Add more comment for mbedtls_ms_time
Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/include/mbedtls/platform_time.h b/include/mbedtls/platform_time.h
index 1161807..5c9f076 100644
--- a/include/mbedtls/platform_time.h
+++ b/include/mbedtls/platform_time.h
@@ -46,12 +46,17 @@
#endif /* MBEDTLS_PLATFORM_MS_TIME_TYPE_MACRO */
/**
- * \brief Get time in milliseconds.
+ * \brief Get time in milliseconds.
*
- * \return Current time in milliseconds
+ * \return Current time in milliseconds which is monotonically increasing.
*
* \note If MBEDTLS_PLATFORM_MS_TIME_ALT defined, users can provide their own
* implementation.
+ *
+ * \warning This function is used for time difference only. The start time is
+ * not defined. A well defined time function is not required in
+ * TLS negotiation.
+ *
*/
mbedtls_ms_time_t mbedtls_ms_time(void);