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
20 #include "iommu-priv.h"
21
of_iommu_xlate(struct device * dev,struct of_phandle_args * iommu_spec)22 static int of_iommu_xlate(struct device *dev,
23 struct of_phandle_args *iommu_spec)
24 {
25 const struct iommu_ops *ops;
26 int ret;
27
28 if (!of_device_is_available(iommu_spec->np))
29 return -ENODEV;
30
31 ret = iommu_fwspec_init(dev, of_fwnode_handle(iommu_spec->np));
32 if (ret)
33 return ret;
34
35 ops = iommu_ops_from_fwnode(&iommu_spec->np->fwnode);
36 if (!ops->of_xlate || !try_module_get(ops->owner))
37 return -ENODEV;
38
39 ret = ops->of_xlate(dev, iommu_spec);
40 module_put(ops->owner);
41 return ret;
42 }
43
of_iommu_configure_dev_id(struct device_node * master_np,struct device * dev,const u32 * id)44 static int of_iommu_configure_dev_id(struct device_node *master_np,
45 struct device *dev,
46 const u32 *id)
47 {
48 struct of_phandle_args iommu_spec = { .args_count = 1 };
49 int err;
50
51 err = of_map_id(master_np, *id, "iommu-map",
52 "iommu-map-mask", &iommu_spec.np,
53 iommu_spec.args);
54 if (err)
55 return err;
56
57 err = of_iommu_xlate(dev, &iommu_spec);
58 of_node_put(iommu_spec.np);
59 return err;
60 }
61
of_iommu_configure_dev(struct device_node * master_np,struct device * dev)62 static int of_iommu_configure_dev(struct device_node *master_np,
63 struct device *dev)
64 {
65 struct of_phandle_args iommu_spec;
66 int err = -ENODEV, idx = 0;
67
68 while (!of_parse_phandle_with_args(master_np, "iommus",
69 "#iommu-cells",
70 idx, &iommu_spec)) {
71 err = of_iommu_xlate(dev, &iommu_spec);
72 of_node_put(iommu_spec.np);
73 idx++;
74 if (err)
75 break;
76 }
77
78 return err;
79 }
80
81 struct of_pci_iommu_alias_info {
82 struct device *dev;
83 struct device_node *np;
84 };
85
of_pci_iommu_init(struct pci_dev * pdev,u16 alias,void * data)86 static int of_pci_iommu_init(struct pci_dev *pdev, u16 alias, void *data)
87 {
88 struct of_pci_iommu_alias_info *info = data;
89 u32 input_id = alias;
90
91 return of_iommu_configure_dev_id(info->np, info->dev, &input_id);
92 }
93
of_iommu_configure_device(struct device_node * master_np,struct device * dev,const u32 * id)94 static int of_iommu_configure_device(struct device_node *master_np,
95 struct device *dev, const u32 *id)
96 {
97 return (id) ? of_iommu_configure_dev_id(master_np, dev, id) :
98 of_iommu_configure_dev(master_np, dev);
99 }
100
of_pci_check_device_ats(struct device * dev,struct device_node * np)101 static void of_pci_check_device_ats(struct device *dev, struct device_node *np)
102 {
103 struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
104
105 if (fwspec && of_property_read_bool(np, "ats-supported"))
106 fwspec->flags |= IOMMU_FWSPEC_PCI_RC_ATS;
107 }
108
109 /*
110 * Returns:
111 * 0 on success, an iommu was configured
112 * -ENODEV if the device does not have any IOMMU
113 * -EPROBEDEFER if probing should be tried again
114 * -errno fatal errors
115 */
of_iommu_configure(struct device * dev,struct device_node * master_np,const u32 * id)116 int of_iommu_configure(struct device *dev, struct device_node *master_np,
117 const u32 *id)
118 {
119 bool dev_iommu_present;
120 int err;
121
122 if (!master_np)
123 return -ENODEV;
124
125 /* Serialise to make dev->iommu stable under our potential fwspec */
126 mutex_lock(&iommu_probe_device_lock);
127 if (dev_iommu_fwspec_get(dev)) {
128 mutex_unlock(&iommu_probe_device_lock);
129 return 0;
130 }
131 dev_iommu_present = dev->iommu;
132
133 /*
134 * We don't currently walk up the tree looking for a parent IOMMU.
135 * See the `Notes:' section of
136 * Documentation/devicetree/bindings/iommu/iommu.txt
137 */
138 if (dev_is_pci(dev)) {
139 struct of_pci_iommu_alias_info info = {
140 .dev = dev,
141 .np = master_np,
142 };
143
144 pci_request_acs();
145 err = pci_for_each_dma_alias(to_pci_dev(dev),
146 of_pci_iommu_init, &info);
147 of_pci_check_device_ats(dev, master_np);
148 } else {
149 err = of_iommu_configure_device(master_np, dev, id);
150 }
151
152 if (err && dev_iommu_present)
153 iommu_fwspec_free(dev);
154 else if (err && dev->iommu)
155 dev_iommu_free(dev);
156 mutex_unlock(&iommu_probe_device_lock);
157
158 /*
159 * If we're not on the iommu_probe_device() path (as indicated by the
160 * initial dev->iommu) then try to simulate it. This should no longer
161 * happen unless of_dma_configure() is being misused outside bus code.
162 */
163 if (!err && dev->bus && !dev_iommu_present)
164 err = iommu_probe_device(dev);
165
166 if (err && err != -EPROBE_DEFER)
167 dev_dbg(dev, "Adding to IOMMU failed: %d\n", err);
168
169 return err;
170 }
171
172 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)173 iommu_resv_region_get_type(struct device *dev,
174 struct resource *phys,
175 phys_addr_t start, size_t length)
176 {
177 phys_addr_t end = start + length - 1;
178
179 /*
180 * IOMMU regions without an associated physical region cannot be
181 * mapped and are simply reservations.
182 */
183 if (phys->start >= phys->end)
184 return IOMMU_RESV_RESERVED;
185
186 /* may be IOMMU_RESV_DIRECT_RELAXABLE for certain cases */
187 if (start == phys->start && end == phys->end)
188 return IOMMU_RESV_DIRECT;
189
190 dev_warn(dev, "treating non-direct mapping [%pr] -> [%pap-%pap] as reservation\n", phys,
191 &start, &end);
192 return IOMMU_RESV_RESERVED;
193 }
194
195 /**
196 * of_iommu_get_resv_regions - reserved region driver helper for device tree
197 * @dev: device for which to get reserved regions
198 * @list: reserved region list
199 *
200 * IOMMU drivers can use this to implement their .get_resv_regions() callback
201 * for memory regions attached to a device tree node. See the reserved-memory
202 * device tree bindings on how to use these:
203 *
204 * Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
205 */
of_iommu_get_resv_regions(struct device * dev,struct list_head * list)206 void of_iommu_get_resv_regions(struct device *dev, struct list_head *list)
207 {
208 #if IS_ENABLED(CONFIG_OF_ADDRESS)
209 struct of_phandle_iterator it;
210 int err;
211
212 of_for_each_phandle(&it, err, dev->of_node, "memory-region", NULL, 0) {
213 const __be32 *maps, *end;
214 struct resource phys;
215 int size;
216
217 memset(&phys, 0, sizeof(phys));
218
219 /*
220 * The "reg" property is optional and can be omitted by reserved-memory regions
221 * that represent reservations in the IOVA space, which are regions that should
222 * not be mapped.
223 */
224 if (of_property_present(it.node, "reg")) {
225 err = of_address_to_resource(it.node, 0, &phys);
226 if (err < 0) {
227 dev_err(dev, "failed to parse memory region %pOF: %d\n",
228 it.node, err);
229 continue;
230 }
231 }
232
233 maps = of_get_property(it.node, "iommu-addresses", &size);
234 if (!maps)
235 continue;
236
237 end = maps + size / sizeof(__be32);
238
239 while (maps < end) {
240 struct device_node *np;
241 u32 phandle;
242
243 phandle = be32_to_cpup(maps++);
244 np = of_find_node_by_phandle(phandle);
245
246 if (np == dev->of_node) {
247 int prot = IOMMU_READ | IOMMU_WRITE;
248 struct iommu_resv_region *region;
249 enum iommu_resv_type type;
250 phys_addr_t iova;
251 size_t length;
252
253 if (of_dma_is_coherent(dev->of_node))
254 prot |= IOMMU_CACHE;
255
256 maps = of_translate_dma_region(np, maps, &iova, &length);
257 if (length == 0) {
258 dev_warn(dev, "Cannot reserve IOVA region of 0 size\n");
259 continue;
260 }
261 type = iommu_resv_region_get_type(dev, &phys, iova, length);
262
263 region = iommu_alloc_resv_region(iova, length, prot, type,
264 GFP_KERNEL);
265 if (region)
266 list_add_tail(®ion->list, list);
267 }
268 }
269 }
270 #endif
271 }
272 EXPORT_SYMBOL(of_iommu_get_resv_regions);
273