From mboxrd@z Thu Jan 1 00:00:00 1970 From: subashrp@gmail.com (Subash Patel) Date: Fri, 30 Mar 2012 12:44:47 +0530 Subject: [PATCHv7 9/9] ARM: dma-mapping: add support for IOMMU mapper In-Reply-To: <4F6B304E.5010402@gmail.com> References: <1330527862-16234-1-git-send-email-m.szyprowski@samsung.com> <1330527862-16234-10-git-send-email-m.szyprowski@samsung.com> <4F688B2D.20808@gmail.com> <4F6B304E.5010402@gmail.com> Message-ID: <4F755D67.5020802@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi KyongHo, On 03/22/2012 07:29 PM, Subash Patel wrote: > Hi KyongHo, > > On 03/21/2012 05:26 AM, KyongHo Cho wrote: >> On Tue, Mar 20, 2012 at 10:50 PM, Subash Patel wrote: >>> Sorry for digging this very late. But as part of integrating dma_map v7& >>> sysmmu v12 on 3.3-rc5, I am facing below issue: >>> >>> a) By un-selecting IOMMU in menu config, I am able to allocate memory in >>> vb2-dma-contig >>> >>> b) When I enable SYSMMU support for the IP's, I am receiving below >>> fault: >>> >>> Unhandled fault: external abort on non-linefetch (0x818) at 0xb6f55000 >>> >>> I think this has something to do with the access to the SYSMMU >>> registers for >>> writing the page table. Has anyone of you faced this issue while testing >>> these(dma_map+iommu) patches on kernel mentioned above? This must be >>> something related to recent changes, as I didn't have issues with these >>> patches on 3.2 kernel. >>> >> >> 0xb6f55000 is not an address of SYSMMU register if your kernel starts >> at 0xc0000000. >> >> Can you tell me any detailed information or situation? > I hate to say this, but I am not able to catch the fault location even > with JTAG. Once the fault comes, the debugger looses all control over. I > think now possible method is reproduction at your end :) Thanks to you, Issue is now figured out. This was due to generic Power Domain code added recently. SYSMMU registers were not getting enabled due to this. I reverted the PD changes from the machine to architecture specific, and voila, SYSMMU is back into action using the dma-mapping-v7. I will have to see how the same would behave when the complete PD changes comes to mainline from maintainers for-next in future. >> >> Regards, >> >> KyongHo. > Regards, > Subash Regards, Subash