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From: Thierry Reding <treding at 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 <kwizart at gmail.com>
Cc: Heiko Stuebner <heiko at sntech.de>
Cc: Daniel Kurtz <djkurtz at chromium.org>
Reviewed-by: Heiko Stuebner <heiko at sntech.de>
Tested-by: Heiko Stuebner <heiko at sntech.de>
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/rockchip-iommu.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.c
index 6a8b1ec4a48a..9f74fddcd304 100644
--- a/drivers/iommu/rockchip-iommu.c
+++ b/drivers/iommu/rockchip-iommu.c
@@ -1015,8 +1015,15 @@ static struct platform_driver rk_iommu_driver = {
static int __init rk_iommu_init(void)
{
+ struct device_node *np;
int ret;
+ np = of_find_matching_node(NULL, rk_iommu_dt_ids);
+ if (!np)
+ return 0;
+
+ of_node_put(np);
+
ret = bus_set_iommu(&platform_bus_type, &rk_iommu_ops);
if (ret)
return ret;
--
2.1.3
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