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 3BD64C02198 for ; Wed, 12 Feb 2025 11:03:14 +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-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=SrZ7q3UddXW1p49/GdRvgpUzejtlAUiY6e9x0tcKinE=; b=DO3j5FAZAhablEcb5FePsnD0F3 p11ibfe2Cthev0FBIAKY5sjGzKcztJXvHJv9loTUFRsd/eWpGJZ5YPVKz8LrKWbV7U9rhLKxEn/ll ylX7RSNNjX+8fo3OUeMVupgz15sbw21AHildm1ySmvLkXsn1Ajgk8nGBTzGwHd8AWJfetNys0bGJC EUJutCWDqrJ2X0yfEYBNeh2BVCnfdPKBmEoQbhN7VpVg3fBHFaoFVdvIExFK1QexrRNUBIWmk77dR Zf9TEEqarTuzqzCtuSr+Cy+RV3+jswwhYNt6GaEahj2zXpxTVJ6SYEgJ+JU35XziSG/+y0r+6QhDE j0TdTK7g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tiAWE-000000075yl-04HN; Wed, 12 Feb 2025 11:03:02 +0000 Received: from nyc.source.kernel.org ([147.75.193.91]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tiAJF-0000000736L-2aVT; Wed, 12 Feb 2025 10:49:39 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id 70768A402E4; Wed, 12 Feb 2025 10:47:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 01860C4CEDF; Wed, 12 Feb 2025 10:49:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1739357376; bh=SrZ7q3UddXW1p49/GdRvgpUzejtlAUiY6e9x0tcKinE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=fsCk99ecgG1X1H4oCmDUZgnbAUfRIvj8fWtdlwdoQ07gzWE7fmKGgOCFbXT8zxU8z E17uZ/CKSWTiBSsXf6Z6vZWKYpqlNlcKGIyrhcObTMnI1Vs8SOuMqX9285cpyLhl3h i4BACZrSu2IrhvuCBWekSlYRZzO3qid0P9Ajy4xYJi/PyBLZ+A2HVA8MjrFX049Kga aC8profD5qguMrsDfEYi5k14CfG/ZS5ZwDrn1/hjq/RJX6KfdiM3+g5V+nuBxEflNE BuOxNawNPtWooUTQhU4pS84J5mQd1EBbum7ylQPZiEkomLW6MNCo51OZTDyrBZ+Ri7 Mh4FqItv9flOg== Date: Wed, 12 Feb 2025 11:49:34 +0100 From: Maxime Ripard To: Florent Tomasin Cc: Nicolas Dufresne , Vinod Koul , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Boris Brezillon , Steven Price , Liviu Dudau , Maarten Lankhorst , Thomas Zimmermann , David Airlie , Simona Vetter , Sumit Semwal , Benjamin Gaignard , Brian Starkey , John Stultz , "T . J . Mercier" , Christian =?utf-8?B?S8O2bmln?= , Matthias Brugger , AngeloGioacchino Del Regno , Yong Wu , dmaengine@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, nd@arm.com, Akash Goel Subject: Re: [RFC PATCH 1/5] dt-bindings: dma: Add CMA Heap bindings Message-ID: <20250212-sweet-nano-penguin-e85e7d@houat> References: <771534be8dfa2a3bdc3876502752f518224b9298.1738228114.git.florent.tomasin@arm.com> <20250212-naughty-chipmunk-of-potency-7e0ced@houat> <8ee8e684-0164-4e70-b42e-3827c7885685@arm.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha384; protocol="application/pgp-signature"; boundary="hofcel2epznouj7x" Content-Disposition: inline In-Reply-To: <8ee8e684-0164-4e70-b42e-3827c7885685@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250212_024937_793692_ED773560 X-CRM114-Status: GOOD ( 24.17 ) 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 --hofcel2epznouj7x Content-Type: text/plain; protected-headers=v1; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Subject: Re: [RFC PATCH 1/5] dt-bindings: dma: Add CMA Heap bindings MIME-Version: 1.0 On Wed, Feb 12, 2025 at 10:29:32AM +0000, Florent Tomasin wrote: >=20 >=20 > On 12/02/2025 10:01, Maxime Ripard wrote: > > On Wed, Feb 12, 2025 at 09:49:56AM +0000, Florent Tomasin wrote: > >> Note that the CMA patches were initially shared to help reproduce my > >> environment of development, I can isolate them in a separate patch > >> series and include a reference or "base-commit:" tag to it in the > >> Panthor protected mode RFC, to help progress this review in another > >> thread. It will avoid overlapping these two topics: > >> > >> - Multiple standalone CMA heaps support > >> - Panthor protected mode handling > >=20 > > You keep insisting on using CMA here, but it's really not clear to me > > why you would need CMA in the first place. > >=20 > > By CMA, do you mean the CMA allocator, and thus would provide buffers > > through the usual dma_alloc_* API, or would any allocator providing > > physically contiguous memory work? >=20 > You are correct only the CMA allocator is relevant. I needed a way to > sub-allocate from a carved-out memory. I'm still confused, sorry. You're saying that you require CMA but... > > In the latter case, would something like this work: > > https://lore.kernel.org/all/20240515-dma-buf-ecc-heap-v1-1-54cbbd049511= @kernel.org/ >=20 > Thanks for sharing this link, I was not aware previous work was done > on this aspect. The new carveout heap introduced in the series could > probably be a good alternative. I will play-around with it and share > some updates. =2E.. you seem to be ok with a driver that doesn't use it? Maxime --hofcel2epznouj7x Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iJUEABMJAB0WIQTkHFbLp4ejekA/qfgnX84Zoj2+dgUCZ6x8uQAKCRAnX84Zoj2+ dhpNAX9dpZ7jCHWS9XEKQqdeu+k8bL1z43DeFaKsONHamJEssyPacY4cU20LNyHZ dE3EP2gBfigcyv0UGOHYi7iyKQFw7lfvXnKfZ2/xUjJoWzSqoXVjjOm3bVKTr4WT bTbtf2LYNw== =IIBH -----END PGP SIGNATURE----- --hofcel2epznouj7x--