doc/nrf/app_dev/../nrf54h20: doc on S2RAM support in bootloader

Described configuration of S2RAM support by the MCUboot.

Signed-off-by: Andrzej Puzdrowski <[email protected]>

Author: nvlsianpu

doc/nrf/app_dev/device_guides/nrf54h/ug_nrf54h20_mcuboot_dfu.rst

@@ -86,6 +86,21 @@ For detailed information on ECIES-X25519 support, refer to the :ref:`ug_nrf54h_e
    On the nRF54H20 SoC, private and public keys are currently stored in the image.
    Embedding keys directly within the firmware image could pose a potential security risk.
 
+Suspend to RAM (S2RAM) support
+******************************
+
+MCUboot on the nRF54H20 SoC might supports Suspend to RAM (S2RAM) functionality in the Application.
+It is able to detect wake-up from S2RAM and redirect execution to the Application's resume routine.
+To enable S2RAM support for your project, set the following MCUboot Kconfig options:
+* :kconfig:option:`CONFIG_PM` - Power management support.
+* :kconfig:option:`CONFIG_PM_S2RAM` - Suspend to RAM support.
+* :kconfig:option:`CONFIG_PM_S2RAM_CUSTOM_MARKING` - Custom S2RAM making support.
+* :kconfig:option:`CONFIG_SOC_NRF54H20_PM_S2RAM_OVERRIDE` - Override Nordic s2ram implementation by MCUbooot.
+
+Also ensure that your board DTS file includes the following zephyr nodes for describing linker section used:
+* a 'zephyr,memory-region' compatible node with nodelabel 'pm_s2ram' of 32 B size for placing S2RAM cpu context RAM.
+* a 'zephyr,memory-region' compatible node with nodelabel 'mcuboot_s2ram' of 4 B size for placing MCUboot's S2RAM magic variable.
+
 DFU configuration example
 *************************