The BIOS does set the base addresses; however, the HAL then changes them if
you let it. If you use IoReportResources() instead of HalAssign...() you
will get the BIOS-assigned values not the Hals. In the event the Hal
created a conflict by changing a BIOS assigned address of another device to
overlap your BIOS-assigned values you will need to find new addresses on
One nice thing the Hal does for you in is correct IRQ numbers for you. If
you do raw config cycles you will find a different IRQ assigned than if you
use the HalGetBusData call. The Hal replaces the raw IRQ value with the SMP
vector for you. If you set /PCILOCK you can use the HalAssign...() fxns and
it won't change the BIOS assigned values but will still translate the IRQ
values for you.
Also Max brought up the subject of bridges. We had the discussion on
getting around the Hal when it comes to PCI-PCI bridges a few months ago.
It is sometimes necessary and can be done through IO space. However, it is
important to remember that there are many kinds of PCI bridges. The Hal
only blocks access to those which report themselves through config space as
PCI-PCI bridges with a Type 1 config space. You can use PCI-PCI bridges
which report themselves as PCI-Other bridges or as vanilla PCI devices and
use a Type 0 config space (Intel 21554 for instance.) And of course the Hal
never stops you from reprogramming PCI-Host bus bridges (Galileo), PCI-Other
bridges (PLX), etc.
----- Original Message -----
From: Don Burn <[email protected]
To: NT Developers Interest List <[email protected]
Sent: Friday, February 25, 2000 2:19 PM
Subject: [ntdev] Re: SRAM Based PCI FPGA
> Sorry you got this one wrong, Max is right. The HAL sets the base
> addresses. There is a boot.ini switch /PCILOCK to indicate that the
> addresses setup by the BIOS not be touched. I spent many a painful
> day learning about this on a project where we had to get two machines
> to boot identically.
> Don Burn
> PS. In general Linux is not a good reference on how NT or most of the
> other OS'es on Intel platforms work.
> > [email protected]
> > [email protected]
> > > Base addresses are assigned by PCI config space code in HAL -
> > > HalAssignSlotResources function.
> > No, IRQs and BASE addresses are most certainly set up by the BIOS. If
> > set PnP OS=yes, then the BIOS may (often does) skip this mapping and
> > it to the O/S but NT in not famous for getting this right.
> You are currently subscribed to ntdev as: [email protected]
> To unsubscribe send a blank email to $subst('Email.Unsub')