Thanks for your reply, but, unfortunately, the doc you mentioned doesn't give any info in regard to my question. I will try to re-phrase it.
We are planning to use W25Q128FWSIQ, which is in the referenced PCL. We may also to use Micron devices, but it's not my question. I will refer to Winbond W25Q128FWSIQ.
The flash device can be configured to be used in one of 3 modes: SPI, dual-SPI or quad-SPI. To be more accurate it can be used in the 4th mode as well: QPI, but I don't think the QPI will be supported by SoC.
Does the flash device need to be configured to one of the modes mentioned above to boot from it? Or, otherwise, will the SoC re-configure the FAST_SPI controller itself according to any of the mentioned flash memory configurations?
Thanks for your updates.
It is important to let you know that in some occasions SPI part does not require a Quad Enable bit to be set, either because Quad is not supported or because the manufacturer permanently enables Quad capability (e.g. Micron, Numonyx).
However, we suggest you review sections 3.1 and 220.127.116.11, on pages 17, 18, 19, and 33 of the Apollo Lake SoC SPI and Signed Master Image Profile (SMIP) Programming Guide document #559702, where you find guidelines that should answer your questions.
We hope that this information may help you.