linux-kernel - Re: [PATCH 0/3] iommu/drm/msm: Allow non-coherent masters to use system cache

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Message-ID: <20210728140052.GB22887@mms-0441>
Date:   Wed, 28 Jul 2021 17:00:53 +0300
From:   Georgi Djakov <djakov@...nel.org>
To:     Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>
Cc:     Will Deacon <will@...nel.org>, Robin Murphy <robin.murphy@....com>,
        Joerg Roedel <joro@...tes.org>,
        Jordan Crouse <jcrouse@...eaurora.org>,
        Rob Clark <robdclark@...il.com>,
        Akhil P Oommen <akhilpo@...eaurora.org>,
        isaacm@...eaurora.org, iommu@...ts.linux-foundation.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-arm-msm@...r.kernel.org,
        freedreno <freedreno@...ts.freedesktop.org>,
        Kristian H Kristensen <hoegsberg@...gle.com>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH 0/3] iommu/drm/msm: Allow non-coherent masters to use
 system cache

On Mon, Jan 11, 2021 at 07:45:02PM +0530, Sai Prakash Ranjan wrote:
> commit ecd7274fb4cd ("iommu: Remove unused IOMMU_SYS_CACHE_ONLY flag")
> removed unused IOMMU_SYS_CACHE_ONLY prot flag and along with it went
> the memory type setting required for the non-coherent masters to use
> system cache. Now that system cache support for GPU is added, we will
> need to set the right PTE attribute for GPU buffers to be sys cached.
> Without this, the system cache lines are not allocated for GPU.
> 
> So the patches in this series introduces a new prot flag IOMMU_LLC,
> renames IO_PGTABLE_QUIRK_ARM_OUTER_WBWA to IO_PGTABLE_QUIRK_PTW_LLC
> and makes GPU the user of this protection flag.

Hi Sai,

Thank you for the patchset! Are you planning to refresh it, as it does
not apply anymore?

Thanks,
Georgi

> 
> The series slightly depends on following 2 patches posted earlier and
> is based on msm-next branch:
>  * https://lore.kernel.org/patchwork/patch/1363008/
>  * https://lore.kernel.org/patchwork/patch/1363010/
> 
> Sai Prakash Ranjan (3):
>   iommu/io-pgtable: Rename last-level cache quirk to
>     IO_PGTABLE_QUIRK_PTW_LLC
>   iommu/io-pgtable-arm: Add IOMMU_LLC page protection flag
>   drm/msm: Use IOMMU_LLC page protection flag to map gpu buffers
> 
>  drivers/gpu/drm/msm/adreno/a6xx_gpu.c   | 3 +++
>  drivers/gpu/drm/msm/adreno/adreno_gpu.c | 2 +-
>  drivers/gpu/drm/msm/msm_iommu.c         | 3 +++
>  drivers/gpu/drm/msm/msm_mmu.h           | 4 ++++
>  drivers/iommu/io-pgtable-arm.c          | 9 ++++++---
>  include/linux/io-pgtable.h              | 6 +++---
>  include/linux/iommu.h                   | 6 ++++++
>  7 files changed, 26 insertions(+), 7 deletions(-)
> 
> 
> base-commit: 00fd44a1a4700718d5d962432b55c09820f7e709
> -- 
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
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