Re: [PATCH v7 03/60] sparc/PCI: Unify pci_register_region()

[Bjorn Helgaas <helgaas@kernel.org>]

On Wed, Oct 21, 2015 at 11:16:53AM -0700, Yinghai Lu wrote:
> On Tue, Oct 20, 2015 at 7:35 PM, Bjorn Helgaas <helgaas@kernel.org> wrote:
> > On Tue, Oct 20, 2015 at 03:30:44PM -0700, Yinghai Lu wrote:
> > I doubt I would agree with a change like this, but maybe, if you can
> > explain what's unique about the sparc architecture that would require
> > a change like this.
> 
> Then how about this one ?
> 
> otherwise we need to compare res with pbm->mem_space or pbm->mem64_space
> to get direct parent for request_resource_conflict() calling in
> pci_register_legacy_regions().

Lots of other architectures have both mem32 and mem64 apertures.  You
haven't explained what's unique about sparc yet.  Does
pci_find_parent_resource() not work on sparc?  If not, is that because the
resource tree looks different on sparc than on other architectures?  If so,
is that difference something intentional that we want to keep, or should we
converge on a single resource tree format across all architectures?

> also check if if return is NULL to decide if it is valid region.
> ---
>  drivers/pci/host-bridge.c |   10 +++++++++-
>  include/linux/pci.h       |    5 +++--
>  2 files changed, 12 insertions(+), 3 deletions(-)
> 
> Index: linux-2.6/drivers/pci/host-bridge.c
> ===================================================================
> --- linux-2.6.orig/drivers/pci/host-bridge.c
> +++ linux-2.6/drivers/pci/host-bridge.c
> @@ -70,12 +70,17 @@ static bool region_contains(struct pci_b
>      return region1->start <= region2->start && region1->end >= region2->end;
>  }
> 
> -void pcibios_bus_to_resource(struct pci_bus *bus, struct resource *res,
> +/*
> + * return host bridge window resource
> + */
> +struct resource *pcibios_bus_to_resource(struct pci_bus *bus,
> +                 struct resource *res,
>                   struct pci_bus_region *region)
>  {
>      struct pci_host_bridge *bridge = pci_find_host_bridge(bus);
>      struct resource_entry *window;
>      resource_size_t offset = 0;
> +    struct resource *res_ret = NULL;
> 
>      resource_list_for_each_entry(window, &bridge->windows) {
>          struct pci_bus_region bus_region;
> @@ -88,11 +93,14 @@ void pcibios_bus_to_resource(struct pci_
> 
>          if (region_contains(&bus_region, region)) {
>              offset = window->offset;
> +            res_ret = window->res;
>              break;
>          }
>      }
> 
>      res->start = region->start + offset;
>      res->end = region->end + offset;
> +
> +    return res_ret;
>  }
>  EXPORT_SYMBOL(pcibios_bus_to_resource);
> Index: linux-2.6/include/linux/pci.h
> ===================================================================
> --- linux-2.6.orig/include/linux/pci.h
> +++ linux-2.6/include/linux/pci.h
> @@ -781,8 +781,9 @@ void pci_fixup_cardbus(struct pci_bus *)
> 
>  void pcibios_resource_to_bus(struct pci_bus *bus, struct
> pci_bus_region *region,
>                   struct resource *res);
> -void pcibios_bus_to_resource(struct pci_bus *bus, struct resource *res,
> -                 struct pci_bus_region *region);
> +struct resource *pcibios_bus_to_resource(struct pci_bus *bus,
> +                     struct resource *res,
> +                     struct pci_bus_region *region);
>  void pcibios_scan_specific_bus(int busn);
>  struct pci_bus *pci_find_bus(int domain, int busnr);
>  void pci_bus_add_devices(const struct pci_bus *bus);
> --
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