[PATCH v7 5/6] iommu/mediatek: Improve safety for mediatek,smi property in larb nodes

From: Yong Wu
Date: Mon Oct 17 2022 - 22:44:18 EST


No functional change. Just improve safety from dts.

All the larbs that connect to one IOMMU must connect with the same
smi-common. This patch checks all the mediatek,smi property for each
larb, If their mediatek,smi are different, it will return fails.
Also avoid there is no available smi-larb nodes.

Suggested-by: Guenter Roeck <groeck@xxxxxxxxxxxx>
Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
---
drivers/iommu/mtk_iommu.c | 53 +++++++++++++++++++++++++++------------
1 file changed, 37 insertions(+), 16 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 9cbff48f03c0..f7ac102e343f 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -1042,7 +1042,7 @@ static const struct component_master_ops mtk_iommu_com_ops = {
static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **match,
struct mtk_iommu_data *data)
{
- struct device_node *larbnode, *smicomm_node, *smi_subcomm_node;
+ struct device_node *larbnode, *frst_avail_smicomm_node = NULL;
struct platform_device *plarbdev, *pcommdev;
struct device_link *link;
int i, larb_nr, ret;
@@ -1054,6 +1054,7 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
return -EINVAL;

for (i = 0; i < larb_nr; i++) {
+ struct device_node *smicomm_node, *smi_subcomm_node;
u32 id;

larbnode = of_parse_phandle(dev->of_node, "mediatek,larbs", i);
@@ -1094,27 +1095,47 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m
goto err_larbdev_put;
}

+ /* Get smi-(sub)-common dev from the last larb. */
+ smi_subcomm_node = of_parse_phandle(larbnode, "mediatek,smi", 0);
+ if (!smi_subcomm_node) {
+ ret = -EINVAL;
+ goto err_larbdev_put;
+ }
+
+ /*
+ * It may have two level smi-common. the node is smi-sub-common if it
+ * has a new mediatek,smi property. otherwise it is smi-commmon.
+ */
+ smicomm_node = of_parse_phandle(smi_subcomm_node, "mediatek,smi", 0);
+ if (smicomm_node)
+ of_node_put(smi_subcomm_node);
+ else
+ smicomm_node = smi_subcomm_node;
+
+ /*
+ * All the larbs that connect to one IOMMU must connect with the same
+ * smi-common.
+ */
+ if (!frst_avail_smicomm_node) {
+ frst_avail_smicomm_node = smicomm_node;
+ } else if (frst_avail_smicomm_node != smicomm_node) {
+ dev_err(dev, "mediatek,smi property is not right @larb%d.", id);
+ of_node_put(smicomm_node);
+ ret = -EINVAL;
+ goto err_larbdev_put;
+ } else {
+ of_node_put(smicomm_node);
+ }
+
component_match_add(dev, match, component_compare_dev, &plarbdev->dev);
platform_device_put(plarbdev);
}

- /* Get smi-(sub)-common dev from the last larb. */
- smi_subcomm_node = of_parse_phandle(larbnode, "mediatek,smi", 0);
- if (!smi_subcomm_node)
+ if (!frst_avail_smicomm_node)
return -EINVAL;

- /*
- * It may have two level smi-common. the node is smi-sub-common if it
- * has a new mediatek,smi property. otherwise it is smi-commmon.
- */
- smicomm_node = of_parse_phandle(smi_subcomm_node, "mediatek,smi", 0);
- if (smicomm_node)
- of_node_put(smi_subcomm_node);
- else
- smicomm_node = smi_subcomm_node;
-
- pcommdev = of_find_device_by_node(smicomm_node);
- of_node_put(smicomm_node);
+ pcommdev = of_find_device_by_node(frst_avail_smicomm_node);
+ of_node_put(frst_avail_smicomm_node);
if (!pcommdev)
return -ENODEV;
data->smicomm_dev = &pcommdev->dev;
--
2.18.0