[coreboot] option roms in SeaBIOS and Coreboot

[ron minnich]

On Wed, Nov 26, 2008 at 8:58 AM, Kevin O'Connor <kevin at koconnor.net> wrote:
> On Wed, Nov 26, 2008 at 08:46:43AM -0800, ron minnich wrote:
>> On Wed, Nov 26, 2008 at 8:39 AM, Kevin O'Connor <kevin at koconnor.net> wrote:
>> > In order to minimize the number of address decoders needed, a device
>> > may share a decoder between the Expansion ROM Base Address register
>> > and other Base Address registers. When expansion ROM decode is
>> > enabled, the decoder is used for accesses to the expansion ROM and
>> > device independent software must not access the device through any
>> > other Base Address registers.
>>
>> Wow, I hope no hardware ever implemented that bad idea :-)
>>
>> Anybody know? how is an expansion rom supposed to actually get to the
>> hardware at that point, I wonder. ...
>
> The steps are: enable option rom decode, copy option rom to memory,
> disable option rom decode, run option rom.  So, the option rom runs
> when it can access the device.

Yes, my mistake in the early days of this was assuming XIP for option roms ...

ron