Enet Layer 2 CPSW SWITCH Example
Introduction
The layer 2 cpsw switch example is dedicated to demonstrate usage of Enet CPSW3G peripheral operation as a basic switch.
On AM62PX, we can do ethernet based communication using CPSW HW mechanism
This is a standard ethernet switch + port HW
This example does the following:
Target-side application:
Target-side application running on a Cortex-R5F core.
Application receives the broadcast packet for switch operation, copies the payload into a new packet which is then sent back out to the source port as well as to all the other ports on the device.
The application has a menu to enable/disable features, such as getting MAC address and stats. This menu along with application logs is implemented via UART.
Host-side functionality
Software applications like Colasoft Pkt Builder or packETH tool could be used to generate and send packets, Wireshark can be used to receive and verify packet contents
The data path enabled in this example is as follows:
Host side (PC) application sends a broadcast packet to MAC port.
Target side application receives the broadcast packet, updates the MAC addresses in the Layer-2 header and sends the packet back out to the source port as well as to all the other ports on the device.
Application like Wireshark (PC) receives the packet and it can be seen in the capture window.
Cut-thru Switching
Cut-through feature allows forwarding packets from one external port to another without being stored in Port FIFOs, thus reducing overall latency for packet forwarding.
Limitations:
Cut-through forwarding is only supported between external ports and there is currently no support for Cut-Through to host port.
Cut-Thru is not supported with 10/100 half-duplex.
Cut-Thru is not supported with any form of flow control.
If Intersperced Express Traffic (IET) is enabled, then Cut-through can only be enabled on an express priority queue and not on preemptible queues.
Steps to enable Cut-thru switching:
Set cutThruEnable Control register.
Set rxPriCutThruEn(RX priority queue) and txPriCutThruEn(TX priority queue) which represents the priorty queues for which cut-through feature needs to be enabled.
Set portSpeedAutoEn for automatic detection of speed.
Set CPSW frequency in Mhz, which is used in auto speed detection for cut-thru operations.
Supported Combinations
Parameter |
Value |
|---|---|
CPU + OS |
wkup-r5fss0-0_freertos |
Toolchain |
ti-arm-clang |
Board |
am62px-sk |
Example folder |
source/networking/enet/core/examples/enet_layer2_cpsw_switch/V0 |
Steps to Run the Example
Build the example
When using CCS projects to build, import the CCS project for the required combination and build it using the CCS project menu (see Using SDK with CCS Projects).
When using makefiles to build, note the required combination and build using make command (see Using SDK with Makefiles)
HW Setup
Note
Make sure you have setup the EVM with cable connections. Refer to the appropriate EVM Setup guide:
In addition do below steps. Since the example runs on wkup R5, we cannot use CCS loading. Use example flashing methods shown in the EVM Setup guide above.
AM62PX-SK
For CPSW based example
Connect two ethernet cables to the CPSW RGMII 1 and CPSW RGMII 2 ports in AM62PX-SK from host PC as shown below
Ethernet cable for CPSW based ethernet
Run the example
Attention
If you need to reload and run again, a CPU power-cycle is MUST
Launch a CCS debug session and run the example executable, see CCS Launch, Load and Run
You will see logs in the UART terminal as shown in the next section.
We can start sending multicast packets from Colasoft Pkt Builder or packETH tool.
In the Colasoft Pkt Builder, click on Add icon , select any layer2 Packet and click ok.
Edit the source and destination address in the decode editor.
Click on send icon and select the ethernet adapater.
Click start, packets will be send to the target.
Capture the packets in Wireshark.
Colasoft Pkt Builder to generate and send packets
Sample output for Multiport example
==========================
Layer 2 CPSW SWITCH Test
==========================
Init all peripheral clocks
----------------------------------------------
Enabling clocks!
Create RX tasks
----------------------------------------------
cpsw-3g: Create RX task
Open all peripherals
----------------------------------------------
cpsw-3g: Open enet
EnetAppUtils_reduceCoreMacAllocation: Reduced Mac Address Allocation for CoreId:1 From 4 To 1
Init all configs
----------------------------------------------
cpsw-3g: init config
cpsw-3g: Open port 1
EnetPhy_bindDriver:1842
cpsw-3g: Open port 2
EnetPhy_bindDriver:1842
PHY 0 is alive
PHY 1 is alive
Attach core id 1 on all peripherals
----------------------------------------------
cpsw-3g: Attach core
cpsw-3g: Open DMA
initQs() txFreePktInfoQ initialized with 16 pkts
cpsw-3g: Waiting for link up...
Cpsw_handleLinkUp:1450
MAC Port 2: link up
Cpsw_handleLinkUp:1450
MAC Port 1: link up
cpsw-3g: Port 1 link is up
cpsw-3g: Port 2 link is up
cpsw-3g: MAC port addr: 58:a1:5f:b8:8c:e6
Enet L2 cpsw Menu:
's' - Print statistics
'r' - Reset statistics
'm' - Show allocated MAC addresses
'p' - Enable Policer for rate limiting
'x' - Stop the test
s
Print statistics
----------------------------------------------
cpsw-3g - Port 1 statistics
--------------------------------
cpsw-3g - Port 2 statistics
--------------------------------
p
Rate limiting Enabled port 1 on Src MAC 02:00:00:00:00:08
s
Print statistics
----------------------------------------------
rxGoodFrames = 100000
rxOctets = 101800000
txGoodFrames = 100000
txBcastFrames = 100000
txOctets = 101800000
octetsFrames512to1023 = 200000
netOctets = 203600000
txPri[0] = 100000
txPriBcnt[0] = 101800000
cpsw-3g - Port 1 statistics
--------------------------------
txGoodFrames = 150000
txBcastFrames = 100000
txOctets = 152700000
octetsFrames512to1023 = 150000
netOctets = 152700000
txPri[0] = 150000
txPriBcnt[0] = 152700000
rxGoodFrames = 100000
rxOctets = 101800000
txGoodFrames = 100000
txBcastFrames = 100000
txOctets = 101800000
octetsFrames512to1023 = 200000
netOctets = 203600000
txPri[0] = 100000
txPriBcnt[0] = 101800000
cpsw-3g - Port 2 statistics
--------------------------------
rxGoodFrames = 100000
rxBcastFrames = 100000
rxOctets = 101800000
txGoodFrames = 50000
txOctets = 50900000
octetsFrames512to1023 = 150000
netOctets = 152700000
aleUnknownBcast = 1
aleUnknownBcastBcnt = 1018
txPri[0] = 50000
txPriBcnt[0] = 50900000
On Wireshark we can see the packets received:
Testing Switch Policer configuration
Enable the policer using ‘p’ option in target UART terminal menu option.
Send Layer-2 packets with below configurations
Source MAC address - 02:00:00:00:00:08
ingress port - PORT 1
Destination MAC address - any
Ether_type = 0x8600
Data rate - more than 25 mbps
Observe that packets are switched by limiting data rate to 25 mpbs.
Observe that the dropped packets are marked with ‘alePolicyMatchRed’ in CPSW statistics print.