[coreboot] r3393 - trunk/util/flashrom

Carl-Daniel Hailfinger c-d.hailfinger.devel.2006 at gmx.net
Sat Jun 28 23:00:25 CEST 2008

On 28.06.2008 22:30, Stefan Reinauer wrote:
> Carl-Daniel Hailfinger wrote:
>> On 28.06.2008 19:37, Stefan Reinauer wrote:
>>> I was having a cleanup of the whole SPI/LPC bus handling in mind:
>>> we have _1_ global variable (per instance of "flashes"?) instead of one
>>> per supported chipset.
>>> This variable is an ENUM
>>> enum flash_bus {
>>> }
>> Looks nice. Can we add a bus for those old (29*) parallel flash chips?
>> I assume differentiating between LPC and FWH will be difficult because
>> FWH is just a LPC variant and some chipsets do not allow us to detect
> I don't think it makes much sense to differentiate between 29* types,
> lpc and fwh:
> The physical bus looks exactly the same from a software perspective;
> until after you scanned the bus and know which category the chip you
> found belongs to. And then the data is not exactly interesting anymore.

Differentiating between LPC/FWH is important for the unlock procedure of
some chips.
Keeping the 29* parallel flash chips in a separate category fixes the
AMIC chip confusion by 29EE probing.

>>> I think this matches the physical actualities much better than the
>>> design-less hack that is used at the moment. Also the code could be much
>>> nicer in many places, as we could use case statements instead of endless
>>> if () else if () else if() statements
>> What happens if there is more than one flash bus? Do we call the probe
>> functions compatible with the bus once per bus? If we do that, we can
>> stop after the first detected chip.
> Not necessarily. You can have multiple chips on the same FWH "bus", so
> stopping after you find the first chip is not an option.

I meant bus/address pairs where appropriate. There can be only one chip
per bus/address pair.

> But, I suggest we consider multiple flash busses once we see that happen
> in the real world. At least the ICH is always strapped to either FWH
> _or_ SPI.

Except if you have a Kontron board (for which multiple flash chip
support was written in the first place).



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