[Skiboot] [RFC PATCH 2/5] pci: Don't create -T location codes on non-FSP machines

[Benjamin Herrenschmidt]

On Fri, 2015-08-21 at 13:13 +1000, Daniel Axtens wrote:
> On Thu, 2015-08-20 at 11:29 +1000, Benjamin Herrenschmidt wrote:
> > This is a temporary workaround. We disable the code that adds the
> > "-T" portion of the location code to network devices on non-FSP machines.
> > 
> > This code is a bit fragile, and it does incorrect things on dual-slot
> > mezzanines such as the one in Habanero. If we need to support this
> > on OpenPower, we will need to add a concept of sibling slots to the
> > infrastructure to properly handle the numbering.
> > 
> 
> The entire code is a messy hack that happens to work but isn't correct
> in the general case. (I know this because I wrote it.)
> 
> We ultimately need a better way of correctly numbering ports on network
> adapters - I think Ben suggested this was usually done by some (Forth?)
> code on the card?

That or some UEFI ... :-) For the special case of the mezzanine on
Habanero we could put some logic in the platform code but it's not
urgent.

> > Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
> > ---
> >  core/pci.c | 6 +++++-
> >  1 file changed, 5 insertions(+), 1 deletion(-)
> > 
> > diff --git a/core/pci.c b/core/pci.c
> > index 479c435..1c2247e 100644
> > --- a/core/pci.c
> > +++ b/core/pci.c
> > @@ -1180,7 +1180,11 @@ static void pci_add_loc_code(struct dt_node *np, struct pci_device *pd)
> >  > > 	> > class_code = dt_prop_get_u32(np, "class-code");
> >  > > 	> > class = class_code >> 16;
> >  > > 	> > sub = (class_code >> 8) & 0xff;
> > -> > 	> > if (class == 0x02 && sub == 0x00) {
> > +
> > +> > 	> > /* XXX Don't do that on openpower for now, we will need to sort things
> > +> > 	> >  * out later, otherwise the mezzanine slot on Habanero gets weird results
> > +> > 	> >  */
> > +> > 	> > if (class == 0x02 && sub == 0x00 && fsp_present()) {
> >  > > 	> > 	> > /* There's usually several spaces at the end of the property.
> >  > > 	> > 	> >    Test for, but don't rely on, that being the case */
> >  > > 	> > 	> > len = strlen(blcode);
>