psa: Export "internally" mbedtls_md_info_from_psa()

Export mbedtls_md_info_from_psa() from psa_crypto.c
to make it available to psa_crypto_rsa/ecp.c.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 2f3d2e8..2176d9f 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -1923,7 +1923,7 @@
     defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_OAEP) || \
     defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PSS) || \
     defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA)
-static const mbedtls_md_info_t *mbedtls_md_info_from_psa( psa_algorithm_t alg )
+const mbedtls_md_info_t *mbedtls_md_info_from_psa( psa_algorithm_t alg )
 {
     switch( alg )
     {
diff --git a/library/psa_crypto_core.h b/library/psa_crypto_core.h
index ec7ac80..da69044 100644
--- a/library/psa_crypto_core.h
+++ b/library/psa_crypto_core.h
@@ -30,6 +30,8 @@
 #include "psa/crypto.h"
 #include "psa/crypto_se_driver.h"
 
+#include <mbedtls/md_internal.h>
+
 /** The data structure representing a key slot, containing key material
  * and metadata for one key.
  */
@@ -212,6 +214,15 @@
  */
 psa_status_t mbedtls_to_psa_error( int ret );
 
+/** Get Mbed TLS MD information of a hash algorithm given its PSA identifier
+ *
+ * \param[in] alg  PSA hash algorithm identifier
+ *
+ * \return  The Mbed TLS MD information of the hash algorithm. \c NULL if the
+ *          PSA hash algorithm is not supported.
+ */
+const mbedtls_md_info_t *mbedtls_md_info_from_psa( psa_algorithm_t alg );
+
 /** Import a key in binary format.
  *
  * \note The signature of this function is that of a PSA driver