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 DC15A3A5424; Tue, 17 Mar 2026 10:26:43 +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=1773743203; cv=none; b=MpbVerwFtURHKLz5h4TbDVUG+li/gfyCGBm3Txai3jPlfC4nBuMZckKdazf9GqoUCSnLFaw0m8lUWIob9D3//sTc4gIZQn3azMsSw8KJEu1TyzQFG8rD1muTW42DaZnzws+TxoNPAqI5214++689MBFF6fAnaBdVkpLYSFF4GKE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773743203; c=relaxed/simple; bh=leILco6ESwbAPx5/ChEkDeGOl9TARpFn5FFt7fhV91M=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=JS/RbMrO0ucygMZzynQZdNEwZbu38/NZjYSZoL4ApW2LaDGKu5/fQeaJt1dpvUryWBKbtSMheAllPabTmAjpHhVeDW0Y4WCajxVcbPr6c7ZYIL6QCZFpnjUwx7pWZmhMqpuV31xrhKLT2UP1CL7ksliEsqmt8wAaTuMrGDn6Edg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=EK+pGd/Q; 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="EK+pGd/Q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 150C7C4CEF7; Tue, 17 Mar 2026 10:26:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773743203; bh=leILco6ESwbAPx5/ChEkDeGOl9TARpFn5FFt7fhV91M=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=EK+pGd/Qe+hHDmgY8MA52uxvkIPEOhyj8ZVsNmndCnSG5dr/RFkQ9EnPdTtgdc61H Cv1BQnZ3IDVErs0ElcARTaHFjSgtOIlIttxmykiFG8ScBTqIlcuYsDPneEBfXC7EYC Xkspxjnc6XfG8/+Gl8Htahhn2o+gOhHRob/jNy+0w4tkPw5+r5eNhsc1WethmBcvky xWXG2L5QQNS+FE1dYze7XpRzUc/frOLIjc4Nb3FErpzmNekXVc2Q/wMIWWsO/HxGE/ VcqQcQuMnZ8Of7QoctvtautlGcfI4NcN1sQiB7KTCaig1mVy2DW5gr/cfnhvZYZf5/ CxzWscbT1RSHQ== Date: Tue, 17 Mar 2026 15:56:40 +0530 From: Vinod Koul To: Frank Li Cc: Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 0/6] dmaengine: Add common dma_slave_config and split it into src and dst parts Message-ID: References: <20260114-dma_common_config-v1-0-64feb836ff04@nxp.com> Precedence: bulk X-Mailing-List: dmaengine@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On 09-03-26, 10:27, Frank Li wrote: > On Mon, Mar 09, 2026 at 12:24:33PM +0100, Vinod Koul wrote: > > On 14-01-26, 12:12, Frank Li wrote: > > > Many DMA engine drivers store a dma_slave_config per channel. Propagate > > > this configuration into struct dma_chan to avoid duplicating the same > > > code in each driver. > > > > > > Much of dma_slave_config is identical for source and destination. Split > > > the configuration into src and dst groups and use a union to preserve > > > backward compatibility. This reduces the need for drivers to repeatedly > > > check the DMA transfer direction. > > > > The reason why we had both the src/dstn sides was intended method to > > allow upport ofr device to device dma. Some interest was shown for that > > at that time. > > I dont think we have such a user even now... > > My means is the field name is identical, not value identical although most > case is the identical. but it is possible, especial FIFO space windows, > > sound/soc/fsl/fsl_asrc_dma.c use DEV_TO_DEV, at least src and addr use > differece address. Yeah so this would break if we go ahead. Thanks for looking this up -- ~Vinod