Re: [PATCH v2] powerpc: fsl_pci: Add forced PCI Agent enumeration

[Aaron Sierra <asierra@xes-inc.com>]

----- Original Message -----
> From: "Scott Wood" <scottwood@freescale.com>
> Sent: Tuesday, August 26, 2014 3:52:56 PM
> 
> On Mon, 2014-08-25 at 18:54 -0500, Aaron Sierra wrote:
> > The following commit prevents the MPC8548E on the XPedite5200 PrPMC
> > module from enumerating its PCI/PCI-X bus:
> > 
> >     powerpc/fsl-pci: use 'Header Type' to identify PCIE mode
> > 
> > The previous patch prevents any Freescale PCI-X bridge from enumerating
> > the bus, if it is hardware strapped into Agent mode.
> > 
> > In PCI-X, the Host is responsible for driving the PCI-X initialization
> > pattern to devices on the bus, so that they know whether to operate in
> > conventional PCI or PCI-X mode as well as what the bus timing will be.
> > For a PCI-X PrPMC, the pattern is driven by the mezzanine carrier it is
> > installed onto. Therefore, PrPMCs are PCI-X Agents, but one per system
> > may still enumerate the bus.
> > 
> > This patch causes the device node of any PCI/PCI-X bridge strapped into
> > Agent mode to be checked for the fsl,pci-agent-force-enum property. If
> > the property is present in the node, the bridge will be allowed to
> > enumerate the bus.
> > 
> > Cc: Minghuan Lian <Minghuan.Lian@freescale.com>
> > Signed-off-by: Aaron Sierra <asierra@xes-inc.com>
> > ---
> >  .../bindings/pci/fsl,pci-agent-force-enum.txt      | 27
> >  ++++++++++++++++++++++
> >  arch/powerpc/sysdev/fsl_pci.c                      |  3 ++-
> >  2 files changed, 29 insertions(+), 1 deletion(-)
> >  create mode 100644
> >  Documentation/devicetree/bindings/pci/fsl,pci-agent-force-enum.txt
> > 
> > diff --git
> > a/Documentation/devicetree/bindings/pci/fsl,pci-agent-force-enum.txt
> > b/Documentation/devicetree/bindings/pci/fsl,pci-agent-force-enum.txt
> > new file mode 100644
> > index 0000000..d8ac4a7
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/pci/fsl,pci-agent-force-enum.txt
> 
> This ought to be part of a general fsl,pci binding, rather than its own
> file.  Unfortunately there isn't such a binding yet, but let's call this
> something like "fsl,pci.txt" anyway so that there's a place to add the
> rest of the binding to.

Ok, no problem.
 
> Also, CC devicetree@vger.kernel.org on all device tree patches.

Will do.

> Otherwise it looks OK.
> 
> -Scott