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 X-Spam-Level: X-Spam-Status: No, score=-6.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CAFE5C56202 for ; Thu, 26 Nov 2020 04:50:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 763E72145D for ; Thu, 26 Nov 2020 04:50:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="Rg0nz22T" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387686AbgKZEuk (ORCPT ); Wed, 25 Nov 2020 23:50:40 -0500 Received: from mail.kernel.org ([198.145.29.99]:36890 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387684AbgKZEuk (ORCPT ); Wed, 25 Nov 2020 23:50:40 -0500 Received: from localhost (unknown [122.179.79.180]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 010B82145D; Thu, 26 Nov 2020 04:50:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1606366240; bh=t8TaVfhJXLJs3qX8q4hwu4FUKcPn1ZUAgVG39jnLMz0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Rg0nz22TB9YyMCDBgxlFqiZLPKGX10kdP0XYWmwet/TPpJtqXhzMhdTgcp27DaVEC 0Ji/jqmGLa2v5ojhaN6fRc/NktWSsxjGlzBD2JamDl7MnhUjEgXrq7PDKDD2cPaRLA o1sa+aiWI273/Q5t2Fho8Wb7Vjb1OlAOVXk43Xo4= Date: Thu, 26 Nov 2020 10:20:35 +0530 From: Vinod Koul To: "Reddy, MallikarjunaX" Cc: dmaengine@vger.kernel.org, devicetree@vger.kernel.org, robh+dt@kernel.org, linux-kernel@vger.kernel.org, andriy.shevchenko@intel.com, chuanhua.lei@linux.intel.com, cheol.yong.kim@intel.com, qi-ming.wu@intel.com, malliamireddy009@gmail.com, peter.ujfalusi@ti.com Subject: Re: [PATCH v9 2/2] Add Intel LGM SoC DMA support. Message-ID: <20201126045035.GI8403@vkoul-mobl> References: <67be905aa3bcb9faac424f2a134e88d076700419.1605158930.git.mallikarjunax.reddy@linux.intel.com> <20201118173840.GW50232@vkoul-mobl> <20201121121701.GB8403@vkoul-mobl> <20201124172149.GT8403@vkoul-mobl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On 25-11-20, 18:39, Reddy, MallikarjunaX wrote: > > > > > desc needs to be configure for each dma channel and the remapped address of > > > > > the IGP & EGP is desc base adress. > > > > Why should this address not passed as src_addr/dst_addr? > > > src_addr/dst_addr is the data pointer. Data pointer indicates address > > > pointer of data buffer. > > > > > > ldma_chan_desc_cfg() carries the descriptor address. > > > > > > The descriptor list entry contains the data pointer, which points to the > > > data section in the memory. > > > > > > So we should not use src_addr/dst_addr as desc base address. > > Okay sounds reasonable. why is this using in API here? > descriptor base address needs to be write into the dma register (DMA_CDBA). Why cant descriptor be allocated by damenegine driver, passed to client as we normally do in prep_* callbacks ? Why do you need a custom API -- ~Vinod