From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0b-0031df01.pphosted.com (mx0b-0031df01.pphosted.com [205.220.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 47B932F8EA6 for ; Thu, 25 Jun 2026 05:27:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=205.220.180.131 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782365275; cv=none; b=DspFOzadvtiCGEuZtqsBwcPo5cdZgBBPDO/vRSjru9thYwEY/2hIHvumGMWiO7413sbw0eQe2KXZISfTkG94/epnuFH4IQzKQd9gpCq2YjBR+H2eTLY25C7zjHPcdzmiLQ4fHyGYf43uRvHMmepX+tyzjz4tGkmrnfUjLocTr2U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782365275; c=relaxed/simple; bh=utZWytu5ai9CNGXAFQcug6qUDSlwkkNLzLZU6nCx/Mk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=iVSnjGYFfaT0i3sd3zYW1Wq76c/ogs5EdNwXLKlo9TS3IwQzmoUudz3IIq4xYSwZWTtkuiQZExocifMxqD4QCySs/eAkszMDcoJixTZZqs6c9nsaJj5CB4qm/23I8zQ4dISxACZawoXCu1KRBS6n7VRuzHMc39hVGw3OTPWeI6o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oss.qualcomm.com; spf=pass smtp.mailfrom=oss.qualcomm.com; dkim=pass (2048-bit key) header.d=qualcomm.com header.i=@qualcomm.com header.b=g5oG5rve; dkim=pass (2048-bit key) header.d=oss.qualcomm.com header.i=@oss.qualcomm.com header.b=L9VE+Qsq; arc=none smtp.client-ip=205.220.180.131 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oss.qualcomm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=oss.qualcomm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=qualcomm.com header.i=@qualcomm.com header.b="g5oG5rve"; dkim=pass (2048-bit key) header.d=oss.qualcomm.com header.i=@oss.qualcomm.com header.b="L9VE+Qsq" Received: from pps.filterd (m0279873.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 65P3eHSx1102876 for ; Thu, 25 Jun 2026 05:27:53 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=qualcomm.com; h= cc:content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=qcppdkim1; bh= 68QmrLLXwE4JrUm3cojVwQjQkH3bZQyo8VxIUTcnh8U=; b=g5oG5rvee8BQgALl vh66gsQhJa+vEZoh8oZa+cPblCRO3VmZU4gjyNWkpiDKAfG9s8g30NoFvtx8wWmx sO1CAwSx/hiCW+Rhv+Vlp+IMjE4uZom63OTaxaN8Kv0+2qD9UMOCiO8w29O1O43W ezBj4RcfRrfQJMPZji9KnDdwo7zF7B804StRC+eVu1tlpN6bkbTe5S1hqKOyfzwA AEGsdF+nnYpyiXH51FK10IKfaVWkVJS+IHV0fQfHdnRgPIYg/+M9YPfoYZ+SQs8Q PNOFUEDxbK0R5uwLFx9myM7HoCQ3V9VA6AxqzpIg2QiSyuMzRv0uwywOUxh01C5y Y5pjew== Received: from mail-pg1-f200.google.com (mail-pg1-f200.google.com [209.85.215.200]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 4f0ueu8mgk-1 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NOT) for ; Thu, 25 Jun 2026 05:27:52 +0000 (GMT) Received: by mail-pg1-f200.google.com with SMTP id 41be03b00d2f7-c860544c077so2362561a12.3 for ; Wed, 24 Jun 2026 22:27:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oss.qualcomm.com; s=google; t=1782365272; x=1782970072; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=68QmrLLXwE4JrUm3cojVwQjQkH3bZQyo8VxIUTcnh8U=; b=L9VE+QsqkzW50CPE1yYwpvleLyj5iuaawj3VU63Oq+1rYQhjqtlqo3YDlwPkghinH/ 26LH4EzCJBtfwmTPaKnxQVJLaj7bC1Wg72q/mj+5oUk1NehKj9+anLWiepYuyBHK4F/J xSw7FPHkU53m6UVqnuB5dlv8mMJbeplkmYIbVAh3bJ9lWU7Cc58T4BhLVk1VMWma2RjN cAtsF9CKe01pqF+MsthJO44n8lFBc6enZD/wXxC4s6NnGo/v23atT8+v7z8X0fUM9PfA 1k/Sq4unKXJH27neVVLOKeGCWtliaIv+uw3QpEckxIcMpfrKLrVrRnFVBbSfzBUHXjh2 J8Xw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1782365272; x=1782970072; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=68QmrLLXwE4JrUm3cojVwQjQkH3bZQyo8VxIUTcnh8U=; b=f/mXa7beO2uYthtCUUBxS6LSWvT9dsLnQdimWOwTsUtMF6CGy41P3SY+T1U5dzWr2+ EwNhMpb+WmaZyW+wmEck5IV1x5Wp+ujdT2cWHc8jZK4z7W0xumVeNOW8lVk9T2dcWO66 cjEBTqISJLjo+eG2XbFlTFwePZtPA7d0CP7vBrKzRRDvPJqNfXmh2PobjQF08RBPL9x+ RZvEj2t/2GyYIP+86X3fYiBeVuiUeVt5tkvHN3GG5aCkDw3zjo37fUWNQSJ9A3aQM1lQ rz4Hfmi+7mVSYJZ0vuaeCUw9LOBH0DdwaoDRr+1qOrmctwCQY8+T6VgfVtNi33QviUvk TILQ== X-Forwarded-Encrypted: i=1; AFNElJ/jPsH9CNcCUI3VKlDhYuwwXl2zKzbHjVaJh+H8PXEVg1loq5097gIVDinnhpoe8U/EIUKzwU7nrwwVyvg=@vger.kernel.org X-Gm-Message-State: AOJu0YyvATm2JeB29ZRdhfj3SVkSlbzBx0mwvfDd22erixRwwRvv+Wmx AV9xChU5h+DIjYm9S0ulYNtIW7RsVy/JoMtD9RTcHWMgyngrOKE9Ml8G5tS2p42+OQ1INk1MT1G tweam9RdNc2aGceyHQjDOHjt/TVt9nLVFZfjlGwg0qu4qgfm51+W7Np5tHqc8U3pwXH8= X-Gm-Gg: AfdE7cnsfy7RCfe+4RCHXKdqE/db0B7JG2xYKfitVLV6accrD79suCVvIxA0B3SZUI1 r6j7GxNxzNHx8s+AaOt98zdBtDuJUp08VzIfUZZgIgazjeJfRhsubxO/6tyRJgm6QIiZW396Fxa oEP31BTBLijt2wVqktang1gQsZ1xQ3oDCMbc4VzJBhRozNt9pJImj3VG4gI6P1Uqz0GE+CncbEt ELeYhi9ooUzUXP7hy3mp45oVUpojF+2Nr9ucc0Kt8G0k2BVW1MqgseDAbaV0mWdZti9SEr+eHu7 VcYkOBPI6/erdWOlC4gzVJOx4JWBRDM1YBVuFAxJKXtoPBj79mwDtI0TFKFuhgfJjBRVQfFTq31 rxt+i9UO4NBbhbXNhNU9sPhc/FeIg3swDAD+U07zNKBXT3fbvBGzJiRwqOt4qlwyzOW7wN/n7kc w+7p/LlbN+xDMaMWxF0MqvhJoCk+LlWD20 X-Received: by 2002:a05:6a20:b786:b0:3b3:10e1:a87f with SMTP id adf61e73a8af0-3bd4af033a0mr1353202637.31.1782365271672; Wed, 24 Jun 2026 22:27:51 -0700 (PDT) X-Received: by 2002:a05:6a20:b786:b0:3b3:10e1:a87f with SMTP id adf61e73a8af0-3bd4af033a0mr1353170637.31.1782365271237; Wed, 24 Jun 2026 22:27:51 -0700 (PDT) Received: from [10.50.49.21] (blr-bdr-fw-01_GlobalNAT_AllZones-Outside.qualcomm.com. [103.229.18.19]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-c93522747efsm302606a12.22.2026.06.24.22.27.42 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 24 Jun 2026 22:27:50 -0700 (PDT) Message-ID: Date: Thu, 25 Jun 2026 10:57:40 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC v7 0/9] firmware: arm_scmi: vendors: Qualcomm Generic Vendor Extensions To: Sudeep Holla Cc: Cristian Marussi , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Sibi Sankar , MyungJoo Ham , Kyungmin Park , Chanwoo Choi , Dmitry Osipenko , Thierry Reding , Jonathan Hunter , Bjorn Andersson , Konrad Dybcio , Rajendra Nayak , Pankaj Patil , linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, arm-scmi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-pm@vger.kernel.org, linux-tegra@vger.kernel.org, Amir Vajid , Ramakrishna Gottimukkula References: <20260610-rfc_v7_scmi_memlat-v7-0-f3f68c608f25@oss.qualcomm.com> <20260616-responsible-junglefowl-of-chaos-7eda7d@sudeepholla> <8725caf9-cebb-49ce-b2c8-4960a6073322@oss.qualcomm.com> <20260623-busy-beautiful-trout-8cc2ea@sudeepholla> Content-Language: en-US From: Pragnesh Papaniya In-Reply-To: <20260623-busy-beautiful-trout-8cc2ea@sudeepholla> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Proofpoint-ORIG-GUID: FBL0yG0YcH2KpWzQzXzGA12yhKayffEf X-Proofpoint-Spam-Info: AW1haW4tMjYwNjI1MDA0NCBTYWx0ZWRfX7tHLp1hf9hrD uCxgfB30tSgEaDHx/CbOvVGBsde8szOu59s0itVKfXRZBVeY3H9j8deo/AW+UuawRbaSzYiRNkG zMcKkhp863QBA/HQas4OzcR5yYb1gMQ= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNjI1MDA0NCBTYWx0ZWRfX7HY40eZ46lMt F/kANCKJ2awycsHepG84GAaawM6jbhmxxe21Vjs8GbT8EhHdurMFbjdpFaCzwt2FxfGiYtjexSB rY+PkzWHANl+LRumTpwnApqDlFYwLhAFJV/s0jIo6/F5qF+gqRerJc1vl7S8/vQzsBWUUzKoqIB 4vosvg55E7+9R8MKts53KEPzn+UnbrNQKqZuH5N0IARcgIqRbIBc0omcRk6EaYx50XNOVUHBFEm UENzZ6P8hsqvZW0HXjZcVXeXomQnGxUbD/5k1fxDwKvWgGZ3DOEpc2xAFPRK+lP/PBWLsGe/OVs PXgtvcv5Yw5Iz7imt+3KshKi1ypZh/kNS74CsIkDd/RJVSdIDk/8iJzwu0VWv84Y9gXxBrXKFNC 2KYux+LtB8tyzuyX6KMC8Uxv7tBRWMynO7Fkz4H1BneB2BdHHkrjdmAHFa3gnjCkXx60ARsrynF a2arAWkXq/zn3GrTKUQ== X-Authority-Analysis: v=2.4 cv=b/SCJNGx c=1 sm=1 tr=0 ts=6a3cbc58 cx=c_pps a=oF/VQ+ItUULfLr/lQ2/icg==:117 a=Ou0eQOY4+eZoSc0qltEV5Q==:17 a=IkcTkHD0fZMA:10 a=FelO9ux0wxsA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=rJkE3RaqiGZ5pbrm-msn:22 a=VwQbUJbxAAAA:8 a=TXgiicuEePHzAitInHsA:9 a=QEXdDO2ut3YA:10 a=3WC7DwWrALyhR5TkjVHa:22 X-Proofpoint-GUID: FBL0yG0YcH2KpWzQzXzGA12yhKayffEf X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.125,FMLib:17.12.100.49 definitions=2026-06-25_01,2026-06-24_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 lowpriorityscore=0 suspectscore=0 phishscore=0 bulkscore=0 adultscore=0 clxscore=1015 spamscore=0 malwarescore=0 impostorscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2606250044 On 23-Jun-26 2:17 PM, Sudeep Holla wrote: > On Fri, Jun 19, 2026 at 06:01:23PM +0530, Pragnesh Papaniya wrote: >> >> On 16-Jun-26 1:57 PM, Sudeep Holla wrote: >> >>> Not sure if it was discussed in the previous versions or not, it would be >>> good if you can capture why some of bus scaling doesn't work with the existing >>> SCMI performance protocol and the monitors don't fit the MPAM mode. >>> >>> Please capture them in 1/9 as a motivation for this vendor protocol. It will >>> then help to understand it better as I am still struggling to. Sorry for that. >> >> Thanks for the input! >> >> SCMI perf protocol exports perf domains to kernel where kernel can set >> the frequency but here the scaling governor runs on the SCP while kernel >> just observes frequency changes made by remote governor. > > OK if it is sort of read-only w.r.t kernel, why not perf domain notifications > work to consume the change done by the SCMI platform. > > And why do you have set operations in the vendor protocol being proposed then. > It all looks like something just cooked up to make things work. I need > detailed reasoning as why the existing perf protocol can't work considering > all the existing notifications in place. Please do take another look at the documentation and driver changes to see how it all comes together, since it's apparent that we use SET operation for a ton of things. Taking another stab at explaining how the MEMLAT uses all the ops exposed by the vendor protocol. We use the SET operation to pass on various tuneables (IPM CEIL, stall floors, write-back filter, freq-scale params, adaptive low/high freq, sample ms), the core-freq -> mem-freq map, and min/max clamps) required to run the MEMLAT algorithm on the SCP. You might ask why can't we have these values stored somewhere on the SCP itself? We would like to but all of these are tuneable values, that can change for various boards for the same SoC. The START/STOP operations are meant to start/stop the algorithm, in this case the bus scaling algorithm. We use the GET operation to get the current frequency of memory that we are trying to scale. It can be also used to read back all the parameters that we are trying to set. Another thing to note is that exposing the current frequency to the userspace was something that the community wanted. With all of ^^ in mind, re-using the perf protocol becomes impossible. https://lore.kernel.org/lkml/k4lpzxtrq3x6riyv6etxiobn7nbpczf2bp3m4oc752nhjknlit@uo53kbppzim7/ https://lore.kernel.org/lkml/20241115003809epcms1p518df149458f3023d33ec6d87a315e8f6@epcms1p5/ We'll add more call flow diagrams as part of the documentation for the next re-spin to make reviews a bit more easier. -Pragnesh > >> While MPAM is not enabled/supported on all hardware (Hamoa). > > Fair enough but I still don't fully understand to rule that out yet. >