A driver can call the following functions to notify the network stack that the driver's state has changed.
void mac_tx_update(mac_handle_t mh);
The mac_tx_update(9F) function notifies the framework that more TX descriptors are available. If mc_tx() returns a non-empty chain of packets, then the driver must call mac_tx_update() as soon as possible after resources are available to inform the MAC layer to retry the packets that were returned as not sent. See Transmit Data Path for more information about the mc_tx() entry point.
void mac_link_update(mac_handle_t mh, link_state_t new_state);
The mac_link_update(9F) function notifies the MAC layer that the state of the media link has changed. The new_state argument must be one of the following values:
The media link is up.
The media link is down.
The media link is unknown.