Re: [PATCH v5 2/4] dt-bindings: x86: apic: Introduce new optional bool property for lapic

From: Rob Herring
Date: Wed Nov 30 2022 - 16:21:55 EST



On Thu, 24 Nov 2022 16:41:41 +0800, Rahul Tanwar wrote:
> Intel defines a few possible interrupt delivery modes. With respect
> to boot/init time, mainly two interrupt delivery modes are possible.
> PIC Mode - Legacy external 8259 compliant PIC interrupt controller.
> Virtual Wire Mode - use lapic as virtual wire interrupt delivery mode.
>
> For ACPI or MPS spec compliant systems, it is figured out by some read
> only bit field/s available in their respective defined data structures.
> But for OF based systems, it is by default set to PIC mode. Presently,
> it is hardcoded to legacy PIC mode for OF based x86 systems with no
> option to choose the configuration between PIC mode & virtual wire mode.
>
> For this purpose, introduce a new boolean property for interrupt
> controller node of lapic which can allow it to be configured to virtual
> wire mode as well.
>
> Property name: 'intel,virtual-wire-mode'
> Type: Boolean
>
> If not present/not defined, interrupt delivery mode defaults to legacy PIC
> mode. If present/defined, interrupt delivery mode is set to virtual wire
> mode.
>
> Suggested-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Signed-off-by: Rahul Tanwar <rtanwar@xxxxxxxxxxxxx>
> ---
> .../interrupt-controller/intel,ce4100-lapic.yaml | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>

Reviewed-by: Rob Herring <robh@xxxxxxxxxx>