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>

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index c0c7820d4c46b406465e0d2d8e059a80ce819476..8dc19b8f5d45c533b75ad81189602de42fb2f4ef 100644 (file)
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -405,6 +405,9 @@ int dmar_disabled = 0;
 int dmar_disabled = 1;
 #endif /*CONFIG_INTEL_IOMMU_DEFAULT_ON*/
 
+int intel_iommu_enabled = 0;
+EXPORT_SYMBOL_GPL(intel_iommu_enabled);
+
 static int dmar_map_gfx = 1;
 static int dmar_forcedac;
 static int intel_iommu_strict;
@@ -3647,6 +3650,8 @@ int __init intel_iommu_init(void)
 
        bus_register_notifier(&pci_bus_type, &device_nb);
 
+       intel_iommu_enabled = 1;
+
        return 0;
 }
 

diff --git a/include/linux/dma_remapping.h b/include/linux/dma_remapping.h
index ef90cbd8e1735c781083a2321760741107c2827b..57c9a8ae4f2df2127dffe7e88aee95b5f2cdce1a 100644 (file)
--- 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