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 685F0C433EF for ; Tue, 12 Apr 2022 13:29:09 +0000 (UTC) Received: from h2850616.stratoserver.net (localhost [IPv6:::1]) by phobos.denx.de (Postfix) with ESMTP id EE64383110; Tue, 12 Apr 2022 15:29:06 +0200 (CEST) Authentication-Results: phobos.denx.de; dmarc=pass (p=none dis=none) header.from=kernel.org Authentication-Results: phobos.denx.de; spf=pass smtp.mailfrom=u-boot-bounces@lists.denx.de Authentication-Results: phobos.denx.de; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="rB3Iuc0/"; dkim-atps=neutral Received: by phobos.denx.de (Postfix, from userid 109) id 88194835B9; Tue, 12 Apr 2022 15:29:04 +0200 (CEST) Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by phobos.denx.de (Postfix) with ESMTPS id 688BF80508 for ; Tue, 12 Apr 2022 15:29:00 +0200 (CEST) Authentication-Results: phobos.denx.de; dmarc=pass (p=none dis=none) header.from=kernel.org Authentication-Results: phobos.denx.de; spf=pass smtp.mailfrom=robh@kernel.org Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A062661AAC for ; Tue, 12 Apr 2022 13:28:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A78BAC385BA for ; Tue, 12 Apr 2022 13:28:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1649770136; bh=s7nJoeaNh+Bm9gQXazSzbrIfCbTuVtDJKGZl1a2MBv4=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=rB3Iuc0/0nyZThazgfVn2toaGAAGDirOd+FkpuSCDnsldlUpMv/D9TVz4G5OjtAx/ 2hPxe5gSvAk37k6iLeyi1hHTnFP9i8hAfwiyRrH4TNbisLkMps8ub1tuuhkzoK23el mD2kD+WJ9X809tvDmgrZV2KEEEMqTPHCb61JyrHZmVaFa4xs1FMCmgm9DN0E07clbN kv00c3nI66Ls1eASRMRX2bq7Xpxwh970fXv8rMYHIWG4RMFq5ShCYH18OWYhrD3CPa 9jmrfd3jrHmBlW9lYOMZpOGJCmuds55+jS+NCyKlt26vbwK7DKkx8LQ/mErc6ovBZw lBBOp4kCJq/8g== Received: by mail-io1-f46.google.com with SMTP id e22so22219253ioe.11 for ; Tue, 12 Apr 2022 06:28:56 -0700 (PDT) X-Gm-Message-State: AOAM533bRkK0kxuyWgz+jDLNJKqjHx73AnOOgZdixzXCP9nd8lnuRZqU KxSoLLLutjqCuj3sQzFCG1oxF7DxNQ9J9rhkIA== X-Google-Smtp-Source: ABdhPJwTuePb8CKw+rJbd/zReqTReo6IqKRlZbWnXa7zLeIR3bcuTqaAwyWo1jkOkN/GqzKic+hgBNrpeRfSwx9/nTQ= X-Received: by 2002:a05:6638:24d0:b0:326:34d2:5c22 with SMTP id y16-20020a05663824d000b0032634d25c22mr4011610jat.91.1649770135838; Tue, 12 Apr 2022 06:28:55 -0700 (PDT) MIME-Version: 1.0 References: <20220329151659.16894-1-abdellatif.elkhlifi@arm.com> <20220406194711.GN14282@bill-the-cat> <20220407125424.GA32742@e121910.cambridge.arm.com> <20220407125811.GO14282@bill-the-cat> <20220412114315.GA18372@e121910.cambridge.arm.com> <20220412120106.GH14282@bill-the-cat> In-Reply-To: <20220412120106.GH14282@bill-the-cat> From: Rob Herring Date: Tue, 12 Apr 2022 08:28:42 -0500 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 0/6] introduce Arm FF-A support To: Tom Rini , Abdellatif El Khlifi Cc: Rob Herring , U-Boot Mailing List , vishnu.banavath@arm.com, xueliang.zhong@arm.com, nd , Rui Miguel Silva Content-Type: text/plain; charset="UTF-8" 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 0.103.5 at phobos.denx.de X-Virus-Status: Clean On Tue, Apr 12, 2022 at 7:01 AM Tom Rini wrote: > > On Tue, Apr 12, 2022 at 12:43:15PM +0100, Abdellatif El Khlifi wrote: > > On Thu, Apr 07, 2022 at 08:58:11AM -0400, Tom Rini wrote: > > > On Thu, Apr 07, 2022 at 01:54:24PM +0100, Abdellatif El Khlifi wrote: > > > > On Wed, Apr 06, 2022 at 03:47:11PM -0400, Tom Rini wrote: > > > > > On Tue, Mar 29, 2022 at 04:16:53PM +0100, abdellatif.elkhlifi@arm.com wrote: > > > > > > From: Abdellatif El Khlifi > > > > > > > > > > > > This patchset adds support for Arm FF-A (Arm Firmware Framework for Armv8-A v1.0). > > > > > > > > > > > > FF-A support is generic by design and can be used by any Arm platform. > > > > > > > > > > > > The features added are as follows: > > > > > > > > > > > > 1/ FF-A device driver > > > > > > 2/ armffa command > > > > > > 3/ FF-A Sandbox driver > > > > > > 4/ FF-A Sandbox test cases > > > > > > 5/ FF-A MM communication > > > > > > > > > > > > > > > > > > The suggested design sees FF-A as a data bus allowing data exchange with the firmware > > > > > > running under TrustZone HW (such as Optee). The same approach was followed in the > > > > > > FF-A driver in Linux kernel (https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/firmware/arm_ffa/bus.c?h=v5.15#n211)) > > > > > > > > > > > > u-boot boards using FF-A can provide a device tree node in a -u-boot.dtsi file. > > > > > > Since the node can not be hosted in Linux device tree, we suggest using u-boot device tree. > > > > > > > > > > Why can't the node be in the upstream tree? It should be, so that it > > > > > can be shared between all users. Especially since there's in-Linux > > > > > users? > > > > > > > > > > -- > > > > > Tom > > > > > > > > Linux already has an FF-A bus driver and doesn't use a device tree node for FF-A. > > > > > > > > The Linux driver registers FF-A as a bus: > > > > > > > > int arm_ffa_bus_init(void) > > > > { > > > > return bus_register(&ffa_bus_type); > > > > } > > > > > > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/firmware/arm_ffa/bus.c?h=v5.15#n211 > > > > > > > > So, there is no user for the node in Linux. That's why we suggest hosting the node in the u-boot device tree (a u-boot.dtsi file) > > > > > > OK, but you can still push it upstream as it's not required to have an > > > in tree user. > > > > During the review of Corstone-1000 patchset, Rui Silva had a discussion with the Linux device tree maintainer > > (Rob Herring). Rob is not in favour of an FFA node in the kernel device tree. This is why we are including the FFA node > > in u-boot device tree (u-boot.dtsi files). Sigh. There is not a 'kernel device tree' and a 'u-boot device tree'. There is only 1. For SystemReadyIR compliance, that is a hard requirement. > I'm a bit confused now, can you please link to the kernel thread? Or > Rob, can you chime in here please? The FFA DT binding was rejected in favor of making FFA discoverable. The FFA spec was amended to address that. DT is only for what we failed to make discoverable. For hardware, we're stuck with it. We shouldn't repeat that for software interfaces. Rob