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    SubjectRe: [RFT PATCH v3] PCI: move pci_read_bridge_bases to the generic PCI layer
    Hi Guenter,

    On Wed, Jul 22, 2015 at 03:22:57PM +0100, Guenter Roeck wrote:
    > On 07/22/2015 02:14 AM, Lorenzo Pieralisi wrote:
    > > Bjorn, Guenter,
    > >
    > > On Thu, Jul 09, 2015 at 11:59:16AM +0100, Lorenzo Pieralisi wrote:
    > >> When a PCI bus is scanned, upon PCI bridge detection the kernel
    > >> has to read the bridge registers to set-up its resources so that
    > >> the PCI resource hierarchy can be validated properly.
    > >>
    > >> Most if not all architectures read PCI bridge registers in the
    > >> pcibios_fixup_bus hook, that is called by the PCI generic layer
    > >> whenever a PCI bus is scanned.
    > >>
    > >> Since pci_read_bridge_bases is an arch agnostic operation (and it
    > >> is carried out on all architectures) it can be moved to the generic
    > >> PCI layer in order to consolidate code and remove the respective
    > >> calls from the architectures back-ends.
    > >>
    > >> The PCI_PROBE_ONLY flag is not checked before calling
    > >> pci_read_bridge_buses in the generic layer since reading the bridge
    > >> bases is not related to resources assignment; this implies that it
    > >> can be carried out safely on PCI_PROBE_ONLY systems too and should
    > >> not affect architectures (alpha, mips) that check the PCI_PROBE_ONLY
    > >> flag before reading the bridge bases.
    > >>
    > >> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
    > >> Cc: Ralf Baechle <ralf@linux-mips.org>
    > >> Cc: James E.J. Bottomley <jejb@parisc-linux.org>
    > >> Cc: Michael Ellerman <mpe@ellerman.id.au>
    > >> Cc: Bjorn Helgaas <bhelgaas@google.com>
    > >> Cc: Richard Henderson <rth@twiddle.net>
    > >> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
    > >> Cc: David Howells <dhowells@redhat.com>
    > >> Cc: Russell King <linux@arm.linux.org.uk>
    > >> Cc: Tony Luck <tony.luck@intel.com>
    > >> Cc: David S. Miller <davem@davemloft.net>
    > >> Cc: Ingo Molnar <mingo@redhat.com>
    > >> Cc: Guenter Roeck <linux@roeck-us.net>
    > >> Cc: Michal Simek <monstr@monstr.eu>
    > >> Cc: Chris Zankel <chris@zankel.net>
    > >> ---
    > >> v2->v3:
    > >>
    > >> - Dropped RFC status
    > >> - Removed bridge resources claiming from pci_read_bridge_bases()
    > >
    > > What do you want me to do with this patch ? I removed the resource
    > > claiming - ie the only controversial bit, I can only test on
    > > arm64, I would like to make some progress on this otherwise
    > > I will have to add the bridge bases read to arm64 pcibios_fixup_bus()
    > > and be done with this.
    > >
    >
    > Lorenzo,
    >
    > please give me a few days to test it. I was out on vacation for
    > the last two weeks, and I am still struggling to get my test systems
    > back to a working state.

    No worries, I just wanted to make sure we can make progress on this,
    I do not think there is anything controversial in this set, it just
    requires testing the mechanical change on all affected archs, that's
    the problem.

    Thanks a lot for your help !
    Lorenzo


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