nrf7002 firmware interface documentation and fmac headers

[vbart]

Hi, I am currently evaluating a Rust driver for the nrf7002-ek on a nrf5340-dk. I have been using the Zephyr nrfwifi driver for reference.

There are a large number of nrf_wifi_fmac and OSAL functions which are not defined in Zephyr. (For example, fmac_main.c). These appear to be defined in nrfxlib. However it seems that per this pull request the header files will not longer accessible in the future which describe the OSAL and fmac interfaces. I cannot find other definitions of these files, especially fmac_api.h, in Zephyr or the SDK, so this will make using the device from Rust somewhat painful and probably make builds fail if you were using the nrf sdk.

I would prefer if Nordic released a datasheet describing the communication interface to the nrf700x devices. This would allow me to remove the overhead of the osal interface. Currently the nrf7002 datasheet in chapter 7 does not describe in adequate detail how to use the device, only a few register addresses and how to access the OTP.

[Marte Myrvold]

Hi,

Is there a specific reason you want to create a Rust driver for the nRF7002 instead of using the driver in the nRF Connect SDK or upstream Zephyr? If there is something specific you want to achieve, it could be possible that there is a simpler solution.

There is also a Linux driver available, which you can use for reference. You can find it here: https://github.com/NordicPlayground/nrf70-linux-driver. Please note that this is provided as-is and is not intended for production use.

Best regards,
Marte

[vbart]

Hi,

The rest of the firmware would be written in Rust: most likely using embassy-nrf. Trying to use zephyr or the nrf connect sdk in the same codebase would be very painful to integrate.

I can work with using nrfxlib and calling that code from Rust (and use the kernel driver for reference). The pull request I mentioned in the original message seems to imply the API provided in nrfxlib for the nrf7001/2 is going away and would make tracking newer firmware interfaces harder.

[Marte Myrvold]

Hi,

The nRF70 driver is removed from nrfxlib because it is moved to upstream Zephyr, so the API will be available in upstream Zephyr.

You can try to ask your local sales representative from Nordic Semiconductor for more detailed information about the nRF70 series.

Best regards,
Marte

[vbart]

I found the upstream zephyr repository with the nrf_wifi hal (which has the fmac interface): https://github.com/zephyrproject-rtos/hal_nordic/tree/master/drivers/nrf_wifi

Thank you for Marte for answering my questions and pointing me to the Linux driver as well for reference.