On Thu, Nov 13, 2014 at 08:37:36PM +0100, Lucas Stach wrote:
> The fixup to enable relaxed ordering on all PCI devices was
> executed unconditionally if the Tegra PCI host driver was
> built into the kernel. This doesn't play nice with a
> multiplatform kernel executed on other platforms which
> may not need this fixup.
>
> Make sure to only apply the fixup if the root port is
> a Tegra.
>
> Signed-off-by: Lucas Stach <[email protected]>
> ---
> drivers/pci/host/pci-tegra.c | 26 +++++++++++++++++++++++++-
> 1 file changed, 25 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c
> index 3d43874319be..d5a14f22ebb8 100644
> --- a/drivers/pci/host/pci-tegra.c
> +++ b/drivers/pci/host/pci-tegra.c
> @@ -647,10 +647,34 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_NVIDIA, 0x0bf1,
> tegra_pcie_fixup_class);
> DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_NVIDIA, 0x0e1c,
> tegra_pcie_fixup_class);
> DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_NVIDIA, 0x0e1d,
> tegra_pcie_fixup_class);
>
> +static int tegra_pcie_root_is_tegra(struct pci_dev *dev)
> +{
> + struct pci_bus *bus = dev->bus;
> + struct pci_dev *root_bridge;
> +
> + /* walk up the PCIe hierarchy to the first level below the root bus */
> + while (bus->parent && bus->parent->self)
> + bus = bus->parent;
> +
> + /*
> + * If there is no bridge on the bus the passed device is the root
> + * bridge itself.
> + */
> + root_bridge = bus->self ? bus->self : dev;
> + if (root_bridge->vendor == PCI_VENDOR_ID_NVIDIA &&
> + (root_bridge->device == 0x0bf0 || root_bridge->device == 0x0bf1 ||
> + root_bridge->device == 0x0e1c || root_bridge->device == 0x0e1d ||
> + root_bridge->device == 0x0e12 || root_bridge->device == 0x0e13))
This looks like a good fix. Can you rework it slightly to:
- Use "root_port" instead of "root_bridge" to match the spec terminology.
When people say "root bridge," they usually mean a host bridge, which
is not a PCI device.
- Is it feasible to factor out the hierarchy traversal into something
like a separate pcie_root_port(pci_dev *) interface? I think that
might be useful other places as well.
Bjorn
> + return 1;
> +
> + return 0;
> +}
> /* Tegra PCIE requires relaxed ordering */
> static void tegra_pcie_relax_enable(struct pci_dev *dev)
> {
> - pcie_capability_set_word(dev, PCI_EXP_DEVCTL, PCI_EXP_DEVCTL_RELAX_EN);
> + if (tegra_pcie_root_is_tegra(dev))
> + pcie_capability_set_word(dev, PCI_EXP_DEVCTL,
> + PCI_EXP_DEVCTL_RELAX_EN);
> }
> DECLARE_PCI_FIXUP_FINAL(PCI_ANY_ID, PCI_ANY_ID, tegra_pcie_relax_enable);
>
> --
> 2.1.1
>
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