iommu: Export intel_iommu_enabled to signal when iommu is in use

In i915 driver, we do not enable either rc6 or semaphores on SNB when dmar
is enabled. The new 'intel_iommu_enabled' variable signals when the
iommu code is in operation.

Cc: Ted Phelps <phelps@gnusto.com>
Cc: Peter <pab1612@gmail.com>
Cc: Lukas Hejtmanek <xhejtman@fi.muni.cz>
Cc: Andrew Lutomirski <luto@mit.edu>
CC: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Eugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/dma_remapping.h b/include/linux/dma_remapping.h
index ef90cbd8e173..57c9a8ae4f2d 100644
--- a/include/linux/dma_remapping.h
+++ b/include/linux/dma_remapping.h
@@ -31,6 +31,7 @@ extern void free_dmar_iommu(struct intel_iommu *iommu);
 extern int iommu_calculate_agaw(struct intel_iommu *iommu);
 extern int iommu_calculate_max_sagaw(struct intel_iommu *iommu);
 extern int dmar_disabled;
+extern int intel_iommu_enabled;
 #else
 static inline int iommu_calculate_agaw(struct intel_iommu *iommu)
 {
@@ -44,6 +45,7 @@ static inline void free_dmar_iommu(struct intel_iommu *iommu)
 {
 }
 #define dmar_disabled   (1)
+#define intel_iommu_enabled (0)
 #endif