1 files changed, 282 insertions, 0 deletions
diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
new file mode 100644
index 000000000..42cffb0ee
--- /dev/null
+++ b/drivers/iommu/of_iommu.c
@@ -0,0 +1,282 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * OF helpers for IOMMU
+ *
+ * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
+ */
+
+#include <linux/export.h>
+#include <linux/iommu.h>
+#include <linux/limits.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_iommu.h>
+#include <linux/of_pci.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+#include <linux/fsl/mc.h>
+
+#define NO_IOMMU	1
+
+static 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;
+	int ret;
+
+	ops = iommu_ops_from_fwnode(fwnode);
+	if ((ops && !ops->of_xlate) ||
+	    !of_device_is_available(iommu_spec->np))
+		return NO_IOMMU;
+
+	ret = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops);
+	if (ret)
+		return ret;
+	/*
+	 * The otherwise-empty fwspec handily serves to indicate the specific
+	 * IOMMU device we're waiting for, which will be useful if we ever get
+	 * a proper probe-ordering dependency mechanism in future.
+	 */
+	if (!ops)
+		return driver_deferred_probe_check_state(dev);
+
+	if (!try_module_get(ops->owner))
+		return -ENODEV;
+
+	ret = ops->of_xlate(dev, iommu_spec);
+	module_put(ops->owner);
+	return ret;
+}
+
+static int of_iommu_configure_dev_id(struct device_node *master_np,
+				     struct device *dev,
+				     const u32 *id)
+{
+	struct of_phandle_args iommu_spec = { .args_count = 1 };
+	int err;
+
+	err = of_map_id(master_np, *id, "iommu-map",
+			 "iommu-map-mask", &iommu_spec.np,
+			 iommu_spec.args);
+	if (err)
+		return err == -ENODEV ? NO_IOMMU : err;
+
+	err = of_iommu_xlate(dev, &iommu_spec);
+	of_node_put(iommu_spec.np);
+	return err;
+}
+
+static int of_iommu_configure_dev(struct device_node *master_np,
+				  struct device *dev)
+{
+	struct of_phandle_args iommu_spec;
+	int err = NO_IOMMU, idx = 0;
+
+	while (!of_parse_phandle_with_args(master_np, "iommus",
+					   "#iommu-cells",
+					   idx, &iommu_spec)) {
+		err = of_iommu_xlate(dev, &iommu_spec);
+		of_node_put(iommu_spec.np);
+		idx++;
+		if (err)
+			break;
+	}
+
+	return err;
+}
+
+struct of_pci_iommu_alias_info {
+	struct device *dev;
+	struct device_node *np;
+};
+
+static int of_pci_iommu_init(struct pci_dev *pdev, u16 alias, void *data)
+{
+	struct of_pci_iommu_alias_info *info = data;
+	u32 input_id = alias;
+
+	return of_iommu_configure_dev_id(info->np, info->dev, &input_id);
+}
+
+static int of_iommu_configure_device(struct device_node *master_np,
+				     struct device *dev, const u32 *id)
+{
+	return (id) ? of_iommu_configure_dev_id(master_np, dev, id) :
+		      of_iommu_configure_dev(master_np, dev);
+}
+
+const struct iommu_ops *of_iommu_configure(struct device *dev,
+					   struct device_node *master_np,
+					   const u32 *id)
+{
+	const struct iommu_ops *ops = NULL;
+	struct iommu_fwspec *fwspec;
+	int err = NO_IOMMU;
+
+	if (!master_np)
+		return NULL;
+
+	/* Serialise to make dev->iommu stable under our potential fwspec */
+	mutex_lock(&iommu_probe_device_lock);
+	fwspec = dev_iommu_fwspec_get(dev);
+	if (fwspec) {
+		if (fwspec->ops) {
+			mutex_unlock(&iommu_probe_device_lock);
+			return fwspec->ops;
+		}
+		/* In the deferred case, start again from scratch */
+		iommu_fwspec_free(dev);
+	}
+
+	/*
+	 * We don't currently walk up the tree looking for a parent IOMMU.
+	 * See the `Notes:' section of
+	 * Documentation/devicetree/bindings/iommu/iommu.txt
+	 */
+	if (dev_is_pci(dev)) {
+		struct of_pci_iommu_alias_info info = {
+			.dev = dev,
+			.np = master_np,
+		};
+
+		pci_request_acs();
+		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);
+	}
+
+	/*
+	 * Two success conditions can be represented by non-negative err here:
+	 * >0 : there is no IOMMU, or one was unavailable for non-fatal reasons
+	 *  0 : we found an IOMMU, and dev->fwspec is initialised appropriately
+	 * <0 : any actual error
+	 */
+	if (!err) {
+		/* The fwspec pointer changed, read it again */
+		fwspec = dev_iommu_fwspec_get(dev);
+		ops    = fwspec->ops;
+	}
+	mutex_unlock(&iommu_probe_device_lock);
+
+	/*
+	 * If we have reason to believe the IOMMU driver missed the initial
+	 * probe for dev, replay it to get things in order.
+	 */
+	if (!err && dev->bus)
+		err = iommu_probe_device(dev);
+
+	/* Ignore all other errors apart from EPROBE_DEFER */
+	if (err == -EPROBE_DEFER) {
+		ops = ERR_PTR(err);
+	} else if (err < 0) {
+		dev_dbg(dev, "Adding to IOMMU failed: %d\n", err);
+		ops = NULL;
+	}
+
+	return ops;
+}
+
+static enum iommu_resv_type __maybe_unused
+iommu_resv_region_get_type(struct device *dev,
+			   struct resource *phys,
+			   phys_addr_t start, size_t length)
+{
+	phys_addr_t end = start + length - 1;
+
+	/*
+	 * IOMMU regions without an associated physical region cannot be
+	 * mapped and are simply reservations.
+	 */
+	if (phys->start >= phys->end)
+		return IOMMU_RESV_RESERVED;
+
+	/* may be IOMMU_RESV_DIRECT_RELAXABLE for certain cases */
+	if (start == phys->start && end == phys->end)
+		return IOMMU_RESV_DIRECT;
+
+	dev_warn(dev, "treating non-direct mapping [%pr] -> [%pap-%pap] as reservation\n", phys,
+		 &start, &end);
+	return IOMMU_RESV_RESERVED;
+}
+
+/**
+ * of_iommu_get_resv_regions - reserved region driver helper for device tree
+ * @dev: device for which to get reserved regions
+ * @list: reserved region list
+ *
+ * IOMMU drivers can use this to implement their .get_resv_regions() callback
+ * for memory regions attached to a device tree node. See the reserved-memory
+ * device tree bindings on how to use these:
+ *
+ *   Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
+ */
+void of_iommu_get_resv_regions(struct device *dev, struct list_head *list)
+{
+#if IS_ENABLED(CONFIG_OF_ADDRESS)
+	struct of_phandle_iterator it;
+	int err;
+
+	of_for_each_phandle(&it, err, dev->of_node, "memory-region", NULL, 0) {
+		const __be32 *maps, *end;
+		struct resource phys;
+		int size;
+
+		memset(&phys, 0, sizeof(phys));
+
+		/*
+		 * The "reg" property is optional and can be omitted by reserved-memory regions
+		 * that represent reservations in the IOVA space, which are regions that should
+		 * not be mapped.
+		 */
+		if (of_find_property(it.node, "reg", NULL)) {
+			err = of_address_to_resource(it.node, 0, &phys);
+			if (err < 0) {
+				dev_err(dev, "failed to parse memory region %pOF: %d\n",
+					it.node, err);
+				continue;
+			}
+		}
+
+		maps = of_get_property(it.node, "iommu-addresses", &size);
+		if (!maps)
+			continue;
+
+		end = maps + size / sizeof(__be32);
+
+		while (maps < end) {
+			struct device_node *np;
+			u32 phandle;
+
+			phandle = be32_to_cpup(maps++);
+			np = of_find_node_by_phandle(phandle);
+
+			if (np == dev->of_node) {
+				int prot = IOMMU_READ | IOMMU_WRITE;
+				struct iommu_resv_region *region;
+				enum iommu_resv_type type;
+				phys_addr_t iova;
+				size_t length;
+
+				if (of_dma_is_coherent(dev->of_node))
+					prot |= IOMMU_CACHE;
+
+				maps = of_translate_dma_region(np, maps, &iova, &length);
+				if (length == 0) {
+					dev_warn(dev, "Cannot reserve IOVA region of 0 size\n");
+					continue;
+				}
+				type = iommu_resv_region_get_type(dev, &phys, iova, length);
+
+				region = iommu_alloc_resv_region(iova, length, prot, type,
+								 GFP_KERNEL);
+				if (region)
+					list_add_tail(&region->list, list);
+			}
+		}
+	}
+#endif
+}
+EXPORT_SYMBOL(of_iommu_get_resv_regions);