Re: [PATCH v7 2/2] PCI: keystone: Fix pci_ops for AM654x SoC
From: Bjorn Helgaas
Date: Wed May 15 2024 - 15:26:24 EST
On Tue, May 14, 2024 at 04:14:54PM -0500, Bjorn Helgaas wrote:
> On Tue, May 14, 2024 at 05:41:48PM +0530, Siddharth Vadapalli wrote:
> > On Mon, May 13, 2024 at 04:53:50PM -0500, Bjorn Helgaas wrote:
> ...
> > > I'm not quite clear on the mechanism, but it would be helpful to at
> > > least know what's wrong and on what platform. E.g., currently v4.90
> > > suffers Completion Timeouts and 45 second boot delays? And this patch
> > > fixes that?
> >
> > Yes, the Completion Timeouts cause the 45 second boot delays and this
> > patch fixes that.
>
> And this problem happens on AM654x/v4.90a, right? I really want the
> commit log to say what platform is affected!
>
> Maybe something like this?
>
> PCI: keystone: Enable BAR 0 only for v3.65a
>
> The BAR 0 initialization done by ks_pcie_v3_65_add_bus() should
> happen for v3.65a devices only. On other devices, BAR 0 should be
> left disabled, as it is by dw_pcie_setup_rc().
>
> After 6ab15b5e7057 ("PCI: dwc: keystone: Convert .scan_bus()
> callback to use add_bus"), ks_pcie_v3_65_add_bus() enabled BAR 0 for
> both v3.65a and v4.90a devices. On the AM654x SoC, which uses
> v4.90a, enabling BAR 0 causes Completion Timeouts when setting up
> MSI-X. These timeouts delay boot of the AM654x by about 45 seconds.
>
> Move the BAR 0 initialization to ks_pcie_msi_host_init(), which is
> only used for v3.65a devices, and remove ks_pcie_v3_65_add_bus().
I haven't heard anything so I amended it to the above. But please
correct me if it's wrong.
Bjorn