On Fri, Dec 28, 2012 at 09:53:47AM +0530, Prathyush K wrote: > On Thu, Dec 27, 2012 at 7:45 PM, Marek Szyprowski > <m.szyprowski@xxxxxxxxxxx>wrote: > > > Hello, > > > > > > On 12/27/2012 8:14 AM, Prathyush K wrote: > > > >> This patch adds EXPORT_SYMBOL calls to the three arm iommu > >> functions - arm_iommu_create_mapping, arm_iommu_free_mapping > >> and arm_iommu_attach_device. These functions can now be called > >> from dynamic modules. > >> > > > > Could You describe a bit more why those functions might be needed by > > dynamic modules? > > > > Hi Marek, > > We are adding iommu support to exynos gsc and s5p-mfc. > And these two drivers need to be built as modules to improve boot time. > > We're calling these three functions from inside these drivers: > e.g. > mapping = arm_iommu_create_mapping(&platform_bus_type, 0x20000000, SZ_256M, > 4); > arm_iommu_attach_device(mdev, mapping); The driver shouldn't have to call these low-level functions directly, something's wrong if you need that. How is the DMA address management different here from other system/io mmus? is that 256M window a hardware restriction? -Olof -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>