According to IEEE 802.1AS-2011, the BMCA used in gPTP is the same
as that used in IEEE 1588 with the following exceptions:
(1) Announce messages received on a slave port that were not sent
by the receiving time-aware system are used immediately,
i.e., there is no foreign-master qualification.
(2) A port that the BMCA determines should be a master port enters
the master state immediately, i.e., there is no pre-master state.
(3) The uncalibrated state is not needed and, therefore, not used.
(4) All time-aware systems are required to participate in best master
selection (even if it is not grandmaster capable).
This patch is to support (1) by using a specific FOREIGN_MASTER_THRESHOLD
case. (Treat FOREIGN_MASTER_THRESHOLD as 1.)
To support (2) and (3), reuse ptp_fsm and drop pre-master/uncalibrated
states. The (4) item is supported since IEEE 802.1AS reuses OC/BC.
Signed-off-by: Erik Hons <erik.hons@ni.com>
Signed-off-by: Rodney Greenstreet <rodney.greenstreet@ni.com>
Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
The state machines in 1588 do not specify an event that causes a transition
out of the initializing state. This was left as a local issue. For this
transition, the current code assigns the next state outside of the FSM. But
doing so prevents an alternative FSM to handle this transition differently.
By introducing a new event, this patch places this transition where it
belongs, namely under the control of the FSM code,
Signed-off-by: Richard Cochran <richardcochran@gmail.com>
The state machine needs to know whether a new master has just been
selected in order to choose between the slave and uncalibrated states.
Signed-off-by: Richard Cochran <richardcochran@gmail.com>
We already have a grand master state. Adding this event will simplify the
overall logic, since it will avoid the silly requirement to set the
qualification timeout to zero when entering the grand master state.
Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Yangbo Lu
Richard Cochran