[coreboot] [PATCH] Raw payload extraction support in cbfstool
peter at stuge.se
Wed Sep 29 02:13:42 CEST 2010
Carl-Daniel Hailfinger wrote:
> > I'd suggest a setting which makes flashrom skip all parallel flash
> > chips, to remove any need for calibration.
> That would break some Winbond LPC flash chips which require a few
> milliseconds of delay between JEDEC toggle reads on erase.
> And we also noticed that some SPI chips will react badly (corruption)
> to a too tight RDSR instruction schedule.
Yay. I guess they would be disabled too, unless calibration has run.
> Given that LPC/FWH/SPI flash chips usually tolerate longer than
> expected delays without problem, you could hook up programmer_delay
> to udelay and save a second or so for calibration if you don't need
> parallel flash.
That sounds good!
> > (To be more precise, the deciding factor is whether the chip is on
> > the local bus, or if there are some bus master(s) in between, but
> > that's generally equivalent to parallel vs. all others.)
> Network cards with parallel flash would be classified as "local bus"?
I believe bridges can make things more complicated. The assumption is
that any bus master will always ensure correct timing for the bus
where the chip is connected. You mentioned that there are exceptions,
to that, but I think it'll hold in general. A bridge in a PCI chip
that decodes into ROM may or may not ensure correct timing. I think
it would have to be set on a per-chip basis.
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