of_reserved_mem.c

  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/ioport.h>
 16#include <linux/libfdt.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#include <linux/slab.h>
 25#include <linux/memblock.h>
 26#include <linux/kmemleak.h>
 27#include <linux/cma.h>
 28#include <linux/dma-map-ops.h>
 29
 30#include "of_private.h"
 31
 32static struct reserved_mem reserved_mem_array[MAX_RESERVED_REGIONS] __initdata;
 33static struct reserved_mem *reserved_mem __refdata = reserved_mem_array;
 34static int total_reserved_mem_cnt = MAX_RESERVED_REGIONS;
 35static int reserved_mem_count;
 36
 37static int __init early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
 38	phys_addr_t align, phys_addr_t start, phys_addr_t end, bool nomap,
 39	phys_addr_t *res_base)
 40{
 41	phys_addr_t base;
 42	int err = 0;
 43
 44	end = !end ? MEMBLOCK_ALLOC_ANYWHERE : end;
 45	align = !align ? SMP_CACHE_BYTES : align;
 46	base = memblock_phys_alloc_range(size, align, start, end);
 47	if (!base)
 48		return -ENOMEM;
 49
 50	*res_base = base;
 51	if (nomap) {
 52		err = memblock_mark_nomap(base, size);
 53		if (err)
 54			memblock_phys_free(base, size);
 55	}
 56
 57	if (!err)
 58		kmemleak_ignore_phys(base);
 59
 60	return err;
 61}
 62
 63/*
 64 * alloc_reserved_mem_array() - allocate memory for the reserved_mem
 65 * array using memblock
 66 *
 67 * This function is used to allocate memory for the reserved_mem
 68 * array according to the total number of reserved memory regions
 69 * defined in the DT.
 70 * After the new array is allocated, the information stored in
 71 * the initial static array is copied over to this new array and
 72 * the new array is used from this point on.
 73 */
 74static void __init alloc_reserved_mem_array(void)
 75{
 76	struct reserved_mem *new_array;
 77	size_t alloc_size, copy_size, memset_size;
 78
 79	alloc_size = array_size(total_reserved_mem_cnt, sizeof(*new_array));
 80	if (alloc_size == SIZE_MAX) {
 81		pr_err("Failed to allocate memory for reserved_mem array with err: %d", -EOVERFLOW);
 82		return;
 83	}
 84
 85	new_array = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
 86	if (!new_array) {
 87		pr_err("Failed to allocate memory for reserved_mem array with err: %d", -ENOMEM);
 88		return;
 89	}
 90
 91	copy_size = array_size(reserved_mem_count, sizeof(*new_array));
 92	if (copy_size == SIZE_MAX) {
 93		memblock_free(new_array, alloc_size);
 94		total_reserved_mem_cnt = MAX_RESERVED_REGIONS;
 95		pr_err("Failed to allocate memory for reserved_mem array with err: %d", -EOVERFLOW);
 96		return;
 97	}
 98
 99	memset_size = alloc_size - copy_size;
100
101	memcpy(new_array, reserved_mem, copy_size);
102	memset(new_array + reserved_mem_count, 0, memset_size);
103
104	reserved_mem = new_array;
105}
106
107static void __init fdt_init_reserved_mem_node(struct reserved_mem *rmem);
108/*
109 * fdt_reserved_mem_save_node() - save fdt node for second pass initialization
110 */
111static void __init fdt_reserved_mem_save_node(unsigned long node, const char *uname,
112					      phys_addr_t base, phys_addr_t size)
113{
114	struct reserved_mem *rmem = &reserved_mem[reserved_mem_count];
115
116	if (reserved_mem_count == total_reserved_mem_cnt) {
117		pr_err("not enough space for all defined regions.\n");
118		return;
119	}
120
121	rmem->fdt_node = node;
122	rmem->name = uname;
123	rmem->base = base;
124	rmem->size = size;
125
126	/* Call the region specific initialization function */
127	fdt_init_reserved_mem_node(rmem);
128
129	reserved_mem_count++;
130	return;
131}
132
133static int __init early_init_dt_reserve_memory(phys_addr_t base,
134					       phys_addr_t size, bool nomap)
135{
136	if (nomap) {
137		/*
138		 * If the memory is already reserved (by another region), we
139		 * should not allow it to be marked nomap, but don't worry
140		 * if the region isn't memory as it won't be mapped.
141		 */
142		if (memblock_overlaps_region(&memblock.memory, base, size) &&
143		    memblock_is_region_reserved(base, size))
144			return -EBUSY;
145
146		return memblock_mark_nomap(base, size);
147	}
148	return memblock_reserve(base, size);
149}
150
151/*
152 * __reserved_mem_reserve_reg() - reserve all memory described in 'reg' property
153 */
154static int __init __reserved_mem_reserve_reg(unsigned long node,
155					     const char *uname)
156{
157	phys_addr_t base, size;
158	int i, len;
159	const __be32 *prop;
160	bool nomap, default_cma;
161
162	prop = of_flat_dt_get_addr_size_prop(node, "reg", &len);
163	if (!prop)
164		return -ENOENT;
165
166	nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
167	default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL);
168
169	if (default_cma && cma_skip_dt_default_reserved_mem()) {
170		pr_err("Skipping dt linux,cma-default for \"cma=\" kernel param.\n");
171		return -EINVAL;
172	}
173
174	for (i = 0; i < len; i++) {
175		u64 b, s;
176
177		of_flat_dt_read_addr_size(prop, i, &b, &s);
178
179		base = b;
180		size = s;
181
182		if (size && early_init_dt_reserve_memory(base, size, nomap) == 0) {
183			/* Architecture specific contiguous memory fixup. */
184			if (of_flat_dt_is_compatible(node, "shared-dma-pool") &&
185			    of_get_flat_dt_prop(node, "reusable", NULL))
186				dma_contiguous_early_fixup(base, size);
187			pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n",
188				uname, &base, (unsigned long)(size / SZ_1M));
189		} else {
190			pr_err("Reserved memory: failed to reserve memory for node '%s': base %pa, size %lu MiB\n",
191			       uname, &base, (unsigned long)(size / SZ_1M));
192		}
193	}
194	return 0;
195}
196
197/*
198 * __reserved_mem_check_root() - check if #size-cells, #address-cells provided
199 * in /reserved-memory matches the values supported by the current implementation,
200 * also check if ranges property has been provided
201 */
202static int __init __reserved_mem_check_root(unsigned long node)
203{
204	const __be32 *prop;
205
206	prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
207	if (!prop || be32_to_cpup(prop) != dt_root_size_cells)
208		return -EINVAL;
209
210	prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
211	if (!prop || be32_to_cpup(prop) != dt_root_addr_cells)
212		return -EINVAL;
213
214	prop = of_get_flat_dt_prop(node, "ranges", NULL);
215	if (!prop)
216		return -EINVAL;
217	return 0;
218}
219
220static void __init __rmem_check_for_overlap(void);
221
222/**
223 * fdt_scan_reserved_mem_reg_nodes() - Store info for the "reg" defined
224 * reserved memory regions.
225 *
226 * This function is used to scan through the DT and store the
227 * information for the reserved memory regions that are defined using
228 * the "reg" property. The region node number, name, base address, and
229 * size are all stored in the reserved_mem array by calling the
230 * fdt_reserved_mem_save_node() function.
231 */
232void __init fdt_scan_reserved_mem_reg_nodes(void)
233{
234	const void *fdt = initial_boot_params;
235	phys_addr_t base, size;
236	int node, child;
237
238	if (!fdt)
239		return;
240
241	node = fdt_path_offset(fdt, "/reserved-memory");
242	if (node < 0) {
243		pr_info("Reserved memory: No reserved-memory node in the DT\n");
244		return;
245	}
246
247	/* Attempt dynamic allocation of a new reserved_mem array */
248	alloc_reserved_mem_array();
249
250	if (__reserved_mem_check_root(node)) {
251		pr_err("Reserved memory: unsupported node format, ignoring\n");
252		return;
253	}
254
255	fdt_for_each_subnode(child, fdt, node) {
256		const char *uname;
257		bool default_cma = of_get_flat_dt_prop(child, "linux,cma-default", NULL);
258		u64 b, s;
259
260		if (!of_fdt_device_is_available(fdt, child))
261			continue;
262		if (default_cma && cma_skip_dt_default_reserved_mem())
263			continue;
264
265		if (!of_flat_dt_get_addr_size(child, "reg", &b, &s))
266			continue;
267
268		base = b;
269		size = s;
270
271		if (size) {
272			uname = fdt_get_name(fdt, child, NULL);
273			fdt_reserved_mem_save_node(child, uname, base, size);
274		}
275	}
276
277	/* check for overlapping reserved regions */
278	__rmem_check_for_overlap();
279}
280
281static int __init __reserved_mem_alloc_size(unsigned long node, const char *uname);
282
283/*
284 * fdt_scan_reserved_mem() - scan a single FDT node for reserved memory
285 */
286int __init fdt_scan_reserved_mem(void)
287{
288	int node, child;
289	int dynamic_nodes_cnt = 0, count = 0;
290	int dynamic_nodes[MAX_RESERVED_REGIONS];
291	const void *fdt = initial_boot_params;
292
293	node = fdt_path_offset(fdt, "/reserved-memory");
294	if (node < 0)
295		return -ENODEV;
296
297	if (__reserved_mem_check_root(node) != 0) {
298		pr_err("Reserved memory: unsupported node format, ignoring\n");
299		return -EINVAL;
300	}
301
302	fdt_for_each_subnode(child, fdt, node) {
303		const char *uname;
304		int err;
305
306		if (!of_fdt_device_is_available(fdt, child))
307			continue;
308
309		uname = fdt_get_name(fdt, child, NULL);
310
311		err = __reserved_mem_reserve_reg(child, uname);
312		if (!err)
313			count++;
314		/*
315		 * Save the nodes for the dynamically-placed regions
316		 * into an array which will be used for allocation right
317		 * after all the statically-placed regions are reserved
318		 * or marked as no-map. This is done to avoid dynamically
319		 * allocating from one of the statically-placed regions.
320		 */
321		if (err == -ENOENT && of_get_flat_dt_prop(child, "size", NULL)) {
322			dynamic_nodes[dynamic_nodes_cnt] = child;
323			dynamic_nodes_cnt++;
324		}
325	}
326	for (int i = 0; i < dynamic_nodes_cnt; i++) {
327		const char *uname;
328		int err;
329
330		child = dynamic_nodes[i];
331		uname = fdt_get_name(fdt, child, NULL);
332		err = __reserved_mem_alloc_size(child, uname);
333		if (!err)
334			count++;
335	}
336	total_reserved_mem_cnt = count;
337	return 0;
338}
339
340/*
341 * __reserved_mem_alloc_in_range() - allocate reserved memory described with
342 *	'alloc-ranges'. Choose bottom-up/top-down depending on nearby existing
343 *	reserved regions to keep the reserved memory contiguous if possible.
344 */
345static int __init __reserved_mem_alloc_in_range(phys_addr_t size,
346	phys_addr_t align, phys_addr_t start, phys_addr_t end, bool nomap,
347	phys_addr_t *res_base)
348{
349	bool prev_bottom_up = memblock_bottom_up();
350	bool bottom_up = false, top_down = false;
351	int ret, i;
352
353	for (i = 0; i < reserved_mem_count; i++) {
354		struct reserved_mem *rmem = &reserved_mem[i];
355
356		/* Skip regions that were not reserved yet */
357		if (rmem->size == 0)
358			continue;
359
360		/*
361		 * If range starts next to an existing reservation, use bottom-up:
362		 *	|....RRRR................RRRRRRRR..............|
363		 *	       --RRRR------
364		 */
365		if (start >= rmem->base && start <= (rmem->base + rmem->size))
366			bottom_up = true;
367
368		/*
369		 * If range ends next to an existing reservation, use top-down:
370		 *	|....RRRR................RRRRRRRR..............|
371		 *	              -------RRRR-----
372		 */
373		if (end >= rmem->base && end <= (rmem->base + rmem->size))
374			top_down = true;
375	}
376
377	/* Change setting only if either bottom-up or top-down was selected */
378	if (bottom_up != top_down)
379		memblock_set_bottom_up(bottom_up);
380
381	ret = early_init_dt_alloc_reserved_memory_arch(size, align,
382			start, end, nomap, res_base);
383
384	/* Restore old setting if needed */
385	if (bottom_up != top_down)
386		memblock_set_bottom_up(prev_bottom_up);
387
388	return ret;
389}
390
391/*
392 * __reserved_mem_alloc_size() - allocate reserved memory described by
393 *	'size', 'alignment'  and 'alloc-ranges' properties.
394 */
395static int __init __reserved_mem_alloc_size(unsigned long node, const char *uname)
396{
397	phys_addr_t start = 0, end = 0;
398	phys_addr_t base = 0, align = 0, size;
399	int i, len;
400	const __be32 *prop;
401	bool nomap, default_cma;
402	int ret;
403
404	prop = of_get_flat_dt_prop(node, "size", &len);
405	if (!prop)
406		return -EINVAL;
407
408	if (len != dt_root_size_cells * sizeof(__be32)) {
409		pr_err("invalid size property in '%s' node.\n", uname);
410		return -EINVAL;
411	}
412	size = dt_mem_next_cell(dt_root_size_cells, &prop);
413
414	prop = of_get_flat_dt_prop(node, "alignment", &len);
415	if (prop) {
416		if (len != dt_root_addr_cells * sizeof(__be32)) {
417			pr_err("invalid alignment property in '%s' node.\n",
418				uname);
419			return -EINVAL;
420		}
421		align = dt_mem_next_cell(dt_root_addr_cells, &prop);
422	}
423
424	nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
425	default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL);
426
427	if (default_cma && cma_skip_dt_default_reserved_mem()) {
428		pr_err("Skipping dt linux,cma-default for \"cma=\" kernel param.\n");
429		return -EINVAL;
430	}
431
432	/* Need adjust the alignment to satisfy the CMA requirement */
433	if (IS_ENABLED(CONFIG_CMA)
434	    && of_flat_dt_is_compatible(node, "shared-dma-pool")
435	    && of_get_flat_dt_prop(node, "reusable", NULL)
436	    && !nomap)
437		align = max_t(phys_addr_t, align, CMA_MIN_ALIGNMENT_BYTES);
438
439	prop = of_flat_dt_get_addr_size_prop(node, "alloc-ranges", &len);
440	if (prop) {
441		for (i = 0; i < len; i++) {
442			u64 b, s;
443
444			of_flat_dt_read_addr_size(prop, i, &b, &s);
445
446			start = b;
447			end = b + s;
448
449			base = 0;
450			ret = __reserved_mem_alloc_in_range(size, align,
451					start, end, nomap, &base);
452			if (ret == 0) {
453				pr_debug("allocated memory for '%s' node: base %pa, size %lu MiB\n",
454					uname, &base,
455					(unsigned long)(size / SZ_1M));
456				break;
457			}
458		}
459	} else {
460		ret = early_init_dt_alloc_reserved_memory_arch(size, align,
461							0, 0, nomap, &base);
462		if (ret == 0)
463			pr_debug("allocated memory for '%s' node: base %pa, size %lu MiB\n",
464				uname, &base, (unsigned long)(size / SZ_1M));
465	}
466
467	if (base == 0) {
468		pr_err("failed to allocate memory for node '%s': size %lu MiB\n",
469		       uname, (unsigned long)(size / SZ_1M));
470		return -ENOMEM;
471	}
472	/* Architecture specific contiguous memory fixup. */
473	if (of_flat_dt_is_compatible(node, "shared-dma-pool") &&
474	    of_get_flat_dt_prop(node, "reusable", NULL))
475		dma_contiguous_early_fixup(base, size);
476	/* Save region in the reserved_mem array */
477	fdt_reserved_mem_save_node(node, uname, base, size);
478	return 0;
479}
480
481static const struct of_device_id __rmem_of_table_sentinel
482	__used __section("__reservedmem_of_table_end");
483
484/*
485 * __reserved_mem_init_node() - call region specific reserved memory init code
486 */
487static int __init __reserved_mem_init_node(struct reserved_mem *rmem)
488{
489	extern const struct of_device_id __reservedmem_of_table[];
490	const struct of_device_id *i;
491	int ret = -ENOENT;
492
493	for (i = __reservedmem_of_table; i < &__rmem_of_table_sentinel; i++) {
494		reservedmem_of_init_fn initfn = i->data;
495		const char *compat = i->compatible;
496
497		if (!of_flat_dt_is_compatible(rmem->fdt_node, compat))
498			continue;
499
500		ret = initfn(rmem);
501		if (ret == 0) {
502			pr_info("initialized node %s, compatible id %s\n",
503				rmem->name, compat);
504			break;
505		}
506	}
507	return ret;
508}
509
510static int __init __rmem_cmp(const void *a, const void *b)
511{
512	const struct reserved_mem *ra = a, *rb = b;
513
514	if (ra->base < rb->base)
515		return -1;
516
517	if (ra->base > rb->base)
518		return 1;
519
520	/*
521	 * Put the dynamic allocations (address == 0, size == 0) before static
522	 * allocations at address 0x0 so that overlap detection works
523	 * correctly.
524	 */
525	if (ra->size < rb->size)
526		return -1;
527	if (ra->size > rb->size)
528		return 1;
529
530	if (ra->fdt_node < rb->fdt_node)
531		return -1;
532	if (ra->fdt_node > rb->fdt_node)
533		return 1;
534
535	return 0;
536}
537
538static void __init __rmem_check_for_overlap(void)
539{
540	int i;
541
542	if (reserved_mem_count < 2)
543		return;
544
545	sort(reserved_mem, reserved_mem_count, sizeof(reserved_mem[0]),
546	     __rmem_cmp, NULL);
547	for (i = 0; i < reserved_mem_count - 1; i++) {
548		struct reserved_mem *this, *next;
549
550		this = &reserved_mem[i];
551		next = &reserved_mem[i + 1];
552
553		if (this->base + this->size > next->base) {
554			phys_addr_t this_end, next_end;
555
556			this_end = this->base + this->size;
557			next_end = next->base + next->size;
558			pr_err("OVERLAP DETECTED!\n%s (%pa--%pa) overlaps with %s (%pa--%pa)\n",
559			       this->name, &this->base, &this_end,
560			       next->name, &next->base, &next_end);
561		}
562	}
563}
564
565/**
566 * fdt_init_reserved_mem_node() - Initialize a reserved memory region
567 * @rmem: reserved_mem struct of the memory region to be initialized.
568 *
569 * This function is used to call the region specific initialization
570 * function for a reserved memory region.
571 */
572static void __init fdt_init_reserved_mem_node(struct reserved_mem *rmem)
573{
574	unsigned long node = rmem->fdt_node;
575	int err = 0;
576	bool nomap;
577
578	nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
579
580	err = __reserved_mem_init_node(rmem);
581	if (err != 0 && err != -ENOENT) {
582		pr_info("node %s compatible matching fail\n", rmem->name);
583		if (nomap)
584			memblock_clear_nomap(rmem->base, rmem->size);
585		else
586			memblock_phys_free(rmem->base, rmem->size);
587	} else {
588		phys_addr_t end = rmem->base + rmem->size - 1;
589		bool reusable =
590			(of_get_flat_dt_prop(node, "reusable", NULL)) != NULL;
591
592		pr_info("%pa..%pa (%lu KiB) %s %s %s\n",
593			&rmem->base, &end, (unsigned long)(rmem->size / SZ_1K),
594			nomap ? "nomap" : "map",
595			reusable ? "reusable" : "non-reusable",
596			rmem->name ? rmem->name : "unknown");
597	}
598}
599
600struct rmem_assigned_device {
601	struct device *dev;
602	struct reserved_mem *rmem;
603	struct list_head list;
604};
605
606static LIST_HEAD(of_rmem_assigned_device_list);
607static DEFINE_MUTEX(of_rmem_assigned_device_mutex);
608
609/**
610 * of_reserved_mem_device_init_by_idx() - assign reserved memory region to
611 *					  given device
612 * @dev:	Pointer to the device to configure
613 * @np:		Pointer to the device_node with 'reserved-memory' property
614 * @idx:	Index of selected region
615 *
616 * This function assigns respective DMA-mapping operations based on reserved
617 * memory region specified by 'memory-region' property in @np node to the @dev
618 * device. When driver needs to use more than one reserved memory region, it
619 * should allocate child devices and initialize regions by name for each of
620 * child device.
621 *
622 * Returns error code or zero on success.
623 */
624int of_reserved_mem_device_init_by_idx(struct device *dev,
625				       struct device_node *np, int idx)
626{
627	struct rmem_assigned_device *rd;
628	struct device_node *target;
629	struct reserved_mem *rmem;
630	int ret;
631
632	if (!np || !dev)
633		return -EINVAL;
634
635	target = of_parse_phandle(np, "memory-region", idx);
636	if (!target)
637		return -ENODEV;
638
639	if (!of_device_is_available(target)) {
640		of_node_put(target);
641		return 0;
642	}
643
644	rmem = of_reserved_mem_lookup(target);
645	of_node_put(target);
646
647	if (!rmem || !rmem->ops || !rmem->ops->device_init)
648		return -EINVAL;
649
650	rd = kmalloc(sizeof(struct rmem_assigned_device), GFP_KERNEL);
651	if (!rd)
652		return -ENOMEM;
653
654	ret = rmem->ops->device_init(rmem, dev);
655	if (ret == 0) {
656		rd->dev = dev;
657		rd->rmem = rmem;
658
659		mutex_lock(&of_rmem_assigned_device_mutex);
660		list_add(&rd->list, &of_rmem_assigned_device_list);
661		mutex_unlock(&of_rmem_assigned_device_mutex);
662
663		dev_info(dev, "assigned reserved memory node %s\n", rmem->name);
664	} else {
665		kfree(rd);
666	}
667
668	return ret;
669}
670EXPORT_SYMBOL_GPL(of_reserved_mem_device_init_by_idx);
671
672/**
673 * of_reserved_mem_device_init_by_name() - assign named reserved memory region
674 *					   to given device
675 * @dev: pointer to the device to configure
676 * @np: pointer to the device node with 'memory-region' property
677 * @name: name of the selected memory region
678 *
679 * Returns: 0 on success or a negative error-code on failure.
680 */
681int of_reserved_mem_device_init_by_name(struct device *dev,
682					struct device_node *np,
683					const char *name)
684{
685	int idx = of_property_match_string(np, "memory-region-names", name);
686
687	return of_reserved_mem_device_init_by_idx(dev, np, idx);
688}
689EXPORT_SYMBOL_GPL(of_reserved_mem_device_init_by_name);
690
691/**
692 * of_reserved_mem_device_release() - release reserved memory device structures
693 * @dev:	Pointer to the device to deconfigure
694 *
695 * This function releases structures allocated for memory region handling for
696 * the given device.
697 */
698void of_reserved_mem_device_release(struct device *dev)
699{
700	struct rmem_assigned_device *rd, *tmp;
701	LIST_HEAD(release_list);
702
703	mutex_lock(&of_rmem_assigned_device_mutex);
704	list_for_each_entry_safe(rd, tmp, &of_rmem_assigned_device_list, list) {
705		if (rd->dev == dev)
706			list_move_tail(&rd->list, &release_list);
707	}
708	mutex_unlock(&of_rmem_assigned_device_mutex);
709
710	list_for_each_entry_safe(rd, tmp, &release_list, list) {
711		if (rd->rmem && rd->rmem->ops && rd->rmem->ops->device_release)
712			rd->rmem->ops->device_release(rd->rmem, dev);
713
714		kfree(rd);
715	}
716}
717EXPORT_SYMBOL_GPL(of_reserved_mem_device_release);
718
719/**
720 * of_reserved_mem_lookup() - acquire reserved_mem from a device node
721 * @np:		node pointer of the desired reserved-memory region
722 *
723 * This function allows drivers to acquire a reference to the reserved_mem
724 * struct based on a device node handle.
725 *
726 * Returns a reserved_mem reference, or NULL on error.
727 */
728struct reserved_mem *of_reserved_mem_lookup(struct device_node *np)
729{
730	const char *name;
731	int i;
732
733	if (!np->full_name)
734		return NULL;
735
736	name = kbasename(np->full_name);
737	for (i = 0; i < reserved_mem_count; i++)
738		if (!strcmp(reserved_mem[i].name, name))
739			return &reserved_mem[i];
740
741	return NULL;
742}
743EXPORT_SYMBOL_GPL(of_reserved_mem_lookup);
744
745/**
746 * of_reserved_mem_region_to_resource() - Get a reserved memory region as a resource
747 * @np:		node containing 'memory-region' property
748 * @idx:	index of 'memory-region' property to lookup
749 * @res:	Pointer to a struct resource to fill in with reserved region
750 *
751 * This function allows drivers to lookup a node's 'memory-region' property
752 * entries by index and return a struct resource for the entry.
753 *
754 * Returns 0 on success with @res filled in. Returns -ENODEV if 'memory-region'
755 * is missing or unavailable, -EINVAL for any other error.
756 */
757int of_reserved_mem_region_to_resource(const struct device_node *np,
758				       unsigned int idx, struct resource *res)
759{
760	struct reserved_mem *rmem;
761
762	if (!np)
763		return -EINVAL;
764
765	struct device_node __free(device_node) *target = of_parse_phandle(np, "memory-region", idx);
766	if (!target || !of_device_is_available(target))
767		return -ENODEV;
768
769	rmem = of_reserved_mem_lookup(target);
770	if (!rmem)
771		return -EINVAL;
772
773	resource_set_range(res, rmem->base, rmem->size);
774	res->flags = IORESOURCE_MEM;
775	res->name = rmem->name;
776	return 0;
777}
778EXPORT_SYMBOL_GPL(of_reserved_mem_region_to_resource);
779
780/**
781 * of_reserved_mem_region_to_resource_byname() - Get a reserved memory region as a resource
782 * @np:		node containing 'memory-region' property
783 * @name:	name of 'memory-region' property entry to lookup
784 * @res:	Pointer to a struct resource to fill in with reserved region
785 *
786 * This function allows drivers to lookup a node's 'memory-region' property
787 * entries by name and return a struct resource for the entry.
788 *
789 * Returns 0 on success with @res filled in, or a negative error-code on
790 * failure.
791 */
792int of_reserved_mem_region_to_resource_byname(const struct device_node *np,
793					      const char *name,
794					      struct resource *res)
795{
796	int idx;
797
798	if (!name)
799		return -EINVAL;
800
801	idx = of_property_match_string(np, "memory-region-names", name);
802	if (idx < 0)
803		return idx;
804
805	return of_reserved_mem_region_to_resource(np, idx, res);
806}
807EXPORT_SYMBOL_GPL(of_reserved_mem_region_to_resource_byname);
808
809/**
810 * of_reserved_mem_region_count() - Return the number of 'memory-region' entries
811 * @np:		node containing 'memory-region' property
812 *
813 * This function allows drivers to retrieve the number of entries for a node's
814 * 'memory-region' property.
815 *
816 * Returns the number of entries on success, or negative error code on a
817 * malformed property.
818 */
819int of_reserved_mem_region_count(const struct device_node *np)
820{
821	return of_count_phandle_with_args(np, "memory-region", NULL);
822}
823EXPORT_SYMBOL_GPL(of_reserved_mem_region_count);