[RFC PATCH v6 2/7] dma: Add simple dma_noop_mmap

[Alexandre Torgue]

Hi,

Apologize for this bad sent.
Please forget it.

regards

On 02/03/2017 10:20 AM, Alexandre TORGUE wrote:
> From: Vladimir Murzin <vladimir.murzin at arm.com>
>
> This patch adds a simple implementation of mmap to dma_noop_ops.
>
> Cc: Joerg Roedel <jroedel at suse.de>
> Cc: Christian Borntraeger <borntraeger at de.ibm.com>
> Reported-by: Benjamin Gaignard <benjamin.gaignard at linaro.org>
> Tested-by: Benjamin Gaignard <benjamin.gaignard at linaro.org>
> Tested-by: Andras Szemzo <sza at esh.hu>
> Signed-off-by: Vladimir Murzin <vladimir.murzin at arm.com>
> ---
>  lib/dma-noop.c | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
>
> diff --git a/lib/dma-noop.c b/lib/dma-noop.c
> index a14eee5..70504eb 100644
> --- a/lib/dma-noop.c
> +++ b/lib/dma-noop.c
> @@ -66,6 +66,26 @@ static int dma_noop_supported(struct device *dev, u64 mask)
>  	return 1;
>  }
>
> +static int dma_noop_mmap(struct device *dev, struct vm_area_struct *vma,
> +			 void *cpu_addr, dma_addr_t dma_addr, size_t size,
> +			 unsigned long attrs)
> +{
> +	unsigned long user_count = vma_pages(vma);
> +	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
> +	unsigned long pfn = page_to_pfn(virt_to_page(cpu_addr));
> +	unsigned long off = vma->vm_pgoff;
> +	int ret = -ENXIO;
> +
> +	if (off < count && user_count <= (count - off)) {
> +		ret = remap_pfn_range(vma, vma->vm_start,
> +				      pfn + off,
> +				      user_count << PAGE_SHIFT,
> +				      vma->vm_page_prot);
> +	}
> +
> +	return ret;
> +}
> +
>  struct dma_map_ops dma_noop_ops = {
>  	.alloc			= dma_noop_alloc,
>  	.free			= dma_noop_free,
> @@ -73,6 +93,7 @@ struct dma_map_ops dma_noop_ops = {
>  	.map_sg			= dma_noop_map_sg,
>  	.mapping_error		= dma_noop_mapping_error,
>  	.dma_supported		= dma_noop_supported,
> +	.mmap			= dma_noop_mmap,
>  };
>
>  EXPORT_SYMBOL(dma_noop_ops);
> -- 2.0.0
>
>
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