From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 B9DE23D7D70; Thu, 6 Aug 2026 10:18:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786011520; cv=none; b=Im9vX4F6hdDzkbTkBjzrdUMspUWGqeDznVVf+Mu6KzJolE6Kz29z0/d9U2VK35Uw89Szg+ZmZAXUrNvKTSchYmtgSLblPqhxyf/rncaHh1iIxWRl/1avcx0WtqbjOxavnV3HtuPtOW8YopPZ16QNn6VqqzzUaQz5Th4Wh/2hYSc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786011520; c=relaxed/simple; bh=a/ktzM+M5NJYxFpdP7NSDQ/AP6CYbmbaQ3o9nnBo8kc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=h87eQTY3uk+YppBWmn3hCvRY/HyIYlB/imUkbleLZXi3vAFNG2tt8XY7RrZzYtswDoivSH9FtYRAH8hRIvy/HcGQJsfW5jxSR0YdiiFi8nyDNMsNU+8+L4iR1M45Oc26KA3U0bTmNyrUtnDPqMBRc1WlxDTI2uHSoW6XaP5nrHM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=FMcD5jJG; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="FMcD5jJG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BC43F1F000E9; Thu, 6 Aug 2026 10:18:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786011519; bh=AuCl1BP2ZnvHnrPdM8vJ14bFDLWZlulNvgD/oSTdoFQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=FMcD5jJGfLn/oTIhXTMG0/8x13GSrVz1mNbmeKN30b23v38HrRCdaJcc9lz+XyY8j wRB+x4VI+jpGuFKP5Y2twEG1qZEqcqfLxLkqvqYZzMJdGOH+d3iDem2yMaCTHzbTHA jp77vwib+kWvxe+Cm/MUH+OsskomOsDuB0xoqpTVMrC8DwlPqwNJeY/6BnbRRRmz37 8cOwPCpedJiFndFiOQRM7V2OO/8WHSFw1mUnaI3xbSZO5KjMknrnw4Q47eI13ZfZ9x TVuOj/+y0Rm/SeZWI9aLI9uO/27f028elPvZWRRrBM62I7fOheCJUijZNfbEJ+MJZv lD8WZxdxuZt3w== Message-ID: <4460a2c3-6b4a-4a7d-ba86-51c1c8363781@kernel.org> Date: Thu, 6 Aug 2026 12:18:28 +0200 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 04/12] media: iris: Add helper to create a context bank device To: Vikash Garodia , Dmitry Baryshkov Cc: Dikshita Agarwal , Abhinav Kumar , Bryan O'Donoghue , Mauro Carvalho Chehab , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Bjorn Andersson , Konrad Dybcio , Stanimir Varbanov , Neil Armstrong , Bryan O'Donoghue , Stephan Gerhold , linux-media@vger.kernel.org, linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Konrad Dybcio , stable@vger.kernel.org, Vishnu Reddy , Daniel J Blueman References: <20260731-vpu_iommu_iova_handling-v2-0-da52b5228dbd@oss.qualcomm.com> <20260731-vpu_iommu_iova_handling-v2-4-da52b5228dbd@oss.qualcomm.com> <36b53e0d-82e2-4fbb-a2b6-3fd7b9c98663@oss.qualcomm.com> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 06/08/2026 12:08, Vikash Garodia wrote: > > > On 8/6/2026 2:27 PM, Dmitry Baryshkov wrote: >> On Fri, Jul 31, 2026 at 11:52:19PM +0530, Vikash Garodia wrote: >>> The VPU issues DMA through several SMMU streams, and the hardware does >>> not give every stream the same addressable range. The non-pixel stream >>> is restricted to use 0-600MB of IOVA space, while the pixel stream can >>> address the full range. A stream can only be confined to its range if it >>> has an IOMMU domain of its own, and the IOMMU core attaches a domain per >>> struct device, so each stream needs its own device. >>> Add iris_create_cb_dev(), which looks up a named child of the iris node >>> and registers it as a platform device parented to the iris core. The >>> child's fwnode is handed to platform_device_register_full() so the OF >>> core applies that subnode's "iommus" property and the new device gets >>> its own IOMMU domain. The DMA mask comes from platform data, and the >>> segment size and boundary are capped at 32 bits to match the addressing >>> the VPU performs. >>> Return NULL when the named child is absent, so callers can treat a >>> device tree without context bank subnodes as a supported configuration >>> rather than an error. >>> Backports are intended since the first DTS of 8550 binding schema. >> >> What does this mean in the commit message? >> >>> >>> Fixes: 41661853ae8e ("arm64: dts: qcom: sm8550: add iris DT node") >> >> How can driver fix the DT? >> > > The idea is to backport the driver fixes till the kernels when the first > DTS landed. Ideally the fixes tags the commit which introduced the bug, > while in this case, was thinking to keep it for DTS. Fixes tag does not represent the backport, so your idea is wrong. You point here to the commit which introduced incorrect code. If DTS is incorrect, then a DTS patch fixes it. How a driver can fix DRIVER-INDEPENDENT hardware description? It's contradictory to the "independent" part. Best regards, Krzysztof