diff --git a/docs/getting_started/porting-guide.rst b/docs/getting_started/porting-guide.rst
index 6b8bbc6..f331616 100644
--- a/docs/getting_started/porting-guide.rst
+++ b/docs/getting_started/porting-guide.rst
@@ -562,21 +562,14 @@
    doesn't print anything to the console. If ``PLAT_LOG_LEVEL_ASSERT`` isn't
    defined, it defaults to ``LOG_LEVEL``.
 
-If the platform port uses the Activity Monitor Unit, the following constants
+If the platform port uses the Activity Monitor Unit, the following constant
 may be defined:
 
 -  **PLAT_AMU_GROUP1_COUNTERS_MASK**
    This mask reflects the set of group counters that should be enabled.  The
    maximum number of group 1 counters supported by AMUv1 is 16 so the mask
    can be at most 0xffff. If the platform does not define this mask, no group 1
-   counters are enabled. If the platform defines this mask, the following
-   constant needs to also be defined.
-
--  **PLAT_AMU_GROUP1_NR_COUNTERS**
-   This value is used to allocate an array to save and restore the counters
-   specified by ``PLAT_AMU_GROUP1_COUNTERS_MASK`` on CPU suspend.
-   This value should be equal to the highest bit position set in the
-   mask, plus 1.  The maximum number of group 1 counters in AMUv1 is 16.
+   counters are enabled.
 
 File : plat_macros.S [mandatory]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~