Re: [PATCH] drm/msm: Only enable A6xx LLCC code on A6xx

[Jordan Crouse]

On Mon, Jan 04, 2021 at 08:30:41PM +0100, Konrad Dybcio wrote:
> Using this code on A5xx (and probably older too) causes a
> smmu bug.
> 
> Fixes: 474dadb8b0d5 ("drm/msm/a6xx: Add support for using system cache(LLC)")
> Signed-off-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxxxxxx>
> Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxxx>

Yep, I can see how this would be not ideal.

Reviewed-by: Jordan Crouse <jcrouse@xxxxxxxxxxxxxx>

> ---
>  drivers/gpu/drm/msm/adreno/adreno_gpu.c | 21 ++++++++++++---------
>  drivers/gpu/drm/msm/adreno/adreno_gpu.h |  5 +++++
>  2 files changed, 17 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> index 6cf9975e951e..f09175698827 100644
> --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> @@ -191,8 +191,6 @@ adreno_iommu_create_address_space(struct msm_gpu *gpu,
>  		struct platform_device *pdev)
>  {
>  	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> -	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> -	struct io_pgtable_domain_attr pgtbl_cfg;
>  	struct iommu_domain *iommu;
>  	struct msm_mmu *mmu;
>  	struct msm_gem_address_space *aspace;
> @@ -202,13 +200,18 @@ adreno_iommu_create_address_space(struct msm_gpu *gpu,
>  	if (!iommu)
>  		return NULL;
>  
> -	/*
> -	 * This allows GPU to set the bus attributes required to use system
> -	 * cache on behalf of the iommu page table walker.
> -	 */
> -	if (!IS_ERR(a6xx_gpu->htw_llc_slice)) {
> -		pgtbl_cfg.quirks = IO_PGTABLE_QUIRK_ARM_OUTER_WBWA;
> -		iommu_domain_set_attr(iommu, DOMAIN_ATTR_IO_PGTABLE_CFG, &pgtbl_cfg);
> +
> +	if (adreno_is_a6xx(adreno_gpu)) {
> +		struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> +		struct io_pgtable_domain_attr pgtbl_cfg;
> +		/*
> +		* This allows GPU to set the bus attributes required to use system
> +		* cache on behalf of the iommu page table walker.
> +		*/
> +		if (!IS_ERR(a6xx_gpu->htw_llc_slice)) {
> +			pgtbl_cfg.quirks = IO_PGTABLE_QUIRK_ARM_OUTER_WBWA;
> +			iommu_domain_set_attr(iommu, DOMAIN_ATTR_IO_PGTABLE_CFG, &pgtbl_cfg);
> +		}
>  	}
>  
>  	mmu = msm_iommu_new(&pdev->dev, iommu);
> diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.h b/drivers/gpu/drm/msm/adreno/adreno_gpu.h
> index 4574d85c5680..08421fa54a50 100644
> --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.h
> +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.h
> @@ -226,6 +226,11 @@ static inline int adreno_is_a540(struct adreno_gpu *gpu)
>  	return gpu->revn == 540;
>  }
>  
> +static inline bool adreno_is_a6xx(struct adreno_gpu *gpu)
> +{
> +	return ((gpu->revn < 700 && gpu->revn > 599));
> +}
> +
>  static inline int adreno_is_a618(struct adreno_gpu *gpu)
>  {
>         return gpu->revn == 618;
> -- 
> 2.29.2
> 

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