BL2: Support RAM_LOAD with separate S/NS images

Change-Id: I05c397e0be8b855c1352d45a3fafb9b9820ce105
Signed-off-by: Jamie Fox <jamie.fox@arm.com>
diff --git a/docs/platform/ext/readme.rst b/docs/platform/ext/readme.rst
index 1057e03..da37c46 100644
--- a/docs/platform/ext/readme.rst
+++ b/docs/platform/ext/readme.rst
@@ -274,9 +274,13 @@
 The ``imgtool.py`` tool is used to handle the tasks related to signing the
 binary. It requires the following definition:
 
-- ``IMAGE_LOAD_ADDRESS`` - Defines the address to where the image is loaded and
-  is executed from. Only used if ``MCUBOOT_UPGRADE_STRATEGY`` is configured to
-  be ``RAM_LOAD``.
+- ``S_IMAGE_LOAD_ADDRESS`` - Defines the address to where the Secure (or
+  combined Secure and Non-secure) image is loaded and is executed from. Only
+  used if ``MCUBOOT_UPGRADE_STRATEGY`` is configured to be ``RAM_LOAD``.
+
+- ``NS_IMAGE_LOAD_ADDRESS`` - Defines the address to where the Non-secure image
+  is loaded and is executed from. Only used if ``MCUBOOT_UPGRADE_STRATEGY`` is
+  configured to be ``RAM_LOAD`` and ``MCUBOOT_IMAGE_NUMBER`` is greater than 1.
 
 ***************************************
 Expose target support for HW components
@@ -291,6 +295,6 @@
 
 --------------
 
-*Copyright (c) 2017-2021, Arm Limited. All rights reserved.*
+*Copyright (c) 2017-2022, Arm Limited. All rights reserved.*
 *Copyright (c) 2020-2022 Cypress Semiconductor Corporation (an Infineon company)
 or an affiliate of Cypress Semiconductor Corporation. All rights reserved.*
diff --git a/docs/technical_references/design_docs/tfm_secure_boot.rst b/docs/technical_references/design_docs/tfm_secure_boot.rst
index fd4c0bf..675cd31 100644
--- a/docs/technical_references/design_docs/tfm_secure_boot.rst
+++ b/docs/technical_references/design_docs/tfm_secure_boot.rst
@@ -210,10 +210,6 @@
 address, the location in RAM where the image is copied to, is stored in the
 image header.
 
-.. Note::
-
-    Only single image boot is supported with ``RAM load`` upgrade mode.
-
 Summary of different modes for image upgrade
 ============================================
 Different implementations of the image upgrade operation (whether through
@@ -763,9 +759,11 @@
 To enable RAM loading, please set ``MCUBOOT_UPGRADE_STRATEGY`` to "RAM_LOAD"
 (either in the configuration file or through the command line), and then specify
 a destination load address in RAM where the image can be copied to and executed
-from. The ``IMAGE_LOAD_ADDRESS`` macro must be specified in the target dependent
-files, for example with Musca-S, its ``flash_layout.h`` file in the ``platform``
-folder should include ``#define IMAGE_LOAD_ADDRESS #0xA0020000``
+from. The ``S_IMAGE_LOAD_ADDRESS`` macro must be specified in the target
+dependent files, and if multiple image boot is enabled then
+``NS_IMAGE_LOAD_ADDRESS`` must also be defined. For example with Musca-S, its
+``flash_layout.h`` file in the ``platform`` folder should include ``#define
+S_IMAGE_LOAD_ADDRESS #0xA0020000``
 
 Executing firmware upgrade on Musca-S board
 --------------------------------------------