Document some functions in internal headers
diff --git a/library/psa_crypto_slot_management.h b/library/psa_crypto_slot_management.h
index a2e52ba..6746bad 100644
--- a/library/psa_crypto_slot_management.h
+++ b/library/psa_crypto_slot_management.h
@@ -26,15 +26,33 @@
* The value is a compile-time constant for now, for simplicity. */
#define PSA_KEY_SLOT_COUNT 32
-/** Access a key slot at the given handle. */
+/** Access a key slot at the given handle.
+ *
+ * \param handle Key handle to query.
+ * \param[out] p_slot On success, `*p_slot` contains a pointer to the
+ * key slot in memory designated by \p handle.
+ *
+ * \retval PSA_SUCCESS
+ * Success: \p handle is a handle to `*p_slot`. Note that `*p_slot`
+ * may be empty or occupied.
+ * \retval PSA_ERROR_INVALID_HANDLE
+ * \p handle is out of range or is not in use.
+ * \retval PSA_ERROR_BAD_STATE
+ * The library has not been initialized.
+ */
psa_status_t psa_get_key_slot( psa_key_handle_t handle,
psa_key_slot_t **p_slot );
-/** Initialize the key slot structures. */
+/** Initialize the key slot structures.
+ *
+ * \retval PSA_SUCCESS
+ * Currently this function always succeeds.
+ */
psa_status_t psa_initialize_key_slots( void );
-/** Delete all data from key slots in memory. This does not affect persistent
- * storage. */
+/** Delete all data from key slots in memory.
+ *
+ * This does not affect persistent storage. */
void psa_wipe_all_key_slots( void );
#endif /* PSA_CRYPTO_SLOT_MANAGEMENT_H */