Re: [PATCH 3/3] dt-bindings: PCI: Convert generic host binding to DT schema

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Rob,

On Sat, Nov 16, 2019 at 1:53 AM Rob Herring <robh@kernel.org> wrote:
> Convert the generic PCI host binding to DT schema. The derivative Juno,
> PLDA XpressRICH3-AXI, and Designware ECAM bindings all just vary in
> their compatible strings. The simplest way to convert those to
> schema is just add them into the common generic PCI host schema.
>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Cc: Andrew Murray <andrew.murray@arm.com>
> Cc: Zhou Wang <wangzhou1@hisilicon.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: David Daney <david.daney@cavium.com>
> Signed-off-by: Rob Herring <robh@kernel.org>

> index 515b2f9542e5..000000000000
> --- a/Documentation/devicetree/bindings/pci/designware-pcie-ecam.txt
> +++ /dev/null

> -Example:
> -
> -    pcie1: pcie@7f000000 {
> -        compatible = "socionext,synquacer-pcie-ecam", "snps,dw-pcie-ecam";
> -        device_type = "pci";
> -        reg = <0x0 0x7f000000 0x0 0xf00000>;
> -        bus-range = <0x0 0xe>;
> -        #address-cells = <3>;
> -        #size-cells = <2>;
> -        ranges = <0x1000000 0x00 0x00010000 0x00 0x7ff00000 0x0 0x00010000>,
> -                 <0x2000000 0x00 0x70000000 0x00 0x70000000 0x0 0x0f000000>,
> -                 <0x3000000 0x3f 0x00000000 0x3f 0x00000000 0x1 0x00000000>;
> -
> -        #interrupt-cells = <0x1>;
> -        interrupt-map-mask = <0x0 0x0 0x0 0x0>;

An all-zeroes interrupt-map-mask seems to be very common on embedded
SoCs, where all devices are mapped to a single interrupt.

However, schemas/pci/pci-bus.yaml says:

  interrupt-map-mask:
    items:
      - description: PCI high address cell
        minimum: 0
        maximum: 0xf800
      - description: PCI mid address cell
        const: 0
      - description: PCI low address cell
        const: 0
      - description: PCI IRQ cell
        minimum: 1
        maximum: 7

and thus complains about an all-zeroes mask, e.g.

    arch/arm64/boot/dts/renesas/r8a7795-salvator-x.dt.yaml:
pcie@fe000000: interrupt-map-mask:0:3: 0 is less than the minimum of 1

> -        interrupt-map = <0x0 0x0 0x0 0x0 &gic 0x0 0x0 0x0 182 0x4>;
> -        msi-map = <0x0 &its 0x0 0x10000>;
> -        dma-coherent;
> -    };

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds