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, 40 insertions, 0 deletions

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 9a2f1960873b..8d3e847d4845 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1615,6 +1615,46 @@ out:
 	return ret;
 }
 
+struct iommu_instance {
+	struct list_head list;
+	struct fwnode_handle *fwnode;
+	const struct iommu_ops *ops;
+};
+static LIST_HEAD(iommu_instance_list);
+static DEFINE_SPINLOCK(iommu_instance_lock);
+
+void iommu_register_instance(struct fwnode_handle *fwnode,
+			     const struct iommu_ops *ops)
+{
+	struct iommu_instance *iommu = kzalloc(sizeof(*iommu), GFP_KERNEL);
+
+	if (WARN_ON(!iommu))
+		return;
+
+	of_node_get(to_of_node(fwnode));
+	INIT_LIST_HEAD(&iommu->list);
+	iommu->fwnode = fwnode;
+	iommu->ops = ops;
+	spin_lock(&iommu_instance_lock);
+	list_add_tail(&iommu->list, &iommu_instance_list);
+	spin_unlock(&iommu_instance_lock);
+}
+
+const struct iommu_ops *iommu_get_instance(struct fwnode_handle *fwnode)
+{
+	struct iommu_instance *instance;
+	const struct iommu_ops *ops = NULL;
+
+	spin_lock(&iommu_instance_lock);
+	list_for_each_entry(instance, &iommu_instance_list, list)
+		if (instance->fwnode == fwnode) {
+			ops = instance->ops;
+			break;
+		}
+	spin_unlock(&iommu_instance_lock);
+	return ops;
+}
+
 int iommu_fwspec_init(struct device *dev, struct fwnode_handle *iommu_fwnode,
 		      const struct iommu_ops *ops)
 {