[PATCH v2 4/4] iommu/msm: Mark driver BROKEN

[Thierry Reding <thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

From: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>

The MSM IOMMU driver unconditionally calls bus_set_iommu(), which is a
very stupid thing to do on multi-platform kernels. While marking the
driver BROKEN may seem a little extreme, there is no other way to make
the driver skip initialization. One of the problems is that it doesn't
have devicetree binding documentation and the driver doesn't contain a
struct of_device_id table either, so no way to check that it is indeed
valid to set up the IOMMU operations for this driver.

This fixes a problem on Tegra20 where the DRM driver will try to use the
obviously non-existent MSM IOMMU.

Marking the driver BROKEN shouldn't do any harm, since there aren't any
users currently. There is no struct of_device_id table, so the device
can't be instantiated from device tree, and I couldn't find any code
that would instantiate a matching platform_device either, so the driver
is effectively unused.

Reported-by: Nicolas Chauvet <kwizart-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: David Brown <davidb-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
Cc: Daniel Walker <dwalker-zu3NM2574RrQT0dZR+AlfA@public.gmane.org>
Cc: Bryan Huntsman <bryanh-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
Cc: Olav Haugan <ohaugan-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
Acked-by: Rob Clark <robdclark-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Signed-off-by: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
---
 drivers/iommu/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index b280f0e21c8c..619bfd7bab1a 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -63,6 +63,7 @@ config MSM_IOMMU
 	bool "MSM IOMMU Support"
 	depends on ARM
 	depends on ARCH_MSM8X60 || ARCH_MSM8960 || COMPILE_TEST
+	depends on BROKEN
 	select IOMMU_API
 	help
 	  Support for the IOMMUs found on certain Qualcomm SOCs.
-- 
2.1.3