Re: [PATCH] PCI: generic: Fix address window calculation for non-zero starting bus.

[Rob Herring <robherring2@gmail.com>]

On Thu, Oct 8, 2015 at 2:54 PM, David Daney <ddaney.cavm@gmail.com> wrote:
> From: David Daney <david.daney@cavium.com>
>
> Make the offset from the beginning of the "reg" property be from the
> starting bus number, rather than zero.  Hoist the invariant size
> calculation out of the mapping for loop.
>
> Update host-generic-pci.txt to clarify the semantics of the "reg"
> property with respect to non-zero starting bus numbers.
>
> Signed-off-by: David Daney <david.daney@cavium.com>

Acked-by: Rob Herring <robh@kernel.org>

> ---
> This is a replacement for:
>
> https://lkml.org/lkml/2015/10/2/653
>
> Since that patch is getting too much push-back, this is the only other
> option for fixing the driver to be internally consistent in its
> treatment of the offset from "reg" to the first bus in the "bus-range"
> property.
>
>  Documentation/devicetree/bindings/pci/host-generic-pci.txt | 5 +++--
>  drivers/pci/host/pci-host-generic.c                        | 4 ++--
>  2 files changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/pci/host-generic-pci.txt b/Documentation/devicetree/bindings/pci/host-generic-pci.txt
> index cf3e205..3f1d3fc 100644
> --- a/Documentation/devicetree/bindings/pci/host-generic-pci.txt
> +++ b/Documentation/devicetree/bindings/pci/host-generic-pci.txt
> @@ -34,8 +34,9 @@ Properties of the host controller node:
>  - #size-cells    : Must be 2.
>
>  - reg            : The Configuration Space base address and size, as accessed
> -                   from the parent bus.
> -
> +                   from the parent bus.  The base address corresponds to
> +                   the first bus in the "bus-range" property.  If no
> +                   "bus-range" is specified, this will be bus 0 (the default).
>
>  Properties of the /chosen node:
>
> diff --git a/drivers/pci/host/pci-host-generic.c b/drivers/pci/host/pci-host-generic.c
> index fe9a81b..bb93346 100644
> --- a/drivers/pci/host/pci-host-generic.c
> +++ b/drivers/pci/host/pci-host-generic.c
> @@ -169,6 +169,7 @@ static int gen_pci_parse_map_cfg_windows(struct gen_pci *pci)
>         struct resource *bus_range;
>         struct device *dev = pci->host.dev.parent;
>         struct device_node *np = dev->of_node;
> +       u32 sz = 1 << pci->cfg.ops->bus_shift;
>
>         err = of_address_to_resource(np, 0, &pci->cfg.res);
>         if (err) {
> @@ -196,10 +197,9 @@ static int gen_pci_parse_map_cfg_windows(struct gen_pci *pci)
>         bus_range = pci->cfg.bus_range;
>         for (busn = bus_range->start; busn <= bus_range->end; ++busn) {
>                 u32 idx = busn - bus_range->start;
> -               u32 sz = 1 << pci->cfg.ops->bus_shift;
>
>                 pci->cfg.win[idx] = devm_ioremap(dev,
> -                                                pci->cfg.res.start + busn * sz,
> +                                                pci->cfg.res.start + idx * sz,
>                                                  sz);
>                 if (!pci->cfg.win[idx])
>                         return -ENOMEM;
> --
> 1.9.1
>