On Wed, Apr 18, 2012 at 9:44 AM, Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> wrote: > This patch add a complete implementation of DMA-mapping API for > devices which have IOMMU support. Hi Marek, It looks like this patch breaks no-MMU builds on ARM, at least according to git bisect. Here is a link to a linux-next failure: http://kisskb.ellerman.id.au/kisskb/buildresult/6291233/ arch/arm/mm/dma-mapping.c:726:42: error: 'pgprot_kernel' undeclared (first use in this function) make[2]: *** [arch/arm/mm/dma-mapping.o] Error 1 Please have a look, thanks. Paul. --- > > This implementation tries to optimize dma address space usage by remapping > all possible physical memory chunks into a single dma address space chunk. > > DMA address space is managed on top of the bitmap stored in the > dma_iommu_mapping structure stored in device->archdata. Platform setup > code has to initialize parameters of the dma address space (base address, > size, allocation precision order) with arm_iommu_create_mapping() > function. > To reduce the size of the bitmap, all allocations are aligned to the > specified order of base 4 KiB pages. > > dma_alloc_* functions allocate physical memory in chunks, each with > alloc_pages() function to avoid failing if the physical memory gets > fragmented. In worst case the allocated buffer is composed of 4 KiB page > chunks. > > dma_map_sg() function minimizes the total number of dma address space > chunks by merging of physical memory chunks into one larger dma address > space chunk. If requested chunk (scatter list entry) boundaries > match physical page boundaries, most calls to dma_map_sg() requests will > result in creating only one chunk in dma address space. > > dma_map_page() simply creates a mapping for the given page(s) in the dma > address space. > > All dma functions also perform required cache operation like their > counterparts from the arm linear physical memory mapping version. > > This patch contains code and fixes kindly provided by: > - Krishna Reddy <vdumpa@xxxxxxxxxx>, > - Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxx>, > - Hiroshi DOYU <hdoyu@xxxxxxxxxx> > > Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> > Acked-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx> > Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> > Tested-By: Subash Patel <subash.ramaswamy@xxxxxxxxxx> > --- > arch/arm/Kconfig | 8 + > arch/arm/include/asm/device.h | 3 + > arch/arm/include/asm/dma-iommu.h | 34 ++ > arch/arm/mm/dma-mapping.c | 727 > +++++++++++++++++++++++++++++++++++++- > arch/arm/mm/vmregion.h | 2 +- > 5 files changed, 759 insertions(+), 15 deletions(-) > create mode 100644 arch/arm/include/asm/dma-iommu.h > -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
