[PATCH v9 2/7] iommu/mediatek: Fix two IOMMU share pagetable issue
AngeloGioacchino Del Regno
angelogioacchino.delregno at collabora.com
Fri Mar 17 02:34:00 PDT 2023
Il 17/03/23 09:55, Yong Wu ha scritto:
> From: "Chengci.Xu" <chengci.xu at mediatek.com>
>
> Prepare for mt8188 to fix a two IOMMU HWs share pagetable issue.
>
> We have two MM IOMMU HWs in mt8188, one is VPP-IOMMU, another is VDO-IOMMU.
> The 2 MM IOMMU HWs share pagetable don't work in this case:
> a) VPP-IOMMU probe firstly.
> b) VDO-IOMMU probe.
> c) The master for VDO-IOMMU probe (means frstdata is vpp-iommu).
> d) The master in another domain probe. No matter it is vdo or vpp.
> Then it still create a new pagetable in step d). The problem is
> "frstdata->bank[0]->m4u_dom" was not initialized. Then when d) enter, it
> still create a new one.
>
> In this patch, we create a new variable "share_dom" for this share
> pgtable case, it should be helpful for readable. and put all the share
> pgtable logic in the mtk_iommu_domain_finalise.
>
> In mt8195, the master of VPP-IOMMU probes before than VDO-IOMMU
> from its dtsi node sequence, we don't see this issue in it. Prepare for
> mt8188.
>
> Signed-off-by: Chengci.Xu <chengci.xu at mediatek.com>
> Signed-off-by: Yong Wu <yong.wu at mediatek.com>
I'm not sure whether this is *not* a fix... if a specific platform wasn't
affected, this may still be a logic mistake... to be cautious, I would
still add a Fixes tag to this one.
Otherwise, I would reword the commit title and remove the "Fix" word, so
that it would look something like...
iommu/mediatek: Prepare for pagetables domain sharing
I'm sorry for noticing that only at v9, but the previous versions had a bit
more stuff to address and couldn't really focus on analyzing this one.
If there's anything I've misunderstood about this patch, please feel free
to explain.
Regards,
Angelo
More information about the linux-arm-kernel
mailing list