/**
* \brief Calculates backoff duration and handles the start of the CCA
*/
static void csma_backoff_calculation(void)
{
uint32_t current_CAP_duration_sym;
uint32_t current_CAP_end_sym;
uint32_t next_backoff_boundary_us;
uint32_t now_time_sym;
uint32_t guard_time_before_next_beacon;
/* \TODO consider CFP and BLE mode */
current_CAP_duration_sym = TAL_GET_SUPERFRAME_DURATION_TIME(
tal_pib.SuperFrameOrder);
current_CAP_end_sym = tal_add_time_symbols(tal_pib.BeaconTxTime,
current_CAP_duration_sym);
/*
* Add some guard time to ensure that the transaction is completed
* before
* the timer fires that is going to track the next beacon.
*/
guard_time_before_next_beacon = TAL_RADIO_WAKEUP_TIME_SYM <<
(tal_pib.BeaconOrder + 2);
guard_time_before_next_beacon += TAL_CONVERT_US_TO_SYMBOLS(
PRE_BEACON_GUARD_TIME_US);
current_CAP_end_sym = tal_sub_time_symbols(current_CAP_end_sym,
guard_time_before_next_beacon);
/* Calculate next backoff period boundary. */
{
uint32_t time_since_last_beacon_sym;
uint32_t next_backoff_boundary_period;
pal_get_current_time(&now_time_sym);
now_time_sym = TAL_CONVERT_US_TO_SYMBOLS(now_time_sym);
time_since_last_beacon_sym = tal_sub_time_symbols(now_time_sym,
tal_pib.BeaconTxTime);
next_backoff_boundary_period = time_since_last_beacon_sym /
aUnitBackoffPeriod;
if ((time_since_last_beacon_sym % aUnitBackoffPeriod) > 0) {
next_backoff_boundary_period++;
}
next_backoff_boundary_us
= TAL_CONVERT_SYMBOLS_TO_US(
pal_add_time_us(tal_pib.BeaconTxTime,
(next_backoff_boundary_period *
aUnitBackoffPeriod)));
}
/* Check if we are still within the CAP. */
if (next_backoff_boundary_us >=
TAL_CONVERT_SYMBOLS_TO_US(current_CAP_end_sym)) {
/* current CAP is over, wait for next CAP */
tal_csma_state = BACKOFF_WAITING_FOR_BEACON;
start_beacon_loss_timer();
} else { /* next backoff boundary is within current CAP */
uint32_t remaining_periods_in_CAP; /* \TODO check if variable
* size can be reduced */
/* Check if the remaining backoff time will expire in current
* CAP. */
remaining_periods_in_CAP = tal_sub_time_symbols(
current_CAP_end_sym, now_time_sym) /
aUnitBackoffPeriod;
if (remaining_backoff_periods > remaining_periods_in_CAP) {
/*
* Reduce the backoff peridos by the remaining duration
* in
* the current CAP and continue in next CAP.
*/
remaining_backoff_periods -= remaining_periods_in_CAP;
tal_csma_state = BACKOFF_WAITING_FOR_BEACON;
start_beacon_loss_timer();
} else { /* there are enough backoff periods in current CAP */
uint32_t time_after_transaction_sym; /* \TODO check if
* variable size
* can be reduced
**/
uint32_t transaction_duration_sym; /* \TODO check if
* variable size can
* be reduced */
/* Add some guard time to wakeup the transceiver. */
transaction_duration_sym
= (transaction_duration_periods *
aUnitBackoffPeriod) +
TAL_CONVERT_US_TO_SYMBOLS(
SLEEP_TO_TRX_OFF_TYP_US +
CCA_GUARD_DURATION_US);
time_after_transaction_sym
= tal_add_time_symbols(TAL_CONVERT_US_TO_SYMBOLS(
next_backoff_boundary_us),
transaction_duration_sym);
/* Check if the entire transaction fits into the current
* CAP. */
if (time_after_transaction_sym < current_CAP_end_sym) {
retval_t timer_status;
uint32_t callback_start_time;
/* Calculate the time needed to backoff. */
cca_starttime_us
= pal_add_time_us(
next_backoff_boundary_us,
TAL_CONVERT_SYMBOLS_TO_US(
remaining_backoff_periods *
aUnitBackoffPeriod));
/*
* Ensure that wakeup time is available before
* CCA.
* The required duration depends on the current
* trx status.
* Assume here the worst case: trx is in SLEEP.
*/
/*
* \TODO depending on the duration that we need
* to backoff,
* set trx to SLEEP, TRX_OFF or PLL_ON
* meanwhile.
*/
while (pal_sub_time_us(cca_starttime_us,
TAL_CONVERT_SYMBOLS_TO_US(
now_time_sym)) <
(SLEEP_TO_TRX_OFF_TYP_US +
CCA_GUARD_DURATION_US)) {
cca_starttime_us
= pal_add_time_us(
cca_starttime_us,
TAL_CONVERT_SYMBOLS_TO_US(
aUnitBackoffPeriod));
}
/*
* Start the CCA timer.
* Add some time to locate the next backoff
* boundary
* once CCA timer fires.
*/
callback_start_time
= pal_sub_time_us(cca_starttime_us,
(SLEEP_TO_TRX_OFF_TYP_US +
CCA_PREPARATION_DURATION_US));
timer_status = pal_timer_start(TAL_CSMA_CCA,
callback_start_time,
TIMEOUT_ABSOLUTE,
(FUNC_PTR)cca_timer_handler_cb,
NULL);
if (timer_status == MAC_SUCCESS) {
tal_csma_state
= BACKOFF_WAITING_FOR_CCA_TIMER;
} else if (timer_status ==
PAL_TMR_INVALID_TIMEOUT) {
/* Start the CCA immediately. */
cca_timer_handler_cb(NULL);
} else {
tal_csma_state = CSMA_ACCESS_FAILURE;
Assert("CCA timer start problem" == 0);
}
/* debug pin to switch on: define
* ENABLE_DEBUG_PINS, pal_config.h */
PIN_BACKOFF_START();
} else {
/* Restart again after next beacon. */
NB = 0;
remaining_backoff_periods
= (uint8_t)(rand() &
((1 << BE) - 1));
tal_csma_state = BACKOFF_WAITING_FOR_BEACON;
start_beacon_loss_timer();
}
}
}
}
/**
* @brief Continues processing a data indication from the TAL for
* non-polling and non-scanning states of the MAC
* (mac_poll_state == MAC_POLL_IDLE, mac_scan_state == MAC_SCAN_IDLE).
*
* @param b_ptr Pointer to the buffer header.
* @param f_ptr Pointer to the frame_info_t structure.
*
* @return bool True if frame has been processed, or false otherwise.
*/
static bool process_data_ind_not_transient(buffer_t *b_ptr, frame_info_t *f_ptr)
{
bool processed_in_not_transient = false;
/*
* We are in MAC_POLL_IDLE and MAC_SCAN_IDLE now,
* so continue with the real MAC states.
*/
switch (mac_state) {
#if (MAC_START_REQUEST_CONFIRM == 1)
case MAC_PAN_COORD_STARTED:
{
switch (mac_parse_data.frame_type) {
case FCF_FRAMETYPE_MAC_CMD:
{
switch (mac_parse_data.mac_command) {
#if (MAC_ASSOCIATION_INDICATION_RESPONSE == 1)
case ASSOCIATIONREQUEST:
mac_process_associate_request(b_ptr);
processed_in_not_transient = true;
break;
#endif /* (MAC_ASSOCIATION_INDICATION_RESPONSE == 1) */
#if (MAC_DISASSOCIATION_BASIC_SUPPORT == 1)
case DISASSOCIATIONNOTIFICATION:
mac_process_disassociate_notification(b_ptr);
processed_in_not_transient = true;
break;
#endif /* (MAC_DISASSOCIATION_BASIC_SUPPORT == 1) */
#if (MAC_INDIRECT_DATA_FFD == 1)
case DATAREQUEST:
if (indirect_data_q.size > 0) {
mac_process_data_request(b_ptr);
processed_in_not_transient = true;
} else {
mac_handle_tx_null_data_frame();
}
break;
#endif /* (MAC_INDIRECT_DATA_FFD == 1) */
#if (MAC_ORPHAN_INDICATION_RESPONSE == 1)
case ORPHANNOTIFICATION:
mac_process_orphan_notification(b_ptr);
processed_in_not_transient = true;
break;
#endif /* (MAC_ORPHAN_INDICATION_RESPONSE == 1) */
case BEACONREQUEST:
mac_process_beacon_request(b_ptr);
processed_in_not_transient = true;
break;
#if (MAC_PAN_ID_CONFLICT_AS_PC == 1)
case PANIDCONFLICTNOTIFICAION:
mac_sync_loss(MAC_PAN_ID_CONFLICT);
break;
#endif /* (MAC_PAN_ID_CONFLICT_AS_PC == 1) */
#ifdef GTS_SUPPORT
case GTSREQUEST:
mac_process_gts_request(b_ptr);
processed_in_not_transient = true;
#endif /* GTS_SUPPORT */
default:
break;
}
}
break;
case FCF_FRAMETYPE_DATA:
mac_process_data_frame(b_ptr);
processed_in_not_transient = true;
break;
#if (MAC_PAN_ID_CONFLICT_AS_PC == 1)
case FCF_FRAMETYPE_BEACON:
/* PAN-Id conflict detection as PAN-Coordinator. */
/* Node is not scanning. */
check_for_pan_id_conflict_as_pc(false);
break;
#endif /* (MAC_PAN_ID_CONFLICT_AS_PC == 1) */
default:
break;
}
}
break;
/* MAC_PAN_COORD_STARTED */
#endif /* (MAC_START_REQUEST_CONFIRM == 1) */
case MAC_IDLE:
#if (MAC_ASSOCIATION_REQUEST_CONFIRM == 1)
case MAC_ASSOCIATED:
#endif /* (MAC_ASSOCIATION_REQUEST_CONFIRM == 1) */
#if (MAC_START_REQUEST_CONFIRM == 1)
case MAC_COORDINATOR:
#endif /* (MAC_START_REQUEST_CONFIRM == 1) */
{
/* Is it a Beacon from our parent? */
switch (mac_parse_data.frame_type) {
#if (MAC_SYNC_REQUEST == 1)
case FCF_FRAMETYPE_BEACON:
{
uint32_t beacon_tx_time_symb;
/* Check for PAN-Id conflict being NOT a PAN
* Corodinator. */
#if (MAC_PAN_ID_CONFLICT_NON_PC == 1)
if (mac_pib.mac_AssociatedPANCoord &&
(MAC_IDLE !=
mac_state)) {
check_for_pan_id_conflict_non_pc(false);
}
#endif /* (MAC_PAN_ID_CONFLICT_NON_PC == 1) */
/* Check if the beacon is received from my
* parent. */
if ((mac_parse_data.src_panid ==
tal_pib.PANId) &&
(((mac_parse_data.src_addr_mode
== FCF_SHORT_ADDR) &&
(mac_parse_data.src_addr.
short_address ==
mac_pib.mac_CoordShortAddress))
||
((mac_parse_data.src_addr_mode
== FCF_LONG_ADDR) &&
(mac_parse_data.src_addr.
long_address ==
mac_pib.mac_CoordExtendedAddress))))
{
beacon_tx_time_symb
= TAL_CONVERT_US_TO_SYMBOLS(
f_ptr->time_stamp);
#if (_DEBUG_ > 0)
retval_t set_status =
#endif
set_tal_pib_internal(macBeaconTxTime,
(void *)&beacon_tx_time_symb);
#if (_DEBUG_ > 0)
Assert(MAC_SUCCESS == set_status);
#endif
if ((MAC_SYNC_TRACKING_BEACON ==
mac_sync_state)
||
(MAC_SYNC_BEFORE_ASSOC
==
mac_sync_state)
) {
uint32_t nxt_bcn_tm;
uint32_t beacon_int_symb;
/* Process a received beacon. */
mac_process_beacon_frame(b_ptr);
/* Initialize beacon tracking
* timer. */
{
retval_t tmr_start_res
= FAILURE;
#ifdef BEACON_SUPPORT
if (tal_pib.BeaconOrder
<
NON_BEACON_NWK)
{
beacon_int_symb
=
TAL_GET_BEACON_INTERVAL_TIME(
tal_pib.BeaconOrder);
} else
#endif /* BEACON_SUPPORT */
{
beacon_int_symb
=
TAL_GET_BEACON_INTERVAL_TIME(
BO_USED_FOR_MAC_PERS_TIME);
}
pal_timer_stop(
T_Beacon_Tracking_Period);
#if (_DEBUG_ > 0)
if (pal_is_timer_running(
T_Beacon_Tracking_Period))
{
Assert(
"Bcn tmr running" ==
0);
}
#endif
do {
/*
* Calculate the
* time for next
* beacon
* transmission
*/
beacon_tx_time_symb
=
tal_add_time_symbols(
beacon_tx_time_symb,
beacon_int_symb);
/*
* Take into
* account the
* time taken by
* the radio to
* wakeup from
* sleep state
*/
nxt_bcn_tm
=
tal_sub_time_symbols(
beacon_tx_time_symb,
TAL_RADIO_WAKEUP_TIME_SYM <<
(
tal_pib
.
BeaconOrder
+
2));
tmr_start_res
=
pal_timer_start(
T_Beacon_Tracking_Period,
TAL_CONVERT_SYMBOLS_TO_US(
nxt_bcn_tm),
TIMEOUT_ABSOLUTE,
(
FUNC_PTR)mac_t_tracking_beacons_cb,
NULL);
} while (MAC_SUCCESS !=
tmr_start_res);
#ifdef GTS_DEBUG
port_pin_toggle_output_level(
DEBUG_PIN1);
port_pin_set_output_level(
DEBUG_PIN2,
0);
#endif
}
/*
* Initialize superframe timer
* if required only
* for devices because
* Superframe timer is already
* running for
* coordinator.
*/
/* TODO */
if (MAC_ASSOCIATED ==
mac_state) {
mac_superframe_state
= MAC_ACTIVE_CAP;
/* Check whether the
* radio needs to be
* woken up. */
mac_trx_wakeup();
/* Set transceiver in rx
* mode, otherwise it
* may stay in
* TRX_OFF). */
tal_rx_enable(PHY_RX_ON);
if (tal_pib.
SuperFrameOrder
<
tal_pib
.
BeaconOrder)
{
pal_timer_start(
T_Superframe,
TAL_CONVERT_SYMBOLS_TO_US(
TAL_GET_SUPERFRAME_DURATION_TIME(
tal_pib
.
SuperFrameOrder)),
TIMEOUT_RELATIVE,
(
FUNC_PTR)mac_t_start_inactive_device_cb,
NULL);
#ifdef GTS_DEBUG
port_pin_set_output_level(
DEBUG_PIN2,
1);
#endif
}
#ifdef GTS_SUPPORT
if (mac_final_cap_slot <
FINAL_CAP_SLOT_DEFAULT)
{
uint32_t
gts_tx_time
= (
TAL_CONVERT_SYMBOLS_TO_US(
TAL_GET_SUPERFRAME_DURATION_TIME(
tal_pib
.
SuperFrameOrder))
>>
4)
* (
mac_final_cap_slot
+
1);
pal_timer_start(
T_CAP, gts_tx_time,
TIMEOUT_RELATIVE,
(
FUNC_PTR)mac_t_gts_cb,
NULL);
#ifdef GTS_DEBUG
port_pin_set_output_level(
DEBUG_PIN3,
1);
#endif
}
#endif /* GTS_SUPPORT */
}
/* Initialize missed beacon
* timer. */
mac_start_missed_beacon_timer();
/* A device that is neither
* scanning nor polling shall go
* to sleep now. */
if (
(MAC_COORDINATOR !=
mac_state)
&&
(MAC_SCAN_IDLE ==
mac_scan_state)
&&
(MAC_POLL_IDLE ==
mac_poll_state)
) {
/*
* If the last received
* beacon frame from our
* parent
* has indicated pending
* broadbast data, we
* need to
* stay awake, until the
* broadcast data has
* been received.
*/
if (!
mac_bc_data_indicated)
{
/* Set radio to
* sleep if
* allowed */
mac_sleep_trans();
}
}
} else if (MAC_SYNC_ONCE ==
mac_sync_state) {
mac_process_beacon_frame(b_ptr);
/* Do this after processing the
* beacon. */
mac_sync_state = MAC_SYNC_NEVER;
/* A device that is neither
* scanning nor polling shall go
* to sleep now. */
if (
(MAC_COORDINATOR !=
mac_state)
&&
(MAC_SCAN_IDLE ==
mac_scan_state)
&&
(MAC_POLL_IDLE ==
mac_poll_state)
) {
/*
* If the last received
* beacon frame from our
* parent
* has indicated pending
* broadbast data, we
* need to
* stay awake, until the
* broadcast data has
* been received.
*/
if (!
mac_bc_data_indicated)
{
/* Set radio to
* sleep if
* allowed */
mac_sleep_trans();
}
}
} else {
/* Process the beacon frame */
bmm_buffer_free(b_ptr);
}
processed_in_not_transient = true;
} else {
