diff --git a/docs/getting_started/porting-guide.rst b/docs/getting_started/porting-guide.rst
index 2d17f12..2ad7256 100644
--- a/docs/getting_started/porting-guide.rst
+++ b/docs/getting_started/porting-guide.rst
@@ -1890,6 +1890,21 @@
 of the system counter, which is retrieved from the first entry in the frequency
 modes table.
 
+Function : plat_arm_set_twedel_scr_el3() [optional]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+::
+
+    Argument : void
+    Return   : uint32_t
+
+This function is used in v8.6+ systems to set the WFE trap delay value in
+SCR_EL3. If this function returns TWED_DISABLED or is left unimplemented, this
+feature is not enabled.  The only hook provided is to set the TWED fields in
+SCR_EL3, there are similar fields in HCR_EL2, SCTLR_EL2, and SCTLR_EL1 to adjust
+the WFE trap delays in lower ELs and these fields should be set by the
+appropriate EL2 or EL1 code depending on the platform configuration.
+
 #define : PLAT_PERCPU_BAKERY_LOCK_SIZE [optional]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~