From: Thierry Reding <tred...@nvidia.com>
The Rockchip IOMMU driver unconditionally executes code and registers a
struct iommu_ops with the platform bus irrespective of whether it runs
on a Rockchip 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
Rockchip 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 Rockchip IOMMU.
Reported-by: Nicolas Chauvet <kwiz...@gmail.com>
Cc: Heiko Stuebner <he...@sntech.de>
Cc: Daniel Kurtz <djku...@chromium.org>
Signed-off-by: Thierry Reding <tred...@nvidia.com>
---
drivers/iommu/rockchip-iommu.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.c
index 6a8b1ec4a48a..869e9c9d5df7 100644
--- a/drivers/iommu/rockchip-iommu.c
+++ b/drivers/iommu/rockchip-iommu.c
@@ -1017,6 +1017,9 @@ static int __init rk_iommu_init(void)
{
int ret;
+ if (!of_find_matching_node(NULL, rk_iommu_dt_ids))
+ return 0;
+
ret = bus_set_iommu(&platform_bus_type, &rk_iommu_ops);
if (ret)
return ret;
@@ -1025,6 +1028,9 @@ static int __init rk_iommu_init(void)
}
static void __exit rk_iommu_exit(void)
{
+ if (!of_find_matching_node(NULL, rk_iommu_dt_ids))
+ return;
+
platform_driver_unregister(&rk_iommu_driver);
}
--
2.1.3
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