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/libfdt.h>
16 #include <linux/of.h>
17 #include <linux/of_fdt.h>
18 #include <linux/of_platform.h>
19 #include <linux/mm.h>
20 #include <linux/sizes.h>
21 #include <linux/of_reserved_mem.h>
22 #include <linux/sort.h>
23 #include <linux/slab.h>
24 #include <linux/memblock.h>
25 #include <linux/kmemleak.h>
26 #include <linux/cma.h>
27 #include <linux/dma-map-ops.h>
28 ANDROID_KABI_DECLONLY(dma_map_ops);
29
30 #include "of_private.h"
31
32 static struct reserved_mem reserved_mem[MAX_RESERVED_REGIONS];
33 static int reserved_mem_count;
34
early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,phys_addr_t align,phys_addr_t start,phys_addr_t end,bool nomap,phys_addr_t * res_base)35 static int __init early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
36 phys_addr_t align, phys_addr_t start, phys_addr_t end, bool nomap,
37 phys_addr_t *res_base)
38 {
39 phys_addr_t base;
40 int err = 0;
41
42 end = !end ? MEMBLOCK_ALLOC_ANYWHERE : end;
43 align = !align ? SMP_CACHE_BYTES : align;
44 base = memblock_phys_alloc_range(size, align, start, end);
45 if (!base)
46 return -ENOMEM;
47
48 *res_base = base;
49 if (nomap) {
50 err = memblock_mark_nomap(base, size);
51 if (err)
52 memblock_phys_free(base, size);
53 }
54
55 if (!err)
56 kmemleak_ignore_phys(base);
57
58 return err;
59 }
60
61 static void __init fdt_init_reserved_mem_node(struct reserved_mem *rmem);
62 /*
63 * fdt_reserved_mem_save_node() - save fdt node for second pass initialization
64 */
fdt_reserved_mem_save_node(unsigned long node,const char * uname,phys_addr_t base,phys_addr_t size)65 static void __init fdt_reserved_mem_save_node(unsigned long node, const char *uname,
66 phys_addr_t base, phys_addr_t size)
67 {
68 struct reserved_mem *rmem = &reserved_mem[reserved_mem_count];
69
70 if (reserved_mem_count == ARRAY_SIZE(reserved_mem)) {
71 pr_err("not enough space for all defined regions.\n");
72 return;
73 }
74
75 rmem->fdt_node = node;
76 rmem->name = uname;
77 rmem->base = base;
78 rmem->size = size;
79
80 /* Call the region specific initialization function */
81 fdt_init_reserved_mem_node(rmem);
82
83 reserved_mem_count++;
84 return;
85 }
86
early_init_dt_reserve_memory(phys_addr_t base,phys_addr_t size,bool nomap)87 static int __init early_init_dt_reserve_memory(phys_addr_t base,
88 phys_addr_t size, bool nomap)
89 {
90 if (nomap) {
91 /*
92 * If the memory is already reserved (by another region), we
93 * should not allow it to be marked nomap, but don't worry
94 * if the region isn't memory as it won't be mapped.
95 */
96 if (memblock_overlaps_region(&memblock.memory, base, size) &&
97 memblock_is_region_reserved(base, size))
98 return -EBUSY;
99
100 return memblock_mark_nomap(base, size);
101 }
102 return memblock_reserve(base, size);
103 }
104
105 /*
106 * __reserved_mem_reserve_reg() - reserve all memory described in 'reg' property
107 */
__reserved_mem_reserve_reg(unsigned long node,const char * uname)108 static int __init __reserved_mem_reserve_reg(unsigned long node,
109 const char *uname)
110 {
111 int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);
112 phys_addr_t base, size;
113 int len;
114 const __be32 *prop;
115 bool nomap;
116
117 prop = of_get_flat_dt_prop(node, "reg", &len);
118 if (!prop)
119 return -ENOENT;
120
121 if (len && len % t_len != 0) {
122 pr_err("Reserved memory: invalid reg property in '%s', skipping node.\n",
123 uname);
124 return -EINVAL;
125 }
126
127 nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
128
129 while (len >= t_len) {
130 base = dt_mem_next_cell(dt_root_addr_cells, &prop);
131 size = dt_mem_next_cell(dt_root_size_cells, &prop);
132
133 if (size && early_init_dt_reserve_memory(base, size, nomap) == 0) {
134 /* Architecture specific contiguous memory fixup. */
135 if (of_flat_dt_is_compatible(node, "shared-dma-pool") &&
136 of_get_flat_dt_prop(node, "reusable", NULL))
137 dma_contiguous_early_fixup(base, size);
138 pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n",
139 uname, &base, (unsigned long)(size / SZ_1M));
140 } else {
141 pr_err("Reserved memory: failed to reserve memory for node '%s': base %pa, size %lu MiB\n",
142 uname, &base, (unsigned long)(size / SZ_1M));
143 }
144
145 len -= t_len;
146 }
147 return 0;
148 }
149
150 /*
151 * __reserved_mem_check_root() - check if #size-cells, #address-cells provided
152 * in /reserved-memory matches the values supported by the current implementation,
153 * also check if ranges property has been provided
154 */
__reserved_mem_check_root(unsigned long node)155 static int __init __reserved_mem_check_root(unsigned long node)
156 {
157 const __be32 *prop;
158
159 prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
160 if (!prop || be32_to_cpup(prop) != dt_root_size_cells)
161 return -EINVAL;
162
163 prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
164 if (!prop || be32_to_cpup(prop) != dt_root_addr_cells)
165 return -EINVAL;
166
167 prop = of_get_flat_dt_prop(node, "ranges", NULL);
168 if (!prop)
169 return -EINVAL;
170 return 0;
171 }
172
173 static void __init __rmem_check_for_overlap(void);
174
175 /**
176 * fdt_scan_reserved_mem_reg_nodes() - Store info for the "reg" defined
177 * reserved memory regions.
178 *
179 * This function is used to scan through the DT and store the
180 * information for the reserved memory regions that are defined using
181 * the "reg" property. The region node number, name, base address, and
182 * size are all stored in the reserved_mem array by calling the
183 * fdt_reserved_mem_save_node() function.
184 */
fdt_scan_reserved_mem_reg_nodes(void)185 void __init fdt_scan_reserved_mem_reg_nodes(void)
186 {
187 int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);
188 const void *fdt = initial_boot_params;
189 phys_addr_t base, size;
190 const __be32 *prop;
191 int node, child;
192 int len;
193
194 if (!fdt)
195 return;
196
197 node = fdt_path_offset(fdt, "/reserved-memory");
198 if (node < 0) {
199 pr_info("Reserved memory: No reserved-memory node in the DT\n");
200 return;
201 }
202
203 if (__reserved_mem_check_root(node)) {
204 pr_err("Reserved memory: unsupported node format, ignoring\n");
205 return;
206 }
207
208 fdt_for_each_subnode(child, fdt, node) {
209 const char *uname;
210
211 prop = of_get_flat_dt_prop(child, "reg", &len);
212 if (!prop)
213 continue;
214 if (!of_fdt_device_is_available(fdt, child))
215 continue;
216
217 uname = fdt_get_name(fdt, child, NULL);
218 if (len && len % t_len != 0) {
219 pr_err("Reserved memory: invalid reg property in '%s', skipping node.\n",
220 uname);
221 continue;
222 }
223
224 if (len > t_len)
225 pr_warn("%s() ignores %d regions in node '%s'\n",
226 __func__, len / t_len - 1, uname);
227
228 base = dt_mem_next_cell(dt_root_addr_cells, &prop);
229 size = dt_mem_next_cell(dt_root_size_cells, &prop);
230
231 if (size)
232 fdt_reserved_mem_save_node(child, uname, base, size);
233 }
234
235 /* check for overlapping reserved regions */
236 __rmem_check_for_overlap();
237 }
238
239 static int __init __reserved_mem_alloc_size(unsigned long node, const char *uname);
240
241 /*
242 * fdt_scan_reserved_mem() - scan a single FDT node for reserved memory
243 */
fdt_scan_reserved_mem(void)244 int __init fdt_scan_reserved_mem(void)
245 {
246 int node, child;
247 int dynamic_nodes_cnt = 0;
248 int dynamic_nodes[MAX_RESERVED_REGIONS];
249 const void *fdt = initial_boot_params;
250
251 node = fdt_path_offset(fdt, "/reserved-memory");
252 if (node < 0)
253 return -ENODEV;
254
255 if (__reserved_mem_check_root(node) != 0) {
256 pr_err("Reserved memory: unsupported node format, ignoring\n");
257 return -EINVAL;
258 }
259
260 fdt_for_each_subnode(child, fdt, node) {
261 const char *uname;
262 int err;
263
264 if (!of_fdt_device_is_available(fdt, child))
265 continue;
266
267 uname = fdt_get_name(fdt, child, NULL);
268
269 err = __reserved_mem_reserve_reg(child, uname);
270 /*
271 * Save the nodes for the dynamically-placed regions
272 * into an array which will be used for allocation right
273 * after all the statically-placed regions are reserved
274 * or marked as no-map. This is done to avoid dynamically
275 * allocating from one of the statically-placed regions.
276 */
277 if (err == -ENOENT && of_get_flat_dt_prop(child, "size", NULL)) {
278 dynamic_nodes[dynamic_nodes_cnt] = child;
279 dynamic_nodes_cnt++;
280 }
281 }
282 for (int i = 0; i < dynamic_nodes_cnt; i++) {
283 const char *uname;
284
285 child = dynamic_nodes[i];
286 uname = fdt_get_name(fdt, child, NULL);
287 __reserved_mem_alloc_size(child, uname);
288 }
289 return 0;
290 }
291
292 /*
293 * __reserved_mem_alloc_in_range() - allocate reserved memory described with
294 * 'alloc-ranges'. Choose bottom-up/top-down depending on nearby existing
295 * reserved regions to keep the reserved memory contiguous if possible.
296 */
__reserved_mem_alloc_in_range(phys_addr_t size,phys_addr_t align,phys_addr_t start,phys_addr_t end,bool nomap,phys_addr_t * res_base)297 static int __init __reserved_mem_alloc_in_range(phys_addr_t size,
298 phys_addr_t align, phys_addr_t start, phys_addr_t end, bool nomap,
299 phys_addr_t *res_base)
300 {
301 bool prev_bottom_up = memblock_bottom_up();
302 bool bottom_up = false, top_down = false;
303 int ret, i;
304
305 for (i = 0; i < reserved_mem_count; i++) {
306 struct reserved_mem *rmem = &reserved_mem[i];
307
308 /* Skip regions that were not reserved yet */
309 if (rmem->size == 0)
310 continue;
311
312 /*
313 * If range starts next to an existing reservation, use bottom-up:
314 * |....RRRR................RRRRRRRR..............|
315 * --RRRR------
316 */
317 if (start >= rmem->base && start <= (rmem->base + rmem->size))
318 bottom_up = true;
319
320 /*
321 * If range ends next to an existing reservation, use top-down:
322 * |....RRRR................RRRRRRRR..............|
323 * -------RRRR-----
324 */
325 if (end >= rmem->base && end <= (rmem->base + rmem->size))
326 top_down = true;
327 }
328
329 /* Change setting only if either bottom-up or top-down was selected */
330 if (bottom_up != top_down)
331 memblock_set_bottom_up(bottom_up);
332
333 ret = early_init_dt_alloc_reserved_memory_arch(size, align,
334 start, end, nomap, res_base);
335
336 /* Restore old setting if needed */
337 if (bottom_up != top_down)
338 memblock_set_bottom_up(prev_bottom_up);
339
340 return ret;
341 }
342
343 /*
344 * __reserved_mem_alloc_size() - allocate reserved memory described by
345 * 'size', 'alignment' and 'alloc-ranges' properties.
346 */
__reserved_mem_alloc_size(unsigned long node,const char * uname)347 static int __init __reserved_mem_alloc_size(unsigned long node, const char *uname)
348 {
349 int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);
350 phys_addr_t start = 0, end = 0;
351 phys_addr_t base = 0, align = 0, size;
352 int len;
353 const __be32 *prop;
354 bool nomap;
355 int ret;
356
357 prop = of_get_flat_dt_prop(node, "size", &len);
358 if (!prop)
359 return -EINVAL;
360
361 if (len != dt_root_size_cells * sizeof(__be32)) {
362 pr_err("invalid size property in '%s' node.\n", uname);
363 return -EINVAL;
364 }
365 size = dt_mem_next_cell(dt_root_size_cells, &prop);
366
367 prop = of_get_flat_dt_prop(node, "alignment", &len);
368 if (prop) {
369 if (len != dt_root_addr_cells * sizeof(__be32)) {
370 pr_err("invalid alignment property in '%s' node.\n",
371 uname);
372 return -EINVAL;
373 }
374 align = dt_mem_next_cell(dt_root_addr_cells, &prop);
375 }
376
377 nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
378
379 /* Need adjust the alignment to satisfy the CMA requirement */
380 if (IS_ENABLED(CONFIG_CMA)
381 && of_flat_dt_is_compatible(node, "shared-dma-pool")
382 && of_get_flat_dt_prop(node, "reusable", NULL)
383 && !nomap)
384 align = max_t(phys_addr_t, align, CMA_MIN_ALIGNMENT_BYTES);
385
386 prop = of_get_flat_dt_prop(node, "alloc-ranges", &len);
387 if (prop) {
388
389 if (len % t_len != 0) {
390 pr_err("invalid alloc-ranges property in '%s', skipping node.\n",
391 uname);
392 return -EINVAL;
393 }
394
395 base = 0;
396
397 while (len > 0) {
398 start = dt_mem_next_cell(dt_root_addr_cells, &prop);
399 end = start + dt_mem_next_cell(dt_root_size_cells,
400 &prop);
401
402 ret = __reserved_mem_alloc_in_range(size, align,
403 start, end, nomap, &base);
404 if (ret == 0) {
405 pr_debug("allocated memory for '%s' node: base %pa, size %lu MiB\n",
406 uname, &base,
407 (unsigned long)(size / SZ_1M));
408 break;
409 }
410 len -= t_len;
411 }
412
413 } else {
414 ret = early_init_dt_alloc_reserved_memory_arch(size, align,
415 0, 0, nomap, &base);
416 if (ret == 0)
417 pr_debug("allocated memory for '%s' node: base %pa, size %lu MiB\n",
418 uname, &base, (unsigned long)(size / SZ_1M));
419 }
420
421 if (base == 0) {
422 pr_err("failed to allocate memory for node '%s': size %lu MiB\n",
423 uname, (unsigned long)(size / SZ_1M));
424 return -ENOMEM;
425 }
426 /* Architecture specific contiguous memory fixup. */
427 if (of_flat_dt_is_compatible(node, "shared-dma-pool") &&
428 of_get_flat_dt_prop(node, "reusable", NULL))
429 dma_contiguous_early_fixup(base, size);
430 /* Save region in the reserved_mem array */
431 fdt_reserved_mem_save_node(node, uname, base, size);
432 return 0;
433 }
434
435 static const struct of_device_id __rmem_of_table_sentinel
436 __used __section("__reservedmem_of_table_end");
437
438 /*
439 * __reserved_mem_init_node() - call region specific reserved memory init code
440 */
__reserved_mem_init_node(struct reserved_mem * rmem)441 static int __init __reserved_mem_init_node(struct reserved_mem *rmem)
442 {
443 extern const struct of_device_id __reservedmem_of_table[];
444 const struct of_device_id *i;
445 int ret = -ENOENT;
446
447 for (i = __reservedmem_of_table; i < &__rmem_of_table_sentinel; i++) {
448 reservedmem_of_init_fn initfn = i->data;
449 const char *compat = i->compatible;
450
451 if (!of_flat_dt_is_compatible(rmem->fdt_node, compat))
452 continue;
453
454 ret = initfn(rmem);
455 if (ret == 0) {
456 pr_info("initialized node %s, compatible id %s\n",
457 rmem->name, compat);
458 break;
459 }
460 }
461 return ret;
462 }
463
__rmem_cmp(const void * a,const void * b)464 static int __init __rmem_cmp(const void *a, const void *b)
465 {
466 const struct reserved_mem *ra = a, *rb = b;
467
468 if (ra->base < rb->base)
469 return -1;
470
471 if (ra->base > rb->base)
472 return 1;
473
474 /*
475 * Put the dynamic allocations (address == 0, size == 0) before static
476 * allocations at address 0x0 so that overlap detection works
477 * correctly.
478 */
479 if (ra->size < rb->size)
480 return -1;
481 if (ra->size > rb->size)
482 return 1;
483
484 if (ra->fdt_node < rb->fdt_node)
485 return -1;
486 if (ra->fdt_node > rb->fdt_node)
487 return 1;
488
489 return 0;
490 }
491
__rmem_check_for_overlap(void)492 static void __init __rmem_check_for_overlap(void)
493 {
494 int i;
495
496 if (reserved_mem_count < 2)
497 return;
498
499 sort(reserved_mem, reserved_mem_count, sizeof(reserved_mem[0]),
500 __rmem_cmp, NULL);
501 for (i = 0; i < reserved_mem_count - 1; i++) {
502 struct reserved_mem *this, *next;
503
504 this = &reserved_mem[i];
505 next = &reserved_mem[i + 1];
506
507 if (this->base + this->size > next->base) {
508 phys_addr_t this_end, next_end;
509
510 this_end = this->base + this->size;
511 next_end = next->base + next->size;
512 pr_err("OVERLAP DETECTED!\n%s (%pa--%pa) overlaps with %s (%pa--%pa)\n",
513 this->name, &this->base, &this_end,
514 next->name, &next->base, &next_end);
515 }
516 }
517 }
518
519 /**
520 * fdt_init_reserved_mem_node() - Initialize a reserved memory region
521 * @rmem: reserved_mem struct of the memory region to be initialized.
522 *
523 * This function is used to call the region specific initialization
524 * function for a reserved memory region.
525 */
fdt_init_reserved_mem_node(struct reserved_mem * rmem)526 static void __init fdt_init_reserved_mem_node(struct reserved_mem *rmem)
527 {
528 unsigned long node = rmem->fdt_node;
529 int err = 0;
530 bool nomap;
531
532 nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
533
534 err = __reserved_mem_init_node(rmem);
535 if (err != 0 && err != -ENOENT) {
536 pr_info("node %s compatible matching fail\n", rmem->name);
537 if (nomap)
538 memblock_clear_nomap(rmem->base, rmem->size);
539 else
540 memblock_phys_free(rmem->base, rmem->size);
541 } else {
542 phys_addr_t end = rmem->base + rmem->size - 1;
543 bool reusable =
544 (of_get_flat_dt_prop(node, "reusable", NULL)) != NULL;
545
546 pr_info("%pa..%pa (%lu KiB) %s %s %s\n",
547 &rmem->base, &end, (unsigned long)(rmem->size / SZ_1K),
548 nomap ? "nomap" : "map",
549 reusable ? "reusable" : "non-reusable",
550 rmem->name ? rmem->name : "unknown");
551
552 memblock_memsize_record(rmem->name, rmem->base,
553 rmem->size, nomap, reusable);
554 if (reusable && !of_flat_dt_is_compatible(node, "shared-dma-pool"))
555 memblock_memsize_mod_reusable_size(rmem->size);
556 }
557 }
558
559 struct rmem_assigned_device {
560 struct device *dev;
561 struct reserved_mem *rmem;
562 struct list_head list;
563 };
564
565 static LIST_HEAD(of_rmem_assigned_device_list);
566 static DEFINE_MUTEX(of_rmem_assigned_device_mutex);
567
568 /**
569 * of_reserved_mem_device_init_by_idx() - assign reserved memory region to
570 * given device
571 * @dev: Pointer to the device to configure
572 * @np: Pointer to the device_node with 'reserved-memory' property
573 * @idx: Index of selected region
574 *
575 * This function assigns respective DMA-mapping operations based on reserved
576 * memory region specified by 'memory-region' property in @np node to the @dev
577 * device. When driver needs to use more than one reserved memory region, it
578 * should allocate child devices and initialize regions by name for each of
579 * child device.
580 *
581 * Returns error code or zero on success.
582 */
of_reserved_mem_device_init_by_idx(struct device * dev,struct device_node * np,int idx)583 int of_reserved_mem_device_init_by_idx(struct device *dev,
584 struct device_node *np, int idx)
585 {
586 struct rmem_assigned_device *rd;
587 struct device_node *target;
588 struct reserved_mem *rmem;
589 int ret;
590
591 if (!np || !dev)
592 return -EINVAL;
593
594 target = of_parse_phandle(np, "memory-region", idx);
595 if (!target)
596 return -ENODEV;
597
598 if (!of_device_is_available(target)) {
599 of_node_put(target);
600 return 0;
601 }
602
603 rmem = of_reserved_mem_lookup(target);
604 of_node_put(target);
605
606 if (!rmem || !rmem->ops || !rmem->ops->device_init)
607 return -EINVAL;
608
609 rd = kmalloc(sizeof(struct rmem_assigned_device), GFP_KERNEL);
610 if (!rd)
611 return -ENOMEM;
612
613 ret = rmem->ops->device_init(rmem, dev);
614 if (ret == 0) {
615 rd->dev = dev;
616 rd->rmem = rmem;
617
618 mutex_lock(&of_rmem_assigned_device_mutex);
619 list_add(&rd->list, &of_rmem_assigned_device_list);
620 mutex_unlock(&of_rmem_assigned_device_mutex);
621
622 dev_info(dev, "assigned reserved memory node %s\n", rmem->name);
623 } else {
624 kfree(rd);
625 }
626
627 return ret;
628 }
629 EXPORT_SYMBOL_GPL(of_reserved_mem_device_init_by_idx);
630
631 /**
632 * of_reserved_mem_device_init_by_name() - assign named reserved memory region
633 * to given device
634 * @dev: pointer to the device to configure
635 * @np: pointer to the device node with 'memory-region' property
636 * @name: name of the selected memory region
637 *
638 * Returns: 0 on success or a negative error-code on failure.
639 */
of_reserved_mem_device_init_by_name(struct device * dev,struct device_node * np,const char * name)640 int of_reserved_mem_device_init_by_name(struct device *dev,
641 struct device_node *np,
642 const char *name)
643 {
644 int idx = of_property_match_string(np, "memory-region-names", name);
645
646 return of_reserved_mem_device_init_by_idx(dev, np, idx);
647 }
648 EXPORT_SYMBOL_GPL(of_reserved_mem_device_init_by_name);
649
650 /**
651 * of_reserved_mem_device_release() - release reserved memory device structures
652 * @dev: Pointer to the device to deconfigure
653 *
654 * This function releases structures allocated for memory region handling for
655 * the given device.
656 */
of_reserved_mem_device_release(struct device * dev)657 void of_reserved_mem_device_release(struct device *dev)
658 {
659 struct rmem_assigned_device *rd, *tmp;
660 LIST_HEAD(release_list);
661
662 mutex_lock(&of_rmem_assigned_device_mutex);
663 list_for_each_entry_safe(rd, tmp, &of_rmem_assigned_device_list, list) {
664 if (rd->dev == dev)
665 list_move_tail(&rd->list, &release_list);
666 }
667 mutex_unlock(&of_rmem_assigned_device_mutex);
668
669 list_for_each_entry_safe(rd, tmp, &release_list, list) {
670 if (rd->rmem && rd->rmem->ops && rd->rmem->ops->device_release)
671 rd->rmem->ops->device_release(rd->rmem, dev);
672
673 kfree(rd);
674 }
675 }
676 EXPORT_SYMBOL_GPL(of_reserved_mem_device_release);
677
678 /**
679 * of_reserved_mem_lookup() - acquire reserved_mem from a device node
680 * @np: node pointer of the desired reserved-memory region
681 *
682 * This function allows drivers to acquire a reference to the reserved_mem
683 * struct based on a device node handle.
684 *
685 * Returns a reserved_mem reference, or NULL on error.
686 */
of_reserved_mem_lookup(struct device_node * np)687 struct reserved_mem *of_reserved_mem_lookup(struct device_node *np)
688 {
689 const char *name;
690 int i;
691
692 if (!np->full_name)
693 return NULL;
694
695 name = kbasename(np->full_name);
696 for (i = 0; i < reserved_mem_count; i++)
697 if (!strcmp(reserved_mem[i].name, name))
698 return &reserved_mem[i];
699
700 return NULL;
701 }
702 EXPORT_SYMBOL_GPL(of_reserved_mem_lookup);
703