iommu: Make of_iommu_set/get_ops() DT agnostic

The of_iommu_{set/get}_ops() API is used to associate a device
tree node with a specific set of IOMMU operations. The same
kernel interface is required on systems booting with ACPI, where
devices are not associated with a device tree node, therefore
the interface requires generalization.

The struct device fwnode member represents the fwnode token associated
with the device and the struct it points at is firmware specific;
regardless, it is initialized on both ACPI and DT systems and makes an
ideal candidate to use it to associate a set of IOMMU operations to a
given device, through its struct device.fwnode member pointer, paving
the way for representing per-device iommu_ops (ie an iommu instance
associated with a device).

Convert the DT specific of_iommu_{set/get}_ops() interface to
use struct device.fwnode as a look-up token, making the interface
usable on ACPI systems and rename the data structures and the
registration API so that they are made to represent their usage
more clearly.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Tomasz Nowicki <tn@semihalf.com>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Tested-by: Tomasz Nowicki <tn@semihalf.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Joerg Roedel <joro@8bytes.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 436dc21318af..f2960e4de344 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -351,6 +351,9 @@ int iommu_fwspec_init(struct device *dev, struct fwnode_handle *iommu_fwnode,
 		      const struct iommu_ops *ops);
 void iommu_fwspec_free(struct device *dev);
 int iommu_fwspec_add_ids(struct device *dev, u32 *ids, int num_ids);
+void iommu_register_instance(struct fwnode_handle *fwnode,
+			     const struct iommu_ops *ops);
+const struct iommu_ops *iommu_get_instance(struct fwnode_handle *fwnode);
 
 #else /* CONFIG_IOMMU_API */
 
@@ -580,6 +583,17 @@ static inline int iommu_fwspec_add_ids(struct device *dev, u32 *ids,
 	return -ENODEV;
 }
 
+static inline void iommu_register_instance(struct fwnode_handle *fwnode,
+					   const struct iommu_ops *ops)
+{
+}
+
+static inline
+const struct iommu_ops *iommu_get_instance(struct fwnode_handle *fwnode)
+{
+	return NULL;
+}
+
 #endif /* CONFIG_IOMMU_API */
 
 #endif /* __LINUX_IOMMU_H */