improve return codes and logic description
Signed-off-by: Paul Elliott <paul.elliott@arm.com>
diff --git a/tf-psa-crypto/include/psa/crypto.h b/tf-psa-crypto/include/psa/crypto.h
index 06ec304..8d89204 100644
--- a/tf-psa-crypto/include/psa/crypto.h
+++ b/tf-psa-crypto/include/psa/crypto.h
@@ -4900,7 +4900,7 @@
* on the same operation object after a successful
* call to this function until \c
* psa_key_agreement_iop_complete() either returns
- * 0 or an error.
+ * #PSA_SUCCESS or an error.
* \c psa_key_agreement_iop_complete() will return
* #PSA_OPERATION_INCOMPLETE if there is more work
* to do. Alternatively users can call
@@ -5049,10 +5049,10 @@
* maximum time spent in a function call.
*
* \note Users should call this function on the same
- * operation object repeatedly until it either
- * returns 0 or an error. This function will return
- * #PSA_OPERATION_INCOMPLETE if there is more work
- * to do. Alternatively users can call
+ * operation object repeatedly whilst it returns
+ * #PSA_OPERATION_INCOMPLETE, stopping when it
+ * returns either #PSA_SUCCESS or an error.
+ * Alternatively users can call
* \c psa_key_agreement_iop_abort() at any point if
* they no longer want the result.
*