I know that some of you have access to sources of the Boot-ROM for
OMAP and therefore ask what is a better (faster) configuration option
for booting from NAND/MMC1? I can see that there are two options:
1) NAND EMAC USB MMC1
2) NAND USB UART MMC1
so which one will start faster, say for MMC1?
I would think #2 as the EMAC would take longer to go through before moving to the next stage of boot.
is it possible to find out from which source we actually started? I
mean only boot ROM knows where MLO was
I amnot sure I follow you.
I chose to boot from NAND by setting SYS_BOOT pins. NAND is clear and
therefore ROM started from SD. How can I know the source? Reading
SYS_BOOT is useless
Source would then eventually moveto SD where the MLO should be there to be read by the ROM. ROM will follow the steps till if finds a boot source and keep loping until it finds a suitable source to boot from.
yes, I understand the sequence, but the question is how to know where
exactly ROM found a suitable source to boot from
Well, it does not send anything out to tell you. It just boots form the suitable source it finds. You could have I guess a different uboot in each that indicates where it was loaded or add something to uboot to read the register that tells where it booted from.