[PATCH 3/3] iommu: Validate device tree node in dev_iommu_enable

[Peng Fan (OSS)]

From: Peng Fan <peng.fan at nxp.com>

Similar to pinctrl_select_state(), add dev_has_ofnode() check before doing the
real work. Device(scmi_base.0) does not have a real device node, ofnode_null()
is assigned as the device tree node for scmi base protocol device:
'commit 7eb4eb541c14 ("firmware: scmi: install base protocol to SCMI agent")'

However with recent update in
'commit 0535e46d55d7 ("scripts/dtc: Update to upstream version v1.7.2-35-g52f07dcca47c")',
SPL panic in fdt_check_node_offset_()->fdt_next_tag(), because offset is -1
and SPL_OF_LIBFDT_ASSUME_MASK is 0xFF.

So need to validate device tree node.

Reported-by: Ye Li <ye.li at nxp.com>
Closes: https://lore.kernel.org/u-boot/939a9696-27fa-45a1-b428-feffe21ac6d5@oss.nxp.com/
Signed-off-by: Peng Fan <peng.fan at nxp.com>
---
 drivers/iommu/iommu-uclass.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/iommu/iommu-uclass.c b/drivers/iommu/iommu-uclass.c
index bb31cd519d2..31b40e5713a 100644
--- a/drivers/iommu/iommu-uclass.c
+++ b/drivers/iommu/iommu-uclass.c
@@ -79,6 +79,9 @@ int dev_iommu_enable(struct udevice *dev)
 	const struct iommu_ops *ops;
 	int i, count, ret = 0;
 
+	if (!dev_has_ofnode(dev))
+		return 0;
+
 	count = dev_count_phandle_with_args(dev, "iommus",
 					    "#iommu-cells", 0);
 	for (i = 0; i < count; i++) {

-- 
2.51.0