From: Thierry Reding <[email protected]> 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 <[email protected]> Cc: Tony Lindgren <[email protected]> Cc: Suman Anna <[email protected]> Cc: Laurent Pinchart <[email protected]> Signed-off-by: Thierry Reding <[email protected]> --- 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 _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
