api extensions: cross links between cache API and TA flag

Add cross links between documentation on TA cache maintenance
API description and the TA extended property flag related to
that API.

Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Reviewed-by: Joakim Bech <joakim.bech@linaro.org>
diff --git a/architecture/globalplatform_api.rst b/architecture/globalplatform_api.rst
index 9b4d366..a42fbab 100644
--- a/architecture/globalplatform_api.rst
+++ b/architecture/globalplatform_api.rst
@@ -120,6 +120,9 @@
 directive prefixed ``CFG_`` allows one to disable support for the extension when
 building the OP-TEE packages.
 
+
+.. _extensions_cache_maintenance:
+
 Cache Maintenance Support
 =========================
 Following functions have been introduced in order to allow Trusted Applications
@@ -132,10 +135,10 @@
     TEE_Result TEE_CacheInvalidate(char *buf, size_t len);
 
 These functions are available to any Trusted Application defined with the flag
-``TA_FLAG_CACHE_MAINTENANCE`` sets on. When not set, each function returns the
-error code ``TEE_ERROR_NOT_SUPPORTED``. Within these extensions, a Trusted
-Application is able to operate on the data cache, with the following
-specification:
+``TA_FLAG_CACHE_MAINTENANCE`` sets on, see :ref:`ta_property_cache_maintenance`.
+When not set, each function returns the error code ``TEE_ERROR_NOT_SUPPORTED``.
+Within these extensions, a Trusted Application is able to operate on the data
+cache, with the following specification:
 
 .. list-table::
     :widths: 10 60
@@ -163,7 +166,6 @@
       ``TEE_MEMORY_ACCESS_WRITE`` is not set.
     - The memory is **not** user space memory.
 
-
 You may disable this extension by setting the following configuration variable
 in ``conf.mk``:
 
diff --git a/architecture/trusted_applications.rst b/architecture/trusted_applications.rst
index 3929bba..2953115 100644
--- a/architecture/trusted_applications.rst
+++ b/architecture/trusted_applications.rst
@@ -180,15 +180,16 @@
 to handle memory reference invocation parameters that relate to secure data path
 buffers.
 
+.. _ta_property_cache_maintenance:
 
 Cache maintenance Flag
 ----------------------
 ``TA_FLAG_CACHE_MAINTENANCE`` is a bit flag supported by ``TA_FLAGS``. This
-property flag claims access to the cache maintenance API for the TA:
-``TEE_CacheXxxx()``. Refer to the OP-TEE to check if cache API support is
-enabled. TAs that do not set ``TA_FLAG_CACHE_MAINTENANCE`` in the value of their
-``TA_FLAGS`` will not be able to call the cache maintenance API.
-
+property flag, when enabled, allows Trusted Applciation to use the cache
+maintenance API extension of the Internal Core API described in
+:ref:`extensions_cache_maintenance`. TAs that do not set
+``TA_FLAG_CACHE_MAINTENANCE`` in the value of their ``TA_FLAGS`` will not be
+able to call the cache maintenance API.
 
 Deprecated Property Flags
 -------------------------