From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from ahti.lucaweiss.eu (ahti.lucaweiss.eu [128.199.32.197]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B31A0187F; Thu, 23 May 2024 06:16:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=128.199.32.197 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716444989; cv=none; b=TL8v4m2gFSOjABFWgah19ag09BRCUx6s2cMpARxSF08NLav8AHrRCo50jL+pk1TtZWPqzmpFcgziq8ngSRaM2hIliO5SykZh3BHF52YevqEibpm8eiDtu/8KILulao8d/UIMMMUVhcjaG819aiRo5BezrXGVyq+dr8looYxavCw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716444989; c=relaxed/simple; bh=SV2nGiCmM64ztdSCrd0ymcAagBKy+OJxUVIrXcD08FI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=pU+5rPMqEAp+wcdsz1KylH/IvCXKsoBAoOiPqqpDrPoWX1TfrXn4oiyPNGau3QFmSaCz8eWmdywLZJ28NmPc5txS0DS9+mfTxCrWxKBWgtJ7Zh/MV09e/4Qe5M2HGgg+/AIpTegX0mlWUFpf7oDSU+bNjdpp6X++8TVz8KLBl3o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=z3ntu.xyz; spf=pass smtp.mailfrom=z3ntu.xyz; dkim=pass (1024-bit key) header.d=z3ntu.xyz header.i=@z3ntu.xyz header.b=tM2qBpE7; arc=none smtp.client-ip=128.199.32.197 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=z3ntu.xyz Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=z3ntu.xyz Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=z3ntu.xyz header.i=@z3ntu.xyz header.b="tM2qBpE7" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=z3ntu.xyz; s=s1; t=1716444979; bh=SV2nGiCmM64ztdSCrd0ymcAagBKy+OJxUVIrXcD08FI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=tM2qBpE7j4GG1XdLxkGLYwel0fJ4EF9ydmP6rBgc9LHu56XzGBmgRGtQ5oTjXaQTt klB/L0G7RRyhI5L9h6H+3eNXK2Yzonm5blxPWF1hXKQPtApV1tMKaPZgzuCO5xTDbt GbjRY4MGg9jNEF15MeDT0gY3cLGu/ExvWKiEH94g= From: Luca Weiss To: Rob Herring , Krzysztof Kozlowski , Krzysztof Kozlowski Cc: ~postmarketos/upstreaming@lists.sr.ht, phone-devel@vger.kernel.org, Bjorn Andersson , Konrad Dybcio , Krzysztof Kozlowski , Conor Dooley , Andy Gross , linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH RFC 1/2] dt-bindings: soc: qcom,smsm: Allow specifying mboxes instead of qcom,ipc Date: Thu, 23 May 2024 08:16:17 +0200 Message-ID: <5099926.GXAFRqVoOG@g550jk> In-Reply-To: References: <20240424-smsm-mbox-v1-0-555f3f442841@z3ntu.xyz> <6253429.lOV4Wx5bFT@g550jk> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" On Donnerstag, 23. Mai 2024 08:02:13 MESZ Krzysztof Kozlowski wrote: > On 22/05/2024 19:34, Luca Weiss wrote: > > On Mittwoch, 22. Mai 2024 08:49:43 MESZ Krzysztof Kozlowski wrote: > >> On 21/05/2024 22:35, Luca Weiss wrote: > >>> On Dienstag, 21. Mai 2024 10:58:07 MESZ Krzysztof Kozlowski wrote: > >>>> On 20/05/2024 17:11, Luca Weiss wrote: > >>>>> Hi Krzysztof > >>>>> > >>>>> Ack, sounds good. > >>>>> > >>>>> Maybe also from you, any opinion between these two binding styles? > >>>>> > >>>>> So first using index of mboxes for the numbering, where for the known > >>>>> usages the first element (and sometimes the 3rd - ipc-2) are empty <>. > >>>>> > >>>>> The second variant is using mbox-names to get the correct channel-mbox > >>>>> mapping. > >>>>> > >>>>> - qcom,ipc-1 = <&apcs 8 13>; > >>>>> - qcom,ipc-2 = <&apcs 8 9>; > >>>>> - qcom,ipc-3 = <&apcs 8 19>; > >>>>> + mboxes = <0>, <&apcs 13>, <&apcs 9>, <&apcs 19>; > >>>>> > >>>>> vs. > >>>>> > >>>>> - qcom,ipc-1 = <&apcs 8 13>; > >>>>> - qcom,ipc-2 = <&apcs 8 9>; > >>>>> - qcom,ipc-3 = <&apcs 8 19>; > >>>>> + mboxes = <&apcs 13>, <&apcs 9>, <&apcs 19>; > >>>>> + mbox-names = "ipc-1", "ipc-2", "ipc-3"; > >>>> > >>>> Sorry, don't get, ipc-1 is the first mailbox, so why would there be <0> > >>>> in first case? > >>> > >>> Actually not, ipc-0 would be permissible by the driver, used for the 0th host > >>> > >>> e.g. from: > >>> > >>> /* Iterate over all hosts to check whom wants a kick */ > >>> for (host = 0; host < smsm->num_hosts; host++) { > >>> hostp = &smsm->hosts[host]; > >>> > >>> Even though no mailbox is specified in any upstream dts for this 0th host I > >>> didn't want the bindings to restrict that, that's why in the first example > >>> there's an empty element (<0>) for the 0th smsm host > >>> > >>>> Anyway, the question is if you need to know that some > >>>> mailbox is missing. But then it is weird to name them "ipc-1" etc. > >>> > >>> In either case we'd just query the mbox (either by name or index) and then > >>> see if it's there? Not quite sure I understand the sentence.. > >>> Pretty sure either binding would work the same way. > >> > >> The question is: does the driver care only about having some mailboxes > >> or the driver cares about each specific mailbox? IOW, is skipping ipc-0 > >> important for the driver? > > > > There's nothing special from driver side about any mailbox. Some SoCs have > > a mailbox for e.g. hosts 1&2&3, some have only 1&3, and apq8064 even has > > 1&2&3&4. > > > > And if the driver doesn't find a mailbox for a host, it just ignores it > > but then of course it can't 'ring' the mailbox for that host when necessary. > > > > Not sure how much more I can add here, to be fair I barely understand what > > this driver is doing myself apart from the obvious. > > From what you said, it looks like it is enough to just list mailboxes, > e.g. for ipc-1, ipc-2 and ipc-4 (so no ipc-0 and ipc-3): No, for sure we need also the possibility to list ipc-3. And my point is that I'm not sure if any platform will ever need ipc-0, but the code to use that if it ever exists is there - the driver always tries getting an mbox (currently just syscon of course) for every host from 0 to n. These are the current (non-mbox-API) mboxes provided to smsm: $ git grep qcom,ipc- arch/ arch/arm/boot/dts/qcom/qcom-apq8064.dtsi: qcom,ipc-1 = <&l2cc 8 4>; arch/arm/boot/dts/qcom/qcom-apq8064.dtsi: qcom,ipc-2 = <&l2cc 8 14>; arch/arm/boot/dts/qcom/qcom-apq8064.dtsi: qcom,ipc-3 = <&l2cc 8 23>; arch/arm/boot/dts/qcom/qcom-apq8064.dtsi: qcom,ipc-4 = <&sps_sic_non_secure 0x4094 0>; arch/arm/boot/dts/qcom/qcom-msm8974.dtsi: qcom,ipc-1 = <&apcs 8 13>; arch/arm/boot/dts/qcom/qcom-msm8974.dtsi: qcom,ipc-2 = <&apcs 8 9>; arch/arm/boot/dts/qcom/qcom-msm8974.dtsi: qcom,ipc-3 = <&apcs 8 19>; arch/arm64/boot/dts/qcom/msm8916.dtsi: qcom,ipc-1 = <&apcs 8 13>; arch/arm64/boot/dts/qcom/msm8916.dtsi: qcom,ipc-3 = <&apcs 8 19>; arch/arm64/boot/dts/qcom/msm8939.dtsi: qcom,ipc-1 = <&apcs1_mbox 8 13>; arch/arm64/boot/dts/qcom/msm8939.dtsi: qcom,ipc-3 = <&apcs1_mbox 8 19>; arch/arm64/boot/dts/qcom/msm8953.dtsi: qcom,ipc-1 = <&apcs 8 13>; arch/arm64/boot/dts/qcom/msm8953.dtsi: qcom,ipc-3 = <&apcs 8 19>; arch/arm64/boot/dts/qcom/msm8976.dtsi: qcom,ipc-1 = <&apcs 8 13>; arch/arm64/boot/dts/qcom/msm8976.dtsi: qcom,ipc-2 = <&apcs 8 9>; arch/arm64/boot/dts/qcom/msm8976.dtsi: qcom,ipc-3 = <&apcs 8 19>; > > mboxes = <&apcs 13>, <&apcs 9>, <&apcs 19>; > > Best regards, > Krzysztof > >