iommu: Add API to request DMA domain for device

Normally during iommu probing a device, a default doamin will
be allocated and attached to the device. The domain type of
the default domain is statically defined, which results in a
situation where the allocated default domain isn't suitable
for the device due to some limitations. We already have API
iommu_request_dm_for_dev() to replace a DMA domain with an
identity one. This adds iommu_request_dma_domain_for_dev()
to request a dma domain if an allocated identity domain isn't
suitable for the device in question.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 67ee662..2fca04c 100644 (file)
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1907,10 +1907,10 @@ struct iommu_resv_region *iommu_alloc_resv_region(phys_addr_t start,
        return region;
 }
 
-/* Request that a device is direct mapped by the IOMMU */
-int iommu_request_dm_for_dev(struct device *dev)
+static int
+request_default_domain_for_dev(struct device *dev, unsigned long type)
 {
-       struct iommu_domain *dm_domain;
+       struct iommu_domain *domain;
        struct iommu_group *group;
        int ret;
 
@@ -1923,8 +1923,7 @@ int iommu_request_dm_for_dev(struct device *dev)
 
        /* Check if the default domain is already direct mapped */
        ret = 0;
-       if (group->default_domain &&
-           group->default_domain->type == IOMMU_DOMAIN_IDENTITY)
+       if (group->default_domain && group->default_domain->type == type)
                goto out;
 
        /* Don't change mappings of existing devices */
@@ -1934,23 +1933,26 @@ int iommu_request_dm_for_dev(struct device *dev)
 
        /* Allocate a direct mapped domain */
        ret = -ENOMEM;
-       dm_domain = __iommu_domain_alloc(dev->bus, IOMMU_DOMAIN_IDENTITY);
-       if (!dm_domain)
+       domain = __iommu_domain_alloc(dev->bus, type);
+       if (!domain)
                goto out;
 
        /* Attach the device to the domain */
-       ret = __iommu_attach_group(dm_domain, group);
+       ret = __iommu_attach_group(domain, group);
        if (ret) {
-               iommu_domain_free(dm_domain);
+               iommu_domain_free(domain);
                goto out;
        }
 
+       iommu_group_create_direct_mappings(group, dev);
+
        /* Make the direct mapped domain the default for this group */
        if (group->default_domain)
                iommu_domain_free(group->default_domain);
-       group->default_domain = dm_domain;
+       group->default_domain = domain;
 
-       dev_info(dev, "Using iommu direct mapping\n");
+       dev_info(dev, "Using iommu %s mapping\n",
+                type == IOMMU_DOMAIN_DMA ? "dma" : "direct");
 
        ret = 0;
 out:
@@ -1960,6 +1962,18 @@ out:
        return ret;
 }
 
+/* Request that a device is direct mapped by the IOMMU */
+int iommu_request_dm_for_dev(struct device *dev)
+{
+       return request_default_domain_for_dev(dev, IOMMU_DOMAIN_IDENTITY);
+}
+
+/* Request that a device can't be direct mapped by the IOMMU */
+int iommu_request_dma_domain_for_dev(struct device *dev)
+{
+       return request_default_domain_for_dev(dev, IOMMU_DOMAIN_DMA);
+}
+
 const struct iommu_ops *iommu_ops_from_fwnode(struct fwnode_handle *fwnode)
 {
        const struct iommu_ops *ops = NULL;

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index a815cf6..91af22a 100644 (file)
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -362,6 +362,7 @@ extern void iommu_set_fault_handler(struct iommu_domain *domain,
 extern void iommu_get_resv_regions(struct device *dev, struct list_head *list);
 extern void iommu_put_resv_regions(struct device *dev, struct list_head *list);
 extern int iommu_request_dm_for_dev(struct device *dev);
+extern int iommu_request_dma_domain_for_dev(struct device *dev);
 extern struct iommu_resv_region *
 iommu_alloc_resv_region(phys_addr_t start, size_t length, int prot,
                        enum iommu_resv_type type);
@@ -626,6 +627,11 @@ static inline int iommu_request_dm_for_dev(struct device *dev)
        return -ENODEV;
 }
 
+static inline int iommu_request_dma_domain_for_dev(struct device *dev)
+{
+       return -ENODEV;
+}
+
 static inline int iommu_attach_group(struct iommu_domain *domain,
                                     struct iommu_group *group)
 {