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 == -EPROBE_DEFER)
33 return driver_deferred_probe_check_state(dev);
34 if (ret)
35 return ret;
36
37 ops = iommu_ops_from_fwnode(&iommu_spec->np->fwnode);
38 if (!ops->of_xlate || !try_module_get(ops->owner))
39 return -ENODEV;
40
41 ret = ops->of_xlate(dev, iommu_spec);
42 module_put(ops->owner);
43 return ret;
44 }
45
of_iommu_configure_dev_id(struct device_node * master_np,struct device * dev,const u32 * id)46 static int of_iommu_configure_dev_id(struct device_node *master_np,
47 struct device *dev,
48 const u32 *id)
49 {
50 struct of_phandle_args iommu_spec = { .args_count = 1 };
51 int err;
52
53 err = of_map_id(master_np, *id, "iommu-map",
54 "iommu-map-mask", &iommu_spec.np,
55 iommu_spec.args);
56 if (err)
57 return err;
58
59 err = of_iommu_xlate(dev, &iommu_spec);
60 of_node_put(iommu_spec.np);
61 return err;
62 }
63
of_iommu_configure_dev(struct device_node * master_np,struct device * dev)64 static int of_iommu_configure_dev(struct device_node *master_np,
65 struct device *dev)
66 {
67 struct of_phandle_args iommu_spec;
68 int err = -ENODEV, idx = 0;
69
70 while (!of_parse_phandle_with_args(master_np, "iommus",
71 "#iommu-cells",
72 idx, &iommu_spec)) {
73 err = of_iommu_xlate(dev, &iommu_spec);
74 of_node_put(iommu_spec.np);
75 idx++;
76 if (err)
77 break;
78 }
79
80 return err;
81 }
82
83 struct of_pci_iommu_alias_info {
84 struct device *dev;
85 struct device_node *np;
86 };
87
of_pci_iommu_init(struct pci_dev * pdev,u16 alias,void * data)88 static int of_pci_iommu_init(struct pci_dev *pdev, u16 alias, void *data)
89 {
90 struct of_pci_iommu_alias_info *info = data;
91 u32 input_id = alias;
92
93 return of_iommu_configure_dev_id(info->np, info->dev, &input_id);
94 }
95
of_iommu_configure_device(struct device_node * master_np,struct device * dev,const u32 * id)96 static int of_iommu_configure_device(struct device_node *master_np,
97 struct device *dev, const u32 *id)
98 {
99 return (id) ? of_iommu_configure_dev_id(master_np, dev, id) :
100 of_iommu_configure_dev(master_np, dev);
101 }
102
of_pci_check_device_ats(struct device * dev,struct device_node * np)103 static void of_pci_check_device_ats(struct device *dev, struct device_node *np)
104 {
105 struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
106
107 if (fwspec && of_property_read_bool(np, "ats-supported"))
108 fwspec->flags |= IOMMU_FWSPEC_PCI_RC_ATS;
109 }
110
111 /*
112 * Returns:
113 * 0 on success, an iommu was configured
114 * -ENODEV if the device does not have any IOMMU
115 * -EPROBEDEFER if probing should be tried again
116 * -errno fatal errors
117 */
of_iommu_configure(struct device * dev,struct device_node * master_np,const u32 * id)118 int of_iommu_configure(struct device *dev, struct device_node *master_np,
119 const u32 *id)
120 {
121 int err;
122
123 if (!master_np)
124 return -ENODEV;
125
126 /* Serialise to make dev->iommu stable under our potential fwspec */
127 mutex_lock(&iommu_probe_device_lock);
128 if (dev_iommu_fwspec_get(dev)) {
129 mutex_unlock(&iommu_probe_device_lock);
130 return 0;
131 }
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)
153 iommu_fwspec_free(dev);
154 mutex_unlock(&iommu_probe_device_lock);
155
156 if (!err && dev->bus)
157 err = iommu_probe_device(dev);
158
159 if (err && err != -EPROBE_DEFER)
160 dev_dbg(dev, "Adding to IOMMU failed: %d\n", err);
161
162 return err;
163 }
164
165 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)166 iommu_resv_region_get_type(struct device *dev,
167 struct resource *phys,
168 phys_addr_t start, size_t length)
169 {
170 phys_addr_t end = start + length - 1;
171
172 /*
173 * IOMMU regions without an associated physical region cannot be
174 * mapped and are simply reservations.
175 */
176 if (phys->start >= phys->end)
177 return IOMMU_RESV_RESERVED;
178
179 /* may be IOMMU_RESV_DIRECT_RELAXABLE for certain cases */
180 if (start == phys->start && end == phys->end)
181 return IOMMU_RESV_DIRECT;
182
183 dev_warn(dev, "treating non-direct mapping [%pr] -> [%pap-%pap] as reservation\n", phys,
184 &start, &end);
185 return IOMMU_RESV_RESERVED;
186 }
187
188 /**
189 * of_iommu_get_resv_regions - reserved region driver helper for device tree
190 * @dev: device for which to get reserved regions
191 * @list: reserved region list
192 *
193 * IOMMU drivers can use this to implement their .get_resv_regions() callback
194 * for memory regions attached to a device tree node. See the reserved-memory
195 * device tree bindings on how to use these:
196 *
197 * Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
198 */
of_iommu_get_resv_regions(struct device * dev,struct list_head * list)199 void of_iommu_get_resv_regions(struct device *dev, struct list_head *list)
200 {
201 #if IS_ENABLED(CONFIG_OF_ADDRESS)
202 struct of_phandle_iterator it;
203 int err;
204
205 of_for_each_phandle(&it, err, dev->of_node, "memory-region", NULL, 0) {
206 const __be32 *maps, *end;
207 struct resource phys;
208 int size;
209
210 memset(&phys, 0, sizeof(phys));
211
212 /*
213 * The "reg" property is optional and can be omitted by reserved-memory regions
214 * that represent reservations in the IOVA space, which are regions that should
215 * not be mapped.
216 */
217 if (of_property_present(it.node, "reg")) {
218 err = of_address_to_resource(it.node, 0, &phys);
219 if (err < 0) {
220 dev_err(dev, "failed to parse memory region %pOF: %d\n",
221 it.node, err);
222 continue;
223 }
224 }
225
226 maps = of_get_property(it.node, "iommu-addresses", &size);
227 if (!maps)
228 continue;
229
230 end = maps + size / sizeof(__be32);
231
232 while (maps < end) {
233 struct device_node *np;
234 u32 phandle;
235
236 phandle = be32_to_cpup(maps++);
237 np = of_find_node_by_phandle(phandle);
238
239 if (np == dev->of_node) {
240 int prot = IOMMU_READ | IOMMU_WRITE;
241 struct iommu_resv_region *region;
242 enum iommu_resv_type type;
243 phys_addr_t iova;
244 size_t length;
245
246 if (of_dma_is_coherent(dev->of_node))
247 prot |= IOMMU_CACHE;
248
249 maps = of_translate_dma_region(np, maps, &iova, &length);
250 if (length == 0) {
251 dev_warn(dev, "Cannot reserve IOVA region of 0 size\n");
252 continue;
253 }
254 type = iommu_resv_region_get_type(dev, &phys, iova, length);
255
256 region = iommu_alloc_resv_region(iova, length, prot, type,
257 GFP_KERNEL);
258 if (region)
259 list_add_tail(®ion->list, list);
260 }
261 }
262 }
263 #endif
264 }
265 EXPORT_SYMBOL(of_iommu_get_resv_regions);
266