[OLPC-devel] Secure BIOS on the OLPC

[Ivan Krstić]

Mark J. Foster wrote:
> Not to worry, it's a non-obvious answer! ;-) 

Ah, but I have another possibly obvious question!

> The reason that we must be
> able to reset the EC is to stop it from executing code while writing to
> the Flash chip.

That makes sense, but can't the EC reset be put on the same latch as the
#SPIWP? The only time you want to reset the EC is if you're flashing
SPI, so after you set #SPIWP low, you don't ever want to reset the EC.
If 'EC reset' and #SPIWP lived on the same latch, this would Just Work.
I suspect there's a chicken and egg problem with putting the EC reset on
the latch, though?

-- 
Ivan Krstić <krstic at solarsail.hcs.harvard.edu> | GPG: 0x147C722D