From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Deacon Subject: Re: [PATCH 3/9] ARM: dma-mapping: Always pass proper prot flags to iommu_map() Date: Fri, 27 Sep 2013 09:35:24 +0100 Message-ID: <20130927083523.GA8319@mudshark.cambridge.arm.com> References: <1380234982-1677-1-git-send-email-andreas.herrmann@calxeda.com> <1380234982-1677-4-git-send-email-andreas.herrmann@calxeda.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1380234982-1677-4-git-send-email-andreas.herrmann-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Andreas Herrmann Cc: "iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org" , Rob Herring , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" List-Id: iommu@lists.linux-foundation.org On Thu, Sep 26, 2013 at 11:36:15PM +0100, Andreas Herrmann wrote: > ... otherwise it is impossible for the low level iommu driver to > figure out which pte flags should be used. > > In __map_sg_chunk we can derive the flags from dma_data_direction. > > In __iommu_create_mapping we should treat the memory like > DMA_BIDIRECTIONAL and pass both IOMMU_READ and IOMMU_WRITE to > iommu_map. > __iommu_create_mapping is used during dma_alloc_coherent (via > arm_iommu_alloc_attrs). AFAIK dma_alloc_coherent is responsible for > allocation _and_ mapping. I think this implies that access to the > mapped pages should be allowed. > > Cc: Marek Szyprowski > Signed-off-by: Andreas Herrmann Acked-by: Will Deacon This one should go via the dma-mapping tree. Will