[U-Boot] [PATCH 1/1] pci: pci_mvebu: ignore the local device

[Chris Packham]

Hi Marek,

On Fri, May 10, 2019 at 11:44 PM Marek Behun <marek.behun at nic.cz> wrote:
>
> On Fri, 10 May 2019 10:15:25 +0200
> Stefan Roese <sr at denx.de> wrote:
>
> > On 10.05.19 04:56, Marek Behún wrote:
> > > The local device (host "bridge"?) on pci_mvebu controller reports
> > > PCI_CLASS_MEMORY_OTHER in the class register.
> > >
> > > This does not work in U-Boot, because U-Boot then tries to autoconfigure
> > > this device in pci_auto.c. This causes the real connected PCIe device
> > > not to work (in U-Boot nor in Linux).
> >
> > What exactly does not work or is the issue here with the current
> > implementation in Linux? I'm asking, since we have not noticed any
> > issues here?
> >
> ath10k firmware fails to load for network device.
> SATA device timeouts on a PCIe SATA expander.
> As if some PCIe I/O did not work. The devices are still enumerated and
> recognized by Linux, but simply won't work. Nor in U-Boot.

Is there a PCIe bridge involved in either of these? In the pre-history
of Kirkwood (which I believe has the same or similar IP block for
PCIe) I've hit platforms where the PCIe I/O fails because something
about the host bridge interferes with a real bridge on the bus where a
directly connected device worked fine. Marvell were shipping a patch
that adds a fake PCIe bridge in their LSP and I think that is what was
eventually ported to upstream Linux.