1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * OF helpers for IOMMU
4 *
5 * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
6 */
7
8#include <linux/export.h>
9#include <linux/iommu.h>
10#include <linux/limits.h>
11#include <linux/module.h>
12#include <linux/of.h>
13#include <linux/of_address.h>
14#include <linux/of_iommu.h>
15#include <linux/of_pci.h>
16#include <linux/pci.h>
17#include <linux/slab.h>
18#include <linux/fsl/mc.h>
19
20static int of_iommu_xlate(struct device *dev,
21 struct of_phandle_args *iommu_spec)
22{
23 const struct iommu_ops *ops;
24 struct fwnode_handle *fwnode = &iommu_spec->np->fwnode;
25 int ret;
26
27 ops = iommu_ops_from_fwnode(fwnode);
28 if ((ops && !ops->of_xlate) ||
29 !of_device_is_available(device: iommu_spec->np))
30 return -ENODEV;
31
32 ret = iommu_fwspec_init(dev, iommu_fwnode: fwnode, ops);
33 if (ret)
34 return ret;
35 /*
36 * The otherwise-empty fwspec handily serves to indicate the specific
37 * IOMMU device we're waiting for, which will be useful if we ever get
38 * a proper probe-ordering dependency mechanism in future.
39 */
40 if (!ops)
41 return driver_deferred_probe_check_state(dev);
42
43 if (!try_module_get(module: ops->owner))
44 return -ENODEV;
45
46 ret = ops->of_xlate(dev, iommu_spec);
47 module_put(module: ops->owner);
48 return ret;
49}
50
51static int of_iommu_configure_dev_id(struct device_node *master_np,
52 struct device *dev,
53 const u32 *id)
54{
55 struct of_phandle_args iommu_spec = { .args_count = 1 };
56 int err;
57
58 err = of_map_id(np: master_np, id: *id, map_name: "iommu-map",
59 map_mask_name: "iommu-map-mask", target: &iommu_spec.np,
60 id_out: iommu_spec.args);
61 if (err)
62 return err;
63
64 err = of_iommu_xlate(dev, iommu_spec: &iommu_spec);
65 of_node_put(node: iommu_spec.np);
66 return err;
67}
68
69static int of_iommu_configure_dev(struct device_node *master_np,
70 struct device *dev)
71{
72 struct of_phandle_args iommu_spec;
73 int err = -ENODEV, idx = 0;
74
75 while (!of_parse_phandle_with_args(np: master_np, list_name: "iommus",
76 cells_name: "#iommu-cells",
77 index: idx, out_args: &iommu_spec)) {
78 err = of_iommu_xlate(dev, iommu_spec: &iommu_spec);
79 of_node_put(node: iommu_spec.np);
80 idx++;
81 if (err)
82 break;
83 }
84
85 return err;
86}
87
88struct of_pci_iommu_alias_info {
89 struct device *dev;
90 struct device_node *np;
91};
92
93static int of_pci_iommu_init(struct pci_dev *pdev, u16 alias, void *data)
94{
95 struct of_pci_iommu_alias_info *info = data;
96 u32 input_id = alias;
97
98 return of_iommu_configure_dev_id(master_np: info->np, dev: info->dev, id: &input_id);
99}
100
101static int of_iommu_configure_device(struct device_node *master_np,
102 struct device *dev, const u32 *id)
103{
104 return (id) ? of_iommu_configure_dev_id(master_np, dev, id) :
105 of_iommu_configure_dev(master_np, dev);
106}
107
108/*
109 * Returns:
110 * 0 on success, an iommu was configured
111 * -ENODEV if the device does not have any IOMMU
112 * -EPROBEDEFER if probing should be tried again
113 * -errno fatal errors
114 */
115int of_iommu_configure(struct device *dev, struct device_node *master_np,
116 const u32 *id)
117{
118 struct iommu_fwspec *fwspec;
119 int err;
120
121 if (!master_np)
122 return -ENODEV;
123
124 /* Serialise to make dev->iommu stable under our potential fwspec */
125 mutex_lock(&iommu_probe_device_lock);
126 fwspec = dev_iommu_fwspec_get(dev);
127 if (fwspec) {
128 if (fwspec->ops) {
129 mutex_unlock(lock: &iommu_probe_device_lock);
130 return 0;
131 }
132 /* In the deferred case, start again from scratch */
133 iommu_fwspec_free(dev);
134 }
135
136 /*
137 * We don't currently walk up the tree looking for a parent IOMMU.
138 * See the `Notes:' section of
139 * Documentation/devicetree/bindings/iommu/iommu.txt
140 */
141 if (dev_is_pci(dev)) {
142 struct of_pci_iommu_alias_info info = {
143 .dev = dev,
144 .np = master_np,
145 };
146
147 pci_request_acs();
148 err = pci_for_each_dma_alias(to_pci_dev(dev),
149 fn: of_pci_iommu_init, data: &info);
150 } else {
151 err = of_iommu_configure_device(master_np, dev, id);
152 }
153 mutex_unlock(lock: &iommu_probe_device_lock);
154
155 if (err == -ENODEV || err == -EPROBE_DEFER)
156 return err;
157 if (err)
158 goto err_log;
159
160 err = iommu_probe_device(dev);
161 if (err)
162 goto err_log;
163 return 0;
164
165err_log:
166 dev_dbg(dev, "Adding to IOMMU failed: %pe\n", ERR_PTR(err));
167 return err;
168}
169
170static enum iommu_resv_type __maybe_unused
171iommu_resv_region_get_type(struct device *dev,
172 struct resource *phys,
173 phys_addr_t start, size_t length)
174{
175 phys_addr_t end = start + length - 1;
176
177 /*
178 * IOMMU regions without an associated physical region cannot be
179 * mapped and are simply reservations.
180 */
181 if (phys->start >= phys->end)
182 return IOMMU_RESV_RESERVED;
183
184 /* may be IOMMU_RESV_DIRECT_RELAXABLE for certain cases */
185 if (start == phys->start && end == phys->end)
186 return IOMMU_RESV_DIRECT;
187
188 dev_warn(dev, "treating non-direct mapping [%pr] -> [%pap-%pap] as reservation\n", phys,
189 &start, &end);
190 return IOMMU_RESV_RESERVED;
191}
192
193/**
194 * of_iommu_get_resv_regions - reserved region driver helper for device tree
195 * @dev: device for which to get reserved regions
196 * @list: reserved region list
197 *
198 * IOMMU drivers can use this to implement their .get_resv_regions() callback
199 * for memory regions attached to a device tree node. See the reserved-memory
200 * device tree bindings on how to use these:
201 *
202 * Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
203 */
204void of_iommu_get_resv_regions(struct device *dev, struct list_head *list)
205{
206#if IS_ENABLED(CONFIG_OF_ADDRESS)
207 struct of_phandle_iterator it;
208 int err;
209
210 of_for_each_phandle(&it, err, dev->of_node, "memory-region", NULL, 0) {
211 const __be32 *maps, *end;
212 struct resource phys;
213 int size;
214
215 memset(&phys, 0, sizeof(phys));
216
217 /*
218 * The "reg" property is optional and can be omitted by reserved-memory regions
219 * that represent reservations in the IOVA space, which are regions that should
220 * not be mapped.
221 */
222 if (of_find_property(np: it.node, name: "reg", NULL)) {
223 err = of_address_to_resource(dev: it.node, index: 0, r: &phys);
224 if (err < 0) {
225 dev_err(dev, "failed to parse memory region %pOF: %d\n",
226 it.node, err);
227 continue;
228 }
229 }
230
231 maps = of_get_property(node: it.node, name: "iommu-addresses", lenp: &size);
232 if (!maps)
233 continue;
234
235 end = maps + size / sizeof(__be32);
236
237 while (maps < end) {
238 struct device_node *np;
239 u32 phandle;
240
241 phandle = be32_to_cpup(p: maps++);
242 np = of_find_node_by_phandle(handle: phandle);
243
244 if (np == dev->of_node) {
245 int prot = IOMMU_READ | IOMMU_WRITE;
246 struct iommu_resv_region *region;
247 enum iommu_resv_type type;
248 phys_addr_t iova;
249 size_t length;
250
251 if (of_dma_is_coherent(np: dev->of_node))
252 prot |= IOMMU_CACHE;
253
254 maps = of_translate_dma_region(dev: np, addr: maps, start: &iova, length: &length);
255 if (length == 0) {
256 dev_warn(dev, "Cannot reserve IOVA region of 0 size\n");
257 continue;
258 }
259 type = iommu_resv_region_get_type(dev, phys: &phys, start: iova, length);
260
261 region = iommu_alloc_resv_region(start: iova, length, prot, type,
262 GFP_KERNEL);
263 if (region)
264 list_add_tail(new: &region->list, head: list);
265 }
266 }
267 }
268#endif
269}
270EXPORT_SYMBOL(of_iommu_get_resv_regions);
271

source code of linux/drivers/iommu/of_iommu.c