[flashrom] Porting flashrom to OpenBSD

[Carl-Daniel Hailfinger]

On 25.06.2010 17:07, Matthieu Herrb wrote:
> On Fri, Jun 25, 2010 at 03:25:10PM +0100, Stuart Henderson wrote:
>   
>> On 2010/06/25 11:57, Carl-Daniel Hailfinger wrote:
>>     
>>> Hi Jonathan,
>>>
>>> you're in CC of this mail because you sent the "unbreak pciutils" mail
>>> to this list, and the failure mode is related.
>>> http://marc.info/?l=openbsd-ports&m=126918139214769
>>>       
>> Hmmm... So why is PCIOCWRITE failing, even when securelevel is 0 and 
>> allowaperture=2...
>>     
>
> Probably because you do un-aligned PCI config space access.
> Our /dev/pci only supports 32 bit wide read/write, aligned on 4 bytes
> boundaries.
>
> If you need to write to PCI config space, you'll need a separate
> kernel interface, with a high-level interface, so that you don't allow
> random changes in the PCI config space from userland.
>   

Wouldn't allowing 16 bit and 8 bit reads/writes at native alignments in
/dev/pci work for that? I could modify flashrom to use read/modify/write
cycles to emulate 8/16 bit reads/writes with 32 bit reads/writes, but
that may have undesirable side effects on some chipsets.


> The rest of the discussion about not abusing the aperture driver for
> this also stays. 
>   

I never fully understood how /dev/mem and the aperture driver are
related. flashrom uses /dev/mem for memory access. The allowaperture
stuff is something I guessed from reading various OpenBSD docs and
mailing list posts.

Regards,
Carl-Daniel