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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A1444C0218C for ; Fri, 24 Jan 2025 22:32:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Gvg/dHn4jWNsUL9rUhZU6ggD5o/Pe6Fj4E9aLL5kQHM=; b=URPUCaavXGFCbwtUXTUDX+WwJb LnoyjBy4FS7L/7y9xSpGPper8vS2x6aljHeouj6S5iPk182mTdgs4BxpJamSmweR+19GCOMF6vsLL 0v5C5PnrCkRdMWEsxS2ZQOg0PjeierNr1g48REQp8mzrFQbNiZCi3SxgEPsjt43rOsHhcO/n3uDfW Va060tNUidmQ89n/eqqcsWut5L32YAC3QMuzhquC2r4F8DrVJyR9+nwv06WpYze/H9YBisqzbl7ri 0N47ycPCnFeeBmpDBSBhGcpnkhhwER2cltuiKVLpkZaUQcC1K3ulsXb9huTChCUP3K6vncTsNtrdn 1MtB/xJA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tbSDg-0000000Fctn-2shX; Fri, 24 Jan 2025 22:32:08 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tbSCN-0000000Fcci-2eJU for linux-arm-kernel@lists.infradead.org; Fri, 24 Jan 2025 22:30:48 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 8DE585C5816; Fri, 24 Jan 2025 22:30:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 632A4C4CED2; Fri, 24 Jan 2025 22:30:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1737757846; bh=FgB4LXpxo6geqsVUx2MuopKecF2NdlgS186UjbPa+r8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=eztnz89xMtKSacfX/dv7YPIkQVuORAibDekeNZl6OhA8yZXPAEEJwwjCN3E4D7uxs eb7abgbKCnfhWrfemwHBNPEwUP6FReJ0O292DFJSneXlFex+xTar55/cnkMrn/h3il o0JY/k7E+z7QCMncJIiGq0vuZlAev6GfA1NAb1LC5ETmiqG9Mh+Zexx2UpMUZG5yb2 Hc/Kyi0YygXyR0pTAieteajWiD16rVXz+hDr+cmA6iLtN9b3OJX3ySJuNqK7AnqHJL ewniUkmhEMTnfJYtcTKXi88AxGx/ICiU2GFvgdx+91HqahS5lCHGjJXoYwvluH9vDh 8gkC0mF49JKuQ== Date: Fri, 24 Jan 2025 16:30:45 -0600 From: Rob Herring To: Viresh Kumar Cc: Sudeep Holla , Vincent Guittot , Alex =?iso-8859-1?Q?Benn=E9e?= , Bill Mills , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/3] firmware: arm_ffa: Setup of_node for ffa devices Message-ID: <20250124223045.GA2512712-robh@kernel.org> References: <0e863a4baea59865aff0d1b5657f548bc0aa8d2a.1737441631.git.viresh.kumar@linaro.org> <20250121100946.ouzeuh5fopkgmf55@vireshk-i7> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20250121100946.ouzeuh5fopkgmf55@vireshk-i7> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250124_143047_717771_CD16AA62 X-CRM114-Status: GOOD ( 22.64 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Jan 21, 2025 at 03:39:46PM +0530, Viresh Kumar wrote: > On 21-01-25, 09:59, Sudeep Holla wrote: > > On Tue, Jan 21, 2025 at 12:26:39PM +0530, Viresh Kumar wrote: > > > Match and bind the of_node for the FFA device. > > > > I am bit confused and need more details than the above line 😄, because > > > > 1. We don't have any binding for FF-A and compatible "arm,ffa" is not yet > > defined > > Realized now that you weren't cc'd on 1/3. Bounced it to your email id > now. > > > 2. Even if we have binding, we will not have vm_id and UUID which are > > discoverable from the firmware > > Hmm.. > > > 3. DT maintainers rejected the bindings when it was initially proposed > > as it is discoverable. If we need it for a valid reason, we need more > > info, this patch doesn't provide full picture to change their stance. For background, go read this thread[1]. :) > We are working on FFA based Virtio bus/devices. The > dma_alloc_coherent() helpers for the virtqueue (and other DMA-ble > memory helpers) end up calling the dma-core for the parent device, > which is FFA device in our case. > > We want to avoid separate mapping for each buffer sent by the guest > and keep a reserved mem (via DT) for the specific FFA device. With > that, the memory can be mapped at once at the host (shared over FFA) > and all the following DMA allocations can happen from that > memory-region. Well, that's a better explanation than the patches have as they just appear to ignore all the history here. But I still don't really understand. I know next to 0 about FF-A. Sounds like OS specific problems to me though. Rob [1] https://lore.kernel.org/all/20220329151659.16894-1-abdellatif.elkhlifi@arm.com/#r