Hi Nishanth,
Nishanth Peethambaran <nishanth.p@xxxxxxxxx> wrote @ Thu, 20 Jun 2013 10:07:00 +0200:
> It would be better to define a prot flag bit in iommu API and convert
> the attrs to prot flag bit in dma-mapping aPI before calling the iommu
> API.
That's the 1st option.
> On Thu, Jun 20, 2013 at 11:19 AM, Hiroshi Doyu <hdoyu@xxxxxxxxxx> wrote:
....
> > @@ -1280,7 +1281,7 @@ ____iommu_create_mapping(struct device *dev, dma_addr_t *req,
> > break;
> >
> > len = (j - i) << PAGE_SHIFT;
> > - ret = iommu_map(mapping->domain, iova, phys, len, 0);
> > + ret = iommu_map(mapping->domain, iova, phys, len, (int)attrs);
>
> Use dma_get_attr and translate the READ_ONLY attr to a new READ_ONLY
> prot flag bit which needs to be defined in iommu.h
Both DMA_ATTR_READ_ONLY and IOMMU_READ are just logical bit in their
layers respectively and eventually it's converted to H/W dependent
bit.
If IOMMU is considered as one of specific case of DMA, sharing
dma_attr between IOMMU and DMA may not be so bad. IIRC, ARM:
dma-mapping API was implemented based on this concept(?).
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index d8f98b1..161a1b0 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -755,7 +755,7 @@ int iommu_domain_has_cap(struct iommu_domain *domain,
EXPORT_SYMBOL_GPL(iommu_domain_has_cap);
int iommu_map(struct iommu_domain *domain, unsigned long iova,
- phys_addr_t paddr, size_t size, int prot)
+ phys_addr_t paddr, size_t size, struct dma_attr *attrs)
{
unsigned long orig_iova = iova;
unsigned int min_pagesz;
--
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