On Thu, Aug 17, 2017 at 8:56 AM, Joerg Roedel <joro@xxxxxxxxxx> wrote:
> From: Joerg Roedel <jroedel@xxxxxxx>
>
> The map and unmap functions of the IOMMU-API changed their
> semantics: They do no longer guarantee that the hardware
> TLBs are synchronized with the page-table updates they made.
>
> To make conversion easier, new synchronized functions have
> been introduced which give these guarantees again until the
> code is converted to use the new TLB-flush interface of the
> IOMMU-API, which allows certain optimizations.
>
> But for now, just convert this code to use the synchronized
> functions so that it will behave as before.
I like the idea of decoupling tlb inv with map (well that doesn't
really effect any recent hw) and unmap (which does need tlb flush)..
and for a gpu driver it should be pretty easy to back up unmaps.
I did slightly prefer adding a new iommu_{map,unmap}_async() rather
than changing semantics of existing API, but either way:
Acked-by: Rob Clark <robdclark@xxxxxxxxx>
> Cc: Rob Clark <robdclark@xxxxxxxxx>
> Cc: David Airlie <airlied@xxxxxxxx>
> Cc: linux-arm-msm@xxxxxxxxxxxxxxx
> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> Cc: freedreno@xxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
> ---
> drivers/gpu/drm/msm/msm_iommu.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/msm_iommu.c b/drivers/gpu/drm/msm/msm_iommu.c
> index b23d336..b3525b7 100644
> --- a/drivers/gpu/drm/msm/msm_iommu.c
> +++ b/drivers/gpu/drm/msm/msm_iommu.c
> @@ -64,7 +64,8 @@ static int msm_iommu_map(struct msm_mmu *mmu, uint64_t iova,
> size_t ret;
>
> // pm_runtime_get_sync(mmu->dev);
> - ret = iommu_map_sg(iommu->domain, iova, sgt->sgl, sgt->nents, prot);
> + ret = iommu_map_sg_sync(iommu->domain, iova, sgt->sgl,
> + sgt->nents, prot);
> // pm_runtime_put_sync(mmu->dev);
> WARN_ON(ret < 0);
>
> @@ -77,7 +78,7 @@ static int msm_iommu_unmap(struct msm_mmu *mmu, uint64_t iova,
> struct msm_iommu *iommu = to_msm_iommu(mmu);
>
> pm_runtime_get_sync(mmu->dev);
> - iommu_unmap(iommu->domain, iova, len);
> + iommu_unmap_sync(iommu->domain, iova, len);
> pm_runtime_put_sync(mmu->dev);
>
> return 0;
> --
> 2.7.4
>
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