Re: [PATCH 1/6] PCI: iproc: Update iProc PCI binding for INTx support

[Ray Jui]

Hi Rob/Arnd,

On 6/4/2018 7:17 AM, Rob Herring wrote:
> +Arnd
>
> On Tue, May 29, 2018 at 4:58 PM, Ray Jui <ray.jui@xxxxxxxxxxxx> wrote:
> > Update the iProc PCIe binding document for better modeling of the legacy
> > interrupt (INTx) support
> >
> > Signed-off-by: Ray Jui <ray.jui@xxxxxxxxxxxx>
> > ---
> >   .../devicetree/bindings/pci/brcm,iproc-pcie.txt    | 31 +++++++++++++++++-----
> >   1 file changed, 24 insertions(+), 7 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/pci/brcm,iproc-pcie.txt b/Documentation/devicetree/bindings/pci/brcm,iproc-pcie.txt
> > index b8e48b4..7ea24dc 100644
> > --- a/Documentation/devicetree/bindings/pci/brcm,iproc-pcie.txt
> > +++ b/Documentation/devicetree/bindings/pci/brcm,iproc-pcie.txt
> > @@ -13,9 +13,6 @@ controller, used in Stingray
> >     PAXB-based root complex is used for external endpoint devices. PAXC-based
> >   root complex is connected to emulated endpoint devices internal to the ASIC
> >   - reg: base address and length of the PCIe controller I/O register space
> > -- #interrupt-cells: set to <1>
> > -- interrupt-map-mask and interrupt-map, standard PCI properties to define the
> > -  mapping of the PCIe interface to interrupt numbers
> >   - linux,pci-domain: PCI domain ID. Should be unique for each host controller
> >   - bus-range: PCI bus numbers covered
> >   - #address-cells: set to <3>
> > @@ -41,6 +38,16 @@ Required:
> >   - brcm,pcie-ob-axi-offset: The offset from the AXI address to the internal
> >   address used by the iProc PCIe core (not the PCIe address)
> >
> > +Legacy interrupt (INTx) support (optional):
> > +
> > +Note INTx is for PAXB only.
> > +
> > +- interrupt-controller: claims itself as an interrupt controller for INTx
> > +- #interrupt-cells: set to <1>
> > +- interrupt-map-mask and interrupt-map, standard PCI properties to define
> > +the mapping of the PCIe interface to interrupt numbers
> > +- interrupts: interrupt line wired to the generic GIC for INTx support
> > +
> >   MSI support (optional):
> >
> >   For older platforms without MSI integrated in the GIC, iProc PCIe core provides
> > @@ -77,9 +84,14 @@ Example:
> >                  compatible = "brcm,iproc-pcie";
> >                  reg = <0x18012000 0x1000>;
> >
> > +               interrupt-controller;
> >                  #interrupt-cells = <1>;
> > -               interrupt-map-mask = <0 0 0 0>;
> > -               interrupt-map = <0 0 0 0 &gic GIC_SPI 100 IRQ_TYPE_NONE>;
> > +               interrupt-map-mask = <0 0 0 7>;
> > +               interrupt-map = <0 0 0 1 &pcie0 1>,
>
> Are you sure this works? The irq parsing code will ignore
> interrupt-map if interrupt-controller is found. In other words, you
> should have one or the other, but not both.

Yes, it does work. I tested this by using an Intel E1000E PCIe NIC card 
installed in our system and have it fall back to INTx.

> Maybe it happens to work because "pcie0" is this node and your irq
> numbers are the same.

Perhaps it works because we are claiming "pcie0" as an interrupt 
controller by itself and the INTx is modeled under that.

> Arnd, any thoughts on this?

Please let me know if the above model makes sense or not.

Thanks,

Ray

> > +                               <0 0 0 2 &pcie0 2>,
> > +                               <0 0 0 3 &pcie0 3>,
> > +                               <0 0 0 4 &pcie0 4>;
> > +               interrupts = <GIC_SPI 100 IRQ_TYPE_NONE>;
> >
> >                  linux,pci-domain = <0>;
> >
> > @@ -115,9 +127,14 @@ Example:
> >                  compatible = "brcm,iproc-pcie";
> >                  reg = <0x18013000 0x1000>;
> >
> > +               interrupt-controller;
> >                  #interrupt-cells = <1>;
> > -               interrupt-map-mask = <0 0 0 0>;
> > -               interrupt-map = <0 0 0 0 &gic GIC_SPI 106 IRQ_TYPE_NONE>;
> > +               interrupt-map-mask = <0 0 0 7>;
> > +               interrupt-map = <0 0 0 1 &pcie1 1>,
> > +                               <0 0 0 2 &pcie1 2>,
> > +                               <0 0 0 3 &pcie1 3>,
> > +                               <0 0 0 4 &pcie1 4>;
> > +               interrupts = <GIC_SPI 106 IRQ_TYPE_NONE>;
> >
> >                  linux,pci-domain = <1>;
> >
> > --
> > 2.1.4