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

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Message-ID: <808cc0bd-3ff2-a601-9c2d-09705fd36e51@broadcom.com>
Date:   Mon, 4 Jun 2018 18:17:04 -0700
From:   Ray Jui <ray.jui@...adcom.com>
To:     Rob Herring <robh+dt@...nel.org>, Arnd Bergmann <arnd@...db.de>
Cc:     Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Mark Rutland <mark.rutland@....com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "maintainer:BROADCOM BCM7XXX ARM ARCHITECTURE" 
        <bcm-kernel-feedback-list@...adcom.com>, linux-pci@...r.kernel.org,
        devicetree@...r.kernel.org,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH 1/6] PCI: iproc: Update iProc PCI binding for INTx support

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@...adcom.com> wrote:
>> Update the iProc PCIe binding document for better modeling of the legacy
>> interrupt (INTx) support
>>
>> Signed-off-by: Ray Jui <ray.jui@...adcom.com>
>> ---
>>   .../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
>>