Re: PCI Express support for 2.4 kernel

[Jeff Garzik]

Linus Torvalds wrote:
> So if this will only matter for PCI-X drivers and not for discovery etc, I
> wonder if it wouldn't make sense to have this as a totally separate
> function? Instead of trying to make the existing "pci_config_xxxx()" 
> stuff work with PCI-X, wouldn't it be nicer to have the driver just map 
> its config space on probe?

Not a bad idea...  After posting yesterday on this thread, I had the 
thought:  Just like PCI has readl() and sbus has sbus_readl(), why not 
pciex_cfg_readl() ?

Any PCI-Ex drivers would obviously _know_ they are PCI Ex, and they 
could communicate that by virtue of simply using new functions.  Older 
drivers for older hardware would use the old API and not care... 
Further, PCI-Ex operations are already basically readl/writel anyway, so 
going through the forest of pci_cfg_ops pointers and such would just add 
needless layering.


> You could do it with just ioremap(), but you'd really want to abstract it 
> out a bit, and have a "[un]map_pcix_config()" function?

Why not just work within the existing API? 
pci_{enable,disable}_device() seems fairly appropriate, as that's a 
quite clear signal of the bounds within which the driver must work.

pci_enable_device() is already defined as "the PCI device's resources 
may not be available before <this> point."

	Jeff


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