Ethernet - Qualcomm Dragonwing Documentation

This guide covers configuring, operating, and troubleshooting Ethernet connectivity on the Qualcomm Dragonwing IQ-8275 EVK. The platform supports interface enumeration, data path, link speed configuration, MAC address management, MTU configuration, and network diagnostics.

Prerequisites

IQ-8275 EVK hardware
Ethernet cable (RJ45)
Host PC on the same network as the IQ-8275 EVK
SSH client software
Basic Linux command-line knowledge

Architecture

Component	Description
Application Processor Subsystem (APSS)	Runs on a Linux-based operating system
Ethernet driver	Linux kernel driver providing data connectivity over a wired Ethernet interface
PHY driver	Low-level driver managing the Ethernet physical layer; implements a state machine for PHY lifecycle from initialization to link establishment; interacts with MDIO to access PHY registers
Ethernet hardware	1× QEP8081 PHY for 10/100/1000/2500 Mbps, enabled by RJ45 connector

Getting Started

Bring Up Ethernet

Establish access to the device via SSH over Wi-Fi or the serial prompt before proceeding. See the Set up the device section for instructions.

Flash the corresponding CDT on the device to ensure the correct configuration is used for Ethernet bring-up.

Configure MAC Address (optional)

The IQ-8275 EVK ships with a factory MAC address. Skip this step to use it as-is.To change the MAC address:

ip link set dev eth0  XX:XX:XX:YY:YY:YY

This MAC address is valid only for the current boot cycle. After rebooting, the device reverts to the address from persistent storage.

Assign an IP Address

On a public network, the DHCP server assigns an IP address automatically. To assign a static IP address manually:

ip addr add 192.168.1.2 dev end0

Configure MTU

ip link set dev end0 down
ip link set dev end0 mtu 1500
ip link set dev end0 up

Verify Bring-Up

Confirm the following:

end0 is visible in ip output
Interface status shows UP BROADCAST RUNNING MULTICAST
IP address is correctly assigned
MTU is set to the desired value (typically 1500)
No errors in RX/TX packet counters

Ethernet Operations

Check Connectivity

Use ping to verify connectivity between the device and a remote host. The client IP address must be in the same subnet as the device.

ping 169.254.227.240

Configure NIC Settings

ethtool end0
ethtool -S end0

Capture Network Traffic

tcpdump -i any -s 0 -w /var/log/tcpdump.pcap

View Routing Table

ip r s

Configure Link Speed

ethtool -s end0 autoneg on speed 1000 duplex full

Troubleshooting

Collect Diagnostic Logs

Collect dmesg logs

dmesg > /var/log/dmesg_logs.txt

Collect tcpdump logs

tcpdump -i any -s 0 -w /var/log/tcpdump.pcap

Press Ctrl+C to stop capture.

Pull log files to host PC

scp ubuntu@<device_ip>:/var/log/tcpdump.pcap .
scp ubuntu@<device_ip>:/var/log/dmesg_logs.txt .

Common Issues

No Link Detected

dmesg | grep -i phy
ip link show end0
ethtool end0

Solutions: Replace faulty cable, ensure both ends are securely connected, verify link partner is powered on, check for PHY driver errors in dmesg.

Cannot Ping Remote Host

ip link show end0
ip route show
netstat -r
arp -a
tcpdump -i end0 icmp

Solutions: Configure correct IP address and subnet mask; add default gateway if needed.

Slow Network Performance

ethtool end0 | grep -E "Speed|Duplex"
ethtool -S end0 | grep -E "error|drop|collision"
ip link show end0 | grep MTU

Solutions: Force 1000 Mbps full-duplex if auto-negotiation fails; replace cable if errors are detected.

Interface Not Detected

ip link show
dmesg | grep -i ethernet
ls /sys/class/net/

Solutions: Ensure correct CDT is flashed; verify Ethernet driver is compiled in kernel; reboot and check again.

Command Reference

Command	Purpose	Example
`dmesg`	View kernel messages	`dmesg \| grep eth`
`ethtool <if>`	Check link status	`ethtool end0`
`ethtool -S <if>`	View NIC statistics	`ethtool -S end0`
`ip addr show`	Show IP addresses	`ip addr show end0`
`ip route show`	Show routing table	`ip route show`
`ping <host>`	Test connectivity	`ping 192.168.1.10`
`tcpdump -i <if>`	Capture packets	`tcpdump -i end0`
`netstat -r`	Show routes	`netstat -r`
`arp -a`	Show ARP table	`arp -a`

​Prerequisites

​Architecture

​Getting Started

​Bring Up Ethernet

​Ethernet Operations

​Check Connectivity

​Configure NIC Settings

​Capture Network Traffic

​View Routing Table

​Configure Link Speed

​Troubleshooting

​Collect Diagnostic Logs

​Common Issues

​Command Reference

​Resources

Prerequisites

Architecture

Getting Started

Bring Up Ethernet

Ethernet Operations

Check Connectivity

Configure NIC Settings

Capture Network Traffic

View Routing Table

Configure Link Speed

Troubleshooting

Collect Diagnostic Logs

Common Issues

Command Reference

Resources