Re: [PATCH 1/5] drm/msm: Remove pm_runtime operations from msm_iommu

From: Vivek Gautam <vivek.gautam-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
To: Jordan Crouse <jcrouse-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
Cc: linux-arm-msm
	<linux-arm-msm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	freedreno
	<freedreno-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org>,
	dri-devel
	<dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org>
Subject: Re: [PATCH 1/5] drm/msm: Remove pm_runtime operations from msm_iommu
Date: Tue, 26 Jun 2018 15:05:03 +0530	[thread overview]
Message-ID: <CAFp+6iEzgOPs8rT4cDf5s65rr7EPSbhHo_c-o0YL+E+7PN9ySA@mail.gmail.com> (raw)
In-Reply-To: <20180619223006.31519-2-jcrouse-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>

On Wed, Jun 20, 2018 at 4:00 AM, Jordan Crouse <jcrouse@codeaurora.org> wrote:
> Now that the IOMMU is the master of it's own power we don't need to bring
> up the GPU to do IOMMU operations. This is good because bringing up a6xx
> requires the GMU so calling pm_runtime_get_sync() too early in the process
> gets us into some nasty circular dependency situations.
>
> Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
> ---
>  drivers/gpu/drm/msm/msm_iommu.c | 13 +------------
>  1 file changed, 1 insertion(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/msm_iommu.c b/drivers/gpu/drm/msm/msm_iommu.c
> index b23d33622f37..e80c79b3bb5c 100644
> --- a/drivers/gpu/drm/msm/msm_iommu.c
> +++ b/drivers/gpu/drm/msm/msm_iommu.c
> @@ -38,13 +38,8 @@ static int msm_iommu_attach(struct msm_mmu *mmu, const char * const *names,
>                             int cnt)
>  {
>         struct msm_iommu *iommu = to_msm_iommu(mmu);
> -       int ret;
>
> -       pm_runtime_get_sync(mmu->dev);
> -       ret = iommu_attach_device(iommu->domain, mmu->dev);
> -       pm_runtime_put_sync(mmu->dev);
> -
> -       return ret;
> +       return iommu_attach_device(iommu->domain, mmu->dev);
>  }
>
>  static void msm_iommu_detach(struct msm_mmu *mmu, const char * const *names,
> @@ -52,9 +47,7 @@ static void msm_iommu_detach(struct msm_mmu *mmu, const char * const *names,
>  {
>         struct msm_iommu *iommu = to_msm_iommu(mmu);
>
> -       pm_runtime_get_sync(mmu->dev);
>         iommu_detach_device(iommu->domain, mmu->dev);
> -       pm_runtime_put_sync(mmu->dev);
>  }
>
>  static int msm_iommu_map(struct msm_mmu *mmu, uint64_t iova,
> @@ -63,9 +56,7 @@ static int msm_iommu_map(struct msm_mmu *mmu, uint64_t iova,
>         struct msm_iommu *iommu = to_msm_iommu(mmu);
>         size_t ret;
>
> -//     pm_runtime_get_sync(mmu->dev);
>         ret = iommu_map_sg(iommu->domain, iova, sgt->sgl, sgt->nents, prot);
> -//     pm_runtime_put_sync(mmu->dev);
>         WARN_ON(ret < 0);
>
>         return (ret == len) ? 0 : -EINVAL;
> @@ -76,9 +67,7 @@ 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);
> -       pm_runtime_put_sync(mmu->dev);
>
>         return 0;
>  }

Looks good to me.
Reviewed-by: Vivek Gautam <vivek.gautam@codeaurora.org>

Best regards
Vivek

> --
> 2.17.1
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