Improved AES comment
Signed-off-by: Thomas Daubney <thomas.daubney@arm.com>
diff --git a/tf-psa-crypto/drivers/builtin/src/aes.c b/tf-psa-crypto/drivers/builtin/src/aes.c
index eef55e6..085fd4d 100644
--- a/tf-psa-crypto/drivers/builtin/src/aes.c
+++ b/tf-psa-crypto/drivers/builtin/src/aes.c
@@ -1860,8 +1860,9 @@
/*
* AES-192 is an optional feature that may be unavailable when
- * there is an alternative underlying implementation such as a
- * PSA driver.
+ * there is an alternative underlying implementation i.e when
+ * MBEDTLS_AES_SETKEY_ENC_ALT or MBEDTLS_AES_SETKEY_DEC_ALT
+ * are defined.
*/
if (ret == MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED && keybits == 192) {
mbedtls_printf("skipped\n");