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1/*
2 * Device tree based initialization code for reserved memory.
3 *
4 * Copyright (c) 2013, 2015 The Linux Foundation. All Rights Reserved.
5 * Copyright (c) 2013,2014 Samsung Electronics Co., Ltd.
6 * http://www.samsung.com
7 * Author: Marek Szyprowski <m.szyprowski@samsung.com>
8 * Author: Josh Cartwright <joshc@codeaurora.org>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation; either version 2 of the
13 * License or (at your optional) any later version of the license.
14 */
15
16#include <linux/err.h>
17#include <linux/of.h>
18#include <linux/of_fdt.h>
19#include <linux/of_platform.h>
20#include <linux/mm.h>
21#include <linux/sizes.h>
22#include <linux/of_reserved_mem.h>
23#include <linux/sort.h>
24
25#define MAX_RESERVED_REGIONS 16
26static struct reserved_mem reserved_mem[MAX_RESERVED_REGIONS];
27static int reserved_mem_count;
28
29#if defined(CONFIG_HAVE_MEMBLOCK)
30#include <linux/memblock.h>
31int __init __weak early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
32 phys_addr_t align, phys_addr_t start, phys_addr_t end, bool nomap,
33 phys_addr_t *res_base)
34{
35 phys_addr_t base;
36 /*
37 * We use __memblock_alloc_base() because memblock_alloc_base()
38 * panic()s on allocation failure.
39 */
40 end = !end ? MEMBLOCK_ALLOC_ANYWHERE : end;
41 base = __memblock_alloc_base(size, align, end);
42 if (!base)
43 return -ENOMEM;
44
45 /*
46 * Check if the allocated region fits in to start..end window
47 */
48 if (base < start) {
49 memblock_free(base, size);
50 return -ENOMEM;
51 }
52
53 *res_base = base;
54 if (nomap)
55 return memblock_remove(base, size);
56 return 0;
57}
58#else
59int __init __weak early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
60 phys_addr_t align, phys_addr_t start, phys_addr_t end, bool nomap,
61 phys_addr_t *res_base)
62{
63 pr_err("Reserved memory not supported, ignoring region 0x%llx%s\n",
64 size, nomap ? " (nomap)" : "");
65 return -ENOSYS;
66}
67#endif
68
69/**
70 * res_mem_save_node() - save fdt node for second pass initialization
71 */
72void __init fdt_reserved_mem_save_node(unsigned long node, const char *uname,
73 phys_addr_t base, phys_addr_t size)
74{
75 struct reserved_mem *rmem = &reserved_mem[reserved_mem_count];
76
77 if (reserved_mem_count == ARRAY_SIZE(reserved_mem)) {
78 pr_err("Reserved memory: not enough space all defined regions.\n");
79 return;
80 }
81
82 rmem->fdt_node = node;
83 rmem->name = uname;
84 rmem->base = base;
85 rmem->size = size;
86
87 reserved_mem_count++;
88 return;
89}
90
91/**
92 * res_mem_alloc_size() - allocate reserved memory described by 'size', 'align'
93 * and 'alloc-ranges' properties
94 */
95static int __init __reserved_mem_alloc_size(unsigned long node,
96 const char *uname, phys_addr_t *res_base, phys_addr_t *res_size)
97{
98 int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);
99 phys_addr_t start = 0, end = 0;
100 phys_addr_t base = 0, align = 0, size;
101 int len;
102 const __be32 *prop;
103 int nomap;
104 int ret;
105
106 prop = of_get_flat_dt_prop(node, "size", &len);
107 if (!prop)
108 return -EINVAL;
109
110 if (len != dt_root_size_cells * sizeof(__be32)) {
111 pr_err("Reserved memory: invalid size property in '%s' node.\n",
112 uname);
113 return -EINVAL;
114 }
115 size = dt_mem_next_cell(dt_root_size_cells, &prop);
116
117 nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
118
119 prop = of_get_flat_dt_prop(node, "alignment", &len);
120 if (prop) {
121 if (len != dt_root_addr_cells * sizeof(__be32)) {
122 pr_err("Reserved memory: invalid alignment property in '%s' node.\n",
123 uname);
124 return -EINVAL;
125 }
126 align = dt_mem_next_cell(dt_root_addr_cells, &prop);
127 }
128
129 /* Need adjust the alignment to satisfy the CMA requirement */
130 if (IS_ENABLED(CONFIG_CMA) && of_flat_dt_is_compatible(node, "shared-dma-pool"))
131 align = max(align, (phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
132
133 prop = of_get_flat_dt_prop(node, "alloc-ranges", &len);
134 if (prop) {
135
136 if (len % t_len != 0) {
137 pr_err("Reserved memory: invalid alloc-ranges property in '%s', skipping node.\n",
138 uname);
139 return -EINVAL;
140 }
141
142 base = 0;
143
144 while (len > 0) {
145 start = dt_mem_next_cell(dt_root_addr_cells, &prop);
146 end = start + dt_mem_next_cell(dt_root_size_cells,
147 &prop);
148
149 ret = early_init_dt_alloc_reserved_memory_arch(size,
150 align, start, end, nomap, &base);
151 if (ret == 0) {
152 pr_debug("Reserved memory: allocated memory for '%s' node: base %pa, size %ld MiB\n",
153 uname, &base,
154 (unsigned long)size / SZ_1M);
155 break;
156 }
157 len -= t_len;
158 }
159
160 } else {
161 ret = early_init_dt_alloc_reserved_memory_arch(size, align,
162 0, 0, nomap, &base);
163 if (ret == 0)
164 pr_debug("Reserved memory: allocated memory for '%s' node: base %pa, size %ld MiB\n",
165 uname, &base, (unsigned long)size / SZ_1M);
166 }
167
168 if (base == 0) {
169 pr_info("Reserved memory: failed to allocate memory for node '%s'\n",
170 uname);
171 return -ENOMEM;
172 }
173
174 *res_base = base;
175 *res_size = size;
176
177 return 0;
178}
179
180static const struct of_device_id __rmem_of_table_sentinel
181 __used __section(__reservedmem_of_table_end);
182
183/**
184 * res_mem_init_node() - call region specific reserved memory init code
185 */
186static int __init __reserved_mem_init_node(struct reserved_mem *rmem)
187{
188 extern const struct of_device_id __reservedmem_of_table[];
189 const struct of_device_id *i;
190
191 for (i = __reservedmem_of_table; i < &__rmem_of_table_sentinel; i++) {
192 reservedmem_of_init_fn initfn = i->data;
193 const char *compat = i->compatible;
194
195 if (!of_flat_dt_is_compatible(rmem->fdt_node, compat))
196 continue;
197
198 if (initfn(rmem) == 0) {
199 pr_info("Reserved memory: initialized node %s, compatible id %s\n",
200 rmem->name, compat);
201 return 0;
202 }
203 }
204 return -ENOENT;
205}
206
207static int __init __rmem_cmp(const void *a, const void *b)
208{
209 const struct reserved_mem *ra = a, *rb = b;
210
211 if (ra->base < rb->base)
212 return -1;
213
214 if (ra->base > rb->base)
215 return 1;
216
217 return 0;
218}
219
220static void __init __rmem_check_for_overlap(void)
221{
222 int i;
223
224 if (reserved_mem_count < 2)
225 return;
226
227 sort(reserved_mem, reserved_mem_count, sizeof(reserved_mem[0]),
228 __rmem_cmp, NULL);
229 for (i = 0; i < reserved_mem_count - 1; i++) {
230 struct reserved_mem *this, *next;
231
232 this = &reserved_mem[i];
233 next = &reserved_mem[i + 1];
234 if (!(this->base && next->base))
235 continue;
236 if (this->base + this->size > next->base) {
237 phys_addr_t this_end, next_end;
238
239 this_end = this->base + this->size;
240 next_end = next->base + next->size;
241 pr_err("Reserved memory: OVERLAP DETECTED!\n%s (%pa--%pa) overlaps with %s (%pa--%pa)\n",
242 this->name, &this->base, &this_end,
243 next->name, &next->base, &next_end);
244 }
245 }
246}
247
248/**
249 * fdt_init_reserved_mem - allocate and init all saved reserved memory regions
250 */
251void __init fdt_init_reserved_mem(void)
252{
253 int i;
254
255 /* check for overlapping reserved regions */
256 __rmem_check_for_overlap();
257
258 for (i = 0; i < reserved_mem_count; i++) {
259 struct reserved_mem *rmem = &reserved_mem[i];
260 unsigned long node = rmem->fdt_node;
261 int len;
262 const __be32 *prop;
263 int err = 0;
264
265 prop = of_get_flat_dt_prop(node, "phandle", &len);
266 if (!prop)
267 prop = of_get_flat_dt_prop(node, "linux,phandle", &len);
268 if (prop)
269 rmem->phandle = of_read_number(prop, len/4);
270
271 if (rmem->size == 0)
272 err = __reserved_mem_alloc_size(node, rmem->name,
273 &rmem->base, &rmem->size);
274 if (err == 0)
275 __reserved_mem_init_node(rmem);
276 }
277}
278
279static inline struct reserved_mem *__find_rmem(struct device_node *node)
280{
281 unsigned int i;
282
283 if (!node->phandle)
284 return NULL;
285
286 for (i = 0; i < reserved_mem_count; i++)
287 if (reserved_mem[i].phandle == node->phandle)
288 return &reserved_mem[i];
289 return NULL;
290}
291
292/**
293 * of_reserved_mem_device_init() - assign reserved memory region to given device
294 *
295 * This function assign memory region pointed by "memory-region" device tree
296 * property to the given device.
297 */
298int of_reserved_mem_device_init(struct device *dev)
299{
300 struct reserved_mem *rmem;
301 struct device_node *np;
302 int ret;
303
304 np = of_parse_phandle(dev->of_node, "memory-region", 0);
305 if (!np)
306 return -ENODEV;
307
308 rmem = __find_rmem(np);
309 of_node_put(np);
310
311 if (!rmem || !rmem->ops || !rmem->ops->device_init)
312 return -EINVAL;
313
314 ret = rmem->ops->device_init(rmem, dev);
315 if (ret == 0)
316 dev_info(dev, "assigned reserved memory node %s\n", rmem->name);
317
318 return ret;
319}
320EXPORT_SYMBOL_GPL(of_reserved_mem_device_init);
321
322/**
323 * of_reserved_mem_device_release() - release reserved memory device structures
324 *
325 * This function releases structures allocated for memory region handling for
326 * the given device.
327 */
328void of_reserved_mem_device_release(struct device *dev)
329{
330 struct reserved_mem *rmem;
331 struct device_node *np;
332
333 np = of_parse_phandle(dev->of_node, "memory-region", 0);
334 if (!np)
335 return;
336
337 rmem = __find_rmem(np);
338 of_node_put(np);
339
340 if (!rmem || !rmem->ops || !rmem->ops->device_release)
341 return;
342
343 rmem->ops->device_release(rmem, dev);
344}
345EXPORT_SYMBOL_GPL(of_reserved_mem_device_release);
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Device tree based initialization code for reserved memory.
4 *
5 * Copyright (c) 2013, 2015 The Linux Foundation. All Rights Reserved.
6 * Copyright (c) 2013,2014 Samsung Electronics Co., Ltd.
7 * http://www.samsung.com
8 * Author: Marek Szyprowski <m.szyprowski@samsung.com>
9 * Author: Josh Cartwright <joshc@codeaurora.org>
10 */
11
12#define pr_fmt(fmt) "OF: reserved mem: " fmt
13
14#include <linux/err.h>
15#include <linux/of.h>
16#include <linux/of_fdt.h>
17#include <linux/of_platform.h>
18#include <linux/mm.h>
19#include <linux/sizes.h>
20#include <linux/of_reserved_mem.h>
21#include <linux/sort.h>
22#include <linux/slab.h>
23#include <linux/memblock.h>
24
25#define MAX_RESERVED_REGIONS 64
26static struct reserved_mem reserved_mem[MAX_RESERVED_REGIONS];
27static int reserved_mem_count;
28
29static int __init early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
30 phys_addr_t align, phys_addr_t start, phys_addr_t end, bool nomap,
31 phys_addr_t *res_base)
32{
33 phys_addr_t base;
34
35 end = !end ? MEMBLOCK_ALLOC_ANYWHERE : end;
36 align = !align ? SMP_CACHE_BYTES : align;
37 base = memblock_find_in_range(start, end, size, align);
38 if (!base)
39 return -ENOMEM;
40
41 *res_base = base;
42 if (nomap)
43 return memblock_remove(base, size);
44
45 return memblock_reserve(base, size);
46}
47
48/**
49 * fdt_reserved_mem_save_node() - save fdt node for second pass initialization
50 */
51void __init fdt_reserved_mem_save_node(unsigned long node, const char *uname,
52 phys_addr_t base, phys_addr_t size)
53{
54 struct reserved_mem *rmem = &reserved_mem[reserved_mem_count];
55
56 if (reserved_mem_count == ARRAY_SIZE(reserved_mem)) {
57 pr_err("not enough space for all defined regions.\n");
58 return;
59 }
60
61 rmem->fdt_node = node;
62 rmem->name = uname;
63 rmem->base = base;
64 rmem->size = size;
65
66 reserved_mem_count++;
67 return;
68}
69
70/**
71 * __reserved_mem_alloc_size() - allocate reserved memory described by
72 * 'size', 'alignment' and 'alloc-ranges' properties.
73 */
74static int __init __reserved_mem_alloc_size(unsigned long node,
75 const char *uname, phys_addr_t *res_base, phys_addr_t *res_size)
76{
77 int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);
78 phys_addr_t start = 0, end = 0;
79 phys_addr_t base = 0, align = 0, size;
80 int len;
81 const __be32 *prop;
82 bool nomap;
83 int ret;
84
85 prop = of_get_flat_dt_prop(node, "size", &len);
86 if (!prop)
87 return -EINVAL;
88
89 if (len != dt_root_size_cells * sizeof(__be32)) {
90 pr_err("invalid size property in '%s' node.\n", uname);
91 return -EINVAL;
92 }
93 size = dt_mem_next_cell(dt_root_size_cells, &prop);
94
95 prop = of_get_flat_dt_prop(node, "alignment", &len);
96 if (prop) {
97 if (len != dt_root_addr_cells * sizeof(__be32)) {
98 pr_err("invalid alignment property in '%s' node.\n",
99 uname);
100 return -EINVAL;
101 }
102 align = dt_mem_next_cell(dt_root_addr_cells, &prop);
103 }
104
105 nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
106
107 /* Need adjust the alignment to satisfy the CMA requirement */
108 if (IS_ENABLED(CONFIG_CMA)
109 && of_flat_dt_is_compatible(node, "shared-dma-pool")
110 && of_get_flat_dt_prop(node, "reusable", NULL)
111 && !nomap) {
112 unsigned long order =
113 max_t(unsigned long, MAX_ORDER - 1, pageblock_order);
114
115 align = max(align, (phys_addr_t)PAGE_SIZE << order);
116 }
117
118 prop = of_get_flat_dt_prop(node, "alloc-ranges", &len);
119 if (prop) {
120
121 if (len % t_len != 0) {
122 pr_err("invalid alloc-ranges property in '%s', skipping node.\n",
123 uname);
124 return -EINVAL;
125 }
126
127 base = 0;
128
129 while (len > 0) {
130 start = dt_mem_next_cell(dt_root_addr_cells, &prop);
131 end = start + dt_mem_next_cell(dt_root_size_cells,
132 &prop);
133
134 ret = early_init_dt_alloc_reserved_memory_arch(size,
135 align, start, end, nomap, &base);
136 if (ret == 0) {
137 pr_debug("allocated memory for '%s' node: base %pa, size %ld MiB\n",
138 uname, &base,
139 (unsigned long)size / SZ_1M);
140 break;
141 }
142 len -= t_len;
143 }
144
145 } else {
146 ret = early_init_dt_alloc_reserved_memory_arch(size, align,
147 0, 0, nomap, &base);
148 if (ret == 0)
149 pr_debug("allocated memory for '%s' node: base %pa, size %ld MiB\n",
150 uname, &base, (unsigned long)size / SZ_1M);
151 }
152
153 if (base == 0) {
154 pr_info("failed to allocate memory for node '%s'\n", uname);
155 return -ENOMEM;
156 }
157
158 *res_base = base;
159 *res_size = size;
160
161 return 0;
162}
163
164static const struct of_device_id __rmem_of_table_sentinel
165 __used __section(__reservedmem_of_table_end);
166
167/**
168 * __reserved_mem_init_node() - call region specific reserved memory init code
169 */
170static int __init __reserved_mem_init_node(struct reserved_mem *rmem)
171{
172 extern const struct of_device_id __reservedmem_of_table[];
173 const struct of_device_id *i;
174 int ret = -ENOENT;
175
176 for (i = __reservedmem_of_table; i < &__rmem_of_table_sentinel; i++) {
177 reservedmem_of_init_fn initfn = i->data;
178 const char *compat = i->compatible;
179
180 if (!of_flat_dt_is_compatible(rmem->fdt_node, compat))
181 continue;
182
183 ret = initfn(rmem);
184 if (ret == 0) {
185 pr_info("initialized node %s, compatible id %s\n",
186 rmem->name, compat);
187 break;
188 }
189 }
190 return ret;
191}
192
193static int __init __rmem_cmp(const void *a, const void *b)
194{
195 const struct reserved_mem *ra = a, *rb = b;
196
197 if (ra->base < rb->base)
198 return -1;
199
200 if (ra->base > rb->base)
201 return 1;
202
203 return 0;
204}
205
206static void __init __rmem_check_for_overlap(void)
207{
208 int i;
209
210 if (reserved_mem_count < 2)
211 return;
212
213 sort(reserved_mem, reserved_mem_count, sizeof(reserved_mem[0]),
214 __rmem_cmp, NULL);
215 for (i = 0; i < reserved_mem_count - 1; i++) {
216 struct reserved_mem *this, *next;
217
218 this = &reserved_mem[i];
219 next = &reserved_mem[i + 1];
220 if (!(this->base && next->base))
221 continue;
222 if (this->base + this->size > next->base) {
223 phys_addr_t this_end, next_end;
224
225 this_end = this->base + this->size;
226 next_end = next->base + next->size;
227 pr_err("OVERLAP DETECTED!\n%s (%pa--%pa) overlaps with %s (%pa--%pa)\n",
228 this->name, &this->base, &this_end,
229 next->name, &next->base, &next_end);
230 }
231 }
232}
233
234/**
235 * fdt_init_reserved_mem() - allocate and init all saved reserved memory regions
236 */
237void __init fdt_init_reserved_mem(void)
238{
239 int i;
240
241 /* check for overlapping reserved regions */
242 __rmem_check_for_overlap();
243
244 for (i = 0; i < reserved_mem_count; i++) {
245 struct reserved_mem *rmem = &reserved_mem[i];
246 unsigned long node = rmem->fdt_node;
247 int len;
248 const __be32 *prop;
249 int err = 0;
250 bool nomap;
251
252 nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
253 prop = of_get_flat_dt_prop(node, "phandle", &len);
254 if (!prop)
255 prop = of_get_flat_dt_prop(node, "linux,phandle", &len);
256 if (prop)
257 rmem->phandle = of_read_number(prop, len/4);
258
259 if (rmem->size == 0)
260 err = __reserved_mem_alloc_size(node, rmem->name,
261 &rmem->base, &rmem->size);
262 if (err == 0) {
263 err = __reserved_mem_init_node(rmem);
264 if (err != 0 && err != -ENOENT) {
265 pr_info("node %s compatible matching fail\n",
266 rmem->name);
267 memblock_free(rmem->base, rmem->size);
268 if (nomap)
269 memblock_add(rmem->base, rmem->size);
270 }
271 }
272 }
273}
274
275static inline struct reserved_mem *__find_rmem(struct device_node *node)
276{
277 unsigned int i;
278
279 if (!node->phandle)
280 return NULL;
281
282 for (i = 0; i < reserved_mem_count; i++)
283 if (reserved_mem[i].phandle == node->phandle)
284 return &reserved_mem[i];
285 return NULL;
286}
287
288struct rmem_assigned_device {
289 struct device *dev;
290 struct reserved_mem *rmem;
291 struct list_head list;
292};
293
294static LIST_HEAD(of_rmem_assigned_device_list);
295static DEFINE_MUTEX(of_rmem_assigned_device_mutex);
296
297/**
298 * of_reserved_mem_device_init_by_idx() - assign reserved memory region to
299 * given device
300 * @dev: Pointer to the device to configure
301 * @np: Pointer to the device_node with 'reserved-memory' property
302 * @idx: Index of selected region
303 *
304 * This function assigns respective DMA-mapping operations based on reserved
305 * memory region specified by 'memory-region' property in @np node to the @dev
306 * device. When driver needs to use more than one reserved memory region, it
307 * should allocate child devices and initialize regions by name for each of
308 * child device.
309 *
310 * Returns error code or zero on success.
311 */
312int of_reserved_mem_device_init_by_idx(struct device *dev,
313 struct device_node *np, int idx)
314{
315 struct rmem_assigned_device *rd;
316 struct device_node *target;
317 struct reserved_mem *rmem;
318 int ret;
319
320 if (!np || !dev)
321 return -EINVAL;
322
323 target = of_parse_phandle(np, "memory-region", idx);
324 if (!target)
325 return -ENODEV;
326
327 if (!of_device_is_available(target)) {
328 of_node_put(target);
329 return 0;
330 }
331
332 rmem = __find_rmem(target);
333 of_node_put(target);
334
335 if (!rmem || !rmem->ops || !rmem->ops->device_init)
336 return -EINVAL;
337
338 rd = kmalloc(sizeof(struct rmem_assigned_device), GFP_KERNEL);
339 if (!rd)
340 return -ENOMEM;
341
342 ret = rmem->ops->device_init(rmem, dev);
343 if (ret == 0) {
344 rd->dev = dev;
345 rd->rmem = rmem;
346
347 mutex_lock(&of_rmem_assigned_device_mutex);
348 list_add(&rd->list, &of_rmem_assigned_device_list);
349 mutex_unlock(&of_rmem_assigned_device_mutex);
350
351 dev_info(dev, "assigned reserved memory node %s\n", rmem->name);
352 } else {
353 kfree(rd);
354 }
355
356 return ret;
357}
358EXPORT_SYMBOL_GPL(of_reserved_mem_device_init_by_idx);
359
360/**
361 * of_reserved_mem_device_init_by_name() - assign named reserved memory region
362 * to given device
363 * @dev: pointer to the device to configure
364 * @np: pointer to the device node with 'memory-region' property
365 * @name: name of the selected memory region
366 *
367 * Returns: 0 on success or a negative error-code on failure.
368 */
369int of_reserved_mem_device_init_by_name(struct device *dev,
370 struct device_node *np,
371 const char *name)
372{
373 int idx = of_property_match_string(np, "memory-region-names", name);
374
375 return of_reserved_mem_device_init_by_idx(dev, np, idx);
376}
377EXPORT_SYMBOL_GPL(of_reserved_mem_device_init_by_name);
378
379/**
380 * of_reserved_mem_device_release() - release reserved memory device structures
381 * @dev: Pointer to the device to deconfigure
382 *
383 * This function releases structures allocated for memory region handling for
384 * the given device.
385 */
386void of_reserved_mem_device_release(struct device *dev)
387{
388 struct rmem_assigned_device *rd, *tmp;
389 LIST_HEAD(release_list);
390
391 mutex_lock(&of_rmem_assigned_device_mutex);
392 list_for_each_entry_safe(rd, tmp, &of_rmem_assigned_device_list, list) {
393 if (rd->dev == dev)
394 list_move_tail(&rd->list, &release_list);
395 }
396 mutex_unlock(&of_rmem_assigned_device_mutex);
397
398 list_for_each_entry_safe(rd, tmp, &release_list, list) {
399 if (rd->rmem && rd->rmem->ops && rd->rmem->ops->device_release)
400 rd->rmem->ops->device_release(rd->rmem, dev);
401
402 kfree(rd);
403 }
404}
405EXPORT_SYMBOL_GPL(of_reserved_mem_device_release);
406
407/**
408 * of_reserved_mem_lookup() - acquire reserved_mem from a device node
409 * @np: node pointer of the desired reserved-memory region
410 *
411 * This function allows drivers to acquire a reference to the reserved_mem
412 * struct based on a device node handle.
413 *
414 * Returns a reserved_mem reference, or NULL on error.
415 */
416struct reserved_mem *of_reserved_mem_lookup(struct device_node *np)
417{
418 const char *name;
419 int i;
420
421 if (!np->full_name)
422 return NULL;
423
424 name = kbasename(np->full_name);
425 for (i = 0; i < reserved_mem_count; i++)
426 if (!strcmp(reserved_mem[i].name, name))
427 return &reserved_mem[i];
428
429 return NULL;
430}
431EXPORT_SYMBOL_GPL(of_reserved_mem_lookup);