_mark_set(void)
-{
-    /* empty */
-}
-
 struct arm_vector_table {
     uint32_t msp;
     uint32_t reset;
@@ -66,13 +55,13 @@ struct arm_vector_table {
  */
 #define APP_EXE_START_OFFSET 0x800 /* nRF54H20 */
 
-bool pm_s2ram_mark_check_and_clear(void)
+void pm_s2ram_mark_check_and_mediate(void)
 {
     uint32_t reset_reason = nrf_resetinfo_resetreas_local_get(NRF_RESETINFO);
 
     if (reset_reason != NRF_RESETINFO_RESETREAS_LOCAL_UNRETAINED_MASK) {
         /* Normal boot */
-        return false;
+        return;
     }
 
     /* S2RAM resume expected, do doublecheck */
@@ -120,6 +109,4 @@ bool pm_s2ram_mark_check_and_clear(void)
 
 resume_failed:
     FIH_PANIC;
-
-    return true;
 }

From db5e91cc913d4f6c4a7a3c1cce9c404057043455 Mon Sep 17 00:00:00 2001
From: Andrzej Puzdrowski <andrzej.puzdrowski@nordicsemi.no>
Date: Fri, 26 Sep 2025 13:56:46 +0200
Subject: [PATCH 2/2] [nrf noup] boot/zephyr/socs: update nrf54h20 prj.conf for
 S2RAM

nrf-squash! [nrf noup] boot/zephyr/socs: nrf54h20 prj.conf for S2RAM

Updated in order to use optimized configuration.

Signed-off-by: Andrzej Puzdrowski <andrzej.puzdrowski@nordicsemi.no>
---
 boot/zephyr/socs/nrf54h20_cpuapp.conf | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/boot/zephyr/socs/nrf54h20_cpuapp.conf b/boot/zephyr/socs/nrf54h20_cpuapp.conf
index 9e75ccbb9..2a6df8b12 100644
--- a/boot/zephyr/socs/nrf54h20_cpuapp.conf
+++ b/boot/zephyr/socs/nrf54h20_cpuapp.conf
@@ -7,8 +7,4 @@
 # after suspend to RAM (S2RAM) requested by the application.
 # MCUboot does not support S2RAM itself, but serves as an immediate actor while waking up
 # from suspension.
-CONFIG_PM=y
-CONFIG_PM_DEVICE=n
-CONFIG_PM_S2RAM=y
-CONFIG_PM_S2RAM_CUSTOM_MARKING=y
-CONFIG_SOC_NRF54H20_PM_S2RAM_OVERRIDE=y
+CONFIG_SOC_EARLY_RESET_HOOK=y