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

From: Rob Herring
Date: Thu Oct 08 2015 - 18:05:34 EST


On Thu, Oct 8, 2015 at 2:54 PM, David Daney <ddaney.cavm@xxxxxxxxx> wrote:
> From: David Daney <david.daney@xxxxxxxxxx>
>
> 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@xxxxxxxxxx>

Acked-by: Rob Herring <robh@xxxxxxxxxx>

> ---
> 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
>
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