iommu: Add iommu_get_domain_for_dev function

This function can be used to request the current domain a
device is attached to.

Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 7bce522c236792aba66d77e73c7e924f7e1bfa9b..a0a38bd2668bd38b96b08ae357040b16f3977d42 100644 (file)
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1076,6 +1076,24 @@ out_unlock:
 }
 EXPORT_SYMBOL_GPL(iommu_detach_device);
 
+struct iommu_domain *iommu_get_domain_for_dev(struct device *dev)
+{
+       struct iommu_domain *domain;
+       struct iommu_group *group;
+
+       group = iommu_group_get(dev);
+       /* FIXME: Remove this when groups a mandatory for iommu drivers */
+       if (group == NULL)
+               return NULL;
+
+       domain = group->domain;
+
+       iommu_group_put(group);
+
+       return domain;
+}
+EXPORT_SYMBOL_GPL(iommu_get_domain_for_dev);
+
 /*
  * IOMMU groups are really the natrual working unit of the IOMMU, but
  * the IOMMU API works on domains and devices.  Bridge that gap by

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 0546b8710ce308540abd841944aee07ba24fedfb..683a1c4b15e71a7cc4a3be028514368f8ebb0d04 100644 (file)
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -193,6 +193,7 @@ extern int iommu_attach_device(struct iommu_domain *domain,
                               struct device *dev);
 extern void iommu_detach_device(struct iommu_domain *domain,
                                struct device *dev);
+extern struct iommu_domain *iommu_get_domain_for_dev(struct device *dev);
 extern int iommu_map(struct iommu_domain *domain, unsigned long iova,
                     phys_addr_t paddr, size_t size, int prot);
 extern size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova,
@@ -332,6 +333,11 @@ static inline void iommu_detach_device(struct iommu_domain *domain,
 {
 }
 
+static inline struct iommu_domain *iommu_get_domain_for_dev(struct device *dev)
+{
+       return NULL;
+}
+
 static inline int iommu_map(struct iommu_domain *domain, unsigned long iova,
                            phys_addr_t paddr, int gfp_order, int prot)
 {