From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from phobos.denx.de (phobos.denx.de [85.214.62.61]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2F6F4C32793 for ; Wed, 18 Jan 2023 13:47:14 +0000 (UTC) Received: from h2850616.stratoserver.net (localhost [IPv6:::1]) by phobos.denx.de (Postfix) with ESMTP id 0F1DD84CBD; Wed, 18 Jan 2023 14:47:12 +0100 (CET) Authentication-Results: phobos.denx.de; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: phobos.denx.de; spf=pass smtp.mailfrom=u-boot-bounces@lists.denx.de Authentication-Results: phobos.denx.de; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=arm-com.20210112.gappssmtp.com header.i=@arm-com.20210112.gappssmtp.com header.b="8JED8PIl"; dkim-atps=neutral Received: by phobos.denx.de (Postfix, from userid 109) id 724858535B; Wed, 18 Jan 2023 14:47:10 +0100 (CET) Received: from mail-pl1-x630.google.com (mail-pl1-x630.google.com [IPv6:2607:f8b0:4864:20::630]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits)) (No client certificate requested) by phobos.denx.de (Postfix) with ESMTPS id 9B9C783623 for ; Wed, 18 Jan 2023 14:47:07 +0100 (CET) Authentication-Results: phobos.denx.de; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: phobos.denx.de; spf=pass smtp.mailfrom=sudeepholla.maillist@gmail.com Received: by mail-pl1-x630.google.com with SMTP id b17so29432854pld.7 for ; Wed, 18 Jan 2023 05:47:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arm-com.20210112.gappssmtp.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=uFz0V8Kye+QePP/shXlj5A9tKorGsSgkGNklDPr1tbk=; b=8JED8PIluN9gMvLAJwiUa9aOSvRX98lw5u4xzNVpq3LqynQgyC391J8ucoj6zeZ00x KyKSxvOzRMBS3wIfd25gGjFXRUQNRruCW1P6wD9Q+dN89GHceuomDPN6WAUNU2UjdlPG vh8UKMGcScqAOBRHQjhXXUGfguGOWg08vm+HHPKQ7Hf0xAfOpIigYp+EDPA/Bvg79yTV L1/qPJc/Su795UeUyyMuXYnKPRjfHgvqeEHIFDD9iuC/3vKoqveqLvugGtr3CX7LBQYb /ZilxhsM+d7HUv9UG4B0ifpoGw6h93j1nIJXIgSAkXgyMIYPqaMqeVnSs04Eqa/wHLAP 9XXg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=uFz0V8Kye+QePP/shXlj5A9tKorGsSgkGNklDPr1tbk=; b=HaGSMxvZsiN5Lc/cuJLVYY87hGe3/SFJQMTmYLX+0x73KN80oON4qT0k267XUx9zU2 atK6qUTolXWmBhiklRf+MeOR4N8W9F5SOSquU2om2W0UiICJ/JWC0xr9VfFrh0GUGDDZ Slpaz8avEgUdZ24zYZob5wg+jETH/NoVEB0qhtOjqjhhne5ld9YLIGCguF3dPhx6ltZS 2wPzWFcK/d+kNG62Bqsp2Zt0wdNh8S/cX06p5aOVBeOr2F3ZqCG0X2X1mfC3oWvjbCb+ 1nSjGsJ1fch9WGhJZtHYIUWB6g2fh5V7mkqTPkt0PMlmGtXSXzQWKzHpLIETPSFSNzNF heAQ== X-Gm-Message-State: AFqh2krO6E1EJPgT+0hABUp9dj4Hx7jLLWjhnlEYdQN3KNuL/dJMlr9C XKCMRBK5qoMTetTqzTrVOqDv7SOavWbMEwnOSbk= X-Google-Smtp-Source: AMrXdXuaVtDba3gvpQbtuK+noGE/IWp7GdBdSuRHCKnRcm+XK1FS3Ov9yv97S1yErtBwdT2lCQuXyhl9zKv+1Pj8Y34= X-Received: by 2002:a17:90a:5313:b0:229:94a:abf8 with SMTP id x19-20020a17090a531300b00229094aabf8mr801200pjh.76.1674049625943; Wed, 18 Jan 2023 05:47:05 -0800 (PST) MIME-Version: 1.0 References: <20221124132115.GA393@e121910.cambridge.arm.com> <20221219111251.GA22370@e121910.cambridge.arm.com> <20230118124923.GB631605@bill-the-cat> In-Reply-To: <20230118124923.GB631605@bill-the-cat> From: Sudeep Holla Date: Wed, 18 Jan 2023 13:46:54 +0000 Message-ID: Subject: Re: [PATCH v8 03/10] arm_ffa: introduce Arm FF-A low-level driver To: Tom Rini , Sudeep Holla Cc: Rob Herring , Simon Glass , Abdellatif El Khlifi , ilias.apalodimas@linaro.org, jens.wiklander@linaro.org, achin.gupta@arm.com, xueliang.zhong@arm.com, u-boot@lists.denx.de Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.39 X-BeenThere: u-boot@lists.denx.de X-Mailman-Version: 2.1.39 Precedence: list List-Id: U-Boot discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: u-boot-bounces@lists.denx.de Sender: "U-Boot" X-Virus-Scanned: clamav-milter 0.103.6 at phobos.denx.de X-Virus-Status: Clean On Wed, Jan 18, 2023 at 12:49 PM Tom Rini wrote: > > I guess the problem comes down to, can we have one discovery method that > everyone shares, or do we have to let everyone invent a new discovery > method every time? No one needs to invent any discovery method every time if the firmware specification provides one and as Rob mentioned many times in the thread, all new firmware specification must provide one and we are trying to make sure that is the case with all new specs from Arm. > FF-A, Op-tee, U-Boot, coreboot, barebox (and > everyone else I'm unintentionally forgetting) could just discover these > things via device tree. I leave that to the individual projects to decide and agree but fundamentally if the specification provides a way to discover, not sure why we are even discussing an alternative method here. > Or, we could all write our own code to perform > the discovery. For what reason ? I can understand if there is no discovery mechanism but that's not the case in $subject. > And when RISC-V comes along with similar functionality, > we could probe their device tree and see they've implemented the same > concept, but a little differently, but still have the discovery portion > be in the device tree. To which it sounds like your answer is "not in > the device tree". > I see U-boot seem to have made a decision to create DT node for each and everything that needs to be added to DM which seems bit unfortunate but I don't understand the history/motive/background for it but I respect the decision if it is already made. These firmware interfaces are standard on all Arm platforms and can be discovered based on PSCI/SMCCC. Not using the same and use DT node needs unnecessary addition of DT nodes for all the f/w i/f on all the platforms that need the support when one can be just discovered. Sorry for the sudden appearance on this thread, I was avoiding getting into this but thought I will at least express my opinion and also the way the firmware specifications from Arm is expected to be evolved from now on. With that I will leave it to you and other U-boot maintainers and the community in general to decide the right course in this case.