From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752635AbeEKMFD (ORCPT ); Fri, 11 May 2018 08:05:03 -0400 Received: from mail-pl0-f68.google.com ([209.85.160.68]:38899 "EHLO mail-pl0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751000AbeEKMFA (ORCPT ); Fri, 11 May 2018 08:05:00 -0400 X-Google-Smtp-Source: AB8JxZoWTcHmENNwfW5YN4kPBazXmRKECB+x4aNZJ0YsNFTAWlCszEp6XRIv9GAR/bFogy7h+Cap1A== Date: Fri, 11 May 2018 17:34:57 +0530 From: Vinod Koul To: Baolin Wang Cc: Vinod Koul , Dan Williams , Eric Long , Mark Brown , Lars-Peter Clausen , dmaengine@vger.kernel.org, LKML Subject: Re: [PATCH v2 2/2] dmaengine: sprd: Add Spreadtrum DMA configuration Message-ID: <20180511120457.GD30118@vkoul-mobl> References: <67447aabb8e4e051ff39b814a0e169e6a91bb66e.1525863923.git.baolin.wang@linaro.org> <20180511112225.GA30118@vkoul-mobl> <20180511115306.GC30118@vkoul-mobl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11-05-18, 19:58, Baolin Wang wrote: > On 11 May 2018 at 19:53, Vinod Koul wrote: > >> > > >> >> +/* > >> >> + * struct sprd_dma_config - DMA configuration structure > >> >> + * @cfg: dma slave channel runtime config > >> >> + * @src_addr: the source physical address > >> >> + * @dst_addr: the destination physical address > >> >> + * @block_len: specify one block transfer length > >> >> + * @transcation_len: specify one transcation transfer length > >> >> + * @src_step: source transfer step > >> >> + * @dst_step: destination transfer step > >> >> + * @wrap_ptr: wrap pointer address, once the transfer address reaches the > >> >> + * 'wrap_ptr', the next transfer address will jump to the 'wrap_to' address. > >> >> + * @wrap_to: wrap jump to address > >> >> + * @req_mode: specify the DMA request mode > >> >> + * @int_mode: specify the DMA interrupt type > >> >> + */ > >> >> +struct sprd_dma_config { > >> >> + struct dma_slave_config cfg; > >> >> + phys_addr_t src_addr; > >> >> + phys_addr_t dst_addr; > >> > > >> > these are already in cfg so why duplicate, same for few more here. > >> > >> We save them in 'struct sprd_dma_config' as one parameter for > >> sprd_dma_config(), otherwise we need add 2 more parameters (src and > >> dst) for sprd_dma_config(). > > > > I am not sure I follow... > > > > I meant you can use sprd_dma_config.cfg->src_addr/dst_addr and remove src_addr & > > dst_addr in the sprd_dma_config. It duplicate.. > > But we can not set values if dir == DMA_MEM_TO_DEV, since they > represent the device address, right? > sprd_dma_config.cfg->src_addr = sg_dma_address(sg); Ah right and that is another issue to fix then :) we should not store addresses you get for prep_ calls. They are supposed to be stored in the descriptor. Current approach is not correct. You can get different prepare calls (i think fixing this will remove 1 sg limitation).. and use the argument values and store in respective descriptors. Pls do see the other driver examples.. -- ~Vinod