I assume that you are using LSDK 2004 Linux Kernel 5.4.
Please refer to the attached script for switch configuration without bridge.
root@ls1028ardb:~# bash +x enetc_switch_cpu_port_without_bridge_dsa.sh
root@ls1028ardb:~# ifconfig swp3 down
root@ls1028ardb:~# echo $?
0
root@ls1028ardb:~# ifconfig swp3 100.1.1.29 netmask 255.255.255.0
[ 90.042476] mscc_felix 0000:00:00.5 swp3: configuring for inband/qsgmii link mode
[ 90.050569] 8021q: adding VLAN 0 to HW filter on device swp3
root@ls1028ardb:~# echo $?
0
root@ls1028ardb:~# [ 93.131335] mscc_felix 0000:00:00.5 swp3: Link is Up - 1Gbps/Full - flow control off
[ 93.139218] IPv6: ADDRCONF(NETDEV_CHANGE): swp3: link becomes ready
ifconfig swp0 up
root@ls1028ardb:~# echo $?
0
root@ls1028ardb:~# ping -c 5 -s 1 100.1.1.1