From: Thierry Reding <tred...@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 <kwiz...@gmail.com>
Cc: Tony Lindgren <t...@atomide.com>
Cc: Suman Anna <s-a...@ti.com>
Cc: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
Signed-off-by: Thierry Reding <tred...@nvidia.com>
---
drivers/iommu/omap-iommu.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
index bbb7dcef02d3..e4d4f133a3b3 100644
--- a/drivers/iommu/omap-iommu.c
+++ b/drivers/iommu/omap-iommu.c
@@ -1377,6 +1377,9 @@ static int __init omap_iommu_init(void)
const unsigned long flags = SLAB_HWCACHE_ALIGN;
size_t align = 1 << 10; /* L2 pagetable alignement */
+ if (!of_find_matching_node(NULL, omap_iommu_of_match))
+ return 0;
+
p = kmem_cache_create("iopte_cache", IOPTE_TABLE_SIZE, align, flags,
iopte_cachep_ctor);
if (!p)
@@ -1394,6 +1397,9 @@ subsys_initcall(omap_iommu_init);
static void __exit omap_iommu_exit(void)
{
+ if (!of_find_matching_node(NULL, omap_iommu_of_match))
+ return;
+
kmem_cache_destroy(iopte_cachep);
platform_driver_unregister(&omap_iommu_driver);
--
2.1.3
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