[PATCH 01/11] dt-bindings: iommu: arm,smmu-v3: make PRI IRQ optional
Robin Murphy
robin.murphy at arm.com
Wed Apr 27 05:04:26 PDT 2022
On 2022-04-27 12:25, 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.
>
> Signed-off-by: Andre Przywara <andre.przywara at arm.com>
> ---
> .../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
Nit: the commit message doesn't mention this effective relaxation to
allow "eventq, gerror, cmdq-sync, priq" as well - if there's a good
reason for that it probably wants calling out, otherwise AFAICS the last
item should stay as "- const: cmdq-sync" to preserve the existing
canonical order for the 4-item case.
Otherwise,
Reviewed-by: Robin Murphy <robin.murphy at arm.com>
Cheers,
Robin.
>
> '#iommu-cells':
> const: 1
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