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From: Thierry Reding <treding at nvidia.com>
The OMAP IOMMU driver unconditionally executes code and registers a
struct iommu_ops with the platform bus irrespective of whether it runs
on an OMAP 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
OMAP IOMMU 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 OMAP IOMMU.
Reported-by: Nicolas Chauvet <kwizart at gmail.com>
Cc: Tony Lindgren <tony at atomide.com>
Cc: Suman Anna <s-anna at ti.com>
Cc: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Signed-off-by: Thierry Reding <treding at nvidia.com>
---
Changes in v2:
- do not fix up module exit function since it's dead code
- drop reference to struct device_node
drivers/iommu/omap-iommu.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
index f59f857b702e..a4ba851825c2 100644
--- a/drivers/iommu/omap-iommu.c
+++ b/drivers/iommu/omap-iommu.c
@@ -1376,6 +1376,13 @@ static int __init omap_iommu_init(void)
struct kmem_cache *p;
const unsigned long flags = SLAB_HWCACHE_ALIGN;
size_t align = 1 << 10; /* L2 pagetable alignement */
+ struct device_node *np;
+
+ np = of_find_matching_node(NULL, omap_iommu_of_match);
+ if (!np)
+ return 0;
+
+ of_node_put(np);
p = kmem_cache_create("iopte_cache", IOPTE_TABLE_SIZE, align, flags,
iopte_cachep_ctor);
--
2.1.3
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