Re: [PATCH v9 02/15] iommu/mediatek-v1: Free the existed fwspec if the master dev already has

[AngeloGioacchino Del Regno]

Il 12/11/21 11:54, Yong Wu ha scritto:
> 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>
> Tested-by: Frank Wunderlich <frank-w@xxxxxxxxxxxxxxx> # BPI-R2/MT7623
> Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx>

Acked-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>