Re: [Xen-devel] [PATCH v1] swiotlb-xen: implement xen_swiotlb_dma_mmap callback

[Oleksandr Dmytryshyn <oleksandr.dmytryshyn@xxxxxxxxxxxxxxx>]

Hi, Stefano.

Can You please confirm that this implementation of the
xen_swiotlb_dma_mmap is correct?

Oleksandr Dmytryshyn | Product Engineering and Development
GlobalLogic
M +38.067.382.2525
www.globallogic.com

http://www.globallogic.com/email_disclaimer.txt


On Tue, Apr 8, 2014 at 3:08 PM, Oleksandr Dmytryshyn
<oleksandr.dmytryshyn@xxxxxxxxxxxxxxx> wrote:
> From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
>
> This function creates userspace mapping for the DMA-coherent memory.
>
> Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> Signed-off-by: Oleksandr Dmytryshyn <oleksandr.dmytryshyn@xxxxxxxxxxxxxxx>
> ---
>  arch/arm/xen/mm.c         |  1 +
>  drivers/xen/swiotlb-xen.c | 36 ++++++++++++++++++++++++++++++++++++
>  include/xen/swiotlb-xen.h |  5 +++++
>  3 files changed, 42 insertions(+)
>
> diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c
> index b0e77de..91408b1 100644
> --- a/arch/arm/xen/mm.c
> +++ b/arch/arm/xen/mm.c
> @@ -48,6 +48,7 @@ static struct dma_map_ops xen_swiotlb_dma_ops = {
>         .sync_sg_for_device = xen_swiotlb_sync_sg_for_device,
>         .map_sg = xen_swiotlb_map_sg_attrs,
>         .unmap_sg = xen_swiotlb_unmap_sg_attrs,
> +       .mmap = xen_swiotlb_dma_mmap,
>         .map_page = xen_swiotlb_map_page,
>         .unmap_page = xen_swiotlb_unmap_page,
>         .dma_supported = xen_swiotlb_dma_supported,
> diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
> index 5403855..acf0c06 100644
> --- a/drivers/xen/swiotlb-xen.c
> +++ b/drivers/xen/swiotlb-xen.c
> @@ -407,6 +407,42 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, 
> struct page *page,
>  EXPORT_SYMBOL_GPL(xen_swiotlb_map_page);
>
>  /*
> + * Create userspace mapping for the DMA-coherent memory.
> + */
> +int xen_swiotlb_dma_mmap(struct device *dev, struct vm_area_struct *vma,
> +                        void *cpu_addr, dma_addr_t dma_addr, size_t size,
> +                        struct dma_attrs *attrs)
> +{
> +       int ret = -ENXIO;
> +       unsigned long nr_vma_pages = (vma->vm_end - vma->vm_start) >> 
> PAGE_SHIFT;
> +       unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
> +       unsigned long pfn = PFN_DOWN(xen_bus_to_phys(dma_addr));
> +       unsigned long off = vma->vm_pgoff;
> +       pgprot_t prot = vma->vm_page_prot;
> +
> +       prot = dma_get_attr(DMA_ATTR_WRITE_COMBINE, attrs) ?
> +                           pgprot_writecombine(prot) :
> +                           pgprot_dmacoherent(prot);
> +
> +       vma->vm_page_prot = prot;
> +
> +       if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret))
> +               return ret;
> +
> +       if (off < nr_pages && nr_vma_pages <= (nr_pages - off)) {
> +               ret = remap_pfn_range(vma, vma->vm_start,
> +                                       pfn + off,
> +                                       vma->vm_end - vma->vm_start,
> +                                       vma->vm_page_prot);
> +       }
> +
> +       return ret;
> +}
> +EXPORT_SYMBOL_GPL(xen_swiotlb_dma_mmap);
> +
> +/*
>   * Unmap a single streaming mode DMA translation.  The dma_addr and size must
>   * match what was provided for in a previous xen_swiotlb_map_page call.  All
>   * other usages are undefined.
> diff --git a/include/xen/swiotlb-xen.h b/include/xen/swiotlb-xen.h
> index 7b64465..930fa94 100644
> --- a/include/xen/swiotlb-xen.h
> +++ b/include/xen/swiotlb-xen.h
> @@ -15,6 +15,11 @@ xen_swiotlb_free_coherent(struct device *hwdev, size_t 
> size,
>                           void *vaddr, dma_addr_t dma_handle,
>                           struct dma_attrs *attrs);
>
> +extern int
> +xen_swiotlb_dma_mmap(struct device *dev, struct vm_area_struct *vma,
> +                    void *cpu_addr, dma_addr_t dma_addr, size_t size,
> +                    struct dma_attrs *attrs);
> +
>  extern dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
>                                        unsigned long offset, size_t size,
>                                        enum dma_data_direction dir,
> --
> 1.8.2.rc2
>

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel