[PATCH v1] iommu/ipmmu-vmsa: Don't register as BUS IOMMU if machine doesn't have IPMMU-VMSA

[Dmitry Osipenko]

This fixes kernel crashing on NVIDIA Tegra if kernel is compiled in
a multiplatform configuration and IPMMU-VMSA driver is enabled.

Cc: <stable@xxxxxxxxxxxxxxx> # v3.20+
Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
---
 drivers/iommu/ipmmu-vmsa.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/iommu/ipmmu-vmsa.c b/drivers/iommu/ipmmu-vmsa.c
index 9e8495762bc8..78c50db9cd71 100644
--- a/drivers/iommu/ipmmu-vmsa.c
+++ b/drivers/iommu/ipmmu-vmsa.c
@@ -1109,12 +1109,19 @@ static struct platform_driver ipmmu_driver = {
 
 static int __init ipmmu_init(void)
 {
+	struct device_node *np;
 	static bool setup_done;
 	int ret;
 
 	if (setup_done)
 		return 0;
 
+	np = of_find_matching_node(NULL, ipmmu_of_ids);
+	if (!np)
+		return 0;
+
+	of_node_put(np);
+
 	ret = platform_driver_register(&ipmmu_driver);
 	if (ret < 0)
 		return ret;
-- 
2.18.0