From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga14.intel.com ([192.55.52.115]:12242 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932699AbcFAR7m (ORCPT ); Wed, 1 Jun 2016 13:59:42 -0400 Date: Wed, 1 Jun 2016 23:36:11 +0530 From: Vinod Koul To: Niklas =?iso-8859-1?Q?S=F6derlund?= Cc: hch@infradead.org, linux-renesas-soc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, dmaengine@vger.kernel.org, iommu@lists.linux-foundation.org, dan.j.williams@intel.com, robin.murphy@arm.com, laurent.pinchart@ideasonboard.com, linus.walleij@linaro.org, arnd@arndb.de Subject: Re: [PATCHv7 0/6] dmaengine: rcar-dmac: add iommu support for slave transfers Message-ID: <20160601180610.GV16910@localhost> References: <1464794549-6601-1-git-send-email-niklas.soderlund+renesas@ragnatech.se> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1464794549-6601-1-git-send-email-niklas.soderlund+renesas@ragnatech.se> Sender: linux-renesas-soc-owner@vger.kernel.org List-ID: On Wed, Jun 01, 2016 at 05:22:23PM +0200, Niklas S�derlund wrote: > Hi, > > [In this v7 series I have tried to address the questions raised by Christoph > Hellwig and I hope it can awnser your concernes regarding dma-debug.] > > This series tries to solve the problem with DMA with device registers > (MMIO registers) that are behind an IOMMU for the rcar-dmac driver. A > recent patch '9575632 (dmaengine: make slave address physical)' > clarifies that DMA slave address provided by clients is the physical > address. This puts the task of mapping the DMA slave address from a > phys_addr_t to a dma_addr_t on the DMA engine. > > Without an IOMMU this is easy since the phys_addr_t and dma_addr_t are > the same and no special care is needed. However if you have a IOMMU you > need to map the DMA slave phys_addr_t to a dma_addr_t using something > like this. > > This series is based on top of v4.7-rc1. The dmanegine bits looks okay to me. Btw how is the merge planned for this? Do you wnat this to be merged thru dmaengine tree or something else? -- ~Vinod