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-bfb5-429dc...
Reported-by: Frank Wunderlich frank-w@public-files.de Signed-off-by: Yong Wu yong.wu@mediatek.com --- No need fix tag, since it is ok before this cleanup patchset. the issue may be revealed by the patch adding probe_defer what adjust the device probing sequency. --- 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 778e66f5f1aa..6861eeab182d 100644 --- a/drivers/iommu/mtk_iommu_v1.c +++ b/drivers/iommu/mtk_iommu_v1.c @@ -426,6 +426,15 @@ 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 if the dev already has, + * 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)) {