boards/mips: Add networking support to CI20 board

[ldube]

Summary

Introduce networking capabilities to the Creator CI20 board by leveraging the pre-existing dm9000 ethernet driver.

To achieve this, the following changes were made:

• Integrated the jz4780 GPIO module to properly configure and enable the interrupt pin required by the ethernet controller.
• Added dm90x0.h to export the dm9000 initialization function, allowing the board-specific setup code to initialize the network interface.

Testing

$
$ ping 192.168.2.3
PING 192.168.2.3 (192.168.2.3) 56(84) bytes of data.
64 bytes from 192.168.2.3: icmp_seq=1 ttl=64 time=0.301 ms
64 bytes from 192.168.2.3: icmp_seq=2 ttl=64 time=0.333 ms
64 bytes from 192.168.2.3: icmp_seq=3 ttl=64 time=0.356 ms
^C
--- 192.168.2.3 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2025ms
rtt min/avg/max/mdev = 0.301/0.330/0.356/0.022 ms
$ telnet 192.168.2.3
Trying 192.168.2.3...
Connected to 192.168.2.3.
Escape character is '^]'.

NuttShell (NSH) NuttX-13.0.0
nsh> uname -a
NuttX 13.0.0 a02f926 Jul 16 2026 10:55:00 mips ci20
nsh> ls /dev
/dev:
console
null
telnet
telnet0
ttyS0
zero
nsh>

[github-actions]

MemBrowse Memory Report

No memory changes detected for:

• arduino-mega2560
• esp32-devkitc
• hifive1-revb
• mirtoo
• qemu-armv8a
• qemu-intel64
• rx65n-rsk2mb
• s698pm-dkit
• stm32-nucleo-f103rb

[linguini1]

Awesome! Can you add the new config under Configurations in the docs like you did with the nsh config in the last patch?

[acassis]

@xiaoxiang781216 could you please review? Please wait for the board profile Documentation

[xiaoxiang781216]

@xiaoxiang781216 could you please review? Please wait for the board profile Documentation

I am waiting @ldube fix the ci break, the change look good.

[ldube]

@xiaoxiang781216 You committed the fix, I think, e35129b

[ldube]

@linguini1 Yes, I updated the document.

[acassis]

@xiaoxiang781216 You committed the fix, I think, e35129b

Sorry @ldube I only see your question now. I think you already figured it out. When you add a new board profile you should add Documentation to let people know how to use it

[acassis]

@ldube please change the "net" name to "netnsh" this is the default name that Greg selected when telnet is used to access the nsh.
We have this standard namings:
nsh -> only basic serial console access
netnsh -> nsh access over telnet
usbnsh -> nsh access over CDC/ACM device

You can look at other boards to see this pattern, maybe we need to document this rule in some place to avoid contributors to spend time with it.

I didn't pay attention to it when I approved this PR, only after reading your Documentation I noticed your goal to use telnet to access nsh.

[acassis]

I'm confuse here, I noticed you enabled "CONFIG_16550_UART0_SERIAL_CONSOLE=y", so your goal is not to have netnsh be default, correct? If this is the case "net" name is fine!