linux-kernel - Re: [PATCH net-next 1/5] dt-bindings: net: qcom,ipa: deprecate modem-init

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Message-ID: <2f827660-ae9d-01dd-ded8-7fd4c2f8f8ae@ieee.org>
Date:   Mon, 14 Nov 2022 11:48:17 -0600
From:   Alex Elder <elder@...e.org>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Alex Elder <elder@...aro.org>, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org, davem@...emloft.net,
        edumazet@...gle.com, kuba@...nel.org, pabeni@...hat.com
Cc:     andersson@...nel.org, konrad.dybcio@...aro.org, agross@...nel.org,
        elder@...nel.org, linux-arm-msm@...r.kernel.org,
        netdev@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next 1/5] dt-bindings: net: qcom,ipa: deprecate
 modem-init

On 11/14/22 03:56, Krzysztof Kozlowski wrote:
> On 12/11/2022 21:07, Alex Elder wrote:
>> GSI firmware for IPA must be loaded during initialization, either by
>> the AP or by the modem.  The loader is currently specified based on
>> whether the Boolean modem-init property is present.
>>
>> Instead, use a new property with an enumerated value to indicate
>> explicitly how GSI firmware gets loaded.  With this in place, a
>> third approach can be added in an upcoming patch.
>>
>> The new qcom,gsi-loader property has two defined values:
>>    - self:   The AP loads GSI firmware
>>    - modem:  The modem loads GSI firmware
>> The modem-init property must still be supported, but is now marked
>> deprecated.
>>
>> Signed-off-by: Alex Elder <elder@...aro.org>
>> ---
>>   .../devicetree/bindings/net/qcom,ipa.yaml     | 59 +++++++++++++++----
>>   1 file changed, 46 insertions(+), 13 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/net/qcom,ipa.yaml b/Documentation/devicetree/bindings/net/qcom,ipa.yaml
>> index e752b76192df0..0dfd6c721e045 100644
>> --- a/Documentation/devicetree/bindings/net/qcom,ipa.yaml
>> +++ b/Documentation/devicetree/bindings/net/qcom,ipa.yaml
>> @@ -124,12 +124,22 @@ properties:
>>         - const: ipa-clock-enabled-valid
>>         - const: ipa-clock-enabled
>>   
>> +  qcom,gsi-loader:
>> +    enum:
>> +      - self
>> +      - modem
>> +    description:
>> +      This indicates how GSI firmware should be loaded.  If the AP loads
> 
> s/This indicates/Indicate/
> (or any other grammar without describing DT syntax but hardware/system)

OK.

>> +      and validates GSI firmware, this property has value "self".  If the
>> +      modem does this, this property has value "modem".
>> +
>>     modem-init:
>> +    deprecated: true
>>       type: boolean
>>       description:
>> -      If present, it indicates that the modem is responsible for
>> -      performing early IPA initialization, including loading and
>> -      validating firwmare used by the GSI.
>> +      This is the older (deprecated) way of indicating how GSI firmware
>> +      should be loaded.  If present, the modem loads GSI firmware; if
>> +      absent, the AP loads GSI firmware.
>>   
>>     memory-region:
>>       maxItems: 1
>> @@ -155,15 +165,36 @@ required:
>>     - interconnects
>>     - qcom,smem-states
>>   
>> -# If modem-init is not present, the AP loads GSI firmware, and
>> -# memory-region must be specified
>> -if:
>> -  not:
>> -    required:
>> -      - modem-init
>> -then:
>> -  required:
>> -    - memory-region
>> +allOf:
>> +  # If qcom,gsi-loader is present, modem-init must not be present
>> +  - if:
>> +      required:
>> +        - qcom,gsi-loader
>> +    then:
>> +      properties:
>> +        modem-init: false
> 
> This is ok, but will not allow you to keep deprecated property in DTS
> for the transition period. We talked about this that you need to keep
> both or wait few cycles before applying DTS cleanups.

My intention is expressed in the comment.  Is it because of the
"if .... required ... qcom,gsi-loader"?

Should it be "if ... properties ... qcom,gsi-loader"?

I believe I tested the deprecated cases also, but will do it again.
If I coded it wrong I'd like to fix it (even if "it works").

>> +
>> +      # If qcom,gsi-loader is "self", the AP loads GSI firmware, and
>> +      # memory-region must be specified
>> +      if:
>> +        properties:
>> +          qcom,gsi-loader:
>> +            contains:
>> +              const: self
>> +      then:
>> +        required:
>> +          - memory-region
>> +    else:
>> +      # If qcom,gsi-loader is not present, we use deprecated behavior.
>> +      # If modem-init is not present, the AP loads GSI firmware, and
>> +      # memory-region must be specified.
>> +      if:
>> +        not:
>> +          required:
>> +            - modem-init
>> +      then:
>> +        required:
>> +          - memory-region
>>   
>>   additionalProperties: false
>>   
>> @@ -196,7 +227,9 @@ examples:
>>           ipa@...0000 {
>>                   compatible = "qcom,sdm845-ipa";
>>   
>> -                modem-init;
>> +                qcom,gsi-loader = "self";
>> +                memory-region = <&ipa_fw_mem>;
>> +                firmware-name = "qcom/sc7180-trogdor/modem-nolte/mba.mbn";
> 
> Isn't this example based on sdm845?

Yes, you're right.  I'll update it.  I just wanted to supply an
example that actually showed using all these properties.  I'll
make the whole example be for sc7180.

Thank you.

					-Alex

> 
>>   
>>                   iommus = <&apps_smmu 0x720 0x3>;
>>                   reg = <0x1e40000 0x7000>,
> 
> Best regards,
> Krzysztof
>