iommu/arm-smmu: Convert struct device of_node to fwnode usage

Current ARM SMMU driver rely on the struct device.of_node pointer for
device look-up and iommu_ops retrieval.

In preparation for ACPI probing enablement, convert the driver to use
the struct device.fwnode member for device and iommu_ops look-up so that
the driver infrastructure can be used also on systems that do not
associate an of_node pointer to a struct device (eg ACPI), making the
device look-up and iommu_ops retrieval firmware agnostic.

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>
Signed-off-by: Will Deacon <will.deacon@arm.com>

drivers/iommu/arm-smmu.c

@@ -1380,13 +1380,14 @@ static bool arm_smmu_capable(enum iommu_cap cap)
 
 static int arm_smmu_match_node(struct device *dev, void *data)
 {
-	return dev->of_node == data;
+	return dev->fwnode == data;
 }
 
-static struct arm_smmu_device *arm_smmu_get_by_node(struct device_node *np)
+static
+struct arm_smmu_device *arm_smmu_get_by_fwnode(struct fwnode_handle *fwnode)
 {
 	struct device *dev = driver_find_device(&arm_smmu_driver.driver, NULL,
-						np, arm_smmu_match_node);
+						fwnode, arm_smmu_match_node);
 	put_device(dev);
 	return dev ? dev_get_drvdata(dev) : NULL;
 }
@@ -1404,7 +1405,7 @@ static int arm_smmu_add_device(struct device *dev)
 		if (ret)
 			goto out_free;
 	} else if (fwspec && fwspec->ops == &arm_smmu_ops) {
-		smmu = arm_smmu_get_by_node(to_of_node(fwspec->iommu_fwnode));
+		smmu = arm_smmu_get_by_fwnode(fwspec->iommu_fwnode);
 	} else {
 		return -ENODEV;
 	}
@@ -2014,7 +2015,7 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev)
 		}
 	}
 
-	of_iommu_set_ops(dev->of_node, &arm_smmu_ops);
+	iommu_register_instance(dev->fwnode, &arm_smmu_ops);
 	platform_set_drvdata(pdev, smmu);
 	arm_smmu_device_reset(smmu);