can: at91_can: switch to rx-offload implementation
The current at91_can driver uses NAPI to handle RX'ed CAN frames, the
RX IRQ is disabled and a NAPI poll is scheduled. Then in
at91_poll_rx() the RX'ed CAN frames are tried to read in order from
the device.
This approach has 2 drawbacks:
- Under high system load it might take too long from the initial RX
IRQ to the NAPI poll function to run. This causes RX buffer
overflows.
- The algorithm to read the CAN frames in order is not bullet proof
and may fail under certain use cases/system loads.
The rx-offload helper fixes these problems by reading the RX'ed CAN
frames in the interrupt handler and adding it to a list sorted by RX
timestamp. This list of RX'ed SKBs is then passed to the networking
stack via NAPI.
Convert the RX path to rx-offload, pass all CAN error frames with
can_rx_offload_queue_timestamp().
Link: https://lore.kernel.org/all/20231005-at91_can-rx_offload-v2-27-9987d53600e0@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>