Messages in this thread | | | Date | Thu, 5 Oct 2023 14:51:28 -0700 | Subject | Re: [PATCH v4 3/4] dt-bindings: arm: Add new compatible for smc/hvc transport for SCMI | From | Nikunj Kela <> |
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On 10/4/2023 8:53 AM, Sudeep Holla wrote: > On Tue, Oct 03, 2023 at 08:59:45AM -0700, Nikunj Kela wrote: >> On 10/3/2023 3:44 AM, Sudeep Holla wrote: >>> On Mon, Sep 11, 2023 at 12:43:58PM -0700, Nikunj Kela wrote: >>>> Introduce compatible "qcom,scmi-hvc-shmem" for SCMI smc/hvc >>>> transport channel for Qualcomm virtual platforms. >>>> The compatible mandates a shared memory channel. >>>> >>>> Signed-off-by: Nikunj Kela <quic_nkela@quicinc.com> >>>> Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> >>>> --- >>>> .../devicetree/bindings/firmware/arm,scmi.yaml | 12 ++++++++++++ >>>> 1 file changed, 12 insertions(+) >>>> >>>> diff --git a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml >>>> index 8d54ea768d38..4090240f45b1 100644 >>>> --- a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml >>>> +++ b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml >>>> @@ -45,6 +45,9 @@ properties: >>>> - description: SCMI compliant firmware with OP-TEE transport >>>> items: >>>> - const: linaro,scmi-optee >>>> + - description: SCMI compliant firmware with Qualcomm hvc/shmem transport >>>> + items: >>>> + - const: qcom,scmi-hvc-shmem >>> Can it be simply "qcom,scmi-smc" for 2 reasons ? >>> 1. We don't support SMC/HVC without shmem, so what is your argument to add >>> '-shmem' in the compatible here ? >> In our platforms, there are multiple ways to allocate memory. One is >> preallocated shmem as used here, another is dynamically by hypervisor APIs. >> shmem was to just to indicate it is preallocated. >> > Let us keep it without shmem. If it is dynamically allocated, you must not > need another compatible as you can check it at the runtime. > >>> 2. The exact conduit(SMC/HVC) used is detected runtime, so I prefer to keep >>> '-smc' instead of '-hvc' in the compatible just to avoid giving an illusion >>> that HVC is the conduit chosen here based on the compatible. It can be true >>> for other reason but I don't want to mislead here by using HVC. >> IUUC, currently, conduit comes from PSCI dt node. We have been using smc for >> PSCI but want to use hvc here. That being said, I am fine to explore if we >> can change PSCI to use hvc too. >> > I think only OPTEE has explicit conduit other than PSCI and it is continued > for legacy/compatibility reasons IIUC and IIRC. Anything else depends on > the conduit used by PSCI to be consistent. So yes you need to use what the > PSCI conduit is and you don't need the extra information from the DT either > as new property or in the compatible.
Ok, will use conduit then. Thanks!
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