diff mbox series

[v5,1/2] dt-bindings: arm: Add new compatible for smc/hvc transport for SCMI

Message ID 20231006164206.40710-2-quic_nkela@quicinc.com
State Superseded
Headers show
Series Add qcom smc/hvc transport support | expand

Commit Message

Nikunj Kela Oct. 6, 2023, 4:42 p.m. UTC
Introduce compatible "qcom,scmi-smc" for SCMI smc/hvc transport channel for
Qualcomm virtual platforms.

This compatible mandates populating an additional parameter 'capability-id'
from the last 8 bytes of the shmem channel.

Signed-off-by: Nikunj Kela <quic_nkela@quicinc.com>
---
 Documentation/devicetree/bindings/firmware/arm,scmi.yaml | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Sudeep Holla Oct. 9, 2023, 2:41 p.m. UTC | #1
On Fri, Oct 06, 2023 at 09:42:05AM -0700, Nikunj Kela wrote:
> Introduce compatible "qcom,scmi-smc" for SCMI smc/hvc transport channel for
> Qualcomm virtual platforms.
>
> This compatible mandates populating an additional parameter 'capability-id'
> from the last 8 bytes of the shmem channel.
>

While I am happy with the simplification here, I am also bit nervous how
long before Qualcomm abandons this. I hope this is adopted as is in all
internal and downstream code without any modifications and this is not
just a push for upstreaming some change to minimise delta with internal/
downstream code.

--
Regards,
Sudeep
Nikunj Kela Oct. 9, 2023, 2:52 p.m. UTC | #2
On 10/9/2023 7:41 AM, Sudeep Holla wrote:
> On Fri, Oct 06, 2023 at 09:42:05AM -0700, Nikunj Kela wrote:
>> Introduce compatible "qcom,scmi-smc" for SCMI smc/hvc transport channel for
>> Qualcomm virtual platforms.
>>
>> This compatible mandates populating an additional parameter 'capability-id'
>> from the last 8 bytes of the shmem channel.
>>
> While I am happy with the simplification here, I am also bit nervous how
> long before Qualcomm abandons this. I hope this is adopted as is in all
> internal and downstream code without any modifications and this is not
> just a push for upstreaming some change to minimise delta with internal/
> downstream code.
>
> --
> Regards,
> Sudeep

Qualcomm is using patch on all the virtual auto platforms using 
shmem/doorbell as scmi channel. This is already being used without any 
modifications in our downstream code. No delta for this patch series. 
Thanks!
Konrad Dybcio Oct. 9, 2023, 9:03 p.m. UTC | #3
On 10/9/23 16:52, Nikunj Kela wrote:
> 
> On 10/9/2023 7:41 AM, Sudeep Holla wrote:
>> On Fri, Oct 06, 2023 at 09:42:05AM -0700, Nikunj Kela wrote:
>>> Introduce compatible "qcom,scmi-smc" for SCMI smc/hvc transport 
>>> channel for
>>> Qualcomm virtual platforms.
>>>
>>> This compatible mandates populating an additional parameter 
>>> 'capability-id'
>>> from the last 8 bytes of the shmem channel.
>>>
>> While I am happy with the simplification here, I am also bit nervous how
>> long before Qualcomm abandons this. I hope this is adopted as is in all
>> internal and downstream code without any modifications and this is not
>> just a push for upstreaming some change to minimise delta with internal/
>> downstream code.
>>
>> -- 
>> Regards,
>> Sudeep
> 
> Qualcomm is using patch on all the virtual auto platforms using 
> shmem/doorbell as scmi channel. This is already being used without any 
> modifications in our downstream code. No delta for this patch series. 
> Thanks!
AFAICT Sudeep is looking for a solid guarantee that it will continue to 
be used as-is, on more than one platform and on more than one BSP version.

There have been cases where such firmware interfaces had silent ABI 
breaks (or were replaced altogether) between qc downstream branches and 
this would be unacceptable. Understandably, having a unified means of 
communication for *all* Qualcomm chips (i.e. not only auto) going 
forward would likely be expected..

Konrad
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
index 563a87dfb31a..4591523b51a0 100644
--- a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
+++ b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
@@ -38,6 +38,9 @@  properties:
                      with shmem address(4KB-page, offset) as parameters
         items:
           - const: arm,scmi-smc-param
+      - description: SCMI compliant firmware with Qualcomm SMC/HVC transport
+        items:
+          - const: qcom,scmi-smc
       - description: SCMI compliant firmware with SCMI Virtio transport.
                      The virtio transport only supports a single device.
         items:
@@ -313,6 +316,7 @@  else:
           enum:
             - arm,scmi-smc
             - arm,scmi-smc-param
+            - qcom,scmi-smc
   then:
     required:
       - arm,smc-id