Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.34 as permitted sender) client-ip=23.128.96.34;
Message-ID: <978fd46d-8142-41e6-9c62-df678018d6c2@linaro.org>
Date:   Fri, 15 Sep 2023 15:43:27 +0200
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH 00/53] icc-rpmh multi-RSC voting groundwork
Content-Language: en-US
To:     Mike Tipton <quic_mdtipton@quicinc.com>
Cc:     Georgi Djakov <djakov@kernel.org>, Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        cros-qcom-dts-watchers@chromium.org,
        Marijn Suijten <marijn.suijten@somainline.org>,
        linux-arm-msm@vger.kernel.org, linux-pm@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20230708-topic-rpmh_icc_rsc-v1-0-b223bd2ac8dd@linaro.org>
 <c067a45f-9629-d516-9e56-36538e4ff6db@kernel.org>
 <20230807215739.GA9621@hu-mdtipton-lv.qualcomm.com>
 <10520827-dc01-475c-b09a-35cefc9e0a62@linaro.org>
 <20230913012951.GA19284@hu-mdtipton-lv.qualcomm.com>
 <ffc58838-c306-49f3-a90a-95b2cf02ae3d@linaro.org>
 <20230914023239.GA25147@hu-mdtipton-lv.qualcomm.com>
From:   Konrad Dybcio <konrad.dybcio@linaro.org>
Autocrypt: addr=konrad.dybcio@linaro.org; keydata=
 xsFNBF9ALYUBEADWAhxdTBWrwAgDQQzc1O/bJ5O7b6cXYxwbBd9xKP7MICh5YA0DcCjJSOum
 BB/OmIWU6X+LZW6P88ZmHe+KeyABLMP5s1tJNK1j4ntT7mECcWZDzafPWF4F6m4WJOG27kTJ
 HGWdmtO+RvadOVi6CoUDqALsmfS3MUG5Pj2Ne9+0jRg4hEnB92AyF9rW2G3qisFcwPgvatt7
 TXD5E38mLyOPOUyXNj9XpDbt1hNwKQfiidmPh5e7VNAWRnW1iCMMoKqzM1Anzq7e5Afyeifz
 zRcQPLaqrPjnKqZGL2BKQSZDh6NkI5ZLRhhHQf61fkWcUpTp1oDC6jWVfT7hwRVIQLrrNj9G
 MpPzrlN4YuAqKeIer1FMt8cq64ifgTzxHzXsMcUdclzq2LTk2RXaPl6Jg/IXWqUClJHbamSk
 t1bfif3SnmhA6TiNvEpDKPiT3IDs42THU6ygslrBxyROQPWLI9IL1y8S6RtEh8H+NZQWZNzm
 UQ3imZirlPjxZtvz1BtnnBWS06e7x/UEAguj7VHCuymVgpl2Za17d1jj81YN5Rp5L9GXxkV1
 aUEwONM3eCI3qcYm5JNc5X+JthZOWsbIPSC1Rhxz3JmWIwP1udr5E3oNRe9u2LIEq+wH/toH
 kpPDhTeMkvt4KfE5m5ercid9+ZXAqoaYLUL4HCEw+HW0DXcKDwARAQABzShLb25yYWQgRHli
 Y2lvIDxrb25yYWQuZHliY2lvQGxpbmFyby5vcmc+wsGOBBMBCAA4FiEEU24if9oCL2zdAAQV
 R4cBcg5dfFgFAmQ5bqwCGwMFCwkIBwIGFQoJCAsCBBYCAwECHgECF4AACgkQR4cBcg5dfFjO
 BQ//YQV6fkbqQCceYebGg6TiisWCy8LG77zV7DB0VMIWJv7Km7Sz0QQrHQVzhEr3trNenZrf
 yy+o2tQOF2biICzbLM8oyQPY8B///KJTWI2khoB8IJSJq3kNG68NjPg2vkP6CMltC/X3ohAo
 xL2UgwN5vj74QnlNneOjc0vGbtA7zURNhTz5P/YuTudCqcAbxJkbqZM4WymjQhe0XgwHLkiH
 5LHSZ31MRKp/+4Kqs4DTXMctc7vFhtUdmatAExDKw8oEz5NbskKbW+qHjW1XUcUIrxRr667V
 GWH6MkVceT9ZBrtLoSzMLYaQXvi3sSAup0qiJiBYszc/VOu3RbIpNLRcXN3KYuxdQAptacTE
 mA+5+4Y4DfC3rUSun+hWLDeac9z9jjHm5rE998OqZnOU9aztbd6zQG5VL6EKgsVXAZD4D3RP
 x1NaAjdA3MD06eyvbOWiA5NSzIcC8UIQvgx09xm7dThCuQYJR4Yxjd+9JPJHI6apzNZpDGvQ
 BBZzvwxV6L1CojUEpnilmMG1ZOTstktWpNzw3G2Gis0XihDUef0MWVsQYJAl0wfiv/0By+XK
 mm2zRR+l/dnzxnlbgJ5pO0imC2w0TVxLkAp0eo0LHw619finad2u6UPQAkZ4oj++iIGrJkt5
 Lkn2XgB+IW8ESflz6nDY3b5KQRF8Z6XLP0+IEdLOOARkOW7yEgorBgEEAZdVAQUBAQdAwmUx
 xrbSCx2ksDxz7rFFGX1KmTkdRtcgC6F3NfuNYkYDAQgHwsF2BBgBCAAgFiEEU24if9oCL2zd
 AAQVR4cBcg5dfFgFAmQ5bvICGwwACgkQR4cBcg5dfFju1Q//Xta1ShwL0MLSC1KL1lXGXeRM
 8arzfyiB5wJ9tb9U/nZvhhdfilEDLe0jKJY0RJErbdRHsalwQCrtq/1ewQpMpsRxXzAjgfRN
 jc4tgxRWmI+aVTzSRpywNahzZBT695hMz81cVZJoZzaV0KaMTlSnBkrviPz1nIGHYCHJxF9r
 cIu0GSIyUjZ/7xslxdvjpLth16H27JCWDzDqIQMtg61063gNyEyWgt1qRSaK14JIH/DoYRfn
 jfFQSC8bffFjat7BQGFz4ZpRavkMUFuDirn5Tf28oc5ebe2cIHp4/kajTx/7JOxWZ80U70mA
 cBgEeYSrYYnX+UJsSxpzLc/0sT1eRJDEhI4XIQM4ClIzpsCIN5HnVF76UQXh3a9zpwh3dk8i
 bhN/URmCOTH+LHNJYN/MxY8wuukq877DWB7k86pBs5IDLAXmW8v3gIDWyIcgYqb2v8QO2Mqx
 YMqL7UZxVLul4/JbllsQB8F/fNI8AfttmAQL9cwo6C8yDTXKdho920W4WUR9k8NT/OBqWSyk
 bGqMHex48FVZhexNPYOd58EY9/7mL5u0sJmo+jTeb4JBgIbFPJCFyng4HwbniWgQJZ1WqaUC
 nas9J77uICis2WH7N8Bs9jy0wQYezNzqS+FxoNXmDQg2jetX8en4bO2Di7Pmx0jXA4TOb9TM
 izWDgYvmBE8=
In-Reply-To: <20230914023239.GA25147@hu-mdtipton-lv.qualcomm.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 14.09.2023 04:32, Mike Tipton wrote:
> On Wed, Sep 13, 2023 at 10:31:49AM +0200, Konrad Dybcio wrote:
>>> The applicable voters should likely be defined in the target-specific
>>> headers, rather than the common qcom,icc.h. The bit range used for them
>>> could be common, but each target may only support a small subset of the
>>> total set of possible voters across all targets.
>> I'm not sure how client drivers would then choose the
>> correct path other than
>>
>> switch (soc) {
>> case 8450:
>> 	tag = QCOM_ICC_TAG_VOTER_8450_HLOS;
>> 	break;
>> case 8550:
>> 	tag = QCOM_ICC_TAG_VOTER_8550_HLOS;
>> 	break;
>> ...
>> }
>>
>> which would be unacceptable.
> 
> The same general way it's handled for the endpoint bindings, which are
> already target-specific. 
> 
> Any client drivers hardcoding the endpoint bindings in their driver
> would have to include the appropriate, target-specific binding header
> (e.g. qcom,sm8550-rpmh.h). That would only be possible if their driver
> file is itself target-specific. Otherwise, it would have to pull the
> endpoint bindings from devicetree. Or just use the recommended
> of_icc_get() and let devicetree do everything for them. Same for the
> target-specific voter tag bindings.
> 
> Clients can also specify their tags in devicetree. They don't actually
> have to call icc_set_tag() directly. For example:
> 
>     #include <dt-bindings/interconnect/qcom,sm8450.h>
> 
>     interconnects = <&mmss_noc MASTER_MDP QCOM_ICC_TAG_VOTER_DISP
>                      &mc_virt SLAVE_EBI1 QCOM_ICC_TAG_VOTER_DISP>;
> 
> Then when they call of_icc_get() for this path it'll automatically have
> QCOM_ICC_TAG_VOTER_DISP set for them.
I think I'd skew towards the "define everything in the DT" approach.

One thing that makes me uneasy to go on with this approach is the
question whether there is a case in which we would want to switch
from e.g. voting through DISP to voting through APPS (or similar)
from within a single device.

Konrad