[adding Marek, Sjoerd and Joonyoung that were discussing about iommu support in another thread] 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. 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
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