This patch extends the br_mrp_switchdev functions to be able to have a
better understanding what cause the issue and if the SW needs to be used
as a backup.
There are the following cases:
- when the code is compiled without CONFIG_NET_SWITCHDEV. In this case
return success so the SW can continue with the protocol. Depending
on the function, it returns 0 or BR_MRP_SW.
- when code is compiled with CONFIG_NET_SWITCHDEV and the driver doesn't
implement any MRP callbacks. In this case the HW can't run MRP so it
just returns -EOPNOTSUPP. So the SW will stop further to configure the
node.
- when code is compiled with CONFIG_NET_SWITCHDEV and the driver fully
supports any MRP functionality. In this case the SW doesn't need to do
anything. The functions will return 0 or BR_MRP_HW.
- when code is compiled with CONFIG_NET_SWITCHDEV and the HW can't run
completely the protocol but it can help the SW to run it. For
example, the HW can't support completely MRM role(can't detect when it
stops receiving MRP Test frames) but it can redirect these frames to
CPU. In this case it is possible to have a SW fallback. The SW will
try initially to call the driver with sw_backup set to false, meaning
that the HW should implement completely the role. If the driver returns
-EOPNOTSUPP, the SW will try again with sw_backup set to false,
meaning that the SW will detect when it stops receiving the frames but
it needs HW support to redirect the frames to CPU. In case the driver
returns 0 then the SW will continue to configure the node accordingly.
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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