1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/kernel.h>
3 #include <linux/of.h>
4 #include <linux/of_device.h>
5 #include <linux/of_address.h>
6 #include <linux/of_iommu.h>
7 #include <linux/of_reserved_mem.h>
8 #include <linux/dma-direct.h> /* for bus_dma_region */
9 #include <linux/dma-map-ops.h>
10 #include <linux/init.h>
11 #include <linux/mod_devicetable.h>
12 #include <linux/slab.h>
13 #include <linux/platform_device.h>
14
15 #include <asm/errno.h>
16 #include "of_private.h"
17
18 /**
19 * of_match_device - Tell if a struct device matches an of_device_id list
20 * @matches: array of of device match structures to search in
21 * @dev: the of device structure to match against
22 *
23 * Used by a driver to check whether an platform_device present in the
24 * system is in its list of supported devices.
25 */
of_match_device(const struct of_device_id * matches,const struct device * dev)26 const struct of_device_id *of_match_device(const struct of_device_id *matches,
27 const struct device *dev)
28 {
29 if (!matches || !dev->of_node || dev->of_node_reused)
30 return NULL;
31 return of_match_node(matches, dev->of_node);
32 }
33 EXPORT_SYMBOL(of_match_device);
34
35 static void
of_dma_set_restricted_buffer(struct device * dev,struct device_node * np)36 of_dma_set_restricted_buffer(struct device *dev, struct device_node *np)
37 {
38 struct device_node *node, *of_node = dev->of_node;
39 int count, i;
40
41 if (!IS_ENABLED(CONFIG_DMA_RESTRICTED_POOL))
42 return;
43
44 count = of_property_count_elems_of_size(of_node, "memory-region",
45 sizeof(u32));
46 /*
47 * If dev->of_node doesn't exist or doesn't contain memory-region, try
48 * the OF node having DMA configuration.
49 */
50 if (count <= 0) {
51 of_node = np;
52 count = of_property_count_elems_of_size(
53 of_node, "memory-region", sizeof(u32));
54 }
55
56 for (i = 0; i < count; i++) {
57 node = of_parse_phandle(of_node, "memory-region", i);
58 /*
59 * There might be multiple memory regions, but only one
60 * restricted-dma-pool region is allowed.
61 */
62 if (of_device_is_compatible(node, "restricted-dma-pool") &&
63 of_device_is_available(node)) {
64 of_node_put(node);
65 break;
66 }
67 of_node_put(node);
68 }
69
70 /*
71 * Attempt to initialize a restricted-dma-pool region if one was found.
72 * Note that count can hold a negative error code.
73 */
74 if (i < count && of_reserved_mem_device_init_by_idx(dev, of_node, i))
75 dev_warn(dev, "failed to initialise \"restricted-dma-pool\" memory node\n");
76 }
77
78 /**
79 * of_dma_configure_id - Setup DMA configuration
80 * @dev: Device to apply DMA configuration
81 * @np: Pointer to OF node having DMA configuration
82 * @force_dma: Whether device is to be set up by of_dma_configure() even if
83 * DMA capability is not explicitly described by firmware.
84 * @id: Optional const pointer value input id
85 *
86 * Try to get devices's DMA configuration from DT and update it
87 * accordingly.
88 *
89 * If platform code needs to use its own special DMA configuration, it
90 * can use a platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE events
91 * to fix up DMA configuration.
92 */
of_dma_configure_id(struct device * dev,struct device_node * np,bool force_dma,const u32 * id)93 int of_dma_configure_id(struct device *dev, struct device_node *np,
94 bool force_dma, const u32 *id)
95 {
96 const struct iommu_ops *iommu;
97 const struct bus_dma_region *map = NULL;
98 struct device_node *bus_np;
99 u64 dma_start = 0;
100 u64 mask, end, size = 0;
101 bool coherent;
102 int ret;
103
104 if (np == dev->of_node)
105 bus_np = __of_get_dma_parent(np);
106 else
107 bus_np = of_node_get(np);
108
109 ret = of_dma_get_range(bus_np, &map);
110 of_node_put(bus_np);
111 if (ret < 0) {
112 /*
113 * For legacy reasons, we have to assume some devices need
114 * DMA configuration regardless of whether "dma-ranges" is
115 * correctly specified or not.
116 */
117 if (!force_dma)
118 return ret == -ENODEV ? 0 : ret;
119 } else {
120 const struct bus_dma_region *r = map;
121 u64 dma_end = 0;
122
123 /* Determine the overall bounds of all DMA regions */
124 for (dma_start = ~0; r->size; r++) {
125 /* Take lower and upper limits */
126 if (r->dma_start < dma_start)
127 dma_start = r->dma_start;
128 if (r->dma_start + r->size > dma_end)
129 dma_end = r->dma_start + r->size;
130 }
131 size = dma_end - dma_start;
132
133 /*
134 * Add a work around to treat the size as mask + 1 in case
135 * it is defined in DT as a mask.
136 */
137 if (size & 1) {
138 dev_warn(dev, "Invalid size 0x%llx for dma-range(s)\n",
139 size);
140 size = size + 1;
141 }
142
143 if (!size) {
144 dev_err(dev, "Adjusted size 0x%llx invalid\n", size);
145 kfree(map);
146 return -EINVAL;
147 }
148 }
149
150 /*
151 * If @dev is expected to be DMA-capable then the bus code that created
152 * it should have initialised its dma_mask pointer by this point. For
153 * now, we'll continue the legacy behaviour of coercing it to the
154 * coherent mask if not, but we'll no longer do so quietly.
155 */
156 if (!dev->dma_mask) {
157 dev_warn(dev, "DMA mask not set\n");
158 dev->dma_mask = &dev->coherent_dma_mask;
159 }
160
161 if (!size && dev->coherent_dma_mask)
162 size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
163 else if (!size)
164 size = 1ULL << 32;
165
166 /*
167 * Limit coherent and dma mask based on size and default mask
168 * set by the driver.
169 */
170 end = dma_start + size - 1;
171 mask = DMA_BIT_MASK(ilog2(end) + 1);
172 dev->coherent_dma_mask &= mask;
173 *dev->dma_mask &= mask;
174 /* ...but only set bus limit and range map if we found valid dma-ranges earlier */
175 if (!ret) {
176 dev->bus_dma_limit = end;
177 dev->dma_range_map = map;
178 }
179
180 coherent = of_dma_is_coherent(np);
181 dev_dbg(dev, "device is%sdma coherent\n",
182 coherent ? " " : " not ");
183
184 iommu = of_iommu_configure(dev, np, id);
185 if (PTR_ERR(iommu) == -EPROBE_DEFER) {
186 /* Don't touch range map if it wasn't set from a valid dma-ranges */
187 if (!ret)
188 dev->dma_range_map = NULL;
189 kfree(map);
190 return -EPROBE_DEFER;
191 }
192
193 dev_dbg(dev, "device is%sbehind an iommu\n",
194 iommu ? " " : " not ");
195
196 arch_setup_dma_ops(dev, dma_start, size, iommu, coherent);
197
198 if (!iommu)
199 of_dma_set_restricted_buffer(dev, np);
200
201 return 0;
202 }
203 EXPORT_SYMBOL_GPL(of_dma_configure_id);
204
of_device_get_match_data(const struct device * dev)205 const void *of_device_get_match_data(const struct device *dev)
206 {
207 const struct of_device_id *match;
208
209 match = of_match_device(dev->driver->of_match_table, dev);
210 if (!match)
211 return NULL;
212
213 return match->data;
214 }
215 EXPORT_SYMBOL(of_device_get_match_data);
216
217 /**
218 * of_device_modalias - Fill buffer with newline terminated modalias string
219 * @dev: Calling device
220 * @str: Modalias string
221 * @len: Size of @str
222 */
of_device_modalias(struct device * dev,char * str,ssize_t len)223 ssize_t of_device_modalias(struct device *dev, char *str, ssize_t len)
224 {
225 ssize_t sl;
226
227 if (!dev || !dev->of_node || dev->of_node_reused)
228 return -ENODEV;
229
230 sl = of_modalias(dev->of_node, str, len - 2);
231 if (sl < 0)
232 return sl;
233 if (sl > len - 2)
234 return -ENOMEM;
235
236 str[sl++] = '\n';
237 str[sl] = 0;
238 return sl;
239 }
240 EXPORT_SYMBOL_GPL(of_device_modalias);
241
242 /**
243 * of_device_uevent - Display OF related uevent information
244 * @dev: Device to display the uevent information for
245 * @env: Kernel object's userspace event reference to fill up
246 */
of_device_uevent(const struct device * dev,struct kobj_uevent_env * env)247 void of_device_uevent(const struct device *dev, struct kobj_uevent_env *env)
248 {
249 const char *compat, *type;
250 struct alias_prop *app;
251 struct property *p;
252 int seen = 0;
253
254 if ((!dev) || (!dev->of_node))
255 return;
256
257 add_uevent_var(env, "OF_NAME=%pOFn", dev->of_node);
258 add_uevent_var(env, "OF_FULLNAME=%pOF", dev->of_node);
259 type = of_node_get_device_type(dev->of_node);
260 if (type)
261 add_uevent_var(env, "OF_TYPE=%s", type);
262
263 /* Since the compatible field can contain pretty much anything
264 * it's not really legal to split it out with commas. We split it
265 * up using a number of environment variables instead. */
266 of_property_for_each_string(dev->of_node, "compatible", p, compat) {
267 add_uevent_var(env, "OF_COMPATIBLE_%d=%s", seen, compat);
268 seen++;
269 }
270 add_uevent_var(env, "OF_COMPATIBLE_N=%d", seen);
271
272 seen = 0;
273 mutex_lock(&of_mutex);
274 list_for_each_entry(app, &aliases_lookup, link) {
275 if (dev->of_node == app->np) {
276 add_uevent_var(env, "OF_ALIAS_%d=%s", seen,
277 app->alias);
278 seen++;
279 }
280 }
281 mutex_unlock(&of_mutex);
282 }
283 EXPORT_SYMBOL_GPL(of_device_uevent);
284
of_device_uevent_modalias(const struct device * dev,struct kobj_uevent_env * env)285 int of_device_uevent_modalias(const struct device *dev, struct kobj_uevent_env *env)
286 {
287 int sl;
288
289 if ((!dev) || (!dev->of_node) || dev->of_node_reused)
290 return -ENODEV;
291
292 /* Devicetree modalias is tricky, we add it in 2 steps */
293 if (add_uevent_var(env, "MODALIAS="))
294 return -ENOMEM;
295
296 sl = of_modalias(dev->of_node, &env->buf[env->buflen-1],
297 sizeof(env->buf) - env->buflen);
298 if (sl < 0)
299 return sl;
300 if (sl >= (sizeof(env->buf) - env->buflen))
301 return -ENOMEM;
302 env->buflen += sl;
303
304 return 0;
305 }
306 EXPORT_SYMBOL_GPL(of_device_uevent_modalias);
307