[RFC PATCH 1/8] of/device: Allow specifying a custom iommu_spec to of_dma_configure

Mikko Perttunen mperttunen at nvidia.com
Mon Feb 8 16:38:41 UTC 2021


To allow for more customized device tree bindings that point to IOMMUs,
allow manual specification of iommu_spec to of_dma_configure.

The initial use case for this is with Host1x, where the driver manages
a set of device tree-defined IOMMU contexts that are dynamically
allocated to various users. These contexts don't correspond to
platform devices and are instead attached to dummy devices on a custom
software bus.

Signed-off-by: Mikko Perttunen <mperttunen at nvidia.com>
---
 drivers/iommu/of_iommu.c  | 12 ++++++++----
 drivers/of/device.c       |  9 +++++----
 include/linux/of_device.h | 34 +++++++++++++++++++++++++++-------
 include/linux/of_iommu.h  |  6 ++++--
 4 files changed, 44 insertions(+), 17 deletions(-)

diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index e505b9130a1c..3fefa6c63863 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -87,8 +87,7 @@ int of_get_dma_window(struct device_node *dn, const char *prefix, int index,
 }
 EXPORT_SYMBOL_GPL(of_get_dma_window);
 
-static int of_iommu_xlate(struct device *dev,
-			  struct of_phandle_args *iommu_spec)
+int of_iommu_xlate(struct device *dev, struct of_phandle_args *iommu_spec)
 {
 	const struct iommu_ops *ops;
 	struct fwnode_handle *fwnode = &iommu_spec->np->fwnode;
@@ -117,6 +116,7 @@ static int of_iommu_xlate(struct device *dev,
 	module_put(ops->owner);
 	return ret;
 }
+EXPORT_SYMBOL_GPL(of_iommu_xlate);
 
 static int of_iommu_configure_dev_id(struct device_node *master_np,
 				     struct device *dev,
@@ -177,7 +177,8 @@ static int of_iommu_configure_device(struct device_node *master_np,
 
 const struct iommu_ops *of_iommu_configure(struct device *dev,
 					   struct device_node *master_np,
-					   const u32 *id)
+					   const u32 *id,
+					   struct of_phandle_args *iommu_spec)
 {
 	const struct iommu_ops *ops = NULL;
 	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
@@ -209,7 +210,10 @@ const struct iommu_ops *of_iommu_configure(struct device *dev,
 		err = pci_for_each_dma_alias(to_pci_dev(dev),
 					     of_pci_iommu_init, &info);
 	} else {
-		err = of_iommu_configure_device(master_np, dev, id);
+		if (iommu_spec)
+			err = of_iommu_xlate(dev, iommu_spec);
+		else
+			err = of_iommu_configure_device(master_np, dev, id);
 
 		fwspec = dev_iommu_fwspec_get(dev);
 		if (!err && fwspec)
diff --git a/drivers/of/device.c b/drivers/of/device.c
index aedfaaafd3e7..84ada2110c5b 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -88,8 +88,9 @@ int of_device_add(struct platform_device *ofdev)
  * can use a platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE events
  * to fix up DMA configuration.
  */
-int of_dma_configure_id(struct device *dev, struct device_node *np,
-			bool force_dma, const u32 *id)
+int __of_dma_configure(struct device *dev, struct device_node *np,
+			bool force_dma, const u32 *id,
+			struct of_phandle_args *iommu_spec)
 {
 	const struct iommu_ops *iommu;
 	const struct bus_dma_region *map = NULL;
@@ -170,7 +171,7 @@ int of_dma_configure_id(struct device *dev, struct device_node *np,
 	dev_dbg(dev, "device is%sdma coherent\n",
 		coherent ? " " : " not ");
 
-	iommu = of_iommu_configure(dev, np, id);
+	iommu = of_iommu_configure(dev, np, id, iommu_spec);
 	if (PTR_ERR(iommu) == -EPROBE_DEFER) {
 		kfree(map);
 		return -EPROBE_DEFER;
@@ -184,7 +185,7 @@ int of_dma_configure_id(struct device *dev, struct device_node *np,
 	dev->dma_range_map = map;
 	return 0;
 }
-EXPORT_SYMBOL_GPL(of_dma_configure_id);
+EXPORT_SYMBOL_GPL(__of_dma_configure);
 
 int of_device_register(struct platform_device *pdev)
 {
diff --git a/include/linux/of_device.h b/include/linux/of_device.h
index 07ca187fc5e4..40cc3e788cb9 100644
--- a/include/linux/of_device.h
+++ b/include/linux/of_device.h
@@ -55,14 +55,27 @@ static inline struct device_node *of_cpu_device_node_get(int cpu)
 	return of_node_get(cpu_dev->of_node);
 }
 
-int of_dma_configure_id(struct device *dev,
+int __of_dma_configure(struct device *dev,
 		     struct device_node *np,
-		     bool force_dma, const u32 *id);
+		     bool force_dma, const u32 *id,
+		     struct of_phandle_args *iommu_spec);
 static inline int of_dma_configure(struct device *dev,
 				   struct device_node *np,
 				   bool force_dma)
 {
-	return of_dma_configure_id(dev, np, force_dma, NULL);
+	return __of_dma_configure(dev, np, force_dma, NULL, NULL);
+}
+static inline int of_dma_configure_id(struct device *dev,
+				      struct device_node *np,
+				      bool force_dma, const u32 *id)
+{
+	return __of_dma_configure(dev, np, force_dma, id, NULL);
+}
+static inline int
+of_dma_configure_iommu_spec(struct device *dev, struct device_node *np,
+			    bool force_dma, struct of_phandle_args *iommu_spec)
+{
+	return __of_dma_configure(dev, np, force_dma, NULL, iommu_spec);
 }
 #else /* CONFIG_OF */
 
@@ -112,18 +125,25 @@ static inline struct device_node *of_cpu_device_node_get(int cpu)
 	return NULL;
 }
 
-static inline int of_dma_configure_id(struct device *dev,
+static inline int of_dma_configure(struct device *dev,
 				   struct device_node *np,
 				   bool force_dma)
 {
 	return 0;
 }
-static inline int of_dma_configure(struct device *dev,
-				   struct device_node *np,
-				   bool force_dma)
+
+static inline int of_dma_configure_id(struct device *dev,
+				      struct device_node *np,
+				      bool force_dma, const u32 *id)
 {
 	return 0;
 }
+
+static inline int
+of_dma_configure_iommu_spec(struct device *dev, struct device_node *np,
+			    bool force_dma, struct of_phandle_args *iommu_spec)
+{	return 0;
+}
 #endif /* CONFIG_OF */
 
 #endif /* _LINUX_OF_DEVICE_H */
diff --git a/include/linux/of_iommu.h b/include/linux/of_iommu.h
index 16f4b3e87f20..e8d1e6d32d77 100644
--- a/include/linux/of_iommu.h
+++ b/include/linux/of_iommu.h
@@ -14,7 +14,8 @@ 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,
-					const u32 *id);
+					const u32 *id,
+					struct of_phandle_args *iommu_spec);
 
 #else
 
@@ -27,7 +28,8 @@ static inline int of_get_dma_window(struct device_node *dn, const char *prefix,
 
 static inline const struct iommu_ops *of_iommu_configure(struct device *dev,
 					 struct device_node *master_np,
-					 const u32 *id)
+					 const u32 *id,
+					 struct of_phandle_args *iommu_spec);
 {
 	return NULL;
 }
-- 
2.30.0



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