[PATCH v2 25/60][SRU][OEM-5.6] iommu: Add probe_device() and release_device() call-backs

[You-Sheng Yang]

From: Joerg Roedel <jroedel at suse.de>

BugLink: https://bugs.launchpad.net/bugs/1876707

Add call-backs to 'struct iommu_ops' as an alternative to the
add_device() and remove_device() call-backs, which will be removed when
all drivers are converted.

The new call-backs will not setup IOMMU groups and domains anymore,
so also add a probe_finalize() call-back where the IOMMU driver can do
per-device setup work which require the device to be set up with a
group and a domain.

Signed-off-by: Joerg Roedel <jroedel at suse.de>
Tested-by: Marek Szyprowski <m.szyprowski at samsung.com>
Acked-by: Marek Szyprowski <m.szyprowski at samsung.com>
Link: https://lore.kernel.org/r/20200429133712.31431-8-joro@8bytes.org
Signed-off-by: Joerg Roedel <jroedel at suse.de>
(cherry picked from commit a6a4c7e2c5b8b981d1c546a393ff21f2112468c3
linux-next)
Signed-off-by: You-Sheng Yang <vicamo.yang at canonical.com>
---
 drivers/iommu/iommu.c | 63 ++++++++++++++++++++++++++++++++++++++-----
 include/linux/iommu.h |  9 +++++++
 2 files changed, 66 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 1bdfe6bf3a3c..e7c4ac036899 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -175,6 +175,36 @@ static void dev_iommu_free(struct device *dev)
 	dev->iommu = NULL;
 }
 
+static int __iommu_probe_device(struct device *dev)
+{
+	const struct iommu_ops *ops = dev->bus->iommu_ops;
+	struct iommu_device *iommu_dev;
+	struct iommu_group *group;
+	int ret;
+
+	iommu_dev = ops->probe_device(dev);
+	if (IS_ERR(iommu_dev))
+		return PTR_ERR(iommu_dev);
+
+	dev->iommu->iommu_dev = iommu_dev;
+
+	group = iommu_group_get_for_dev(dev);
+	if (!IS_ERR(group)) {
+		ret = PTR_ERR(group);
+		goto out_release;
+	}
+	iommu_group_put(group);
+
+	iommu_device_link(iommu_dev, dev);
+
+	return 0;
+
+out_release:
+	ops->release_device(dev);
+
+	return ret;
+}
+
 int iommu_probe_device(struct device *dev)
 {
 	const struct iommu_ops *ops = dev->bus->iommu_ops;
@@ -192,10 +222,17 @@ int iommu_probe_device(struct device *dev)
 		goto err_free_dev_param;
 	}
 
-	ret = ops->add_device(dev);
+	if (ops->probe_device)
+		ret = __iommu_probe_device(dev);
+	else
+		ret = ops->add_device(dev);
+
 	if (ret)
 		goto err_module_put;
 
+	if (ops->probe_finalize)
+		ops->probe_finalize(dev);
+
 	return 0;
 
 err_module_put:
@@ -205,17 +242,31 @@ int iommu_probe_device(struct device *dev)
 	return ret;
 }
 
+static void __iommu_release_device(struct device *dev)
+{
+	const struct iommu_ops *ops = dev->bus->iommu_ops;
+
+	iommu_device_unlink(dev->iommu->iommu_dev, dev);
+
+	iommu_group_remove_device(dev);
+
+	ops->release_device(dev);
+}
+
 void iommu_release_device(struct device *dev)
 {
 	const struct iommu_ops *ops = dev->bus->iommu_ops;
 
-	if (dev->iommu_group)
+	if (!dev->iommu)
+		return;
+
+	if (ops->release_device)
+		__iommu_release_device(dev);
+	else if (dev->iommu_group)
 		ops->remove_device(dev);
 
-	if (dev->iommu) {
-		module_put(ops->owner);
-		dev_iommu_free(dev);
-	}
+	module_put(ops->owner);
+	dev_iommu_free(dev);
 }
 
 static struct iommu_domain *__iommu_domain_alloc(struct bus_type *bus,
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 1f027b07e499..30170d191e5e 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -225,6 +225,10 @@ struct iommu_iotlb_gather {
  * @iova_to_phys: translate iova to physical address
  * @add_device: add device to iommu grouping
  * @remove_device: remove device from iommu grouping
+ * @probe_device: Add device to iommu driver handling
+ * @release_device: Remove device from iommu driver handling
+ * @probe_finalize: Do final setup work after the device is added to an IOMMU
+ *                  group and attached to the groups domain
  * @device_group: find iommu group for a particular device
  * @domain_get_attr: Query domain attributes
  * @domain_set_attr: Change domain attributes
@@ -275,6 +279,9 @@ struct iommu_ops {
 	phys_addr_t (*iova_to_phys)(struct iommu_domain *domain, dma_addr_t iova);
 	int (*add_device)(struct device *dev);
 	void (*remove_device)(struct device *dev);
+	struct iommu_device *(*probe_device)(struct device *dev);
+	void (*release_device)(struct device *dev);
+	void (*probe_finalize)(struct device *dev);
 	struct iommu_group *(*device_group)(struct device *dev);
 	int (*domain_get_attr)(struct iommu_domain *domain,
 			       enum iommu_attr attr, void *data);
@@ -375,6 +382,7 @@ struct iommu_fault_param {
  *
  * @fault_param: IOMMU detected device fault reporting data
  * @fwspec:	 IOMMU fwspec data
+ * @iommu_dev:	 IOMMU device this device is linked to
  * @priv:	 IOMMU Driver private data
  *
  * TODO: migrate other per device data pointers under iommu_dev_data, e.g.
@@ -384,6 +392,7 @@ struct dev_iommu {
 	struct mutex lock;
 	struct iommu_fault_param	*fault_param;
 	struct iommu_fwspec		*fwspec;
+	struct iommu_device		*iommu_dev;
 	void				*priv;
 };
 
-- 
2.25.1