When the iommu master device enters of_iommu_xlate, the ops may be
NULL(iommu dev is defered), then it will initialize the fwspec here:
[<c0c9c5bc>] (dev_iommu_fwspec_set) from [<c06bda80>]
(iommu_fwspec_init+0xbc/0xd4)
[<c06bd9c4>] (iommu_fwspec_init) from [<c06c0db4>]
(of_iommu_xlate+0x7c/0x12c)
[<c06c0d38>] (of_iommu_xlate) from [<c06c10e8>]
(of_iommu_configure+0x144/0x1e8)
BUT the mtk_iommu_v1.c only supports arm32, the probing flow still is a bit
weird. We always expect create the fwspec internally. otherwise it will
enter here and return fail.
static int mtk_iommu_create_mapping(struct device *dev,
struct of_phandle_args *args)
{
...
if (!fwspec) {
....
} else if (dev_iommu_fwspec_get(dev)->ops != &mtk_iommu_ops) {
>>>>>>>>>>Enter here. return fail.<<<<<<<<<<<<
return -EINVAL;
}
...
}
Thus, Free the existed fwspec if the master device already has fwspec.
This issue is reported at:
https://lore.kernel.org/linux-mediatek/trinity-7d9ebdc9-4849-4d93-bfb5-429dcb4ee449-1626253158870@3c-app-gmx-bs01/
Reported-by: Frank Wunderlich <frank-w@xxxxxxxxxxxxxxx>
Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx>
---
drivers/iommu/mtk_iommu_v1.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c
index be22fcf988ce..1467ba1e4417 100644
--- a/drivers/iommu/mtk_iommu_v1.c
+++ b/drivers/iommu/mtk_iommu_v1.c
@@ -425,6 +425,15 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev)
struct mtk_iommu_data *data;
int err, idx = 0;
+ /*
+ * In the deferred case, free the existed fwspec.
+ * Always initialize the fwspec internally.
+ */
+ if (fwspec) {
+ iommu_fwspec_free(dev);
+ fwspec = dev_iommu_fwspec_get(dev);
+ }
+
while (!of_parse_phandle_with_args(dev->of_node, "iommus",
"#iommu-cells",
idx, &iommu_spec)) {
--
2.18.0
