[PATCH 1/2] powerpc/iommu: expose IOMMU page shift

Nishanth Aravamudan nacc at linux.vnet.ibm.com
Fri Oct 2 10:18:00 PDT 2015

We will leverage this macro in the NVMe driver, which needs to know the
configured IOMMU page shift to properly configure its device's page

Signed-off-by: Nishanth Aravamudan <nacc at linux.vnet.ibm.com>

Given this is available, it seems reasonable to expose -- and it doesn't
really make sense to make the driver do a log2 call on the existing

diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index ca18cff..6fdf857 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -36,6 +36,7 @@
 #define IOMMU_PAGE_MASK_4K       (~((1 << IOMMU_PAGE_SHIFT_4K) - 1))
+#define IOMMU_PAGE_SHIFT(tblptr) (tblptr)->it_page_shift
 #define IOMMU_PAGE_SIZE(tblptr) (ASM_CONST(1) << (tblptr)->it_page_shift)
 #define IOMMU_PAGE_MASK(tblptr) (~((1 << (tblptr)->it_page_shift) - 1))
 #define IOMMU_PAGE_ALIGN(addr, tblptr) _ALIGN_UP(addr, IOMMU_PAGE_SIZE(tblptr))

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