Subject: Re: PCI_MAPREG_TYPE_ROM... or the lack of it
To: None <M.Drochner@fz-juelich.de>
From: Garrett D'Amore <garrett_damore@tadpole.com>
List: tech-kern
Date: 02/25/2006 07:38:39
Matthias Drochner wrote:
> garrett_damore@tadpole.com said:
>
>> The pci_mapreg_map() manual page indicates that you can map a ROM
>> using PCI_MAPREG_TYPE_ROM.
>> Currently this won't work. There is no PCI_MAPREG_TYPE_ROM macro
>> defined.
>>
>
> I didn't follow the thread, so I don't know in which circumstances
> you want to map PCI ROMs.
> I'd recommend however to be very careful with this and never
> allow to do this in generic code in a running system.
> To cite from the PCI spec (3.0, pg. 228):
>
A specific device driver should be able to map ROMs. I need to do this
from the radeonfb driver in order to get e.g. PLL timings.
-- Garrett
> In order to minimize the number of address decoders needed, a device
> may share a decoder between the Expansion ROM [BAR] and other [BARs].
> When expansion ROM decode is enabled [...] device independent
> software must not access the device through any other [BARs].
>
> best regards
> Matthias
>
>
--
Garrett D'Amore, Principal Software Engineer
Tadpole Computer / Computing Technologies Division,
General Dynamics C4 Systems
http://www.tadpolecomputer.com/
Phone: 951 325-2134 Fax: 951 325-2191