Exynos SYSMMU (IOMMU) integration with DT andDMA-mapping subsystem

Quoted 42 lines · Javier Martinez Canillas

Hello Marek,

Quoted 21 lines · Marek Szyprowski

Hello Everyone,

This is yet another attempt to get Exynos SYSMMU driver with integrated with IOMMU & DMA-mapping subsystems. This version includes minor fixes suggested by Joerg Roedel, Cho KyongHo and Robin Murphy.

All patches are also available in the following git repository:
https://git.linaro.org/people/marek.szyprowski/linux-srpol.git
branch v4.1-exynos-iommu-v7.

My plan for merging this patchset is as follows:
- DTS changes and power domain changes should go via Samsung tree to avoid conflicts with other pending DTS patches
- all exynos-iommu patches and dma-mapping/reserved iommu region should go via IOMMU tree,
- all Exynos DRM patches should go via DRM/Exynos tree.

There are no build cross-subsystem dependencies and IOMMU on Exynos is already nonfunctional (and disabled in defconfig), so merging patches in parts doesn't break anything.

Quoted 7 lines

There are knowns issues with Exynos DRM driver and IOMMU support (i.e. Xorg freeze reported by Javier Martinez Canillas:
http://www.spinics.net/lists/linux-samsung-soc/msg44350.html ). They will be handled by a separate fixes to Exynos DRM drivers. This patchset fixes only those issues in Exynos DRM FIMD driver, which prevents booting to console.

I tested your v7 using exynos_defconfig + CONFIG_EXYNOS_IOMMU on both Exynos5250 Snow and Exynos5420 Peach Pit Chromebooks.

I can only reproduce the complete system hang on Xorg if I use the xf86-video-armsoc DDX. If I use the -fbdev DDX instead, X starts correctly and the system does not freeze. Also, this only happens on Exynos5420 Peach Pit, Exynos5250 Snow is working correctly even when using the -armsoc DDX.

Quoted 5 lines

So as you said, this is a separate issue with the Exynos DRM driver IOMMU support and is not related to your series. For the whole series:

Tested-by Javier Martinez Canillas <[email protected]>

Thanks for your test on the boards.

I'll sort out the arch/ side changes into samsung tree in this weekend.