On Tue, 2021-08-24 at 15:35 +0800, Hsin-Yi Wang wrote:

On Fri, Aug 13, 2021 at 3:03 PM Yong Wu [off-list ref] wrote:

quoted

For MM IOMMU, We always add device link between smi-common and
IOMMU HW.
In mt8195, we add smi-sub-common. Thus, if the node is sub-common,
we still
need find again to get smi-common, then do device link.

Signed-off-by: Yong Wu <yong.wu@mediatek.com>
---
 drivers/iommu/mtk_iommu.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index a4479916ad33..a72241724adb 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c

@@ -845,6 +845,17 @@ static int mtk_iommu_mm_dts_parse(struct

device *dev,
        if (!smicomm_node)
                return -EINVAL;

+       /* Find smi-common again if this is smi-sub-common */
+       if (of_property_read_bool(smicomm_node,
"mediatek,smi_sub_common")) {
+               of_node_put(smicomm_node); /* put the sub common */
+
+               smicomm_node = of_parse_phandle(smicomm_node,
"mediatek,smi", 0);

This only checks 1 level here, and does not check if the mediatek,smi
of a sub-common node is not another sub-common node.
So maybe add a check that the updated node here doesn't have
mediatek,smi_sub_common property.

Yes. Currently there are only 2 levels. we could confirm if it is sub-
common from if it has "mediatek,smi", then "mediatek,smi_sub_common" is
unnecessary.

Will fix in the next version.

quoted

+               if (!smicomm_node) {
+                       dev_err(dev, "sub-comm has no common.\n");
+                       return -EINVAL;
+               }
+       }
+
        plarbdev = of_find_device_by_node(smicomm_node);
        of_node_put(smicomm_node);
        data->smicomm_dev = &plarbdev->dev;
--
2.18.0
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