hw/net/can: Introduce Xilinx ZynqMP CAN controller

hw/net/can: Introduce Xilinx ZynqMP CAN controller

The Xilinx ZynqMP CAN controller is developed based on SocketCAN, QEMU CAN bus
implementation. Bus connection and socketCAN connection for each CAN module
can be set through command lines.

Example for using single CAN:
    -object can-bus,id=canbus0 \
    -machine xlnx-zcu102.canbus0=canbus0 \
    -object can-host-socketcan,id=socketcan0,if=vcan0,canbus=canbus0

Example for connecting both CAN to same virtual CAN on host machine:
    -object can-bus,id=canbus0 -object can-bus,id=canbus1 \
    -machine xlnx-zcu102.canbus0=canbus0 \
    -machine xlnx-zcu102.canbus1=canbus1 \
    -object can-host-socketcan,id=socketcan0,if=vcan0,canbus=canbus0 \
    -object can-host-socketcan,id=socketcan1,if=vcan0,canbus=canbus1

To create virtual CAN on the host machine, please check the QEMU CAN docs:
https://github.com/qemu/qemu/blob/master/docs/can.txt

Signed-off-by: Vikram Garhwal <fnu.vikram@xilinx.com>
Message-id: 1605728926-352690-2-git-send-email-fnu.vikram@xilinx.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>