RE: Purpose of pci_remap_iospace

[Bharat Kumar Gogada <bharat.kumar.gogada@xilinx.com>]

> Subject: Re: Purpose of pci_remap_iospace
>
> On Wednesday, July 13, 2016 12:30:44 PM CEST Bharat Kumar Gogada wrote:
> >  > On Wednesday, July 13, 2016 8:11:56 AM CEST Bharat Kumar Gogada
> wrote:
> > > > > Subject: Re: Purpose of pci_remap_iospace
> > >
> > > I notice you have 1MB of I/O space here
> > >
> > > > Kernel Boot log:
> > > > [    2.345294] nwl-pcie fd0e0000.pcie: Link is UP
> > > > [    2.345339] PCI host bridge /amba/pcie@fd0e0000 ranges:
> > > > [    2.345356]   No bus range found for /amba/pcie@fd0e0000, using
> [bus
> > > 00-ff]
> > > > [    2.345382]    IO 0xe0000000..0xe00fffff -> 0x00000000
> > > > [    2.345401]   MEM 0xe0100000..0xeeffffff -> 0xe0100000
> > > > [    2.345498] nwl-pcie fd0e0000.pcie: PCI host bridge to bus 0000:00
> > > > [    2.345517] pci_bus 0000:00: root bus resource [bus 00-ff]
> > > > [    2.345533] pci_bus 0000:00: root bus resource [io  0x0000-0xfffff]
> > >
> > > and all of it gets mapped by the PCI core. Usually you only have 64K
> > > of I/O space per host bridge, and the PCI core should perhaps not
> > > try to map all of it, though I don't think this is actually your problem here.
> > >
> > > > [    2.345550] pci_bus 0000:00: root bus resource [mem 0xe0100000-
> > > 0xeeffffff]
> > > > [    2.345770] pci 0000:00:00.0: cannot attach to SMMU, is it on the same
> > > bus?
> > > > [    2.345786] iommu: Adding device 0000:00:00.0 to group 1
> > > > [    2.346142] pci 0000:01:00.0: cannot attach to SMMU, is it on the same
> > > bus?
> > > > [    2.346158] iommu: Adding device 0000:01:00.0 to group 1
> > > > [    2.346213] pci 0000:00:00.0: BAR 8: assigned [mem 0xe0100000-
> > > 0xe02fffff]
> > > > [    2.346234] pci 0000:01:00.0: BAR 0: assigned [mem 0xe0100000-
> 0xe01fffff
> > > 64bit]
> > > > [    2.346268] pci 0000:01:00.0: BAR 2: assigned [mem 0xe0200000-
> 0xe02fffff
> > > 64bit]
> > > > [    2.346300] pci 0000:01:00.0: BAR 4: no space for [io  size 0x0040]
> > > > [    2.346316] pci 0000:01:00.0: BAR 4: failed to assign [io  size 0x0040]
> > > > [    2.346333] pci 0000:00:00.0: PCI bridge to [bus 01-0c]
> > > > [    2.346350] pci 0000:00:00.0:   bridge window [mem 0xe0100000-
> > > 0xe02fffff]
> > > >
> > > > IO assignment fails.
> > >
> > > I would guess that the I/O space is not registered correctly. Is
> > > this drivers/pci/host/pcie-xilinx.c ? We have had problems with this
> > > in the past, since almost nobody uses I/O space and it requires
> > > several steps to all be done correctly.
> > >
> > Thanks Arnd.
> >
> > we are testing using drivers/pci/host/pcie-xilinx-nwl.c.
>
> According to Documentation/devicetree/bindings/pci/xilinx-nwl-pcie.txt,
> this hardware does not support I/O space.

We received a newer IP version with IO support, so we are trying to test this feature.
>
> Is this on ARM or microblaze?

It is ARM 64-bit.

> This has neither the PCI memory nor the I/O resource, it looks like you never
> call pci_add_resource_offset() to start with, or maybe it fails for some
> reason.

I see that above API is used in ARM drivers, do we need to do it in ARM64 also ?

Regards,
Bharat



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