[coreboot] Run PCI rom before PCI bus scan??

joe at smittys.pointclark.net joe at smittys.pointclark.net
Mon Feb 4 00:15:52 CET 2008

Quoting Tom Sylla <tsylla at gmail.com>:

> joe at smittys.pointclark.net wrote:
>> Here is what I think the PCI rom does with the original bios:
>> 1. powers on and enables device
>> 2. sets up PHY registers
>> 3. sets up it PCI config registers
>> 4. and requests use of the PCI bridge
>> If I could figure out how to do #1 the rest would be fairly simple   
>> to  setup,although I am not exactly sure about PHY registers. Then   
>> I  wouldn't need the pci rom at all.
> I'm not sure it really works this way. A normal platform has some
> mechanism to set the default values for the LAN config registers. It
> can be a dedicated SPI ROM, or a dedicated chunk of your boot ROM, or
> you could program them in your BIOS. I would guess that a PCI ROM is
> expecting all of those registers to have been programmed already.
> Furthermore, many of those settings are *platform specific*, so they
> would not be in any sort of generic PCI ROM that you would get from
> Intel, or generate using their tools.
> I recently designed a platform with an 82571 Intel LOM, and I
> programmed proper values in the SPI, and don't load any PCI ROM at all.
> It works fine in all OSes. The PCI ROM usually just provides things
> like PXE or manageability stuff.
> You need to figure out how your platform is handling this. I think it
> is unlikely that the PCI expansion ROM is doing what you think it is.

Thanks Tom, This makes alot of sense. All the million pages of  
documentation I have read, and read they talk about an eeprom (which  
is the SPI???) and an PCI rom. I guess I am getting the two confused.  
This board has an Intel 82562ET LOM.
How do I access the SPI rom in linux (read/dump/write)? I found this  
program called eepro100-diag and/or ethtool that is supposed to be  
able to this but have not tried them yet. Also Intel speaks of an PHY  
register is that the register that is in the SPI. Thanks for your  
help. I hope you won't mind helping me on this, seeing you have  
already done it before?

Thanks - Joe

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