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 | #define NO_IOMMU 1 |
21 | |
22 | static int of_iommu_xlate(struct device *dev, |
23 | struct of_phandle_args *iommu_spec) |
24 | { |
25 | const struct iommu_ops *ops; |
26 | struct fwnode_handle *fwnode = &iommu_spec->np->fwnode; |
27 | int ret; |
28 | |
29 | ops = iommu_ops_from_fwnode(fwnode); |
30 | if ((ops && !ops->of_xlate) || |
31 | !of_device_is_available(device: iommu_spec->np)) |
32 | return NO_IOMMU; |
33 | |
34 | ret = iommu_fwspec_init(dev, iommu_fwnode: &iommu_spec->np->fwnode, ops); |
35 | if (ret) |
36 | return ret; |
37 | /* |
38 | * The otherwise-empty fwspec handily serves to indicate the specific |
39 | * IOMMU device we're waiting for, which will be useful if we ever get |
40 | * a proper probe-ordering dependency mechanism in future. |
41 | */ |
42 | if (!ops) |
43 | return driver_deferred_probe_check_state(dev); |
44 | |
45 | if (!try_module_get(module: ops->owner)) |
46 | return -ENODEV; |
47 | |
48 | ret = ops->of_xlate(dev, iommu_spec); |
49 | module_put(module: ops->owner); |
50 | return ret; |
51 | } |
52 | |
53 | static int of_iommu_configure_dev_id(struct device_node *master_np, |
54 | struct device *dev, |
55 | const u32 *id) |
56 | { |
57 | struct of_phandle_args iommu_spec = { .args_count = 1 }; |
58 | int err; |
59 | |
60 | err = of_map_id(np: master_np, id: *id, map_name: "iommu-map" , |
61 | map_mask_name: "iommu-map-mask" , target: &iommu_spec.np, |
62 | id_out: iommu_spec.args); |
63 | if (err) |
64 | return err == -ENODEV ? NO_IOMMU : err; |
65 | |
66 | err = of_iommu_xlate(dev, iommu_spec: &iommu_spec); |
67 | of_node_put(node: iommu_spec.np); |
68 | return err; |
69 | } |
70 | |
71 | static int of_iommu_configure_dev(struct device_node *master_np, |
72 | struct device *dev) |
73 | { |
74 | struct of_phandle_args iommu_spec; |
75 | int err = NO_IOMMU, idx = 0; |
76 | |
77 | while (!of_parse_phandle_with_args(np: master_np, list_name: "iommus" , |
78 | cells_name: "#iommu-cells" , |
79 | index: idx, out_args: &iommu_spec)) { |
80 | err = of_iommu_xlate(dev, iommu_spec: &iommu_spec); |
81 | of_node_put(node: iommu_spec.np); |
82 | idx++; |
83 | if (err) |
84 | break; |
85 | } |
86 | |
87 | return err; |
88 | } |
89 | |
90 | struct of_pci_iommu_alias_info { |
91 | struct device *dev; |
92 | struct device_node *np; |
93 | }; |
94 | |
95 | static int of_pci_iommu_init(struct pci_dev *pdev, u16 alias, void *data) |
96 | { |
97 | struct of_pci_iommu_alias_info *info = data; |
98 | u32 input_id = alias; |
99 | |
100 | return of_iommu_configure_dev_id(master_np: info->np, dev: info->dev, id: &input_id); |
101 | } |
102 | |
103 | static int of_iommu_configure_device(struct device_node *master_np, |
104 | struct device *dev, const u32 *id) |
105 | { |
106 | return (id) ? of_iommu_configure_dev_id(master_np, dev, id) : |
107 | of_iommu_configure_dev(master_np, dev); |
108 | } |
109 | |
110 | const struct iommu_ops *of_iommu_configure(struct device *dev, |
111 | struct device_node *master_np, |
112 | const u32 *id) |
113 | { |
114 | const struct iommu_ops *ops = NULL; |
115 | struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); |
116 | int err = NO_IOMMU; |
117 | |
118 | if (!master_np) |
119 | return NULL; |
120 | |
121 | if (fwspec) { |
122 | if (fwspec->ops) |
123 | return fwspec->ops; |
124 | |
125 | /* In the deferred case, start again from scratch */ |
126 | iommu_fwspec_free(dev); |
127 | } |
128 | |
129 | /* |
130 | * We don't currently walk up the tree looking for a parent IOMMU. |
131 | * See the `Notes:' section of |
132 | * Documentation/devicetree/bindings/iommu/iommu.txt |
133 | */ |
134 | if (dev_is_pci(dev)) { |
135 | struct of_pci_iommu_alias_info info = { |
136 | .dev = dev, |
137 | .np = master_np, |
138 | }; |
139 | |
140 | pci_request_acs(); |
141 | err = pci_for_each_dma_alias(to_pci_dev(dev), |
142 | fn: of_pci_iommu_init, data: &info); |
143 | } else { |
144 | err = of_iommu_configure_device(master_np, dev, id); |
145 | } |
146 | |
147 | /* |
148 | * Two success conditions can be represented by non-negative err here: |
149 | * >0 : there is no IOMMU, or one was unavailable for non-fatal reasons |
150 | * 0 : we found an IOMMU, and dev->fwspec is initialised appropriately |
151 | * <0 : any actual error |
152 | */ |
153 | if (!err) { |
154 | /* The fwspec pointer changed, read it again */ |
155 | fwspec = dev_iommu_fwspec_get(dev); |
156 | ops = fwspec->ops; |
157 | } |
158 | /* |
159 | * If we have reason to believe the IOMMU driver missed the initial |
160 | * probe for dev, replay it to get things in order. |
161 | */ |
162 | if (!err && dev->bus) |
163 | err = iommu_probe_device(dev); |
164 | |
165 | /* Ignore all other errors apart from EPROBE_DEFER */ |
166 | if (err == -EPROBE_DEFER) { |
167 | ops = ERR_PTR(error: err); |
168 | } else if (err < 0) { |
169 | dev_dbg(dev, "Adding to IOMMU failed: %d\n" , err); |
170 | ops = NULL; |
171 | } |
172 | |
173 | return ops; |
174 | } |
175 | |
176 | static enum iommu_resv_type __maybe_unused |
177 | iommu_resv_region_get_type(struct device *dev, |
178 | struct resource *phys, |
179 | phys_addr_t start, size_t length) |
180 | { |
181 | phys_addr_t end = start + length - 1; |
182 | |
183 | /* |
184 | * IOMMU regions without an associated physical region cannot be |
185 | * mapped and are simply reservations. |
186 | */ |
187 | if (phys->start >= phys->end) |
188 | return IOMMU_RESV_RESERVED; |
189 | |
190 | /* may be IOMMU_RESV_DIRECT_RELAXABLE for certain cases */ |
191 | if (start == phys->start && end == phys->end) |
192 | return IOMMU_RESV_DIRECT; |
193 | |
194 | dev_warn(dev, "treating non-direct mapping [%pr] -> [%pap-%pap] as reservation\n" , &phys, |
195 | &start, &end); |
196 | return IOMMU_RESV_RESERVED; |
197 | } |
198 | |
199 | /** |
200 | * of_iommu_get_resv_regions - reserved region driver helper for device tree |
201 | * @dev: device for which to get reserved regions |
202 | * @list: reserved region list |
203 | * |
204 | * IOMMU drivers can use this to implement their .get_resv_regions() callback |
205 | * for memory regions attached to a device tree node. See the reserved-memory |
206 | * device tree bindings on how to use these: |
207 | * |
208 | * Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt |
209 | */ |
210 | void of_iommu_get_resv_regions(struct device *dev, struct list_head *list) |
211 | { |
212 | #if IS_ENABLED(CONFIG_OF_ADDRESS) |
213 | struct of_phandle_iterator it; |
214 | int err; |
215 | |
216 | of_for_each_phandle(&it, err, dev->of_node, "memory-region" , NULL, 0) { |
217 | const __be32 *maps, *end; |
218 | struct resource phys; |
219 | int size; |
220 | |
221 | memset(&phys, 0, sizeof(phys)); |
222 | |
223 | /* |
224 | * The "reg" property is optional and can be omitted by reserved-memory regions |
225 | * that represent reservations in the IOVA space, which are regions that should |
226 | * not be mapped. |
227 | */ |
228 | if (of_find_property(np: it.node, name: "reg" , NULL)) { |
229 | err = of_address_to_resource(dev: it.node, index: 0, r: &phys); |
230 | if (err < 0) { |
231 | dev_err(dev, "failed to parse memory region %pOF: %d\n" , |
232 | it.node, err); |
233 | continue; |
234 | } |
235 | } |
236 | |
237 | maps = of_get_property(node: it.node, name: "iommu-addresses" , lenp: &size); |
238 | if (!maps) |
239 | continue; |
240 | |
241 | end = maps + size / sizeof(__be32); |
242 | |
243 | while (maps < end) { |
244 | struct device_node *np; |
245 | u32 phandle; |
246 | |
247 | phandle = be32_to_cpup(p: maps++); |
248 | np = of_find_node_by_phandle(handle: phandle); |
249 | |
250 | if (np == dev->of_node) { |
251 | int prot = IOMMU_READ | IOMMU_WRITE; |
252 | struct iommu_resv_region *region; |
253 | enum iommu_resv_type type; |
254 | phys_addr_t iova; |
255 | size_t length; |
256 | |
257 | maps = of_translate_dma_region(dev: np, addr: maps, start: &iova, length: &length); |
258 | type = iommu_resv_region_get_type(dev, phys: &phys, start: iova, length); |
259 | |
260 | region = iommu_alloc_resv_region(start: iova, length, prot, type, |
261 | GFP_KERNEL); |
262 | if (region) |
263 | list_add_tail(new: ®ion->list, head: list); |
264 | } |
265 | } |
266 | } |
267 | #endif |
268 | } |
269 | EXPORT_SYMBOL(of_iommu_get_resv_regions); |
270 | |