From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vinod Koul Subject: Re: [PATCHv7 0/6] dmaengine: rcar-dmac: add iommu support for slave transfers Date: Wed, 1 Jun 2016 23:36:11 +0530 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-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <1464794549-6601-1-git-send-email-niklas.soderlund+renesas@ragnatech.se> Sender: linux-renesas-soc-owner@vger.kernel.org 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 List-Id: iommu@lists.linux-foundation.org On Wed, Jun 01, 2016 at 05:22:23PM +0200, Niklas S=F6derlund wrote: > Hi, >=20 > [In this v7 series I have tried to address the questions raised by Ch= ristoph=20 > Hellwig and I hope it can awnser your concernes regarding dma-debug.] >=20 > 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. >=20 > Without an IOMMU this is easy since the phys_addr_t and dma_addr_t ar= e > the same and no special care is needed. However if you have a IOMMU y= ou > need to map the DMA slave phys_addr_t to a dma_addr_t using something > like this. >=20 > This series is based on top of v4.7-rc1. The dmanegine bits looks okay to me. Btw how is the merge planned for t= his? Do you wnat this to be merged thru dmaengine tree or something else? --=20 ~Vinod