The original NCSI channel monitoring was implemented based on a
backoff algorithm: the GLS response should be received in the
specified interval. Otherwise, the channel is regarded as dead
and failover should be taken if current channel is an active one.
There are several problems in the implementation: (A) On BCM5718,
we found when the IID (Instance ID) in the GLS command packet
changes from 255 to 1, the response corresponding to IID#1 never
comes in. It means we cannot make the unfair judgement that the
channel is dead when one response is missed. (B) The code's
readability should be improved. (C) We should do failover when
current channel is active one and the channel monitoring should
be marked as disabled before doing failover.

This reworks the channel monitoring to address all above issues.
The fields for channel monitoring is put into separate struct
and the state of channel monitoring is predefined. The channel
is regarded alive if the network controller responses to one of
two GLS commands or both of them in 5 seconds.
Signed-off-by: NGavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: NJoel Stanley <joel@jms.id.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There is only one NCSI request property for now: the response for
the sent command need drive the workqueue or not. So we had one
field (@driven) for the purpose. We lost the flexibility to extend
NCSI request properties.

This replaces @driven with @flags and @req_flags in NCSI request
and NCSI command argument struct. Each bit of the newly introduced
field can be used for one property. No functional changes introduced.
Signed-off-by: NGavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: NJoel Stanley <joel@jms.id.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This introduces NCSI AEN packet handlers that result in (A) the
currently active channel is reconfigured; (B) Currently active
channel is deconfigured and disabled, another channel is chosen
as active one and configured. Case (B) won't happen if hardware
arbitration has been enabled, the channel that was in active
state is suspended simply.
Signed-off-by: NGavin Shan <gwshan@linux.vnet.ibm.com>
Acked-by: NJoel Stanley <joel@jms.id.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This manages NCSI packages and channels:

 * The available packages and channels are enumerated in the first
   time of calling ncsi_start_dev(). The channels' capabilities are
   probed in the meanwhile. The NCSI network topology won't change
   until the NCSI device is destroyed.
 * There in a queue in every NCSI device. The element in the queue,
   channel, is waiting for configuration (bringup) or suspending
   (teardown). The channel's state (inactive/active) indicates the
   futher action (configuration or suspending) will be applied on the
   channel. Another channel's state (invisible) means the requested
   action is being applied.
 * The hardware arbitration will be enabled if all available packages
   and channels support it. All available channels try to provide
   service when hardware arbitration is enabled. Otherwise, one channel
   is selected as the active one at once.
 * When channel is in active state, meaning it's providing service, a
   timer started to retrieve the channe's link status. If the channel's
   link status fails to be updated in the determined period, the channel
   is going to be reconfigured. It's the error handling implementation
   as defined in NCSI spec.
Signed-off-by: NGavin Shan <gwshan@linux.vnet.ibm.com>
Acked-by: NJoel Stanley <joel@jms.id.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The NCSI response packets are sent to MC (Management Controller)
from the remote end. They are responses of NCSI command packets
for multiple purposes: completion status of NCSI command packets,
return NCSI channel's capability or configuration etc.

This defines struct to represent NCSI response packets and introduces
function ncsi_rcv_rsp() which will be used to receive NCSI response
packets and parse them.
Signed-off-by: NGavin Shan <gwshan@linux.vnet.ibm.com>
Acked-by: NJoel Stanley <joel@jms.id.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>