On Wed, Feb 26, 2014 at 12:37 PM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote: > I'm trying to unify the way we handle unassigned PCI BARs, i.e., resources > where we know the type and size, but we haven't assigned an address yet. > The PCI core and the various architectures don't really have a consistent > way of dealing with these. > > Many places currently use "res->start == 0" to indicate unassigned > resources. I don't think that's a good idea in general, because it's > possible for a resource to actually start at zero. Zero is also a > perfectly good BAR value, especially for a host bridge that translates > addresses, so I want to support that, too. > > The IORESOURCE_UNSET flag exists already, but is hardly used at all. In > drivers/pci, we set it for an obscure error case, and clear it when > updating a BAR. The microblaze and powerpc architectures use it the same > way I want to use it here: to indicate a resource with no assigned address. > > Here's the outline of what this series does: > > - Add resource_contains(): true iff r1 contains r2 (for minor cleanup) > - Make %pR print resource size, not address, when IORESOURCE_UNSET > - Stop advertising pci_find_parent_resource() for use in allocation > - Mark PCI resources IORESOURCE_UNSET when BIOS left decoding disabled > - Mark PCI resources IORESOURCE_UNSET while we're trying to assign addresses > - Don't enable PCI decoding when no address has been assigned to BARs > > It might be too aggressive to ignore the initial value of a BAR and try to > reassign it when the BIOS left decoding disabled. If the BIOS left > decoding *enabled*, we can have some confidence that the BAR value is > valid. It's possible the BAR is also valid even if the BIOS turned off > decoding. We could conceivably try to use BAR values that are inside > upstream bridge windows, even if the BAR was initially disabled. But this > first pass just ignores the values in BARs that are disabled. > > I welcome any comments :) > > --- > > Bjorn Helgaas (9): > resource: Add resource_contains() > vsprintf: Add support for IORESOURCE_UNSET in %pR > PCI: Remove pci_find_parent_resource() use for allocation > PCI: Mark resources as IORESOURCE_UNSET if we can't assign them > PCI: Don't clear IORESOURCE_UNSET when updating BAR > PCI: Check IORESOURCE_UNSET before updating BAR > PCI: Don't try to claim IORESOURCE_UNSET resources > PCI: Ignore BAR contents when firmware left decoding disabled > PCI: Don't enable decoding if BAR hasn't been assigned an address > > > drivers/pci/host-bridge.c | 8 -------- > drivers/pci/pci.c | 41 +++++++++++++++++++++++++---------------- > drivers/pci/probe.c | 8 +++++++- > drivers/pci/quirks.c | 5 +++++ > drivers/pci/rom.c | 2 ++ > drivers/pci/setup-res.c | 37 +++++++++++++++++++++++++------------ > include/linux/ioport.h | 12 +++++++++++- > kernel/resource.c | 8 ++------ > lib/vsprintf.c | 13 +++++++++---- > 9 files changed, 86 insertions(+), 48 deletions(-) I applied these to pci/resource for v3.15. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
