Re: [RFC 1/2] dt-bindings: firmware: arm,scmi: Add support for memlat vendor protocol

[Sibi Sankar <quic_sibis@quicinc.com>]

Hey Rob,
Thanks for taking time to review the series.

On 11/4/22 23:33, Rob Herring wrote:
> On Thu, Nov 03, 2022 at 10:28:31AM +0530, Sibi Sankar wrote:
>> Add bindings support for the SCMI QTI memlat (memory latency) vendor
>> protocol. The memlat vendor protocol enables the frequency scaling of
>> various buses (L3/LLCC/DDR) based on the memory latency governor
>> running on the CPUSS Control Processor.
> 
> I thought the interconnect binding was what provided details for bus
> scaling.

The bus scaling in this particular case is done by SCP FW and not
from any kernel client. The SCMI vendor protocol would be used to
pass on the bandwidth requirements during initialization and SCP FW
would vote on it independently after it is

> 
>>
>> Signed-off-by: Sibi Sankar <quic_sibis@quicinc.com>
>> ---
>>   .../devicetree/bindings/firmware/arm,scmi.yaml     | 164 +++++++++++++++++++++
>>   1 file changed, 164 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
>> index 1c0388da6721..efc8a5a8bffe 100644
>> --- a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
>> +++ b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
>> @@ -189,6 +189,47 @@ properties:
>>         reg:
>>           const: 0x18
>>   
>> +  protocol@80:
>> +    type: object
>> +    properties:
>> +      reg:
>> +        const: 0x80
>> +
>> +      qcom,bus-type:
>> +        $ref: /schemas/types.yaml#/definitions/uint32-array
>> +        items:
>> +          minItems: 1
>> +        description:
>> +          Identifier of the bus type to be scaled by the memlat protocol.
>> +
>> +      cpu-map:
> 
> cpu-map only goes under /cpus node.

sure will use a qcom specific node instead

> 
>> +        type: object
>> +        description:
>> +          The list of all cpu cluster configurations to be tracked by the memlat protocol
>> +
>> +        patternProperties:
>> +          '^cluster[0-9]':
>> +            type: object
>> +            description:
>> +              Each cluster node describes the frequency domain associated with the
>> +              CPUFREQ HW engine and bandwidth requirements of the buses to be scaled.
>> +
>> +            properties:
> 
> cpu-map nodes don't have properties.

ack

> 
>> +              operating-points-v2: true
>> +
>> +              qcom,freq-domain:
> 
> Please don't add new users of this. Use the performance-domains binding
> instead.

The plan was to re-use the ^^ to determine frequency domain of
the cpus since they are already present in the dts. I guess using
performance-domains bindings would require a corresponding change in
qcom-cpufreq-hw driver as well. Ack.

> 
>> +                $ref: /schemas/types.yaml#/definitions/phandle-array
>> +                description:
>> +                  Reference to the frequency domain of the CPUFREQ HW engine
>> +                items:
>> +                  - items:
>> +                      - description: phandle to CPUFREQ HW engine
>> +                      - description: frequency domain associated with the cluster
>> +
>> +            required:
>> +              - qcom,freq-domain
>> +              - operating-points-v2
>> +
>>   additionalProperties: false
>>   
>>   patternProperties:
>> @@ -429,4 +470,127 @@ examples:
>>           };
>>       };
>>   
>> +  - |
>> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
>> +
>> +    firmware {
>> +        scmi {
>> +            compatible = "arm,scmi";
>> +
>> +            #address-cells = <1>;
>> +            #size-cells = <0>;
>> +
>> +            mboxes = <&cpucp_mbox>;
>> +            mbox-names = "tx";
>> +            shmem = <&cpu_scp_lpri>;
>> +
>> +            scmi_memlat: protocol@80 {
>> +                reg = <0x80>;
>> +                qcom,bus-type = <0x2>;
>> +
>> +                cpu-map {
>> +                    cluster0 {
>> +                        qcom,freq-domain = <&cpufreq_hw 0>;
>> +                        operating-points-v2 = <&cpu0_opp_table>;
>> +                    };
>> +
>> +                    cluster1 {
>> +                        qcom,freq-domain = <&cpufreq_hw 1>;
>> +                        operating-points-v2 = <&cpu4_opp_table>;
>> +                    };
>> +
>> +                    cluster2 {
>> +                        qcom,freq-domain = <&cpufreq_hw 2>;
>> +                        operating-points-v2 = <&cpu7_opp_table>;
>> +                    };
>> +                };
>> +            };
>> +        };
>> +
>> +        cpu0_opp_table: opp-table-cpu0 {
>> +            compatible = "operating-points-v2";
>> +
>> +            cpu0_opp_300mhz: opp-300000000 {
>> +                opp-hz = /bits/ 64 <300000000>;
>> +                opp-peak-kBps = <9600000>;
>> +            };
>> +
>> +            cpu0_opp_1325mhz: opp-1324800000 {
>> +                opp-hz = /bits/ 64 <1324800000>;
>> +                opp-peak-kBps = <33792000>;
>> +            };
>> +
>> +            cpu0_opp_2016mhz: opp-2016000000 {
>> +                opp-hz = /bits/ 64 <2016000000>;
>> +                opp-peak-kBps = <48537600>;
>> +            };
>> +        };
>> +
>> +        cpu4_opp_table: opp-table-cpu4 {
>> +            compatible = "operating-points-v2";
>> +
>> +            cpu4_opp_691mhz: opp-691200000 {
>> +                opp-hz = /bits/ 64 <691200000>;
>> +                opp-peak-kBps = <9600000>;
>> +            };
>> +
>> +            cpu4_opp_941mhz: opp-940800000 {
>> +                opp-hz = /bits/ 64 <940800000>;
>> +                opp-peak-kBps = <17817600>;
>> +            };
>> +
>> +            cpu4_opp_2611mhz: opp-2611200000 {
>> +                opp-hz = /bits/ 64 <2611200000>;
>> +                opp-peak-kBps = <48537600>;
>> +            };
>> +        };
>> +
>> +        cpu7_opp_table: opp-table-cpu7 {
>> +            compatible = "operating-points-v2";
>> +
>> +            cpu7_opp_806mhz: opp-806400000 {
>> +                opp-hz = /bits/ 64 <806400000>;
>> +                opp-peak-kBps = <9600000>;
>> +            };
>> +
>> +            cpu7_opp_2381mhz: opp-2380800000 {
>> +                opp-hz = /bits/ 64 <2380800000>;
>> +                opp-peak-kBps = <44851200>;
>> +            };
>> +
>> +            cpu7_opp_2515mhz: opp-2515200000 {
>> +                opp-hz = /bits/ 64 <2515200000>;
>> +                opp-peak-kBps = <48537600>;
>> +            };
>> +        };
>> +    };
>> +
>> +
>> +    soc {
>> +        #address-cells = <2>;
>> +        #size-cells = <2>;
>> +
>> +        cpucp_mbox: mailbox@17400000 {
>> +            compatible = "qcom,cpucp-mbox";
>> +            reg =   <0x0 0x17c00000 0x0 0x10>, <0x0 0x18590300 0x0 0x700>;
>> +            interrupts = <GIC_SPI 62 IRQ_TYPE_LEVEL_HIGH>;
>> +            #mbox-cells = <0>;
>> +        };
>> +
>> +        sram@18509400 {
>> +            compatible = "mmio-sram";
>> +            reg = <0x0 0x18509400 0x0 0x400>;
>> +            no-memory-wc;
>> +
>> +            #address-cells = <1>;
>> +            #size-cells = <1>;
>> +            ranges = <0x0 0x0 0x18509400 0x400>;
>> +
>> +            cpu_scp_lpri: scp-sram-section@0 {
>> +                compatible = "arm,scmi-shmem";
>> +                reg = <0x0 0x80>;
>> +            };
>> +        };
>> +    };
>> +
>>   ...
>> -- 
>> 2.7.4
>>
>>