I'm trying to boot my custom board from external flash (from the same family that the internal flash comes from). I've set my project to boot from external flash (SPI Slave), intel hex, 8 bit. I've also set the BMODE pins to boot from external flash. My question is how does the kernel know the correct set of commands to issue over the SPI bus to read from the external flash? I've modified the flash driver provided by analog devices to work with this new chip and I believe I'm flashing my program correctly (it doesn't report any errors when I verify while programming), but when I try to boot the board nothing happens. So I have several questions:
1 - Do I need to write a program that the kernel uses to appropriately read out of the external flash?
2 - What SPI port is the kernel expecting the external flash to be on? I assume it's SPI0 (using SPI0_SEL2) since that's where it boots when it boots from internal flash.
3 - Is there documentation somewhere that details how this is to be done? I've looked through the hardware reference manual, but it only makes references to the external flash/boot mode and none of the details of what's really going on.