From 5210d963c9dde1d6bae95f0d338360d7eb92ce5a Mon Sep 17 00:00:00 2001
From: James Sewart <jamessewart@arista.com>
Date: Thu, 21 Mar 2019 11:31:44 +0000
Subject: [PATCH 5/9] iommu: Add ops entry for vendor specific default domain
 type

This adds an iommu ops entry for iommu vendor driver to specify
the type of the default domain for each device. This is needed
for the vendor driver, which already has its own logic to
determine the use of identity domain for a long time, when it
switches to apply default domain.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 88d589d56ded..516e4d8995c2 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1102,12 +1102,18 @@ struct iommu_group *iommu_group_get_for_dev(struct device *dev)
 	 */
 	if (!group->default_domain) {
 		struct iommu_domain *dom;
+		int domain_type = iommu_def_domain_type;
 
-		dom = __iommu_domain_alloc(dev->bus, iommu_def_domain_type);
-		if (!dom && iommu_def_domain_type != IOMMU_DOMAIN_DMA) {
+		if (ops->is_identity_map)
+			domain_type = ops->is_identity_map(dev) ?
+				      IOMMU_DOMAIN_IDENTITY :
+				      IOMMU_DOMAIN_DMA;
+
+		dom = __iommu_domain_alloc(dev->bus, domain_type);
+		if (!dom && domain_type != IOMMU_DOMAIN_DMA) {
 			dev_warn(dev,
 				 "failed to allocate default IOMMU domain of type %u; falling back to IOMMU_DOMAIN_DMA",
-				 iommu_def_domain_type);
+				 domain_type);
 			dom = __iommu_domain_alloc(dev->bus, IOMMU_DOMAIN_DMA);
 		}
 
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index ffbbc7e39cee..a5007d035218 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -186,6 +186,7 @@ struct iommu_resv_region {
  * @of_xlate: add OF master IDs to iommu grouping
  * @is_attach_deferred: Check if domain attach should be deferred from iommu
  *                      driver init to device driver init (default no)
+ * @is_identity_map: vendor customized identity map adjudicator
  * @pgsize_bitmap: bitmap of all possible supported page sizes
  */
 struct iommu_ops {
@@ -230,6 +231,9 @@ struct iommu_ops {
 	int (*of_xlate)(struct device *dev, struct of_phandle_args *args);
 	bool (*is_attach_deferred)(struct iommu_domain *domain, struct device *dev);
 
+	/* Vendor customized identity map adjudicator */
+	bool (*is_identity_map)(struct device *dev);
+
 	unsigned long pgsize_bitmap;
 };
 
-- 
2.17.1