On 9 January 2015 at 23:34, Javier Martinez Canillas <javier@xxxxxxxxxxxx> wrote: > [adding Marek, Sjoerd and Joonyoung that were discussing about iommu > support in another thread] Thank you Javier. > > Hello Hongbo, > > On Fri, Jan 9, 2015 at 8:31 AM, Hongbo Zhang <hongbo.zhang@xxxxxxxxxx> wrote: >> Add linux-samsung-soc@xxxxxxxxxxxxxxx mailing list. >> >> On 7 January 2015 at 18:31, Hongbo Zhang <hongbo.zhang@xxxxxxxxxx> wrote: >>> Hi Cho KyongHo, Joerg et al, >>> I found the latest Exynos IOMMU driver doesn't work, the line 481: >>> BUG_ON(!has_sysmmu(dev)); >>> in function __exynos_sysmmu_enable() in file exynos-iommu.c triggers >>> kernel panic. >>> >>> Then I found the dev->archdata.iommu isn't initialized at all, it >>> should be the root cause. >>> > > That's correct, I found the same the other day since and thought about > posting a patch to return -ENODEV if !has_sysmmu(dev) instead to avoid > the driver to panic the kernel. But then I realized this is already > fixed in Marek's "[PATCH v3 00/19] Exynos SYSMMU (IOMMU) integration > with DT and DMA-mapping subsystem" series [0]. > >>> Another problem is this driver is added support of device tree, but >>> there is no device tree nodes in the dts file, so I had to search from >>> internet and added those nodes manually. >>> >>> I've found these links of v12 and v13 patches >>> https://lkml.org/lkml/2014/4/27/171 >>> https://lkml.org/lkml/2014/5/12/34 >>> patch v13 was merged into mainline kernel, but as a part of v12, it >>> isn't complete and doesn't work alone, eg dts nodes are missing. >>> (I didn't research much dev->archdata.iommu initialization error is >>> introduced by which patch, but it seems in very old codes there is no >>> such problem) >>> > > Yes, please take a look to Marek series [0]. Keep in mind that the > series does not support all sysmmu revisions so IOMMU is not supported > for some SoCs (e.g: Exynos5). Support for that is planned once that > series land into mainline though [1]. > > May I ask why are you interested in IOMMU support on Exynos? I'm > asking because the reason why I tried to enable IOMMU support (and hit > the same issue) was to try using the Exynos DRM HDMI driver with IOMMU > since I found that HDMI is working on the downstream Samsung kernel > [2] that has IOMMU support, but is not working on mainline. Because I am testing vfio-platform patches, IOMMU is used in this case. http://www.spinics.net/lists/kvm-arm/msg12445.html And I am glad to find a working kernel as you pointed out, then I found these two commits in this tree may solve my problem: 841a7fe TEMP/TO POST: iommu: exynos: Add "mmu-masters" support bd7e4c7 TEMP/TO POST: ARM: dts: add System MMU nodes of Exynos SoCs > > At the end the HDMI problem seems to not be IOMMU related but > something with the power domains and clocking but in case you are > facing the same issue, you may be interested in that discussion [3]. > > Best regards, > Javier > > [0]: http://www.spinics.net/lists/linux-samsung-soc/msg39168.html > [1]: http://www.spinics.net/lists/linux-samsung-soc/msg39980.html > [2]: git@xxxxxxxxxx:exynos-reference/kernel.git > [3]: http://www.spinics.net/lists/linux-samsung-soc/msg40828.html -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
 |