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

[Oleksandr Dmytryshyn <oleksandr.dmytryshyn@xxxxxxxxxxxxxxx>]

On Fri, May 9, 2014 at 5:50 PM, Stefano Stabellini
<stefano.stabellini@xxxxxxxxxxxxx> wrote:
> On Mon, 28 Apr 2014, Oleksandr Dmytryshyn wrote:
>> Hi, Stefano.
>>
>> Can You please confirm that this implementation of the
>> xen_swiotlb_dma_mmap is correct?
>
> Hi Oleksandr,
> sorry for the delay in my reply.
>
> The patch is OK. It needs an Ack from the other Xen x86 maintainers too.
> See this thread as reference:
>
> http://marc.info/?l=xen-devel&m=139586321124533
>
>
>> 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
>> >
>>

Hi, Stefano.

Thank You for reply.

I'll look into that thread.

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

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

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