[PATCH v3 01/10] iommu: Add helper to get minimal page size of domain

[Lu Baolu <baolu.lu-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>]

This makes it possible for other modules to know the minimal
page size supported by a domain without the knowledge of the
structure details.

Signed-off-by: Lu Baolu <baolu.lu-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
---
 include/linux/iommu.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index a5007d035218..46679ef19b7e 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -377,6 +377,14 @@ static inline void iommu_tlb_sync(struct iommu_domain *domain)
 		domain->ops->iotlb_sync(domain);
 }
 
+static inline unsigned long domain_minimal_pgsize(struct iommu_domain *domain)
+{
+	if (domain && domain->pgsize_bitmap)
+		return 1 << __ffs(domain->pgsize_bitmap);
+
+	return 0;
+}
+
 /* PCI device grouping function */
 extern struct iommu_group *pci_device_group(struct device *dev);
 /* Generic device grouping function */
@@ -704,6 +712,11 @@ const struct iommu_ops *iommu_ops_from_fwnode(struct fwnode_handle *fwnode)
 	return NULL;
 }
 
+static inline unsigned long domain_minimal_pgsize(struct iommu_domain *domain)
+{
+	return 0;
+}
+
 #endif /* CONFIG_IOMMU_API */
 
 #ifdef CONFIG_IOMMU_DEBUGFS
-- 
2.17.1