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iommu/rockchip: Play nice in multi-platform builds

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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@gmail.com>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Thierry Reding 2015-02-06 11:44:07 +01:00 committed by Joerg Roedel
parent f938aab2c4
commit 425061b0f5
1 changed files with 7 additions and 0 deletions
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7
drivers/iommu/rockchip-iommu.c
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@ -1015,8 +1015,15 @@ static struct platform_driver rk_iommu_driver = {
static int __init rk_iommu_init(void) static int __init rk_iommu_init(void)
{ {
struct device_node *np;
int ret; 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); ret = bus_set_iommu(&platform_bus_type, &rk_iommu_ops);
if (ret) if (ret)
return ret; return ret;