Hello,
I have a question about relocating the exception vectors for the ARM platform. I am working with cpu/arm720t/start.S and want to use interrupts, but I think I see a problem with the code as it stands now. Consider the following scenario:
1. power on, cpu starts executing from address 0x0, which is located in flash.
2. memsetup.S configures 8MB SRAM to begin at address 0x0 and remaps flash to address 0x01000000.
3. back in start.S u-boot is relocated(copied) from flash to TEXT_BASE = 0x007d0000.
Now the exception vectors are sitting in SRAM @ 0x007d0000 and in flash @ 0x0100000 -- if I want to use interrupts, however, the exception vectors need to be in SRAM at address 0x0.
Currently I have added an additional relocation step to start.S that explicitly copies the vectors from flash to 0x0 (in SRAM) if TEXT_BASE is not equal 0x0 (if TEXT_BASE is equal to 0x0 there is no problem).
Question: Is start.S the correct place to put this, perhaps bracketed with "#ifdef CONFIG_USE_IRQ/#endif"? It seems like a global problem that all arm720t boards that use interrupts would have. Or is memsetup.S a better place for this?
Comments?
Cheers, Curt