diff --git a/master/ethernet.c b/master/ethernet.c
index bd755eb5..b11ed09a 100644
--- a/master/ethernet.c
+++ b/master/ethernet.c
@@ -70,7 +70,11 @@
 
 /****************************************************************************/
 
+// prototypes for private methods
 void ec_eoe_flush(ec_eoe_t *);
+int ec_eoe_send(ec_eoe_t *);
+
+/****************************************************************************/
 
 // state functions
 void ec_eoe_state_rx_start(ec_eoe_t *);
diff --git a/master/fsm_coe.c b/master/fsm_coe.c
index 9b015de1..69765cd0 100644
--- a/master/fsm_coe.c
+++ b/master/fsm_coe.c
@@ -59,6 +59,19 @@
 
 /****************************************************************************/
 
+// prototypes for private methods
+void ec_canopen_abort_msg(const ec_slave_t *, uint32_t);
+int ec_fsm_coe_check_emergency(const ec_fsm_coe_t *, const uint8_t *, size_t);
+int ec_fsm_coe_prepare_dict(ec_fsm_coe_t *, ec_datagram_t *);
+int ec_fsm_coe_dict_prepare_desc(ec_fsm_coe_t *, ec_datagram_t *);
+int ec_fsm_coe_dict_prepare_entry(ec_fsm_coe_t *, ec_datagram_t *);
+int ec_fsm_coe_prepare_down_start(ec_fsm_coe_t *, ec_datagram_t *);
+void ec_fsm_coe_down_prepare_segment_request(ec_fsm_coe_t *, ec_datagram_t *);
+int ec_fsm_coe_prepare_up(ec_fsm_coe_t *, ec_datagram_t *);
+void ec_fsm_coe_up_prepare_segment_request(ec_fsm_coe_t *, ec_datagram_t *);
+
+/****************************************************************************/
+
 void ec_fsm_coe_dict_start(ec_fsm_coe_t *, ec_datagram_t *);
 void ec_fsm_coe_dict_request(ec_fsm_coe_t *, ec_datagram_t *);
 void ec_fsm_coe_dict_check(ec_fsm_coe_t *, ec_datagram_t *);
@@ -267,7 +280,7 @@ int ec_fsm_coe_success(
  * \return The data were an emergency request.
  */
 int ec_fsm_coe_check_emergency(
-        ec_fsm_coe_t *fsm, /**< Finite state machine */
+        const ec_fsm_coe_t *fsm, /**< Finite state machine */
         const uint8_t *data, /**< CoE mailbox data. */
         size_t size /**< CoE mailbox data size. */
         )
diff --git a/master/fsm_eoe.c b/master/fsm_eoe.c
index c061728d..b3ef6898 100644
--- a/master/fsm_eoe.c
+++ b/master/fsm_eoe.c
@@ -33,6 +33,27 @@
 
 /****************************************************************************/
 
+/** Maximum time to wait for a set IP parameter response.
+ */
+#define EC_EOE_RESPONSE_TIMEOUT 3000 // [ms]
+
+/****************************************************************************/
+
+// prototypes for private functions
+void memcpy_swap32(void *, const void *);
+
+int ec_fsm_eoe_prepare_set(ec_fsm_eoe_t *, ec_datagram_t *);
+
+void ec_fsm_eoe_set_ip_start(ec_fsm_eoe_t *, ec_datagram_t *);
+void ec_fsm_eoe_set_ip_request(ec_fsm_eoe_t *, ec_datagram_t *);
+void ec_fsm_eoe_set_ip_check(ec_fsm_eoe_t *, ec_datagram_t *);
+void ec_fsm_eoe_set_ip_response(ec_fsm_eoe_t *, ec_datagram_t *);
+
+void ec_fsm_eoe_end(ec_fsm_eoe_t *, ec_datagram_t *);
+void ec_fsm_eoe_error(ec_fsm_eoe_t *, ec_datagram_t *);
+
+/****************************************************************************/
+
 /** Host-architecture-independent 32-bit swap function.
  *
  * The internal storage of struct in_addr is always big-endian.
@@ -51,22 +72,6 @@ void memcpy_swap32(void *dst, const void *src)
 
 /****************************************************************************/
 
-/** Maximum time to wait for a set IP parameter response.
- */
-#define EC_EOE_RESPONSE_TIMEOUT 3000 // [ms]
-
-/****************************************************************************/
-
-void ec_fsm_eoe_set_ip_start(ec_fsm_eoe_t *, ec_datagram_t *);
-void ec_fsm_eoe_set_ip_request(ec_fsm_eoe_t *, ec_datagram_t *);
-void ec_fsm_eoe_set_ip_check(ec_fsm_eoe_t *, ec_datagram_t *);
-void ec_fsm_eoe_set_ip_response(ec_fsm_eoe_t *, ec_datagram_t *);
-
-void ec_fsm_eoe_end(ec_fsm_eoe_t *, ec_datagram_t *);
-void ec_fsm_eoe_error(ec_fsm_eoe_t *, ec_datagram_t *);
-
-/****************************************************************************/
-
 /** Constructor.
  */
 void ec_fsm_eoe_init(
diff --git a/master/fsm_master.c b/master/fsm_master.c
index 3cbe802a..2290608b 100644
--- a/master/fsm_master.c
+++ b/master/fsm_master.c
@@ -44,6 +44,18 @@
 
 /****************************************************************************/
 
+// prototypes for private methods
+void ec_fsm_master_restart(ec_fsm_master_t *);
+int ec_fsm_master_action_process_sii(ec_fsm_master_t *);
+int ec_fsm_master_action_process_int_request(ec_fsm_master_t *);
+void ec_fsm_master_action_idle(ec_fsm_master_t *);
+void ec_fsm_master_action_next_slave_state(ec_fsm_master_t *);
+void ec_fsm_master_action_configure(ec_fsm_master_t *);
+u64 ec_fsm_master_dc_offset32(ec_fsm_master_t *, u64, u64, unsigned long);
+u64 ec_fsm_master_dc_offset64(ec_fsm_master_t *, u64, u64, unsigned long);
+
+/****************************************************************************/
+
 void ec_fsm_master_state_start(ec_fsm_master_t *);
 void ec_fsm_master_state_broadcast(ec_fsm_master_t *);
 void ec_fsm_master_state_read_state(ec_fsm_master_t *);
diff --git a/master/fsm_pdo.c b/master/fsm_pdo.c
index a5a4b7ad..0d5f87e1 100644
--- a/master/fsm_pdo.c
+++ b/master/fsm_pdo.c
@@ -34,6 +34,14 @@
 
 /****************************************************************************/
 
+// prototypes for private methods
+void ec_fsm_pdo_print(const ec_fsm_pdo_t *);
+int ec_fsm_pdo_running(const ec_fsm_pdo_t *);
+ec_pdo_t *ec_fsm_pdo_conf_action_next_pdo(const ec_fsm_pdo_t *,
+        const struct list_head *);
+
+/****************************************************************************/
+
 void ec_fsm_pdo_read_state_start(ec_fsm_pdo_t *, ec_datagram_t *);
 void ec_fsm_pdo_read_state_pdo_count(ec_fsm_pdo_t *, ec_datagram_t *);
 void ec_fsm_pdo_read_state_pdo(ec_fsm_pdo_t *, ec_datagram_t *);
@@ -94,7 +102,7 @@ void ec_fsm_pdo_clear(
 /** Print the current and desired PDO assignment.
  */
 void ec_fsm_pdo_print(
-        ec_fsm_pdo_t *fsm /**< PDO configuration state machine. */
+        const ec_fsm_pdo_t *fsm /**< PDO configuration state machine. */
         )
 {
     printk(KERN_CONT "Currently assigned PDOs: ");
diff --git a/master/fsm_pdo_entry.c b/master/fsm_pdo_entry.c
index 3de74ce4..3c7be428 100644
--- a/master/fsm_pdo_entry.c
+++ b/master/fsm_pdo_entry.c
@@ -34,6 +34,14 @@
 
 /****************************************************************************/
 
+// prototypes for private methods
+void ec_fsm_pdo_entry_print(const ec_fsm_pdo_entry_t *);
+int ec_fsm_pdo_entry_running(const ec_fsm_pdo_entry_t *);
+ec_pdo_entry_t *ec_fsm_pdo_entry_conf_next_entry(const ec_fsm_pdo_entry_t *,
+        const struct list_head *);
+
+/****************************************************************************/
+
 void ec_fsm_pdo_entry_read_state_start(ec_fsm_pdo_entry_t *, ec_datagram_t *);
 void ec_fsm_pdo_entry_read_state_count(ec_fsm_pdo_entry_t *, ec_datagram_t *);
 void ec_fsm_pdo_entry_read_state_entry(ec_fsm_pdo_entry_t *, ec_datagram_t *);
@@ -82,7 +90,7 @@ void ec_fsm_pdo_entry_clear(
 /** Print the current and desired PDO mapping.
  */
 void ec_fsm_pdo_entry_print(
-        ec_fsm_pdo_entry_t *fsm /**< PDO mapping state machine. */
+        const ec_fsm_pdo_entry_t *fsm /**< PDO mapping state machine. */
         )
 {
     printk(KERN_CONT "Currently mapped PDO entries: ");
diff --git a/master/fsm_slave_config.c b/master/fsm_slave_config.c
index f0f0d250..25887ad6 100644
--- a/master/fsm_slave_config.c
+++ b/master/fsm_slave_config.c
@@ -52,6 +52,11 @@
 
 /****************************************************************************/
 
+// prototypes for private methods
+int ec_fsm_slave_config_running(const ec_fsm_slave_config_t *);
+
+/****************************************************************************/
+
 void ec_fsm_slave_config_state_start(ec_fsm_slave_config_t *);
 void ec_fsm_slave_config_state_init(ec_fsm_slave_config_t *);
 void ec_fsm_slave_config_state_clear_fmmus(ec_fsm_slave_config_t *);
diff --git a/master/fsm_slave_scan.c b/master/fsm_slave_scan.c
index a4bc3db1..e4b56358 100644
--- a/master/fsm_slave_scan.c
+++ b/master/fsm_slave_scan.c
@@ -35,6 +35,19 @@
 
 /****************************************************************************/
 
+// prototypes for private methods
+int ec_fsm_slave_scan_running(const ec_fsm_slave_scan_t *);
+void ec_fsm_slave_scan_enter_sii_size(ec_fsm_slave_scan_t *);
+void ec_fsm_slave_scan_enter_assign_sii(ec_fsm_slave_scan_t *);
+void ec_fsm_slave_scan_enter_datalink(ec_fsm_slave_scan_t *);
+#ifdef EC_REGALIAS
+void ec_fsm_slave_scan_enter_regalias(ec_fsm_slave_scan_t *);
+#endif
+void ec_fsm_slave_scan_enter_preop(ec_fsm_slave_scan_t *);
+void ec_fsm_slave_scan_enter_pdos(ec_fsm_slave_scan_t *);
+
+/****************************************************************************/
+
 void ec_fsm_slave_scan_state_start(ec_fsm_slave_scan_t *);
 void ec_fsm_slave_scan_state_address(ec_fsm_slave_scan_t *);
 void ec_fsm_slave_scan_state_state(ec_fsm_slave_scan_t *);
@@ -57,13 +70,6 @@ void ec_fsm_slave_scan_state_pdos(ec_fsm_slave_scan_t *);
 void ec_fsm_slave_scan_state_end(ec_fsm_slave_scan_t *);
 void ec_fsm_slave_scan_state_error(ec_fsm_slave_scan_t *);
 
-void ec_fsm_slave_scan_enter_datalink(ec_fsm_slave_scan_t *);
-#ifdef EC_REGALIAS
-void ec_fsm_slave_scan_enter_regalias(ec_fsm_slave_scan_t *);
-#endif
-void ec_fsm_slave_scan_enter_preop(ec_fsm_slave_scan_t *);
-void ec_fsm_slave_scan_enter_pdos(ec_fsm_slave_scan_t *);
-
 /****************************************************************************/
 
 /** Constructor.
@@ -115,7 +121,9 @@ void ec_fsm_slave_scan_start(
    \return false, if state machine has terminated
 */
 
-int ec_fsm_slave_scan_running(const ec_fsm_slave_scan_t *fsm /**< slave state machine */)
+int ec_fsm_slave_scan_running(
+        const ec_fsm_slave_scan_t *fsm /**< slave state machine */
+        )
 {
     return fsm->state != ec_fsm_slave_scan_state_end
         && fsm->state != ec_fsm_slave_scan_state_error;
diff --git a/master/fsm_soe.c b/master/fsm_soe.c
index 161e3e3d..b24f03a9 100644
--- a/master/fsm_soe.c
+++ b/master/fsm_soe.c
@@ -56,6 +56,14 @@ enum {
 
 /****************************************************************************/
 
+// prototypes for private methods
+void ec_print_soe_error(const ec_slave_t *, uint16_t);
+void ec_fsm_soe_print_error(ec_fsm_soe_t *);
+int ec_fsm_soe_prepare_read(ec_fsm_soe_t *, ec_datagram_t *);
+void ec_fsm_soe_write_next_fragment(ec_fsm_soe_t *, ec_datagram_t *);
+
+/****************************************************************************/
+
 void ec_fsm_soe_read_start(ec_fsm_soe_t *, ec_datagram_t *);
 void ec_fsm_soe_read_request(ec_fsm_soe_t *, ec_datagram_t *);
 void ec_fsm_soe_read_check(ec_fsm_soe_t *, ec_datagram_t *);
diff --git a/master/master.c b/master/master.c
index 0a5f316a..c66bd12a 100644
--- a/master/master.c
+++ b/master/master.c
@@ -97,8 +97,18 @@ const unsigned int rate_intervals[] = {
 
 /****************************************************************************/
 
+void ec_master_clear_config(ec_master_t *);
 void ec_master_clear_slave_configs(ec_master_t *);
 void ec_master_clear_domains(ec_master_t *);
+int ec_master_thread_start(ec_master_t *, int (*)(void *), const char *);
+void ec_master_thread_stop(ec_master_t *);
+void ec_master_inject_external_datagrams(ec_master_t *);
+ec_datagram_t *ec_master_get_external_datagram(ec_master_t *);
+void ec_master_exec_slave_fsms(ec_master_t *);
+void ec_master_send_datagrams(ec_master_t *, ec_device_index_t);
+int ec_master_calc_topology_rec(ec_master_t *, ec_slave_t *, unsigned int *);
+void ec_master_calc_topology(ec_master_t *);
+void ec_master_calc_transmission_delays(ec_master_t *);
 static int ec_master_idle_thread(void *);
 static int ec_master_operation_thread(void *);
 #ifdef EC_EOE
diff --git a/master/slave.c b/master/slave.c
index 83ebf084..04cf2151 100644
--- a/master/slave.c
+++ b/master/slave.c
@@ -42,7 +42,13 @@ extern const ec_code_msg_t al_status_messages[];
 
 /****************************************************************************/
 
-char *ec_slave_sii_string(ec_slave_t *, unsigned int);
+// prototypes for private methods
+char *ec_slave_sii_string(const ec_slave_t *, unsigned int);
+void ec_slave_find_names_for_pdo(ec_slave_t *, ec_pdo_t *);
+unsigned int ec_slave_get_previous_port(const ec_slave_t *, unsigned int);
+unsigned int ec_slave_get_next_port(const ec_slave_t *, unsigned int);
+uint32_t ec_slave_calc_rtt_sum(const ec_slave_t *);
+ec_slave_t *ec_slave_find_next_dc_slave(ec_slave_t *);
 
 /****************************************************************************/
 
@@ -570,7 +576,7 @@ int ec_slave_fetch_sii_pdos(
 */
 
 char *ec_slave_sii_string(
-        ec_slave_t *slave, /**< EtherCAT slave */
+        const ec_slave_t *slave, /**< EtherCAT slave */
         unsigned int index /**< string index */
         )
 {
@@ -805,7 +811,7 @@ void ec_slave_attach_pdo_names(
  * \return Port index.
  */
 unsigned int ec_slave_get_previous_port(
-        ec_slave_t *slave, /**< EtherCAT slave. */
+        const ec_slave_t *slave, /**< EtherCAT slave. */
         unsigned int port_index /**< Port index. */
         )
 {
@@ -835,7 +841,7 @@ unsigned int ec_slave_get_previous_port(
  * \return Port index.
  */
 unsigned int ec_slave_get_next_port(
-        ec_slave_t *slave, /**< EtherCAT slave. */
+        const ec_slave_t *slave, /**< EtherCAT slave. */
         unsigned int port_index /**< Port index. */
         )
 {
@@ -865,7 +871,7 @@ unsigned int ec_slave_get_next_port(
  * \return Round-trip-time in ns.
  */
 uint32_t ec_slave_calc_rtt_sum(
-        ec_slave_t *slave /**< EtherCAT slave. */
+        const ec_slave_t *slave /**< EtherCAT slave. */
         )
 {
     uint32_t rtt_sum = 0, rtt;