Hi, I’m trying to run mainline kernel (6.1) with Zero 3w with slightly modified version of this https://github.com/radxa/kernel/blob/linux-5.10-gen-rkr4.1/arch/arm64/boot/dts/rockchip/rk3566-radxa-zero-3w-aic8800ds2.dts#L46 dtb. Kernel boots and successfully runs init from eMMC, I can get shell in new rootfs over serial console.
Next thing I want to do is reliable WiFi connection over AIC8800. It works most of the time but sometimes during kernel boot mmc@fe2c0000 device fail during device probe in dw_mci_rk3288_execute_tuning function somewhere there: https://github.com/torvalds/linux/blob/v6.1/drivers/mmc/host/dw_mmc-rockchip.c#L202. Same rootfs with radxa kernel and dtb probes this device consistently. How can I debug the why tuning can fail?
Only suspicious thing that I see is clock speed of the bus from dmesg logs. It seems that with mainline kernel (6.1) bus speed is 150MHz:
...
mmc_host mmc2: Bus speed (slot 0) = 150000000Hz (slot req 150000000Hz, actual 150000000Hz div = 0)
...
and with radxa kernel (5.10) bus speed is 148.5MHz:
mmc_host mmc2: Bus speed (slot 0) = 148500000Hz (slot req 150000000Hz, actual 148500000HZ div = 0)
can this difference in bus speed be be the root cause of the issue?