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Subject: Re: [PATCH v2 1/3] dt-bindings: PCI: ti,j721e: Add bindings to
 specify legacy interrupts
To:     Marc Zyngier <maz@kernel.org>
CC:     Bjorn Helgaas <bhelgaas@google.com>,
        Rob Herring <robh+dt@kernel.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Tom Joseph <tjoseph@cadence.com>, <linux-omap@vger.kernel.org>,
        <linux-pci@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        Lokesh Vutla <lokeshvutla@ti.com>
References: <20210804132912.30685-1-kishon@ti.com>
 <20210804132912.30685-2-kishon@ti.com> <87im0lw8qy.wl-maz@kernel.org>
From:   Kishon Vijay Abraham I <kishon@ti.com>
Message-ID: <14717d53-1727-509c-9a62-02c1e8c5736e@ti.com>
Date:   Mon, 9 Aug 2021 10:08:47 +0530
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Hi Marc,

On 04/08/21 8:35 pm, Marc Zyngier wrote:
> On Wed, 04 Aug 2021 14:29:10 +0100,
> Kishon Vijay Abraham I <kishon@ti.com> wrote:
>>
>> Add bindings to specify interrupt controller for legacy interrupts.
>>
>> Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
>> ---
>>  .../bindings/pci/ti,j721e-pci-host.yaml           | 15 +++++++++++++++
>>  1 file changed, 15 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/pci/ti,j721e-pci-host.yaml b/Documentation/devicetree/bindings/pci/ti,j721e-pci-host.yaml
>> index cc900202df29..f461d7b4c0cc 100644
>> --- a/Documentation/devicetree/bindings/pci/ti,j721e-pci-host.yaml
>> +++ b/Documentation/devicetree/bindings/pci/ti,j721e-pci-host.yaml
>> @@ -74,6 +74,11 @@ properties:
>>  
>>    msi-map: true
>>  
>> +patternProperties:
>> +  "interrupt-controller":
>> +    type: object
>> +    description: interrupt controller to handle legacy interrupts.
>> +
>>  required:
>>    - compatible
>>    - reg
>> @@ -97,6 +102,8 @@ unevaluatedProperties: false
>>  
>>  examples:
>>    - |
>> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
>> +    #include <dt-bindings/interrupt-controller/irq.h>
>>      #include <dt-bindings/soc/ti,sci_pm_domain.h>
>>      #include <dt-bindings/gpio/gpio.h>
>>  
>> @@ -131,5 +138,13 @@ examples:
>>              ranges = <0x01000000 0x0 0x10001000  0x00 0x10001000  0x0 0x0010000>,
>>                       <0x02000000 0x0 0x10011000  0x00 0x10011000  0x0 0x7fef000>;
>>              dma-ranges = <0x02000000 0x0 0x0 0x0 0x0 0x10000 0x0>;
>> +
>> +
>> +            pcie0_intc: interrupt-controller {
>> +                    interrupt-controller;
>> +                    #interrupt-cells = <1>;
>> +                    interrupt-parent = <&gic500>;
>> +                    interrupts = <GIC_SPI 312 IRQ_TYPE_EDGE_RISING>;
> 
> Are you sure about the edge signalling? How is the interrupt
> retriggered when the input is still high, which could well be the case
> for shared INTx?

There is a EOI register which is used for re-triggering the interrupt.
That functionality is broken in J721E but is fixed in J7200 (the
following two patches in the series deals with that).

Thanks,
Kishon