Re: [RFC/RFT PATCH 2/2] ARM64: kernel: pci: implement PCI device resources claiming

[Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>]

Hi Bjorn,

On Wed, May 20, 2015 at 12:25:31AM +0100, Bjorn Helgaas wrote:
> Hi Lorenzo,
> 
> On Thu, May 14, 2015 at 03:42:16PM +0100, Lorenzo Pieralisi wrote:
> > When a device is scanned and added to the PCI bus, its resources
> > should be claimed to validate the BARs configuration and to assign
> > them a parent resource so that the resource hierarchy can be sanity
> > checked.
> > 
> > This patch adds code that carries out PCI device resources claiming to
> > the ARM64 pcibios_add_device implementation so that device resources
> > are claimed by the core PCI layer upon PCI device initialization on
> > ARM64 systems.
> > 
> > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> > Cc: Arnd Bergmann <arnd@arndb.de>
> > Cc: Will Deacon <will.deacon@arm.com>
> > Cc: Liviu Dudau <liviu.dudau@arm.com>
> > Cc: Bjorn Helgaas <bhelgaas@google.com>
> 
> Seems like Suravee proposed a tweak?  Can you post a v2 with that
> incorporated if necessary?

I can post a v2, but I am not happy about that tweak, I want to
understand why pci_read_bridge_bases has to be executed only on
PCI_PROBE_ONLY systems and why it can't be done in generic code in the
first place - ie pci_scan_child_bus(), I guess as I mentioned that in
some archs this can trigger regressions, if you have an opinion please
let me know, when we agree I will drop a v2 on the lists.

Thanks,
Lorenzo

> Bjorn
> 
> > ---
> >  arch/arm64/kernel/pci.c | 10 ++++++++++
> >  1 file changed, 10 insertions(+)
> > 
> > diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c
> > index 4095379..c0a88ca 100644
> > --- a/arch/arm64/kernel/pci.c
> > +++ b/arch/arm64/kernel/pci.c
> > @@ -43,8 +43,18 @@ resource_size_t pcibios_align_resource(void *data, const struct resource *res,
> >   */
> >  int pcibios_add_device(struct pci_dev *dev)
> >  {
> > +	struct resource *res;
> > +	int i;
> > +
> >  	dev->irq = of_irq_parse_and_map_pci(dev, 0, 0);
> >  
> > +	for (i = 0; i < PCI_NUM_RESOURCES; i++) {
> > +		res = &dev->resource[i];
> > +		if (res->parent || !res->flags)
> > +			continue;
> > +		pci_claim_resource(dev, i);
> > +	}
> > +
> >  	return 0;
> >  }
> >  
> > -- 
> > 2.2.1
> > 
>