Platform: Document system startup requirements
Change-Id: I9e21caeceb85f3855cbe2cf9bdbffb221c3d3587
Signed-off-by: Jamie Fox <jamie.fox@arm.com>
diff --git a/platform/readme.rst b/platform/readme.rst
index b3290d6..bbdd6c5 100644
--- a/platform/readme.rst
+++ b/platform/readme.rst
@@ -43,6 +43,18 @@
has to provide for TF-M's Platform Service. For details see
``docs/user_guides/services/tfm_platform_integration_guide.rst``
+**************
+System Startup
+**************
+
+Before calling ``main()``, platform startup code should initialise all system
+clocks, perform runtime initialisation and other steps such as setting the
+vector table. Configuration of the following features is optional as TF-M
+architecture code will check and initialise them:
+
+ - The Security Extension.
+ - The Floating-point Extension.
+
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Debug authentication settings
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