Re: [PATCH V3 2/4] ARM: tegra: pcie: Add tegra3 support

From: Thierry Reding
Date: Tue Jun 11 2013 - 06:16:21 EST


On Tue, Jun 11, 2013 at 10:13:38AM +0530, Jay Agarwal wrote:
> > * PGP Signed by an unknown key
> >
> > On Tue, Jun 04, 2013 at 01:17:15PM -0600, Stephen Warren wrote:
> > > On 06/04/2013 12:57 PM, Jay Agarwal wrote:
> > [...]
> > > > struct tegra_pcie_port {
> > > > @@ -384,7 +408,7 @@ static int tegra_pcie_read_conf(struct pci_bus
> > *bus, unsigned int devfn,
> > > > struct tegra_pcie_port *port;
> > > >
> > > > list_for_each_entry(port, &pcie->ports, list) {
> > > > - if (port->index + 1 == slot) {
> > > > + if (port->index == slot) {
> > >
> > > This and the equivalent change in tegra_pcie_write_conf() seem like a
> > > bug-fix unrelated to the addition of Tegra30 support. Hence, they
> > > should be a separate patch.
> >
> > What exactly is this change supposed to fix? The description doesn't provide
> > any details about why this is required. Furthermore this was done on
> > purpose to model the Tegra PCIe controller according to what typical Linux
> > systems provide.
>
> I have mentioned it in description as -> "Corrected logic in read/write config space to display right device number on bus 0"
>
> > Device 0:00.0 is usually the root complex, and device 0:01.0, 0:02.0 etc are
> > the root ports. The change proposed above makes 0:00.0 the first root port,
> > therefore breaking what systems usually expect.
> >
> I was seeing root port 2 in cardhu being enumerated as pci_bus 0000:03, which I thought should be pci_bus 0000:02, so made this change.

Yes, that's done on purpose to mirror what a typical PCI tree looks
like, as I already explained. So unless this fixes a real bug I'll just
drop it while applying.

Thierry

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