On 4/10/2023 10:20 AM, Krzysztof Kozlowski wrote:
On 09/04/2023 20:19, Nikunj Kela wrote:
Currently, smc/hvc calls are made with smc-id only. The parameters are
all set to zeros. This patch defines two optional device tree bindings,
that can be used to pass parameters in smc/hvc calls.
This is useful when multiple scmi instances are used with common smc-id.
Signed-off-by: Nikunj Kela <quic_nkela@xxxxxxxxxxx>
---
.../devicetree/bindings/firmware/arm,scmi.yaml | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
index 5824c43e9893..08c331a79b80 100644
--- a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
+++ b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
@@ -115,6 +115,22 @@ properties:
description:
SMC id required when using smc or hvc transports
+ arm,smc32-params:
+ $ref: /schemas/types.yaml#/definitions/uint32-array
+ description:
+ An optional parameter list passed in smc32 or hvc32 calls
+ default: 0
+ minItems: 1
+ maxItems: 6
+
+ arm,smc64-params:
+ $ref: /schemas/types.yaml#/definitions/uint64-array
+ description:
+ An optional parameter list passed in smc64 or hvc64 calls
+ default: 0
+ minItems: 1
+ maxItems: 6
These do not look like hardware properties and the fact that you need
two properties for the same also points that you tied it to specific SW
interface.
This is certainly not the H/W property but then smc-id is also not H/W
property either
but that gets passed via DTB. I could use the same property for both
however I wasn't sure
which datatype should be used, uint32-array/uint64-array. Moreover, I
thought if users are
passing parameters, they better know which SMC convention they are using
hence used two
explicit properties.
Why this should be board-specific? Actually better question - why this
should be fixed per board? Doesn't my software want to have different
parameters, depending on some other condition?
Not sure I follow, I didn't say this is board specific. People can use
the parameters to pass
whatever their S/W demands. SMC/HVC calls are made by passing parameters
which is what this patch is enabling.
You also did not provide any DTS user for this, so difficult to judge
usefulness.
The work is still on going and we will push the dts in few months,
however that shouldn't stop
making changes in advance.
Best regards,
Krzysztof
