From nobody Mon Oct 6 15:24:16 2025 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 42B34298CB5; Mon, 21 Jul 2025 11:17:42 +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=1753096663; cv=none; b=GADagV8WfyYYSbYTv0oZDS/PaPGQStK5upr3G45w7jPmfACyN4w8sQA24gLSmMLW2dPYbvKPISX0RvJQLdMrhOtAjLvzavWCVVuCMeqhTDW4D56mUmMz7ClKDnSM37N0YjEgefPMXxrzInnjGA21wyxC7X8LItefk+Llm8NrSWQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753096663; c=relaxed/simple; bh=pkewGPjjFTsNcaE929R2dk9XfsEdn97c4Fm1Zzq1x+Q=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=DQasfn1IVrDLl3oKG8sRvGASZuXC4r/zGdMWrzM8ZZxk6lnhnPm9iytYw1Q0+0G+CiWiSsN24i13fj+7y+4bzRerQBDhqLPLO2Y1Z0dw+aWNmlvrdkdDvRHRXhG00tk/DExnqoKS7gCTQCNQ7eayxad/bzozijpEyAgKb+re6GU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GqV4pDpe; 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="GqV4pDpe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4DBEFC4CEF1; Mon, 21 Jul 2025 11:17:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1753096662; bh=pkewGPjjFTsNcaE929R2dk9XfsEdn97c4Fm1Zzq1x+Q=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=GqV4pDpem7xWd3kdcpmPqvV1GCbzoSWmbz48gxbnNSFR9tKsvgPOcEFjGr+ed191y lNUUyN1qWGANt+vd6COVjF7q1f5dwzaa6Uh7KcJCS8Q50dvVc/oPsSBy1Cp4pXQIAi GArxYtNjWLzh6iGG/8udiFM8jtJ0lPP6oc3btVI/H6MA+ARxAiaHxas9A8vTbszMuV WzdsAp5iipxa5I6P6lLmiHOUH55Q1ZntH8yYf4KrjWpvl4/OvlUENeC7vONjnit5mE H+xK/RXfwOTkRS03nGyS6i21irG26EXUYW4LiNCtfVm6aLyixAx4qG58ZTp3NEHp+S XL40SWpwYS+VA== From: Maxime Ripard Date: Mon, 21 Jul 2025 13:17:30 +0200 Subject: [PATCH v7 1/5] doc: dma-buf: List the heaps by name Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250721-dma-buf-ecc-heap-v7-1-031836e1a942@kernel.org> References: <20250721-dma-buf-ecc-heap-v7-0-031836e1a942@kernel.org> In-Reply-To: <20250721-dma-buf-ecc-heap-v7-0-031836e1a942@kernel.org> To: Rob Herring , Saravana Kannan , Sumit Semwal , Benjamin Gaignard , Brian Starkey , John Stultz , "T.J. Mercier" , =?utf-8?q?Christian_K=C3=B6nig?= , Krzysztof Kozlowski , Conor Dooley , Marek Szyprowski , Robin Murphy , Jonathan Corbet Cc: Andrew Davis , Jared Kangas , Mattijs Korpershoek , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, iommu@lists.linux.dev, linux-doc@vger.kernel.org, Maxime Ripard X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=2482; i=mripard@kernel.org; h=from:subject:message-id; bh=pkewGPjjFTsNcaE929R2dk9XfsEdn97c4Fm1Zzq1x+Q=; b=owGbwMvMwCmsHn9OcpHtvjLG02pJDBl1iudmqnneWB99U9twXZvdjSCWd0Ysmnx3UrJn6/z+H L+XLVajYyoLgzAng6yYIssTmbDTy9sXVznYr/wBM4eVCWQIAxenAExk+yvGSsbjJrP15C0e2ust TRFdkOwlN/G2d+fbU1aRvntKby4w/F51MG1/r9SjbJ3oH57c0vu3MdY7nBLcG79HtWifaepSdpM Dq+fc9WVQsomef+vuLx+VOdaVaU+Ye56Xeas23ChxO7xmHjMA X-Developer-Key: i=mripard@kernel.org; a=openpgp; fpr=BE5675C37E818C8B5764241C254BCFC56BF6CE8D Since we're going to introduce multiple instances of the CMA heap driver, there's no single CMA heap anymore. Let's use the heap name instead to differentiate between all the heaps available in the system. While we're at it, let's also rework the backward compatibility part to make it easier to amend later on. Signed-off-by: Maxime Ripard --- Documentation/userspace-api/dma-buf-heaps.rst | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/Documentation/userspace-api/dma-buf-heaps.rst b/Documentation/= userspace-api/dma-buf-heaps.rst index 1dfe5e7acd5a3c674323775176d81944147e40c0..17bf6829efd7963bc849765db54= d327644e8c395 100644 --- a/Documentation/userspace-api/dma-buf-heaps.rst +++ b/Documentation/userspace-api/dma-buf-heaps.rst @@ -14,15 +14,16 @@ Heaps A heap represents a specific allocator. The Linux kernel currently support= s the following heaps: =20 - The ``system`` heap allocates virtually contiguous, cacheable, buffers. =20 - - The ``cma`` heap allocates physically contiguous, cacheable, - buffers. Only present if a CMA region is present. Such a region is - usually created either through the kernel commandline through the - ``cma`` parameter, a memory region Device-Tree node with the - ``linux,cma-default`` property set, or through the ``CMA_SIZE_MBYTES`` = or - ``CMA_SIZE_PERCENTAGE`` Kconfig options. The heap's name in devtmpfs is - ``default_cma_region``. For backwards compatibility, when the - ``DMABUF_HEAPS_CMA_LEGACY`` Kconfig option is set, a duplicate node is - created following legacy naming conventions; the legacy name might be - ``reserved``, ``linux,cma``, or ``default-pool``. + - The ``default_cma_region`` heap allocates physically contiguous, + cacheable, buffers. Only present if a CMA region is present. Such a + region is usually created either through the kernel commandline + through the ``cma`` parameter, a memory region Device-Tree node with + the ``linux,cma-default`` property set, or through the + ``CMA_SIZE_MBYTES`` or ``CMA_SIZE_PERCENTAGE`` Kconfig options. Prior + to Linux 6.17, its name wasn't stable and could be called + ``reserved``, ``linux,cma``, or ``default-pool``, depending on the + platform. From Linux 6.17 onwards, the creation of these heaps is + controlled through the ``DMABUF_HEAPS_CMA_LEGACY`` Kconfig option for + backwards compatibility. --=20 2.50.1