docs(ff-a): boot order field of SPs manifest
Document `boot-order` field from FF-A partitions manifest, in accordance
to Hafnium's (SPM) implementation.
Signed-off-by: J-Alves <joao.alves@arm.com>
Change-Id: I9fd070100ee52e0d465d2cce830cc91d78bddfc0
diff --git a/docs/components/secure-partition-manager.rst b/docs/components/secure-partition-manager.rst
index 4faabf9..a598e5f 100644
--- a/docs/components/secure-partition-manager.rst
+++ b/docs/components/secure-partition-manager.rst
@@ -533,7 +533,10 @@
SP manifests provide an optional boot order attribute meant to resolve
dependencies such as an SP providing a service required to properly boot
-another SP.
+another SP. SPMC boots the SPs in accordance to the boot order attribute,
+lowest to the highest value. If the boot order attribute is absent from the FF-A
+manifest, the SP is treated as if it had the highest boot order value
+(i.e. lowest booting priority).
It is possible for an SP to call into another SP through a direct request
provided the latter SP has already been booted.