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4e0ee78f HD |
1 | /* |
2 | * OF helpers for IOMMU | |
3 | * | |
4 | * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify it | |
7 | * under the terms and conditions of the GNU General Public License, | |
8 | * version 2, as published by the Free Software Foundation. | |
9 | * | |
10 | * This program is distributed in the hope it will be useful, but WITHOUT | |
11 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
12 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
13 | * more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License along with | |
16 | * this program; if not, write to the Free Software Foundation, Inc., | |
17 | * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. | |
18 | */ | |
19 | ||
20 | #include <linux/export.h> | |
7eba1d51 | 21 | #include <linux/iommu.h> |
4e0ee78f HD |
22 | #include <linux/limits.h> |
23 | #include <linux/of.h> | |
cbff5634 | 24 | #include <linux/of_iommu.h> |
b996444c | 25 | #include <linux/of_pci.h> |
a42a7a1f | 26 | #include <linux/slab.h> |
4e0ee78f | 27 | |
da4b0275 RM |
28 | #define NO_IOMMU 1 |
29 | ||
1cd076bf WD |
30 | static const struct of_device_id __iommu_of_table_sentinel |
31 | __used __section(__iommu_of_table_end); | |
32 | ||
4e0ee78f HD |
33 | /** |
34 | * of_get_dma_window - Parse *dma-window property and returns 0 if found. | |
35 | * | |
36 | * @dn: device node | |
37 | * @prefix: prefix for property name if any | |
38 | * @index: index to start to parse | |
39 | * @busno: Returns busno if supported. Otherwise pass NULL | |
40 | * @addr: Returns address that DMA starts | |
41 | * @size: Returns the range that DMA can handle | |
42 | * | |
43 | * This supports different formats flexibly. "prefix" can be | |
44 | * configured if any. "busno" and "index" are optionally | |
45 | * specified. Set 0(or NULL) if not used. | |
46 | */ | |
47 | int of_get_dma_window(struct device_node *dn, const char *prefix, int index, | |
48 | unsigned long *busno, dma_addr_t *addr, size_t *size) | |
49 | { | |
50 | const __be32 *dma_window, *end; | |
51 | int bytes, cur_index = 0; | |
52 | char propname[NAME_MAX], addrname[NAME_MAX], sizename[NAME_MAX]; | |
53 | ||
54 | if (!dn || !addr || !size) | |
55 | return -EINVAL; | |
56 | ||
57 | if (!prefix) | |
58 | prefix = ""; | |
59 | ||
60 | snprintf(propname, sizeof(propname), "%sdma-window", prefix); | |
61 | snprintf(addrname, sizeof(addrname), "%s#dma-address-cells", prefix); | |
62 | snprintf(sizename, sizeof(sizename), "%s#dma-size-cells", prefix); | |
63 | ||
64 | dma_window = of_get_property(dn, propname, &bytes); | |
65 | if (!dma_window) | |
66 | return -ENODEV; | |
67 | end = dma_window + bytes / sizeof(*dma_window); | |
68 | ||
69 | while (dma_window < end) { | |
70 | u32 cells; | |
71 | const void *prop; | |
72 | ||
73 | /* busno is one cell if supported */ | |
74 | if (busno) | |
75 | *busno = be32_to_cpup(dma_window++); | |
76 | ||
77 | prop = of_get_property(dn, addrname, NULL); | |
78 | if (!prop) | |
79 | prop = of_get_property(dn, "#address-cells", NULL); | |
80 | ||
81 | cells = prop ? be32_to_cpup(prop) : of_n_addr_cells(dn); | |
82 | if (!cells) | |
83 | return -EINVAL; | |
84 | *addr = of_read_number(dma_window, cells); | |
85 | dma_window += cells; | |
86 | ||
87 | prop = of_get_property(dn, sizename, NULL); | |
88 | cells = prop ? be32_to_cpup(prop) : of_n_size_cells(dn); | |
89 | if (!cells) | |
90 | return -EINVAL; | |
91 | *size = of_read_number(dma_window, cells); | |
92 | dma_window += cells; | |
93 | ||
94 | if (cur_index++ == index) | |
95 | break; | |
96 | } | |
97 | return 0; | |
98 | } | |
99 | EXPORT_SYMBOL_GPL(of_get_dma_window); | |
1cd076bf | 100 | |
d7b05582 RM |
101 | static bool of_iommu_driver_present(struct device_node *np) |
102 | { | |
103 | /* | |
104 | * If the IOMMU still isn't ready by the time we reach init, assume | |
105 | * it never will be. We don't want to defer indefinitely, nor attempt | |
106 | * to dereference __iommu_of_table after it's been freed. | |
107 | */ | |
b903dfb2 | 108 | if (system_state >= SYSTEM_RUNNING) |
d7b05582 RM |
109 | return false; |
110 | ||
111 | return of_match_node(&__iommu_of_table, np); | |
112 | } | |
113 | ||
da4b0275 RM |
114 | static int of_iommu_xlate(struct device *dev, |
115 | struct of_phandle_args *iommu_spec) | |
2a0c5754 RM |
116 | { |
117 | const struct iommu_ops *ops; | |
118 | struct fwnode_handle *fwnode = &iommu_spec->np->fwnode; | |
119 | int err; | |
120 | ||
121 | ops = iommu_ops_from_fwnode(fwnode); | |
d7b05582 | 122 | if ((ops && !ops->of_xlate) || |
573d4175 | 123 | !of_device_is_available(iommu_spec->np) || |
d7b05582 | 124 | (!ops && !of_iommu_driver_present(iommu_spec->np))) |
da4b0275 | 125 | return NO_IOMMU; |
2a0c5754 RM |
126 | |
127 | err = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops); | |
128 | if (err) | |
da4b0275 | 129 | return err; |
d7b05582 RM |
130 | /* |
131 | * The otherwise-empty fwspec handily serves to indicate the specific | |
132 | * IOMMU device we're waiting for, which will be useful if we ever get | |
133 | * a proper probe-ordering dependency mechanism in future. | |
134 | */ | |
135 | if (!ops) | |
da4b0275 | 136 | return -EPROBE_DEFER; |
2a0c5754 | 137 | |
da4b0275 | 138 | return ops->of_xlate(dev, iommu_spec); |
2a0c5754 RM |
139 | } |
140 | ||
d87beb74 RM |
141 | struct of_pci_iommu_alias_info { |
142 | struct device *dev; | |
143 | struct device_node *np; | |
144 | }; | |
b996444c | 145 | |
d87beb74 | 146 | static int of_pci_iommu_init(struct pci_dev *pdev, u16 alias, void *data) |
b996444c | 147 | { |
d87beb74 | 148 | struct of_pci_iommu_alias_info *info = data; |
d87beb74 | 149 | struct of_phandle_args iommu_spec = { .args_count = 1 }; |
2a0c5754 | 150 | int err; |
b996444c | 151 | |
d87beb74 | 152 | err = of_pci_map_rid(info->np, alias, "iommu-map", |
2a0c5754 RM |
153 | "iommu-map-mask", &iommu_spec.np, |
154 | iommu_spec.args); | |
155 | if (err) | |
da4b0275 | 156 | return err == -ENODEV ? NO_IOMMU : err; |
b996444c | 157 | |
da4b0275 | 158 | err = of_iommu_xlate(info->dev, &iommu_spec); |
b996444c | 159 | of_node_put(iommu_spec.np); |
c0d05cde | 160 | return err; |
2a0c5754 RM |
161 | } |
162 | ||
163 | const struct iommu_ops *of_iommu_configure(struct device *dev, | |
164 | struct device_node *master_np) | |
165 | { | |
d87beb74 | 166 | const struct iommu_ops *ops = NULL; |
d7b05582 | 167 | struct iommu_fwspec *fwspec = dev->iommu_fwspec; |
da4b0275 | 168 | int err = NO_IOMMU; |
2a0c5754 RM |
169 | |
170 | if (!master_np) | |
171 | return NULL; | |
172 | ||
d7b05582 RM |
173 | if (fwspec) { |
174 | if (fwspec->ops) | |
175 | return fwspec->ops; | |
176 | ||
177 | /* In the deferred case, start again from scratch */ | |
178 | iommu_fwspec_free(dev); | |
179 | } | |
180 | ||
d87beb74 RM |
181 | /* |
182 | * We don't currently walk up the tree looking for a parent IOMMU. | |
183 | * See the `Notes:' section of | |
184 | * Documentation/devicetree/bindings/iommu/iommu.txt | |
185 | */ | |
186 | if (dev_is_pci(dev)) { | |
187 | struct of_pci_iommu_alias_info info = { | |
188 | .dev = dev, | |
189 | .np = master_np, | |
190 | }; | |
191 | ||
192 | err = pci_for_each_dma_alias(to_pci_dev(dev), | |
193 | of_pci_iommu_init, &info); | |
d87beb74 RM |
194 | } else { |
195 | struct of_phandle_args iommu_spec; | |
196 | int idx = 0; | |
197 | ||
198 | while (!of_parse_phandle_with_args(master_np, "iommus", | |
199 | "#iommu-cells", | |
200 | idx, &iommu_spec)) { | |
da4b0275 | 201 | err = of_iommu_xlate(dev, &iommu_spec); |
d87beb74 RM |
202 | of_node_put(iommu_spec.np); |
203 | idx++; | |
da4b0275 | 204 | if (err) |
d87beb74 RM |
205 | break; |
206 | } | |
207 | } | |
da4b0275 RM |
208 | |
209 | /* | |
210 | * Two success conditions can be represented by non-negative err here: | |
211 | * >0 : there is no IOMMU, or one was unavailable for non-fatal reasons | |
212 | * 0 : we found an IOMMU, and dev->fwspec is initialised appropriately | |
213 | * <0 : any actual error | |
214 | */ | |
215 | if (!err) | |
216 | ops = dev->iommu_fwspec->ops; | |
d7b05582 RM |
217 | /* |
218 | * If we have reason to believe the IOMMU driver missed the initial | |
219 | * add_device callback for dev, replay it to get things in order. | |
220 | */ | |
da4b0275 | 221 | if (ops && ops->add_device && dev->bus && !dev->iommu_group) |
d87beb74 | 222 | err = ops->add_device(dev); |
7eba1d51 | 223 | |
a37b19a3 | 224 | /* Ignore all other errors apart from EPROBE_DEFER */ |
da4b0275 RM |
225 | if (err == -EPROBE_DEFER) { |
226 | ops = ERR_PTR(err); | |
227 | } else if (err < 0) { | |
228 | dev_dbg(dev, "Adding to IOMMU failed: %d\n", err); | |
a37b19a3 S |
229 | ops = NULL; |
230 | } | |
231 | ||
7b07cbef | 232 | return ops; |
7eba1d51 WD |
233 | } |
234 | ||
bb8e15d6 | 235 | static int __init of_iommu_init(void) |
1cd076bf WD |
236 | { |
237 | struct device_node *np; | |
238 | const struct of_device_id *match, *matches = &__iommu_of_table; | |
239 | ||
240 | for_each_matching_node_and_match(np, matches, &match) { | |
241 | const of_iommu_init_fn init_fn = match->data; | |
242 | ||
7b07cbef | 243 | if (init_fn && init_fn(np)) |
6bd4f1c7 | 244 | pr_err("Failed to initialise IOMMU %pOF\n", np); |
1cd076bf | 245 | } |
bb8e15d6 KW |
246 | |
247 | return 0; | |
1cd076bf | 248 | } |
bb8e15d6 | 249 | postcore_initcall_sync(of_iommu_init); |