From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 19D9D2AF19; Wed, 12 Feb 2025 10:49:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739357377; cv=none; b=f364/g94c7WFYrTgkCyQjaYjOnC/+6xbx8C0R2ccajUHL1U0cBzC4SPb2hMAgp4uxSPmAYHhtD9FFQem9K1nBQIBJxSzZctW8IeZvCSXC5+nWBoYjXzCX0bRT6AUgGn8Rewirf2/j/i7aLKJ99l+yzN1ycY8YE1u/haGMVeAJzg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739357377; c=relaxed/simple; bh=SrZ7q3UddXW1p49/GdRvgpUzejtlAUiY6e9x0tcKinE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=D+q4+hvyrftlj3ARhQAJrH9LRybl7B2WkTVVkrl0lqNlUYuB+40DyVMGzt7FYHfzCbiXeNhrdLPpBdZ4zrpzmx00xXe7350ll34veVmDadslLsc21ZEJSi6G7AFYxjvAI/nH/lT+lo9C7s4VaHIp1z66COBE+J1LEPHONsRNLpc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fsCk99ec; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="fsCk99ec" 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> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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> --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--