On Tue, Jun 25, 2013 at 11:12:15AM +0100, Hiroshi Doyu wrote:
> Hi Will,
Hi Hiroshi,
> On Mon, 10 Jun 2013 20:34:39 +0200
> Will Deacon <will.deacon@xxxxxxx> wrote:
> ...
> > @@ -1636,13 +1636,27 @@ static dma_addr_t arm_coherent_iommu_map_page(struct device *dev, struct page *p
> > {
> > struct dma_iommu_mapping *mapping = dev->archdata.mapping;
> > dma_addr_t dma_addr;
> > - int ret, len = PAGE_ALIGN(size + offset);
> > + int ret, prot, len = PAGE_ALIGN(size + offset);
> >
> > dma_addr = __alloc_iova(mapping, len);
> > if (dma_addr == DMA_ERROR_CODE)
> > return dma_addr;
> >
> > - ret = iommu_map(mapping->domain, dma_addr, page_to_phys(page), len, 0);
> > + switch (dir) {
> > + case DMA_BIDIRECTIONAL:
> > + prot = IOMMU_READ | IOMMU_WRITE;
> > + break;
> > + case DMA_TO_DEVICE:
> > + prot = IOMMU_READ;
> > + break;
> > + case DMA_FROM_DEVICE:
> > + prot = IOMMU_WRITE;
> > + break;
> > + default:
> > + prot = 0;
> > + }
> > +
> > + ret = iommu_map(mapping->domain, dma_addr, page_to_phys(page), len, prot);
>
> Do we need similar changes for map_sg case as well? They still passes '0' as prot.
Yes, we could use the same trick there (probably worth moving the logic into
a helper function for translating dma_data_direction into IOMMU_* values).
There are also iommu_map calls when allocating DMA buffers, but I think 0 is
the right thing to pass there (i.e. no permission until pages have been
explicitly mapped). Although, to be honest, I don't see why we need to map
the buffer at all when we allocate it.
Will
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