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 | static 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 | |
51 | static 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 | |
69 | static 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 | |
88 | struct of_pci_iommu_alias_info { |
89 | struct device *dev; |
90 | struct device_node *np; |
91 | }; |
92 | |
93 | static 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 | |
101 | static 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 | */ |
115 | int 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 | |
165 | err_log: |
166 | dev_dbg(dev, "Adding to IOMMU failed: %pe\n" , ERR_PTR(err)); |
167 | return err; |
168 | } |
169 | |
170 | static enum iommu_resv_type __maybe_unused |
171 | iommu_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 | */ |
204 | void 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: ®ion->list, head: list); |
265 | } |
266 | } |
267 | } |
268 | #endif |
269 | } |
270 | EXPORT_SYMBOL(of_iommu_get_resv_regions); |
271 | |