iommu/rockchip: Use OF_IOMMU to attach devices automatically

Converts the rockchip-iommu driver to use the OF_IOMMU infrastructure,
which allows attaching master devices to their IOMMUs automatically
according to DT properties.

Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/rockchip-iommu.c

@@ -19,6 +19,7 @@
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/of_iommu.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
@@ -104,6 +105,10 @@ struct rk_iommu {
 	struct iommu_domain *domain; /* domain to which iommu is attached */
 };
 
+struct rk_iommudata {
+	struct rk_iommu *iommu;
+};
+
 static struct device *dma_dev;
 
 static inline void rk_table_flush(struct rk_iommu_domain *dom, dma_addr_t dma,
@@ -807,18 +812,9 @@ static size_t rk_iommu_unmap(struct iommu_domain *domain, unsigned long _iova,
 
 static struct rk_iommu *rk_iommu_from_dev(struct device *dev)
 {
-	struct iommu_group *group;
-	struct device *iommu_dev;
-	struct rk_iommu *rk_iommu;
+	struct rk_iommudata *data = dev->archdata.iommu;
 
-	group = iommu_group_get(dev);
-	if (!group)
-		return NULL;
-	iommu_dev = iommu_group_get_iommudata(group);
-	rk_iommu = dev_get_drvdata(iommu_dev);
-	iommu_group_put(group);
-
-	return rk_iommu;
+	return data ? data->iommu : NULL;
 }
 
 static int rk_iommu_attach_device(struct iommu_domain *domain,
@@ -989,112 +985,55 @@ static void rk_iommu_domain_free(struct iommu_domain *domain)
 		iommu_put_dma_cookie(&rk_domain->domain);
 }
 
-static bool rk_iommu_is_dev_iommu_master(struct device *dev)
-{
-	struct device_node *np = dev->of_node;
-	int ret;
-
-	/*
-	 * An iommu master has an iommus property containing a list of phandles
-	 * to iommu nodes, each with an #iommu-cells property with value 0.
-	 */
-	ret = of_count_phandle_with_args(np, "iommus", "#iommu-cells");
-	return (ret > 0);
-}
-
-static int rk_iommu_group_set_iommudata(struct iommu_group *group,
-					struct device *dev)
-{
-	struct device_node *np = dev->of_node;
-	struct platform_device *pd;
-	int ret;
-	struct of_phandle_args args;
-
-	/*
-	 * An iommu master has an iommus property containing a list of phandles
-	 * to iommu nodes, each with an #iommu-cells property with value 0.
-	 */
-	ret = of_parse_phandle_with_args(np, "iommus", "#iommu-cells", 0,
-					 &args);
-	if (ret) {
-		dev_err(dev, "of_parse_phandle_with_args(%pOF) => %d\n",
-			np, ret);
-		return ret;
-	}
-	if (args.args_count != 0) {
-		dev_err(dev, "incorrect number of iommu params found for %pOF (found %d, expected 0)\n",
-			args.np, args.args_count);
-		return -EINVAL;
-	}
-
-	pd = of_find_device_by_node(args.np);
-	of_node_put(args.np);
-	if (!pd) {
-		dev_err(dev, "iommu %pOF not found\n", args.np);
-		return -EPROBE_DEFER;
-	}
-
-	/* TODO(djkurtz): handle multiple slave iommus for a single master */
-	iommu_group_set_iommudata(group, &pd->dev, NULL);
-
-	return 0;
-}
-
 static int rk_iommu_add_device(struct device *dev)
 {
 	struct iommu_group *group;
 	struct rk_iommu *iommu;
-	int ret;
-
-	if (!rk_iommu_is_dev_iommu_master(dev))
-		return -ENODEV;
-
-	group = iommu_group_get(dev);
-	if (!group) {
-		group = iommu_group_alloc();
-		if (IS_ERR(group)) {
-			dev_err(dev, "Failed to allocate IOMMU group\n");
-			return PTR_ERR(group);
-		}
-	}
-
-	ret = iommu_group_add_device(group, dev);
-	if (ret)
-		goto err_put_group;
-
-	ret = rk_iommu_group_set_iommudata(group, dev);
-	if (ret)
-		goto err_remove_device;
 
 	iommu = rk_iommu_from_dev(dev);
-	if (iommu)
-		iommu_device_link(&iommu->iommu, dev);
+	if (!iommu)
+		return -ENODEV;
 
+	group = iommu_group_get_for_dev(dev);
+	if (IS_ERR(group))
+		return PTR_ERR(group);
 	iommu_group_put(group);
 
+	iommu_device_link(&iommu->iommu, dev);
+
 	return 0;
-
-err_remove_device:
-	iommu_group_remove_device(dev);
-err_put_group:
-	iommu_group_put(group);
-	return ret;
 }
 
 static void rk_iommu_remove_device(struct device *dev)
 {
 	struct rk_iommu *iommu;
 
-	if (!rk_iommu_is_dev_iommu_master(dev))
-		return;
-
 	iommu = rk_iommu_from_dev(dev);
-	if (iommu)
-		iommu_device_unlink(&iommu->iommu, dev);
 
+	iommu_device_unlink(&iommu->iommu, dev);
 	iommu_group_remove_device(dev);
 }
 
+static int rk_iommu_of_xlate(struct device *dev,
+			     struct of_phandle_args *args)
+{
+	struct platform_device *iommu_dev;
+	struct rk_iommudata *data;
+
+	data = devm_kzalloc(dma_dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	iommu_dev = of_find_device_by_node(args->np);
+
+	data->iommu = platform_get_drvdata(iommu_dev);
+	dev->archdata.iommu = data;
+
+	of_dev_put(iommu_dev);
+
+	return 0;
+}
+
 static const struct iommu_ops rk_iommu_ops = {
 	.domain_alloc = rk_iommu_domain_alloc,
 	.domain_free = rk_iommu_domain_free,
@@ -1106,7 +1045,9 @@ static const struct iommu_ops rk_iommu_ops = {
 	.add_device = rk_iommu_add_device,
 	.remove_device = rk_iommu_remove_device,
 	.iova_to_phys = rk_iommu_iova_to_phys,
+	.device_group = generic_device_group,
 	.pgsize_bitmap = RK_IOMMU_PGSIZE_BITMAP,
+	.of_xlate = rk_iommu_of_xlate,
 };
 
 static int rk_iommu_probe(struct platform_device *pdev)
@@ -1178,6 +1119,8 @@ static int rk_iommu_probe(struct platform_device *pdev)
 		goto err_unprepare_clocks;
 
 	iommu_device_set_ops(&iommu->iommu, &rk_iommu_ops);
+	iommu_device_set_fwnode(&iommu->iommu, &dev->of_node->fwnode);
+
 	err = iommu_device_register(&iommu->iommu);
 	if (err)
 		goto err_remove_sysfs;
@@ -1250,6 +1193,8 @@ static int __init rk_iommu_init(void)
 }
 subsys_initcall(rk_iommu_init);
 
+IOMMU_OF_DECLARE(rk_iommu_of, "rockchip,iommu");
+
 MODULE_DESCRIPTION("IOMMU API for Rockchip");
 MODULE_AUTHOR("Simon Xue <xxm@rock-chips.com> and Daniel Kurtz <djkurtz@chromium.org>");
 MODULE_ALIAS("platform:rockchip-iommu");