stm32/mphalport: fix ethernet for stm32f429

[MichaelAkhnoukh]

Ethernet driver was failing to start because of incorrect OTP area address for the stm32f429 as the MAC address is stored in the OTP area.

[dpgeorge]

Good find!

But I think it should be fixed differently: this OTP search code is really specific to PYBD boards and so I'd suggest that there'd just be a general hook at the start of mp_hal_get_mac() which would call into an (optional) board-provided macro to get the MAC address, and if that fails then it falls back to the LAA. Then PYBD boards would define this macro as appropriate.

[MichaelAkhnoukh]

i think this can be easily achieved because each board declares FLASH_OTP_BASE & FLASH_OTP_END macros and since the mac address lives in the last block (32 bytes) before the lock block (16 bytes) then OTP_ADDR can be FLASH_OTP_END - 48 bytes

[dpgeorge]

@MichaelAkhnoukh see #5034 for my attempt to fix this issue.

[MichaelAkhnoukh]

I have a question does the mac address always exists in the otp region for all stm32 based boards?

[dpgeorge]

does the mac address always exists in the otp region for all stm32 based boards?

No. stm32 MCUs don't include any MAC address assignments. And I don't know of any Nucleo/Discovery board that has a MAC address either. When you build a product you generally need to purchase and assign a MAC address yourself. PYBD-based boards are special in this regard because they do already have four MAC addresses assigned to them during production.

[dpgeorge]

Fixed by b1e0484