Re: [PATCH] pcie: Add Xilinx PCIe Host Bridge IP driver

[Bjorn Helgaas]

[+cc Arnd]

On Sun, Feb 16, 2014 at 8:33 AM, Srikanth Thokala <sthokal@xxxxxxxxxx> wrote:
> This is the driver for Xilinx AXI PCIe Host Bridge Soft IP
>
> Signed-off-by: Srikanth Thokala <sthokal@xxxxxxxxxx>
> ---
> - Rebased on v3.14.0-rc2
> ---
>  .../devicetree/bindings/pci/xilinx-pcie.txt        |   43 +
>  drivers/pci/host/Kconfig                           |    7 +
>  drivers/pci/host/Makefile                          |    1 +
>  drivers/pci/host/pci-xilinx.c                      |  985 ++++++++++++++++++++
>  4 files changed, 1036 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/pci/xilinx-pcie.txt
>  create mode 100644 drivers/pci/host/pci-xilinx.c
>
> diff --git a/Documentation/devicetree/bindings/pci/xilinx-pcie.txt b/Documentation/devicetree/bindings/pci/xilinx-pcie.txt
> new file mode 100644
> index 0000000..66a2487
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pci/xilinx-pcie.txt
> @@ -0,0 +1,43 @@
> +* Xilinx AXI PCIe Root Port Bridge DT description
> +
> +Required properties:
> +- #address-cells: Address representation for root ports, set to <3>
> +- #size-cells: Size representation for root ports, set to <2>
> +- compatible: Should contain "xlnx,axi-pcie-1.00.a"
> +- reg: Should contain AXI PCIe registers location and length
> +- interrupts: Should contain AXI PCIe interrupt
> +- ranges: ranges for the PCI memory regions
> +       Please refer to the standard PCI bus binding document for a more
> +       detailed explanation
> +- xlnx,axibar-num: Number of memory regions configured in the hardware,
> +       maximum being three which is configurable in the hardware.
> +- xlnx,include-rc: Root Port (=1) or End Point (=0)
> +- xlnx,pciebar2axibar-0: Translation address from PCIe to AXI
> +       Only one PCIe BAR is applicable in Root port mode, it can be
> +       either 32/64-bit. If it is 64-bit BAR, lower 32 bits are present
> +       in 'xlnx,pciebar2axibar-0' and Upper 32 bits in 'xlnx,pciebar2
> +       axibar-1'. And if it is 32-bit BAR, only 'xlnx,pciebar2axibar-0'
> +       is valid
> +
> +Optional properties
> +- xlnx,pciebar-as: PCIe BAR aperture size is 32 (=0) or 64-bit (=1).
> +- xlnx,pciebar2axibar-1: Translation address from PCIe to AXI, contains
> +       upper 32 bits if PCIe BAR size is 64-bit. When xlnx,pciebar-as
> +       is set, this is a required property and should contain a valid
> +       value (other than FF's)

I hardly know anything about DT, but xlnx,pciebar2axibar-0,
xlnx,pciebar-as, and xlnx,pciebar2axibar-1 look strange to me.  Is
that really the DT way of dealing with 32/64-bit BARs and host bridge
address translation?  I don't see similar things in the other files in
Documentation/devicetree/bindings/pci/, even though some of the other
drivers/pci/host/*.c files do use pci_add_resource_offset(), which
indicates that they support address translation.

Please also include a MAINTAINERS update for drivers/pci/host/pci-xilinx.c.

Bjorn
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