tree e52c3340ac237054e31372f0812fa6ed88fd8a8d
parent 3ae89dce569862f3a20730260e93a6ca995c85d6
author Andrew Jeffery <andrew@aj.id.au> 1611752058 +1030
committer Andrew Jeffery <andrew@aj.id.au> 1611889479 +1030

core: Drop messages sent before binding enables transmission

Some bindings (astlpc) have a handshake that must occur before packets
can be sent across the bus, but after the binding instance has been
constructed. Similarly, some bindings (astlpc) require coordination of
resources between endpoints as part of regular operation, which
motivates the existence of the associated `tx_enabled` state.

If a binding invokes mctp_binding_set_tx_enabled() with a `true`
argument it implies that all required handshaking has been completed
(if it had not, we still would not be able to send packets).

Switch `tx_enabled` from a boolean to a ternary state machine to capture
the `constructed` state of a binding (before required handshaking has
completed). Further, error out if mctp_message_tx_on_bus() is invoked
with a binding in the `constructed` state, as it's possible the
information required to correctly packetise the provided message is
invalid.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Change-Id: If4baf07ab5fe7edd7f522fac29e32fc5c2a6105d