Re: [PATCH RFC v2] platform/x86: p2sb: Allow p2sb_bar() calls during PCI device probe

Lukas Wunner
2023-12-15T15:45:09Z

On Fri, Dec 15, 2023 at 05:37:01PM +0200, Andy Shevchenko wrote:
> On Fri, Dec 15, 2023 at 08:52:10AM +0100, Lukas Wunner wrote:
> > On Thu, Dec 14, 2023 at 06:38:41PM +0200, Andy Shevchenko wrote:
> > > On Tue, Dec 12, 2023 at 08:47:46PM +0900, Shin'ichiro Kawasaki wrote:
> > > > +/* Cache BAR0 of P2SB device from function 0 ot 7 */
> > > > +#define NR_P2SB_RES_CACHE 8
> > >
> > > This is fifth or so definition for the same, isn't it a good time to create
> > > a treewide definition in pci.h?
> >
> > This isn't something defined in the PCI spec but rather an x86-specific
> > constant, so should preferrably live somewhere in arch/x86/include/asm/.
>
> I'm not sure I am following both paragraphs.
>
> > If you have a "maximum number of PCI functions per device" constant in mind
> > then include/uapi/linux/pci.h might be a good fit.
>
> This is indeed what I have had in mind, but why is this x86 specific?
> I didn't get...

If you look at it from the angle that you want to cache the
BAR of function 0 of the P2SB and of up to 7 additional functions,
it's an x86 thing.

If you look at it from the angle "how many functions can a PCIe
device have (absent ARI)", it's a PCIe thing.

It depends on the way you look at it. ;)

Lukas