Re: /proc/bus/pci

[Albert Cahalan <albert@users.sf.net>]

On Thu, 2003-06-05 at 00:23, Linus Torvalds wrote:
> On Wed, 4 Jun 2003, Albert Cahalan wrote:
> >
> > I notice that /proc/bus/pci doesn't offer a sane
> > interface for multiple PCI domains and choice of BAR.
> > What do people think of this?
> > 
> > bus/pci/00/00.0 -> ../hose0/bus0/dev0/fn0/config-space
> 
> Why do we have that stupid "hose" name? Only because of strange alpha 
> naming, or did somebody else also use that incredibly silly name?
> 
> Please talk about "domains", at least it makes some sense as a name.

"hose" does sound pretty crazy, but...

a. "domain" is way overused in OSes and programming
b. "hose" is short
c. with old names like "d4", "hose" is better for tab-completion

I'm sure somebody could name a dozen things called "domain".

> I'm also hoping that /proc/bus will eventually go away, so I don't see a 
> major problem with not understanding multiple domains at that level.
> 
> On a /sys/bus/xxx level we actually should already be able to handle 
> multiple domains, but the naming is broken. However, in /sys we should be 
> able to nicely handling non-zero domains by just extending the name space 
> a bit.

Does this mean you'd like to see per-BAR kobject stuff?
If I'm not mistaken, that is required for sysfs to work.

So sysfs then has:

devices/pci2/02:0b.0 -> ../hose0/bus2/dev11/fn0
devices/hose0/bus2/dev11/fn0/config-space
devices/hose0/bus2/dev11/fn0/bar0
devices/hose0/bus2/dev11/fn0/bar1
devices/hose0/bus2/dev11/fn0/bar2
devices/hose0/bus2/dev11/fn0/class
devices/hose0/bus2/dev11/fn0/power
devices/hose0/bus2/dev11/fn0/subsystem_vendor
devices/hose0/bus2/dev11/fn0/and-so-on

To make this clear, mmap() on bar0 would get you
a mapping of that BAR.