From: Thierry Reding Date: Fri, 6 Feb 2015 11:44:07 +0100 Subject: [PATCH] iommu/rockchip: Play nice in multi-platform builds 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 Cc: Heiko Stuebner Cc: Daniel Kurtz Reviewed-by: Heiko Stuebner Tested-by: Heiko Stuebner Signed-off-by: Thierry Reding Signed-off-by: Joerg Roedel --- 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; -- 2.1.0