diff --git a/include/psa/crypto_extra.h b/include/psa/crypto_extra.h
index e9fa311..84cc5ab 100644
--- a/include/psa/crypto_extra.h
+++ b/include/psa/crypto_extra.h
@@ -578,8 +578,55 @@
  *                      (`PSA_ECC_CURVE_xxx`).
  * \return              \c 0 on failure (\p grpid is not recognized).
  */
-psa_ecc_curve_t mbedtls_ecc_group_to_psa( mbedtls_ecp_group_id grpid,
-                                          size_t *bits );
+static inline psa_ecc_curve_t mbedtls_ecc_group_to_psa( mbedtls_ecp_group_id grpid,
+                                                        size_t *bits )
+{
+    switch( grpid )
+    {
+        case MBEDTLS_ECP_DP_SECP192R1:
+            *bits = 192;
+            return( PSA_ECC_CURVE_SECP_R1 );
+        case MBEDTLS_ECP_DP_SECP224R1:
+            *bits = 224;
+            return( PSA_ECC_CURVE_SECP_R1 );
+        case MBEDTLS_ECP_DP_SECP256R1:
+            *bits = 256;
+            return( PSA_ECC_CURVE_SECP_R1 );
+        case MBEDTLS_ECP_DP_SECP384R1:
+            *bits = 384;
+            return( PSA_ECC_CURVE_SECP_R1 );
+        case MBEDTLS_ECP_DP_SECP521R1:
+            *bits = 521;
+            return( PSA_ECC_CURVE_SECP_R1 );
+        case MBEDTLS_ECP_DP_BP256R1:
+            *bits = 256;
+            return( PSA_ECC_CURVE_BRAINPOOL_P_R1 );
+        case MBEDTLS_ECP_DP_BP384R1:
+            *bits = 384;
+            return( PSA_ECC_CURVE_BRAINPOOL_P_R1 );
+        case MBEDTLS_ECP_DP_BP512R1:
+            *bits = 512;
+            return( PSA_ECC_CURVE_BRAINPOOL_P_R1 );
+        case MBEDTLS_ECP_DP_CURVE25519:
+            *bits = 255;
+            return( PSA_ECC_CURVE_MONTGOMERY );
+        case MBEDTLS_ECP_DP_SECP192K1:
+            *bits = 192;
+            return( PSA_ECC_CURVE_SECP_K1 );
+        case MBEDTLS_ECP_DP_SECP224K1:
+            *bits = 224;
+            return( PSA_ECC_CURVE_SECP_K1 );
+        case MBEDTLS_ECP_DP_SECP256K1:
+            *bits = 256;
+            return( PSA_ECC_CURVE_SECP_K1 );
+        case MBEDTLS_ECP_DP_CURVE448:
+            *bits = 448;
+            return( PSA_ECC_CURVE_MONTGOMERY );
+        default:
+            *bits = 0;
+            return( 0 );
+    }
+}
 
 /** Convert an ECC curve identifier from the PSA encoding to Mbed TLS.
  *