Re: [PATCH 2/5] drm/panfrost: Split panfrost_mmu_map SG list mapping to its own function

[Steven Price <steven.price@arm.com>]

On 17/07/2019 19:33, Rob Herring wrote:
> In preparation to create partial GPU mappings of BOs on page faults,
> split out the SG list handling of panfrost_mmu_map().
> 
> Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
> Cc: Boris Brezillon <boris.brezillon@collabora.com>
> Cc: Robin Murphy <robin.murphy@arm.com>
> Cc: Steven Price <steven.price@arm.com>
> Cc: Alyssa Rosenzweig <alyssa@rosenzweig.io>
> Signed-off-by: Rob Herring <robh@kernel.org>

Reviewed-by: Steven Price <steven.price@arm.com>

> ---
>  drivers/gpu/drm/panfrost/panfrost_mmu.c | 52 +++++++++++++++----------
>  1 file changed, 31 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c b/drivers/gpu/drm/panfrost/panfrost_mmu.c
> index f502e91be42a..5383b837f04b 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
> @@ -167,27 +167,13 @@ static size_t get_pgsize(u64 addr, size_t size)
>  	return SZ_2M;
>  }
>  
> -int panfrost_mmu_map(struct panfrost_gem_object *bo)
> +static int mmu_map_sg(struct panfrost_device *pfdev, u64 iova,
> +		      int prot, struct sg_table *sgt)
>  {
> -	struct drm_gem_object *obj = &bo->base.base;
> -	struct panfrost_device *pfdev = to_panfrost_device(obj->dev);
> -	struct io_pgtable_ops *ops = pfdev->mmu->pgtbl_ops;
> -	u64 iova = bo->node.start << PAGE_SHIFT;
>  	unsigned int count;
>  	struct scatterlist *sgl;
> -	struct sg_table *sgt;
> -	int ret;
> -
> -	if (WARN_ON(bo->is_mapped))
> -		return 0;
> -
> -	sgt = drm_gem_shmem_get_pages_sgt(obj);
> -	if (WARN_ON(IS_ERR(sgt)))
> -		return PTR_ERR(sgt);
> -
> -	ret = pm_runtime_get_sync(pfdev->dev);
> -	if (ret < 0)
> -		return ret;
> +	struct io_pgtable_ops *ops = pfdev->mmu->pgtbl_ops;
> +	u64 start_iova = iova;
>  
>  	mutex_lock(&pfdev->mmu->lock);
>  
> @@ -200,18 +186,42 @@ int panfrost_mmu_map(struct panfrost_gem_object *bo)
>  		while (len) {
>  			size_t pgsize = get_pgsize(iova | paddr, len);
>  
> -			ops->map(ops, iova, paddr, pgsize, IOMMU_WRITE | IOMMU_READ);
> +			ops->map(ops, iova, paddr, pgsize, prot);
>  			iova += pgsize;
>  			paddr += pgsize;
>  			len -= pgsize;
>  		}
>  	}
>  
> -	mmu_hw_do_operation(pfdev, 0, bo->node.start << PAGE_SHIFT,
> -			    bo->node.size << PAGE_SHIFT, AS_COMMAND_FLUSH_PT);
> +	mmu_hw_do_operation(pfdev, 0, start_iova, iova - start_iova,
> +			    AS_COMMAND_FLUSH_PT);
>  
>  	mutex_unlock(&pfdev->mmu->lock);
>  
> +	return 0;
> +}
> +
> +int panfrost_mmu_map(struct panfrost_gem_object *bo)
> +{
> +	struct drm_gem_object *obj = &bo->base.base;
> +	struct panfrost_device *pfdev = to_panfrost_device(obj->dev);
> +	struct sg_table *sgt;
> +	int ret;
> +	int prot = IOMMU_READ | IOMMU_WRITE;
> +
> +	if (WARN_ON(bo->is_mapped))
> +		return 0;
> +
> +	sgt = drm_gem_shmem_get_pages_sgt(obj);
> +	if (WARN_ON(IS_ERR(sgt)))
> +		return PTR_ERR(sgt);
> +
> +	ret = pm_runtime_get_sync(pfdev->dev);
> +	if (ret < 0)
> +		return ret;
> +
> +	mmu_map_sg(pfdev, bo->node.start << PAGE_SHIFT, prot, sgt);
> +
>  	pm_runtime_mark_last_busy(pfdev->dev);
>  	pm_runtime_put_autosuspend(pfdev->dev);
>  	bo->is_mapped = true;
> 

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