Commit a7b67cd5 authored Feb 06, 2015 by Thierry Reding Committed by Joerg Roedel Feb 25, 2015

iommu/exynos: Play nice in multi-platform builds



The Exynos System MMU driver unconditionally executes code and registers
a struct iommu_ops with the platform bus irrespective of whether it runs
on an Exynos SoC or not. This causes problems in multi-platform kernels
where drivers for other SoCs will no longer be able to register their
own struct iommu_ops or even try to use a struct iommu_ops for an IOMMU
that obviously isn't there.

The smallest fix I could think of is to check for the existence of any
Exynos System MMU devices in the device tree and skip initialization
otherwise.

This fixes a problem on Tegra20 where the DRM driver will try to use the
obviously non-existent Exynos System MMU.

Reported-by: Nicolas Chauvet <kwizart@gmail.com>
Cc: Kukjin Kim <kgene@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

parent 367bd978

drivers/iommu/exynos-iommu.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -1186,8 +1186,15 @@ static const struct iommu_ops exynos_iommu_ops = {

		static int __init exynos_iommu_init(void)
		{
		struct device_node *np;
		int ret;

		np = of_find_matching_node(NULL, sysmmu_of_match);
		if (!np)
		return 0;

		of_node_put(np);

		lv2table_kmem_cache = kmem_cache_create("exynos-iommu-lv2table",
		LV2TABLE_SIZE, LV2TABLE_SIZE, 0, NULL);
		if (!lv2table_kmem_cache) {