From: Thierry Reding <treding@nvidia.com>
Date: Fri, 6 Feb 2015 11:44:06 +0100
Subject: [PATCH] iommu/omap: Play nice in multi-platform builds
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@gmail.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Suman Anna <s-anna@ti.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
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 bbb7dcef02d3..19db0b684b7f 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);
--
2.1.0