On Tue, Sep 15, 2015 at 12:10:56PM -0500, Will Davis wrote:
> Add swiotlb stub of the 'map_peer_resource' DMA operation.
>
> Signed-off-by: Will Davis <wdavis@xxxxxxxxxx>
> ---
> include/linux/swiotlb.h | 8 ++++++++
> lib/swiotlb.c | 17 +++++++++++++++++
> 2 files changed, 25 insertions(+)
>
> diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
> index e7a018e..872463a 100644
> --- a/include/linux/swiotlb.h
> +++ b/include/linux/swiotlb.h
> @@ -87,6 +87,14 @@ swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
> int nelems, enum dma_data_direction dir,
> struct dma_attrs *attrs);
>
> +#ifdef CONFIG_HAS_DMA_P2P
> +extern dma_peer_addr_t
> +swiotlb_map_peer_resource(struct device *hwdev, struct device *hwpeer,
> + struct resource *res, unsigned long offset,
> + size_t size, enum dma_data_direction dir,
> + struct dma_attrs *attrs);
> +#endif
> +
> extern void
> swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,
> size_t size, enum dma_data_direction dir);
> diff --git a/lib/swiotlb.c b/lib/swiotlb.c
> index 76f29ec..61522a7 100644
> --- a/lib/swiotlb.c
> +++ b/lib/swiotlb.c
> @@ -945,6 +945,23 @@ swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
> }
> EXPORT_SYMBOL(swiotlb_unmap_sg);
>
> +#ifdef CONFIG_HAS_DMA_P2P
> +/*
> + * Maps a single region from a peer device's resource for DMA streaming. This
> + * is currently unimplemented because there's no bounce buffer abstraction for
> + * peer mappings.
> + */
> +dma_peer_addr_t
> +swiotlb_map_peer_resource(struct device *hwdev, struct device *hwpeer,
> + struct resource *res, unsigned long offset,
> + size_t size, enum dma_data_direction dir,
> + struct dma_attrs *attrs)
> +{
> + return phys_to_dma(hwdev, io_tlb_overflow_buffer);
That seems to be implemented :-)
Did you mean to return DMA_ERROR_CODE instead?
> +}
> +EXPORT_SYMBOL(swiotlb_map_peer_resource);
> +#endif
> +
> /*
> * Make physical memory consistent for a set of streaming mode DMA translations
> * after a transfer.
> --
> 2.5.1
>
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