On 2022-04-28 07:56, Krzysztof Kozlowski wrote:
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
All 4 interrupts are optional, though, since any of them could
potentially use an MSI instead. Do we really want to list out all 15
combinations?
Robin.
