Re: Adding an interrupt to a PCI device via an ACPI entry

[Chris Packham]

On 13/03/24 09:28, Chris Packham wrote:
> Hi All,
>
> Is there a way to add information about a PCI device via an ACPI 
> entry? I'm trying to deal with a device that has an erratum where 
> regular PCI-e MSI interrupts don't work. The workaround is to connect 
> a dedicated INT output line to an interrupt input on the board. The 
> hardware design has done this but I'm trying to figure out how to make 
> that work with ACPI describing the hardware.
>
> I know in devicetree land I can do this with something like
>
> &pcic {
>                 mydevice@1,0 {
>                         compatible = "pci1234,5678";
>                         reg = <0x00000000 0 0 0 0>;
>                         interrupt-parent = <&intc>;
>                         interrupts = <1 IRQ_TYPE_LEVEL_LOW>;
>                 };
> };
>
> And then when my driver is bound to device the usual irq resource 
> stuff will give me the right interrupt line.
>
> Is there a way of expressing this kind of thing in ACPI?

Looking at 
https://www.kernel.org/doc/html/latest/firmware-guide/acpi/enumeration.html#pci-hierarchy-representation 
seems promising.