[PATCH RFC 1/1] iommu/of: Deconfigure iommu on driver detach

[Vivek Gautam <vivek.gautam-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>]

As part of dma_deconfigure, lets deconfigure the iommu too
on driver detach, so that we clear the iommu domain and
related group.

Signed-off-by: Vivek Gautam <vivek.gautam-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
---

As a part of dma_deconfigure, shouldn't we deconfigure the iommu
as well? This should reverse all that we do in of_iommu_configure.
So that we call the .remove_device ops for iommu and eventually
clear all the iommu domain, related group infrastructure.
I am seeing that the loadable modules get the same iommu configurations
after re-loading them, i.e. iommu domain, and iova_domain configurations,
as we didn't cleared them.
So should we be clearing these configurations, and therefore do a
of_iommu_deconfigure() or sort?

 drivers/iommu/of_iommu.c | 11 +++++++++++
 drivers/of/device.c      |  1 +
 include/linux/of_iommu.h |  5 +++++
 3 files changed, 17 insertions(+)

diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index 5c36a8b7656a..1a23e6204ade 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -160,6 +160,17 @@ static int of_pci_iommu_init(struct pci_dev *pdev, u16 alias, void *data)
 	return err;
 }
 
+void of_iommu_deconfigure(struct device *dev)
+{
+	const struct iommu_ops *ops = NULL;
+
+	if (dev->iommu_fwspec && dev->iommu_fwspec->ops)
+		ops = dev->iommu_fwspec->ops;
+
+	if (ops && ops->remove_device && dev->iommu_group)
+		ops->remove_device(dev);
+}
+
 const struct iommu_ops *of_iommu_configure(struct device *dev,
 					   struct device_node *master_np)
 {
diff --git a/drivers/of/device.c b/drivers/of/device.c
index 064c818105bd..e13cb7914dbe 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -177,6 +177,7 @@ EXPORT_SYMBOL_GPL(of_dma_configure);
 void of_dma_deconfigure(struct device *dev)
 {
 	arch_teardown_dma_ops(dev);
+	of_iommu_deconfigure(dev);
 }
 
 int of_device_register(struct platform_device *pdev)
diff --git a/include/linux/of_iommu.h b/include/linux/of_iommu.h
index 4fa654e4b5a9..3d4c22e95c0c 100644
--- a/include/linux/of_iommu.h
+++ b/include/linux/of_iommu.h
@@ -15,6 +15,8 @@ extern int of_get_dma_window(struct device_node *dn, const char *prefix,
 extern const struct iommu_ops *of_iommu_configure(struct device *dev,
 					struct device_node *master_np);
 
+extern void of_iommu_deconfigure(struct device *dev);
+
 #else
 
 static inline int of_get_dma_window(struct device_node *dn, const char *prefix,
@@ -30,6 +32,9 @@ static inline const struct iommu_ops *of_iommu_configure(struct device *dev,
 	return NULL;
 }
 
+static inline void of_iommu_deconfigure(struct device *dev)
+{ }
+
 #endif	/* CONFIG_OF_IOMMU */
 
 extern struct of_device_id __iommu_of_table;
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation