Hii,
I am working on a custom board based on the STM32MP257FK3 SoC. For initial bring-up, I am currently using a Linux/bootloader build that was generated for the STM32MP257F-DK reference board.
On my custom hardware, the DDR memory has been changed from LPDDR4 (used on the DK board) to DDR3. While reviewing the STM32MP25 software stack, I noticed that the DDR type impacts not only the DDR controller configuration but also the PMIC voltage settings, which differ between LPDDR4, DDR3, and DDR4 designs.
I would like clarification on what software changes are strictly required to make DDR3 work correctly on a custom STM32MP257F board.
Specifically, I would like to understand whether supporting a different DDR type requires only Device Tree changes, or if bootloader and driver-level changes are also needed. Also, since DDR type affects power requirements, I would like guidance on the PMIC configuration changes required for DDR3. I want to understand which voltages need to be modified, where these settings are defined in software, and whether they are configured in TF-A, U-Boot, Device Tree, or elsewhere.
