diff --git a/tf-psa-crypto/core/psa_crypto_core.h b/tf-psa-crypto/core/psa_crypto_core.h
index 6dd00730ce..f2d849876c 100644
--- a/tf-psa-crypto/core/psa_crypto_core.h
+++ b/tf-psa-crypto/core/psa_crypto_core.h
@@ -55,15 +55,6 @@ typedef enum {
     PSA_SLOT_PENDING_DELETION,
 } psa_key_slot_state_t;
 
-/* If the size of static key slots is not explicitly defined by the user, then
- * set it to the maximum between PSA_EXPORT_KEY_PAIR_OR_PUBLIC_MAX_SIZE and
- * PSA_CIPHER_MAX_KEY_LENGTH. */
-#if !defined(MBEDTLS_PSA_STATIC_KEY_SLOT_BUFFER_SIZE)
-#define MBEDTLS_PSA_STATIC_KEY_SLOT_BUFFER_SIZE  \
-    ((PSA_EXPORT_KEY_PAIR_OR_PUBLIC_MAX_SIZE > PSA_CIPHER_MAX_KEY_LENGTH) ? \
-     PSA_EXPORT_KEY_PAIR_OR_PUBLIC_MAX_SIZE : PSA_CIPHER_MAX_KEY_LENGTH)
-#endif /* !MBEDTLS_PSA_STATIC_KEY_SLOT_BUFFER_SIZE*/
-
 /** The data structure representing a key slot, containing key material
  * and metadata for one key.
  */
diff --git a/tf-psa-crypto/core/psa_crypto_storage.h b/tf-psa-crypto/core/psa_crypto_storage.h
index 809fd72249..433ecdca51 100644
--- a/tf-psa-crypto/core/psa_crypto_storage.h
+++ b/tf-psa-crypto/core/psa_crypto_storage.h
@@ -17,7 +17,6 @@ extern "C" {
 
 #include "psa/crypto.h"
 #include "psa/crypto_se_driver.h"
-#include "psa_crypto_core.h"
 
 #include <stdint.h>
 #include <string.h>
diff --git a/tf-psa-crypto/include/psa/crypto_extra.h b/tf-psa-crypto/include/psa/crypto_extra.h
index 0cf42c6055..f48c0873b5 100644
--- a/tf-psa-crypto/include/psa/crypto_extra.h
+++ b/tf-psa-crypto/include/psa/crypto_extra.h
@@ -32,6 +32,16 @@ extern "C" {
 #define MBEDTLS_PSA_KEY_SLOT_COUNT 32
 #endif
 
+/* If the size of static key slots is not explicitly defined by the user, then
+ * set it to the maximum between PSA_EXPORT_KEY_PAIR_OR_PUBLIC_MAX_SIZE and
+ * PSA_CIPHER_MAX_KEY_LENGTH.
+ * See mbedtls_config.h for the definition. */
+#if !defined(MBEDTLS_PSA_STATIC_KEY_SLOT_BUFFER_SIZE)
+#define MBEDTLS_PSA_STATIC_KEY_SLOT_BUFFER_SIZE  \
+    ((PSA_EXPORT_KEY_PAIR_OR_PUBLIC_MAX_SIZE > PSA_CIPHER_MAX_KEY_LENGTH) ? \
+     PSA_EXPORT_KEY_PAIR_OR_PUBLIC_MAX_SIZE : PSA_CIPHER_MAX_KEY_LENGTH)
+#endif /* !MBEDTLS_PSA_STATIC_KEY_SLOT_BUFFER_SIZE*/
+
 /** \addtogroup attributes
  * @{
  */