From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jungo Lin Subject: Re: [RFC, v3 9/9] media: platform: Add Mediatek ISP P1 shared memory device Date: Fri, 26 Jul 2019 19:59:46 +0800 Message-ID: <1564142386.1212.621.camel@mtksdccf07> References: <20190611035344.29814-1-jungo.lin@mediatek.com> <20190611035344.29814-10-jungo.lin@mediatek.com> <20190701072532.GB137710@chromium.org> <1562297618.1212.46.camel@mtksdccf07> <1562313579.1212.73.camel@mtksdccf07> <1563870117.1212.455.camel@mtksdccf07> <20190726074116.GA19745@infradead.org> <4460bc91-352a-7f3a-cbed-1b95e743ca8c@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4460bc91-352a-7f3a-cbed-1b95e743ca8c-5wv7dgnIgG8@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: Robin Murphy Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Sean Cheng =?UTF-8?Q?=28=E9=84=AD=E6=98=87=E5=BC=98=29?= , Frederic Chen =?UTF-8?Q?=28=E9=99=B3=E4=BF=8A=E5=85=83=29?= , Rynn Wu =?UTF-8?Q?=28=E5=90=B3=E8=82=B2=E6=81=A9=29?= , srv_heupstream , Rob Herring , Ryan Yu =?UTF-8?Q?=28=E4=BD=99=E5=AD=9F=E4=BF=AE=29?= , Frankie Chiu =?UTF-8?Q?=28=E9=82=B1=E6=96=87=E5=87=B1=29?= , "list-Y9sIeH5OGRo@public.gmane.org:IOMMU DRIVERS" , Matthias Brugger , Sj Huang , "moderated list:ARM/Mediatek SoC support" , Laurent Pinchart , Hans Verkuil , ddavenport-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org, Mauro List-Id: linux-mediatek@lists.infradead.org Hi Robin: On Fri, 2019-07-26 at 12:04 +0100, Robin Murphy wrote: > On 26/07/2019 08:42, Tomasz Figa wrote: > > On Fri, Jul 26, 2019 at 4:41 PM Christoph Hellwig wrote: > >> > >> On Fri, Jul 26, 2019 at 02:15:14PM +0900, Tomasz Figa wrote: > >>> Could you try dma_get_sgtable() with the SCP struct device and then > >>> dma_map_sg() with the P1 struct device? > >> > >> Please don't do that. dma_get_sgtable is a pretty broken API (see > >> the common near the arm implementation) and we should not add more > >> users of it. If you want a piece of memory that can be mapped to > >> multiple devices allocate it using alloc_pages and then just map > >> it to each device. > > > > Thanks for taking a look at this thread. > > > > Unfortunately that wouldn't work. We have a specific reserved memory > > pool that is the only memory area accessible to one of the devices. > > Any idea how to handle this? > > If it's reserved in the sense of being outside struct-page-backed > "kernel memory", then provided you have a consistent CPU physical > address it might be reasonable for other devices to access it via > dma_map_resource(). > > Robin. Thank you for your suggestion. After revising to use dma_map_resource(), it is worked. Below is the current implementation. Pleas kindly help us to check if there is any misunderstanding. #define MTK_ISP_COMPOSER_MEM_SIZE 0x200000 /* * Allocate coherent reserved memory for SCP firmware usage. * The size of SCP composer's memory is fixed to 0x200000 * for the requirement of firmware. */ ptr = dma_alloc_coherent(p1_dev->cam_dev.smem_dev, MTK_ISP_COMPOSER_MEM_SIZE, &addr, GFP_KERNEL); if (!ptr) { dev_err(dev, "failed to allocate compose memory\n"); return -ENOMEM; } p1_dev->composer_scp_addr = addr; p1_dev->composer_virt_addr = ptr; dev_dbg(dev, "scp addr:%pad va:%pK\n", &addr, ptr); /* * This reserved memory is also be used by ISP P1 HW. * Need to get iova address for ISP P1 DMA. */ addr = dma_map_resource(dev, addr, MTK_ISP_COMPOSER_MEM_SIZE, DMA_BIDIRECTIONAL, DMA_ATTR_SKIP_CPU_SYNC); if (dma_mapping_error(dev, addr)) { dev_err(dev, "Failed to map scp iova\n"); ret = -ENOMEM; goto fail_free_mem; } p1_dev->composer_iova = addr; dev_info(dev, "scp iova addr:%pad\n", &addr); Moreover, appropriate Tomasz & Christoph's help on this issue. Best regards, Jungo