From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=205.220.180.131 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794519861; b=CGCcRgUZx838fMLt/LWhM9pbwWy1bZwnV8XwvcQaqJM2WH2O2J5TrTiLwT68FsVs+cqB 53wFRC+4/rogk0UBFuGBcB3eel21mafsLYap7acs2eIsvz7OvQ54fayZ5D9n4L//2DOnP i/6cfmUCYxWNKDp5bSXwtdB7cZYJxX5BWM24liXtZ2xJBp8GrpFwIKAPhVbdEdcCUQhSr o3QuzvXThXuIaHFjK1NGkODpkraLhR2yqrGLvqd4WoWDUn961jOGn9LGLYvBgP7SHzHmh xEO719TbqoIE8FFfRRZYMRQEGYY6o+pVb1i9vojKEjnsOZZmAG62buXYABH53l/Mqug== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794519861; h=DMARC-Filter:Received:DKIM-Signature:Received:Received: DKIM-Signature:X-Google-DKIM-Signature:X-Gm-Message-State:X-Gm-Gg: X-Received:X-Received:Received:Date:From:To:Cc:Subject:Message-ID: In-Reply-To:References:Organization:X-Mailer:MIME-Version: Content-Type:Content-Transfer-Encoding:X-Proofpoint-GUID: X-Proofpoint-Spam-Info:X-Proofpoint-Spam-Details-Enc: X-Proofpoint-ORIG-GUID:X-Authority-Analysis: X-Proofpoint-Virus-Version:X-Proofpoint-Spam-Details; bh=ZeMxHXnCBkE76aNWIiCzfKnISExLlSlffb4po3vqmdI=; b=no/GCsLhkvnA6s7GKxm4OtgPawB6utBXR6gyZEGb5nA7LfkFwchuh1aS8msdvH/fCAzh sW0WATkcrA2YcyMzOt7ACmumzY9OHHAg0oIiZIo0DeeAcLYiX4m1m0VDP7jBZxpd0oQJL 1lRg0U6/WGP9G6c8+aBFekOx3D5qUS/Wrc8X3lDEWlEgFnXhHIVh7Ob4eURRtvCcJOsg7 f8wXNga5TKklZ9NdJh3oOyuZ20wRKZMUdynRlRT+th1h1NDBZuDZ5Bi7XiVyvxncdthpH ehwuJb2V+qStVB+awoEpbBym7tryzuG7L2YgIgRaR63MnyXibH8B/vZDrF4Nh0eqIwQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=oss.qualcomm.com; spf=pass smtp.mailfrom=oss.qualcomm.com; dkim=pass header.d=qualcomm.com header.i=@qualcomm.com header.a=rsa-sha256 header.s=qcppdkim1 header.b=SWGQudK9; dkim=pass header.d=oss.qualcomm.com header.i=@oss.qualcomm.com header.a=rsa-sha256 header.s=google header.b=ZAgLUXUv; arc=none smtp.remote-ip=205.220.180.131 Received: from mx0b-0031df01.pphosted.com (mx0b-0031df01.pphosted.com [205.220.180.131]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2FDB8606A321 for ; Thu, 12 Nov 2026 21:44:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 2FDB8606A321 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none 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.a=rsa-sha256 header.s=qcppdkim1 header.b=SWGQudK9; dkim=pass (2048-bit key) header.d=oss.qualcomm.com header.i=@oss.qualcomm.com header.a=rsa-sha256 header.s=google header.b=ZAgLUXUv Received: from pps.filterd (m0279868.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 6ACJZl6N1840824 for ; Thu, 12 Nov 2026 21:44:14 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= ZeMxHXnCBkE76aNWIiCzfKnISExLlSlffb4po3vqmdI=; b=SWGQudK9aYrpfeUe qRTs6vz+IblA+g6HLzEh+HNTp1JWnELbXeYXlgSZ4D2fPe+3AlgY0nfJCmojVecr C+1aHyfw3yXogZgwWvUmpNvISQm8rSXicGpc0601ymsG3vVC0nnNzwu95tt4+vCs Bcbxjn6HZZ1X+cJSRElTcFVnvSQtwtYku8TUD74ZDphUWF3awQLaBdGsgW4AyT6G W7qzXHipUPiDrXYSvquV31srFzv4S58RZ78Y7ViWJZJBenOG9EhrEswCtIA4dsCW +blKhYiBYZZmgIcAWEdkgIczvQxR8YKz9apSBUid1wHdMvLOpVaKFGoUNnLABD8m RzxBcw== Received: from mail-dl1-f69.google.com (mail-dl1-f69.google.com [74.125.82.69]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 4hwan4tkg3-1 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NOT) for ; Thu, 12 Nov 2026 21:44:13 +0000 (GMT) Received: by mail-dl1-f69.google.com with SMTP id a92af1059eb24-1b3b45597c7so402806c88.1 for ; Thu, 12 Nov 2026 13:44:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oss.qualcomm.com; s=google; t=1794519853; x=1795124653; darn=vger.kernel.org; h=content-transfer-encoding:content-type:mime-version:organization :references:in-reply-to:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to:content-type; bh=ZeMxHXnCBkE76aNWIiCzfKnISExLlSlffb4po3vqmdI=; b=ZAgLUXUvXHLfJwIUZC1/C8MgADJ8bUzvPkeTGkQgmRFBESKj86Eb+up/j8RDo/aGan hWTCNA5UNItE1z0awL2jdVixZNnuUSNZRDnNRbXuVs0fC6SN9vXM5H0w/rEL9QBXDvoF e931G5J8EiW0fEmBtyEODT5lweQLwCQ7+MU6X/Pzy49lGpPBuLRjVYwd3eT62NXEti6/ M00s6UBc/B1F7oA5F5BBIuVnX8WQf3e+hkDxCdyDfEc7/GiZ0rYaHjUa8gelPpkVbJ5b JVkvvkOQNh7yi7xMfsKwWCBynT+7hj8XNgL9vRPLfPeRBIp8To0AFs9lnAoDpw1q5d7J lEaA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1794519853; x=1795124653; h=content-transfer-encoding:content-type:mime-version:organization :references:in-reply-to:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=ZeMxHXnCBkE76aNWIiCzfKnISExLlSlffb4po3vqmdI=; b=2Hp/ZJHEbF/99KQC+y5x++8t11JpQ70h7AkCiE2fT+a7yIU39QcmG0g/Vb4V7w7Oz9 RC9g22esJ262yuITEk+YOEMMvSlhJS+r0PkfXE2HJtutcA6bm+/4FX19pJlWl7vhDzpd yl+dqVGvDsGh9JfvNflbOj5T59IXR/o9ykNcngL2aC9rLDmkBGyaTSGXAhws3gROnhJF mMTkyy952YTzMZ3xg9jYVyaBqqHTKHyuCKFNhWxywGVsW+swrsJcP5UBaZG3YP8PkT2F 2/31gcwYDj0j/sMjm2/N+JJW+hoDLQ7rwBITIbURJa3tgyfplTRN2eNareBGM5Kr+Pwx 8d6A== X-Gm-Message-State: APuU4Z//7KHE3SEEDaIlHMhf9S733VSjzJGIhvBVENqQ+/Zv1kv8ydYR 3LK1VwuenfmWJBT8DgmVTRBbM2kLQunMJr7pmxV95w0UOyYpZ+TFZLmWde0lNikd8x+ERqs2T8+ urpm+bK8oN/eZ/doTqTVW11knrNcnGAw/GEar4Y4uyPRvMCIwlq4pUwbVkK18WiMZ4UU= X-Gm-Gg: AYBFou0fBSpmJOBrHBYb6HDHV1I0jFXE2q/ThCNKODLqzpOooWR/+2Yb+KxGBuAgeuW Ja9dUdoudvImltPm6uGeSDKsMykiia1JTwqHQZ8eytOlDz94jVCv3/CGxwr+oVelrkHqEpoiRDG Zn+W/xyVqSjy0gjZ+QP9f5u/dfNzXs4kNaXw7AvpHiX3XsQcboJ5ZcuxKfNaN4ybPtcbVOXdPwP DIHabD1/rpbdQKswVf2zyTOpqOK2VSlwE4ZvK6CP9fmSe0Jt2D507SnRuRgEmGc9UhdH7S/3Nkc X3bj8Rn9WROi6vYbxsSoec+uPsERat9BEoTPVk71y+wGiKq6pxFFt0sYc397bHJBlxMbCEhp/1h Lej+gXdEyaXyA95Ll213MWZOVyMgTfqmt1HFK+WzNb+c/p+mTOSk/3P0tYap/z2dK+/yH9QQ3D5 uM8twP4RnKcImBssOsOO/L6iRxlTE= X-Received: by 2002:a05:701b:450d:20b0:181:ccdd:ed2a with SMTP id a92af1059eb24-1b50315f88bmr668899c88.43.1794519852990; Thu, 12 Nov 2026 13:44:12 -0800 (PST) X-Received: by 2002:a05:701b:450d:20b0:181:ccdd:ed2a with SMTP id a92af1059eb24-1b50315f88bmr668878c88.43.1794519852364; Thu, 12 Nov 2026 13:44:12 -0800 (PST) Received: from localhost (i-global254.qualcomm.com. [199.106.103.254]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-1b50319e381sm1541771c88.12.2026.11.12.13.44.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Nov 2026 13:44:12 -0800 (PST) Date: Thu, 12 Nov 2026 13:44:07 -0800 From: Jonathan Cameron To: Cristian Marussi Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, arm-scmi@vger.kernel.org, linux-doc@vger.kernel.org, sudeep.holla@kernel.org, james.quinlan@broadcom.com, f.fainelli@gmail.com, vincent.guittot@linaro.org, etienne.carriere@st.com, peng.fan@oss.nxp.com, michal.simek@amd.com, d-gole@ti.com, elif.topuz@arm.com, lukasz.luba@arm.com, philip.radford@arm.com, david@kernel.org, souvik.chakravarty@arm.com, leitao@kernel.org, kas@kernel.org, puranjay@kernel.org, usama.arif@linux.dev, kernel-team@meta.com Subject: Re: [PATCH v15 23/35] firmware: arm_scmi: Add Telemetry generation counter event Message-ID: <20261112134407.0000457f@oss.qualcomm.com> In-Reply-To: References: <20261109091221.2532706-1-cristian.marussi@arm.com> <20261109091221.2532706-24-cristian.marussi@arm.com> <20261110144635.00005964@oss.qualcomm.com> Organization: Qualcomm X-Mailer: Claws Mail 4.4.0 (GTK 3.24.51; x86_64-w64-mingw32) X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Proofpoint-GUID: PB5IZWovi1iQHNEQNTd8OV5vsisJB_Mi X-Proofpoint-Spam-Info: AW1haW4tMjYxMTEyMDA4NiBTYWx0ZWRfXxzz9IEywTCMz 1s86LoY5Ejs1KBUn41Vue8ABtOM4xDWzgtfMdhNXi+6ssc9Te+fnyOLJoyCS96Esit5hSWxK1PM hZLCeuxNsoemP2UzibVY9MN3ZzNQK0E= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMTEyMDA4NiBTYWx0ZWRfX8MGjEvmD96FZ MMIcp4Ucq7Qtk5dwsd+erOiWh7x7K7affbCg6Fdolw/bjT7Jciz0Pb/JClGt82SnS+sL0yTgoqx Fz47fWHPpP5NtcYi+bdaFnwBc0Jv9wRbwtAof4FfAzpXxX2KgDu3uKY6tYCEouNHvp4VBAfw+B8 aq4UI06eGHr//1+nMZZGjbYpMi+HbTnCWv923JncT4tfGwNa/RGCXpQKCXuSCTyGul+ksy5HHYL acW0CaGwPOvpF10GiCuh4YojHAr9aSpl6tUd1IIvwrnkyi3CWGBOg7FQu6VZRY5YJS87X1rJIKg Vng+gILc6R3tPsYN/AuoDTHHkkuT5Pggeo9PwRnMZodV+3VREMTmLExFuTRh1Hbvi3zmyO6KUPf U+gwb5AF6nMHrl6ZVsxbEi3o1IulyDC1t5LK3+HWqcaqwKsz63BYws8nO0QpuR2SMwFqpGFIoJE l/BOVSqlBLe/neBmZAQ== X-Proofpoint-ORIG-GUID: PB5IZWovi1iQHNEQNTd8OV5vsisJB_Mi X-Authority-Analysis: v=2.4 cv=Gd+CDgXL c=1 sm=1 tr=0 ts=6af6332e cx=c_pps a=kVLUcbK0zfr7ocalXnG1qA==:117 a=JYp8KDb2vCoCEuGobkYCKw==:17 a=kj9zAlcOel0A:10 a=zJRp6_cAMcgA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=ZpdpYltYx_vBUK5n70dp:22 a=7CQSdrXTAAAA:8 a=reF3IxvR5ta2O57t2W8A:9 a=CjuIK1q_8ugA:10 a=vr4QvYf-bLy2KjpDp97w:22 a=a-qgeE7W1pNrGK8U0ZQC:22 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.138,FMLib:17.12.100.49 definitions=2026-11-12_03,2026-11-11_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 lowpriorityscore=0 priorityscore=1501 spamscore=0 clxscore=1015 malwarescore=0 phishscore=0 suspectscore=0 impostorscore=0 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2611040001 definitions=main-2611120086 On Thu, 12 Nov 2026 20:17:35 +0000 Cristian Marussi wrote: > On Tue, Nov 10, 2026 at 02:46:35PM -0800, Jonathan Cameron wrote: > > On Mon, 9 Nov 2026 09:12:09 +0000 > > Cristian Marussi wrote: > > > > > Add a per-instance generation counter to track configuration changes which > > > uses the common telemetry events framework. > > Why? What's the usecase for this? > > Needs some more information or I'd leave it for now. > > > > SCMI Telemetry is specified and designed FW/Kernel side to allow for > multiple readers and multiple writers issuing configuration changes: > give that there is NO HW/FW/SPEC limitation in allowing such concurrency > (unlike e.g. for a serial or an RTC) the telemetry driver does NOT > enfroce any kind of exclusive access...last one wins when multiple > acctors tries to configure overlapping stuff...none of kernel problem > userspace should co-ordinate...and I suspect most of the time having > multiple apps trying to concurrently issue conflicting Telemetry request > would be a matter of wrong platform configuration/setup (similarly to > what would happen by running together all the lovely varied network > configiratio solution on a Linux box...) > > As said the Kernel SHOULD NOT care, going back to the networking example > Kernel indeed does NOT active policy netlink access..you are free to shot > into your foot... > > Anyway, co-ordinating access to the Telemetry resources in userspace can > be a pain, so the the generation counter is an optional mechanism to be > alerted when some of the Telemetry has been changed, so that userspace > can spot that something odd is happening (if it was unexpected) and > avoid to sample and analyze bogus data... > > The generic event support upon which this is based, it is meant to > support future events like relaying notifications to userspace...but > given that notifs were NOT implemented for real, it is not present (NOR > the related ABI...) > Ok. That explanation makes sense. Given it effects how userspace will be written against this stack (maybe assuming folk don't just bind a single daemon process to it) it does have to be there fairly early. Maybe a follow up to the initial set like the stuff for already events. Anyhow, add this info to the patch description! Jonathan > Thanks, > Cristian