Hi Lorenzo,
On 20 January 2016 18:10, Lorenzo Pieralisi wrote:
> On Wed, Jan 20, 2016 at 11:13:04AM -0500, Sinan Kaya wrote:
> > On 1/20/2016 11:04 AM, Lorenzo Pieralisi wrote:
> > > Hi,
> > >
> > > I noticed that:
> > >
> > > 79953dd22c1d ("PCI: rcar: Remove dependency on ARM-specific struct
> hw_pci")
> > > cbce7900598c ("PCI: designware: Make driver arch-agnostic")
> > >
> > > added code in the respective host controller drivers to size bridges
> > > and assign resources only if the PCI_PROBE_ONLY flag is clear, which makes
> > > me wonder if there exists PCI_PROBE_ONLY set-ups for the respective
> > > host controllers:
> > >
<snip>
> Resources claiming and assignment should be managed in arch code,
> not in host controllers specific code, and that's the reason I
> complained in this RFC about the scattering of PCI_PROBE_ONLY flag
> checks in host drivers, it is becoming unmanageable (if useful
> at all on designware and rcar, I would like to know if there are
> PCI_PROBE_ONLY set-ups probing those host drivers).
I am pretty sure there are no rcar set-ups that use PCI_PROBE_ONLY,
so I am happy for that code to go.
Thanks
Phil
> Does it make the point clearer ?
>
> > > https://patchwork.ozlabs.org/patch/545671/
> > >
> > > so unless you really have *existing* set-ups that require it, please
> > > remove the respective checks from the host controller drivers, this is
> > > becoming a serious issue, because either:
> > >
> > > - we claim resources if and only if PCI_PROBE_ONLY is set
> > >
> > > Either like this (to be done for every host controllers and ARM
> > > bios32):
> > >
> > > https://patchwork.ozlabs.org/patch/545670/
> > >
> > > or in core ARM/ARM64 code - eg pcibios_fixup_bus() - (to avoid adding a
> > > resource claiming call in ALL PCI host controllers)
> > >
> > > - or we *always* carry out resource claiming regardless of PCI_PROBE_ONLY
> > > (but on ARM we can't really do that since PCI FW set-up on most of the
> > > platforms is not present)
> > >
> > > On PCI_PROBE_ONLY systems resources claiming is mandatory if we want
> > > to get rid of arches workarounds:
> >
> > I'm hoping to see x86 like behavior on ARM64 without any gotchas as
> > there is nothing special about CPU type when it comes to PCI.
>
> As I said, we must enforce it with ACPI, for DT platforms I am all
> ears to decide how we can implement it sanely (I think the only way
> to do it is by claiming the PCI resources on PCI_PROBE_ONLY systems,
> that's not ideal but it simplifies things a lot).
>
> Thanks,
> Lorenzo
>
> >
> > >
> > > https://patchwork.ozlabs.org/patch/545671/
> > >
> > > Comments very appreciated.
> > >
> > > Thanks,
> > > Lorenzo
> > > --
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> > >
> >
> >
> > --
> > Sinan Kaya
> > Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc.
> > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux
> Foundation Collaborative Project
> >
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