1 // SPDX-License-Identifier: GPL-2.0-only
5 * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
8 #include <linux/export.h>
9 #include <linux/iommu.h>
10 #include <linux/limits.h>
11 #include <linux/module.h>
13 #include <linux/of_iommu.h>
14 #include <linux/of_pci.h>
15 #include <linux/pci.h>
16 #include <linux/slab.h>
17 #include <linux/fsl/mc.h>
21 static int of_iommu_xlate(struct device *dev,
22 struct of_phandle_args *iommu_spec)
24 const struct iommu_ops *ops;
25 struct fwnode_handle *fwnode = &iommu_spec->np->fwnode;
28 ops = iommu_ops_from_fwnode(fwnode);
29 if ((ops && !ops->of_xlate) ||
30 !of_device_is_available(iommu_spec->np))
33 ret = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops);
37 * The otherwise-empty fwspec handily serves to indicate the specific
38 * IOMMU device we're waiting for, which will be useful if we ever get
39 * a proper probe-ordering dependency mechanism in future.
42 return driver_deferred_probe_check_state(dev);
44 if (!try_module_get(ops->owner))
47 ret = ops->of_xlate(dev, iommu_spec);
48 module_put(ops->owner);
52 static int of_iommu_configure_dev_id(struct device_node *master_np,
56 struct of_phandle_args iommu_spec = { .args_count = 1 };
59 err = of_map_id(master_np, *id, "iommu-map",
60 "iommu-map-mask", &iommu_spec.np,
63 return err == -ENODEV ? NO_IOMMU : err;
65 err = of_iommu_xlate(dev, &iommu_spec);
66 of_node_put(iommu_spec.np);
70 static int of_iommu_configure_dev(struct device_node *master_np,
73 struct of_phandle_args iommu_spec;
74 int err = NO_IOMMU, idx = 0;
76 while (!of_parse_phandle_with_args(master_np, "iommus",
79 err = of_iommu_xlate(dev, &iommu_spec);
80 of_node_put(iommu_spec.np);
89 struct of_pci_iommu_alias_info {
91 struct device_node *np;
94 static int of_pci_iommu_init(struct pci_dev *pdev, u16 alias, void *data)
96 struct of_pci_iommu_alias_info *info = data;
99 return of_iommu_configure_dev_id(info->np, info->dev, &input_id);
102 static int of_iommu_configure_device(struct device_node *master_np,
103 struct device *dev, const u32 *id)
105 return (id) ? of_iommu_configure_dev_id(master_np, dev, id) :
106 of_iommu_configure_dev(master_np, dev);
109 const struct iommu_ops *of_iommu_configure(struct device *dev,
110 struct device_node *master_np,
113 const struct iommu_ops *ops = NULL;
114 struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
124 /* In the deferred case, start again from scratch */
125 iommu_fwspec_free(dev);
129 * We don't currently walk up the tree looking for a parent IOMMU.
130 * See the `Notes:' section of
131 * Documentation/devicetree/bindings/iommu/iommu.txt
133 if (dev_is_pci(dev)) {
134 struct of_pci_iommu_alias_info info = {
140 err = pci_for_each_dma_alias(to_pci_dev(dev),
141 of_pci_iommu_init, &info);
143 err = of_iommu_configure_device(master_np, dev, id);
147 * Two success conditions can be represented by non-negative err here:
148 * >0 : there is no IOMMU, or one was unavailable for non-fatal reasons
149 * 0 : we found an IOMMU, and dev->fwspec is initialised appropriately
150 * <0 : any actual error
153 /* The fwspec pointer changed, read it again */
154 fwspec = dev_iommu_fwspec_get(dev);
158 * If we have reason to believe the IOMMU driver missed the initial
159 * probe for dev, replay it to get things in order.
161 if (!err && dev->bus && !device_iommu_mapped(dev))
162 err = iommu_probe_device(dev);
164 /* Ignore all other errors apart from EPROBE_DEFER */
165 if (err == -EPROBE_DEFER) {
167 } else if (err < 0) {
168 dev_dbg(dev, "Adding to IOMMU failed: %d\n", err);