On 27/04/2022 13:25, Andre Przywara wrote:
> The Page Request Interface (PRI) is an optional PCIe feature. As such, a
> SMMU would not need to handle it if the PCIe host bridge or the SMMU
> itself do not implement it. Also an SMMU could be connected to a platform
> device, without any PRI functionality whatsoever.
> In all cases there would be no SMMU PRI queue interrupt to be wired up
> to an interrupt controller.
>
> Relax the binding to allow specifying three interrupts, omitting the PRI
> IRQ. At the moment, with the "eventq,gerror,priq,cmdq-sync" order, we
> would need to sacrifice the command queue sync interrupt as well, which
> might not be desired.
> The Linux driver does not care about any order at all, just picks IRQs
> based on their names, and treats all (wired) IRQs as optional.
The last sentence is not a good explanation for the bindings. They are
not about Linux and are used in other projects as well.
>
> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
> ---
> .../bindings/iommu/arm,smmu-v3.yaml | 21 ++++++++++++++-----
> 1 file changed, 16 insertions(+), 5 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu-v3.yaml b/Documentation/devicetree/bindings/iommu/arm,smmu-v3.yaml
> index e87bfbcc69135..6b3111f1f06ce 100644
> --- a/Documentation/devicetree/bindings/iommu/arm,smmu-v3.yaml
> +++ b/Documentation/devicetree/bindings/iommu/arm,smmu-v3.yaml
> @@ -37,12 +37,23 @@ properties:
> hardware supports just a single, combined interrupt line.
> If provided, then the combined interrupt will be used in preference to
> any others.
> - - minItems: 2
> + - minItems: 1
> items:
> - - const: eventq # Event Queue not empty
> - - const: gerror # Global Error activated
> - - const: priq # PRI Queue not empty
> - - const: cmdq-sync # CMD_SYNC complete
> + - enum:
> + - eventq # Event Queue not empty
> + - gerror # Global Error activated
> + - cmdq-sync # CMD_SYNC complete
> + - priq # PRI Queue not empty
> + - enum:
> + - gerror
> + - cmdq-sync
> + - priq
> + - enum:
> + - cmdq-sync
> + - priq
> + - enum:
> + - cmdq-sync
> + - priq
The order should be strict, so if you want the first interrupt optional,
then:
oneOf:
- items:
... 4 items list
- items
... 3 items list
Best regards,
Krzysztof
