zephyr: STM32F74X RMII interface does not work

Describe the bug Hello.

I’m testing MII & RMII controllers with stm32f745. I have a custom board that has stm32f745 + lan9303 mii controller. lan9303 is run in un-managed state, and I tested ping to my desktop PC via NETWORK_SHELL. in this case, ping works very well. And then, I make a test in same condition with stm32f745 + rtl8304 which is rmii controller, but it does not work.

I thought there may be hardware issue, so continued with NUCLEO-F746zg, which has lan8742a RMII controller. and got same result.

I’m originally using Zephyr 2.2.99 but also tested this on 2.7.0 and 3.1.99. Of course I checked “CONFIG_ETH_STM32_HAL_MII=n” for using RMII, and pinmux. and tested on various network configs.

To Reproduce

I tested on simple ‘hello world’ sample. because I thought NET_SHELL is enough to test ethernet controller. Steps to reproduce the behavior:

1. mkdir build; cd build
2. cmake -DBOARD=nucleo_f746zg …
3. make
4. See error

*** Booting Zephyr OS build zephyr-v3.1.0-469-g92bc3e47c0f8  ***
Hello World! nucleo_f746zg
[00:00:02.463,000] <inf> net_config: Initializing network
[00:00:02.463,000] <inf> net_config: Waiting interface 1 (0x20010b10) to be up...
[00:00:02.482,000] <err> eth_stm32_hal: Failed to enqueue frame into RX queue: -115
[00:00:02.482,000] <inf> net_config: Interface 1 (0x20010b10) coming up
[00:00:02.482,000] <inf> net_config: IPv4 address: 192.168.65.125
uart:~$
uart:~$
uart:~$ net ping 192.168.65.16
PING 192.168.65.16
Ping timeout

Expected behavior This is the suceessful case with MII(stm32f745 + lan9303)

uart:~$ net ping 192.168.65.16
PING 192.168.65.16
28 bytes from 192.168.65.16 to 192.168.65.125: icmp_seq=0 ttl=128 time=0.56 ms
28 bytes from 192.168.65.16 to 192.168.65.125: icmp_seq=1 ttl=128 time=0.28 ms
28 bytes from 192.168.65.16 to 192.168.65.125: icmp_seq=2 ttl=128 time=0.30 ms

Environment (please complete the following information):

• OS: Linux ubuntu 18.04
• zephyr-sdk-0.13.2
• Tested on Zephyr 2.2.99, 2.7.0, 3.1.99.