On Mon, Aug 31, 2015 at 11:49:20AM -0500, Bjorn Helgaas wrote:

On Mon, Aug 31, 2015 at 11:33 AM, Lorenzo Pieralisi
[off-list ref] wrote:

quoted

On Mon, Aug 31, 2015 at 02:28:03PM +0100, Bjorn Helgaas wrote:

quoted

On Sat, Aug 29, 2015 at 01:44:57PM +0100, Lorenzo Pieralisi wrote:

quoted

On Fri, Aug 28, 2015 at 10:14:44PM +0100, Bjorn Helgaas wrote:

quoted

On Thu, Jul 30, 2015 at 02:13:59PM +0100, Lorenzo Pieralisi wrote:

quoted

On ARM64 PROBE_ONLY PCI systems resources are not currently claimed,
therefore they can't be enabled since they do not have a valid
parent pointer; this in turn prevents enabling PCI devices on
ARM64 PROBE_ONLY systems, causing PCI devices initialization to
fail.

Where does arm64 claim PCI BAR resources for the non-PROBE_ONLY case?

arm64 (and arm) does not claim resources in arch code, they are always
assigned in the respective host controllers (or the pcibios on arm),
except for the PCI generic host when in PROBE_ONLY mode, where resources
are neither claimed nor assigned (the reason for this patch to exist).
...

quoted

I know it must be there somewhere, but I don't see it.

It is not there, it is done in the host controllers by assigning the
resources (which also "claim" them by assigning the parent pointer).

The host controller drivers should claim the apertures forwarded to
the PCI bus.  For pci-host-generic, this happens when
gen_pci_parse_request_of_pci_ranges() calls devm_request_resource().

Yes, the generic host claims the apertures at DT probing time.

quoted

But that doesn't do anything for the BARs of the PCI devices
themselves, of course.

If this patch fixes a problem that will occur in the future, when we
add arm/arm64 code to claim BARs, let's make this patch part of that
series.  If it fixes a problem in the current tree, I'll merge it now,
but so far I haven't been able to make the connection between this
patch and a problem in the current code.

It fixes a problem in the current tree (I mean when the PCI pull is
merged - it contains code that enables PCI host generic on arm64),
since without it PROBE_ONLY systems (ie PCI host generic on kvmtool) would
try to enable resources and fail, since the resources were not claimed.

It works the same way as arm, I will rework both arches when I am done
refactoring the resource claiming implementation.

Will picked it up already I do not know what's the best way to
merge it I guess it can go via the arm64 tree if you do not have any
objections.

OK, if it fixes a problem in my v4.3 pull request, we need to merge
it.  I missed the connection, probably because I was browsing the
v4.2-rc1 tree, which wouldn't have those changes.

It's OK with me to merge it via the arm64 tree.

Do you need me to do anything with this?  It'd be nice to get it in
before -rc1.  The PCI changes have already been merged, and it'd be
nice to mention the commit that this fixes.

Bjorn