diff --git a/docs/getting_started/porting-guide.rst b/docs/getting_started/porting-guide.rst
index 668af57..4639fd5 100644
--- a/docs/getting_started/porting-guide.rst
+++ b/docs/getting_started/porting-guide.rst
@@ -1461,6 +1461,22 @@
 
 When the MEASURED_BOOT flag is disabled, this function doesn't do anything.
 
+Function : plat_can_cmo()
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+::
+
+    Argument : void
+    Return   : uint64_t
+
+When CONDITIONAL_CMO flag is enabled:
+
+- This function indicates whether cache management operations should be
+  performed. It returns 0 if CMOs should be skipped and non-zero
+  otherwise.
+- The function must not clobber x2 and x3. It's also not safe to rely on stack.
+  Otherwise obey AAPCS.
+
 Modifications specific to a Boot Loader stage
 ---------------------------------------------