From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 6D2EF541E75; Tue, 22 Sep 2026 14:43:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790088193; cv=none; b=Px3km6VVnAzL58dU4VPaYzAp9bBTztb8fTgiRYS71XwRB7nuWQ83+5vcbt/+gRxuf+6Lsryq+byKnr0WD4iWkmf2kAoNL4ypQkyYd/Ztvig5A/KtuyYExHn2knSBf6cJlDjQrCxpKMkwfzOQ8JPZdK+byQpHveTU62qdEz6OrIk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790088193; c=relaxed/simple; bh=L+MjaNC+6vbVKHKiU5TeC+hR3WeQzvMU3EAJtm6uQow=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=cthDUNuL4bjCOmBtQBSYzc4bSvzrcFi4Yb+ZsIa3K58SWXGlr7Qbz2nJtQ6U09YhHZmjpyeg92ZOKU2NcAFaygDV9FFPGdlpizq7CFnlpRkUwSxN5X2U5lPiHLqx5hJ1VYl6PezOw9Oi6AgA+jnuG/+OWbZklXlef/3Q1AUftfk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=i0oQRPoR; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="i0oQRPoR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B8EAF1F000FF; Tue, 22 Sep 2026 14:43:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790088191; bh=k/eih6V79KGOxd/VUr7lVIHhXKuG7/wdFpn9jH1v8Js=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=i0oQRPoR2grx2df/MWOgPanqEOnuePmw4f4ocXMvRD2K/a5y2F4+9KVEkqGSWdMJ7 qFITaKXfA6eF+B7nRGKoUtlz3sykyZIEVcQF4j82paWq+G9T6GLOKWDMBHIWl68xcF ytVKscnXCFzjqT+K9km1qepD7l4J9/4BQ47/Fo0ToJkTcIMomNwBzxw2hwwwtjNLqS lnyNtWr1QPcJ9dWJCT1Eriohimh+vBtNofNDECnyIkOgozBK+WQNCD/VgqGz6ixtfC fZ25v7Huqkoo08tkf6Dq9TR3/ZbszP6/Sl4J3cd/tn7Pnp4PC7+jUruschgy0VhMo5 A17DZeFdiO/zA== Message-ID: <8fd34672-493b-4d70-a2bd-1fe434b5ccda@kernel.org> Date: Tue, 22 Sep 2026 16:42:59 +0200 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 v12 06/25] firmware: arm_scmi: Add basic Telemetry support To: Cristian Marussi , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, arm-scmi@vger.kernel.org, linux-doc@vger.kernel.org Cc: 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, jic23@kernel.org, elif.topuz@arm.com, lukasz.luba@arm.com, philip.radford@arm.com, souvik.chakravarty@arm.com, leitao@kernel.org, kas@kernel.org, puranjay@kernel.org, usama.arif@linux.dev, kernel-team@meta.com References: <20260920091928.2014972-1-cristian.marussi@arm.com> <20260920091928.2014972-7-cristian.marussi@arm.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/20/26 11:19, Cristian Marussi wrote: > Add SCMIv4.0 Telemetry basic support to enable initialization and resources > enumeration: add all the telemetry messages definitions and parsing logic > but only a few simple state gathering protocol operations. As someone unfamiliar with the spec, it would be nice to summarize which parts of the spec this patch implements, so it's easier to cross-reference. Same for the other patches. :) It's a lot to review. So having a better description to guide the reviewer through the patch would really help. I assume we could split this up further, like a) Add basic definition (mechanical from the spec) b) Add telemetry stub and hook it up c) query attributes d) intialize X ... Will result in quite some patches .... so I won't suggest that just yet. Maybe people familiar with the spec have it easier revieweing this. > + > +enum scmi_telemetry_protocol_cmd { > + TELEMETRY_LIST_SHMTI = 0x3, > + TELEMETRY_DE_DESCRIPTION = 0x4, > + TELEMETRY_LIST_UPDATE_INTERVALS = 0x5, > + TELEMETRY_DE_CONFIGURE = 0x6, > + TELEMETRY_DE_ENABLED_LIST = 0x7, > + TELEMETRY_CONFIG_SET = 0x8, > + TELEMETRY_READING_COMPLETE = TELEMETRY_CONFIG_SET, TELEMETRY_READING_COMPLETE is not really a command but listed as a "delated response". Should this be something separate (and not mangled into protocol_cmd ?). Or is "_cmd" not the right term for this collection? I have no SCMI experience, so it might be a rather supid queestion. [...] > +struct scmi_de_desc { > + __le32 id; I'll make a couple of generic comments, that should apply to most definitions in here. In the spec some of these things are prefixed by "de" e.g., "de_id". Was this deliberate? Having the spec match the implementation allows for easier grepping of stuff. > + __le32 grp_id; Spec calls this "group_id" > + __le32 data_sz; Spec calls this "de_data_size" etc. If there is good reason to use slightly different names, best to spell that out in the patch description. > + __le32 attr_1; E.g., grepping the spec for "attr_1" I get no hits. So I have to remember that the spec might call this "de_attributes_1" > +#define IS_NAME_SUPPORTED(d) (le32_get_bits((d)->attr_1, BIT(31))) DE_ATTRIBUTES_1_NAME_SPECIFIED would be clearer. in general, spelling out to which field a define belongs *might* make it harder to get stuff wrong. (spec calls it "Named specified" which sounds like a bug) Same for the other definitions. Again, maybe diverging from the spec is fine. Personally, I would try to stay as close as possible to the naming in the spec. [...] > + > +static void scmi_telemetry_free_tde_put(struct telemetry_info *ti, > + struct telemetry_de *tde) > +{ > + struct scmi_telemetry_de_info *info; > + > + guard(mutex)(&ti->free_mtx); > + /* Save clear and restore */ > + info = READ_ONCE(tde->de.info); Where is the matching WRITE_ONCE? IOW, who is expected to modify this concurrently? > + memset(info, 0, sizeof(*info)); > + memset(tde, 0, offsetof(struct telemetry_de, mtx)); > + tde->de.info = info; > + list_add_tail(&tde->item, &ti->free_des); > +} > + [...] > + > +static int scmi_telemetry_protocol_init(const struct scmi_protocol_handle *ph) > +{ > + struct device *dev = ph->dev; > + struct telemetry_info *ti; > + int ret; > + > + dev_dbg(dev, "Telemetry Version %d.%d\n", > + PROTOCOL_REV_MAJOR(ph->version), PROTOCOL_REV_MINOR(ph->version)); > + > + ti = devm_kzalloc(dev, sizeof(*ti), GFP_KERNEL); > + if (!ti) > + return -ENOMEM; > + > + ti->ph = ph; > + > + ret = scmi_telemetry_protocol_attributes_get(ti); > + if (ret) { > + dev_err(dev, FW_BUG "Cannot retrieve protocol attributes. Abort.\n"); > + return ret; > + } > + > + ret = scmi_telemetry_instance_init(ti); > + if (ret) { > + dev_err(dev, "Cannot initialize instance. Abort.\n"); > + return ret; > + } > + > + ret = scmi_telemetry_enumerate_common_intervals(ti); > + if (ret) { > + dev_err(dev, FW_BUG "Cannot enumerate update intervals. Abort.\n"); > + return ret; > + } > + > + ret = scmi_telemetry_enumerate_shmti(ti); > + if (ret) { > + dev_err(dev, FW_BUG "Cannot enumerate SHMTIs. Abort.\n"); > + return ret; > + } > + > + ti->info.base.version = ph->version; I'm surprised that there is nothing to cleanup on the error paths, but at least the devm_ stuff is being taken care of I guess. It's a lot of code, so I only managed to skim briefly over most of it. -- Cheers, David