xref: /openbmc/linux/lib/genalloc.c (revision 2127c01b)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Basic general purpose allocator for managing special purpose
4  * memory, for example, memory that is not managed by the regular
5  * kmalloc/kfree interface.  Uses for this includes on-device special
6  * memory, uncached memory etc.
7  *
8  * It is safe to use the allocator in NMI handlers and other special
9  * unblockable contexts that could otherwise deadlock on locks.  This
10  * is implemented by using atomic operations and retries on any
11  * conflicts.  The disadvantage is that there may be livelocks in
12  * extreme cases.  For better scalability, one allocator can be used
13  * for each CPU.
14  *
15  * The lockless operation only works if there is enough memory
16  * available.  If new memory is added to the pool a lock has to be
17  * still taken.  So any user relying on locklessness has to ensure
18  * that sufficient memory is preallocated.
19  *
20  * The basic atomic operation of this allocator is cmpxchg on long.
21  * On architectures that don't have NMI-safe cmpxchg implementation,
22  * the allocator can NOT be used in NMI handler.  So code uses the
23  * allocator in NMI handler should depend on
24  * CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG.
25  *
26  * Copyright 2005 (C) Jes Sorensen <jes@trained-monkey.org>
27  */
28 
29 #include <linux/slab.h>
30 #include <linux/export.h>
31 #include <linux/bitmap.h>
32 #include <linux/rculist.h>
33 #include <linux/interrupt.h>
34 #include <linux/genalloc.h>
35 #include <linux/of_device.h>
36 #include <linux/vmalloc.h>
37 
38 static inline size_t chunk_size(const struct gen_pool_chunk *chunk)
39 {
40 	return chunk->end_addr - chunk->start_addr + 1;
41 }
42 
43 static int set_bits_ll(unsigned long *addr, unsigned long mask_to_set)
44 {
45 	unsigned long val, nval;
46 
47 	nval = *addr;
48 	do {
49 		val = nval;
50 		if (val & mask_to_set)
51 			return -EBUSY;
52 		cpu_relax();
53 	} while ((nval = cmpxchg(addr, val, val | mask_to_set)) != val);
54 
55 	return 0;
56 }
57 
58 static int clear_bits_ll(unsigned long *addr, unsigned long mask_to_clear)
59 {
60 	unsigned long val, nval;
61 
62 	nval = *addr;
63 	do {
64 		val = nval;
65 		if ((val & mask_to_clear) != mask_to_clear)
66 			return -EBUSY;
67 		cpu_relax();
68 	} while ((nval = cmpxchg(addr, val, val & ~mask_to_clear)) != val);
69 
70 	return 0;
71 }
72 
73 /*
74  * bitmap_set_ll - set the specified number of bits at the specified position
75  * @map: pointer to a bitmap
76  * @start: a bit position in @map
77  * @nr: number of bits to set
78  *
79  * Set @nr bits start from @start in @map lock-lessly. Several users
80  * can set/clear the same bitmap simultaneously without lock. If two
81  * users set the same bit, one user will return remain bits, otherwise
82  * return 0.
83  */
84 static int bitmap_set_ll(unsigned long *map, int start, int nr)
85 {
86 	unsigned long *p = map + BIT_WORD(start);
87 	const int size = start + nr;
88 	int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
89 	unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
90 
91 	while (nr - bits_to_set >= 0) {
92 		if (set_bits_ll(p, mask_to_set))
93 			return nr;
94 		nr -= bits_to_set;
95 		bits_to_set = BITS_PER_LONG;
96 		mask_to_set = ~0UL;
97 		p++;
98 	}
99 	if (nr) {
100 		mask_to_set &= BITMAP_LAST_WORD_MASK(size);
101 		if (set_bits_ll(p, mask_to_set))
102 			return nr;
103 	}
104 
105 	return 0;
106 }
107 
108 /*
109  * bitmap_clear_ll - clear the specified number of bits at the specified position
110  * @map: pointer to a bitmap
111  * @start: a bit position in @map
112  * @nr: number of bits to set
113  *
114  * Clear @nr bits start from @start in @map lock-lessly. Several users
115  * can set/clear the same bitmap simultaneously without lock. If two
116  * users clear the same bit, one user will return remain bits,
117  * otherwise return 0.
118  */
119 static int bitmap_clear_ll(unsigned long *map, int start, int nr)
120 {
121 	unsigned long *p = map + BIT_WORD(start);
122 	const int size = start + nr;
123 	int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
124 	unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
125 
126 	while (nr - bits_to_clear >= 0) {
127 		if (clear_bits_ll(p, mask_to_clear))
128 			return nr;
129 		nr -= bits_to_clear;
130 		bits_to_clear = BITS_PER_LONG;
131 		mask_to_clear = ~0UL;
132 		p++;
133 	}
134 	if (nr) {
135 		mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
136 		if (clear_bits_ll(p, mask_to_clear))
137 			return nr;
138 	}
139 
140 	return 0;
141 }
142 
143 /**
144  * gen_pool_create - create a new special memory pool
145  * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
146  * @nid: node id of the node the pool structure should be allocated on, or -1
147  *
148  * Create a new special memory pool that can be used to manage special purpose
149  * memory not managed by the regular kmalloc/kfree interface.
150  */
151 struct gen_pool *gen_pool_create(int min_alloc_order, int nid)
152 {
153 	struct gen_pool *pool;
154 
155 	pool = kmalloc_node(sizeof(struct gen_pool), GFP_KERNEL, nid);
156 	if (pool != NULL) {
157 		spin_lock_init(&pool->lock);
158 		INIT_LIST_HEAD(&pool->chunks);
159 		pool->min_alloc_order = min_alloc_order;
160 		pool->algo = gen_pool_first_fit;
161 		pool->data = NULL;
162 		pool->name = NULL;
163 	}
164 	return pool;
165 }
166 EXPORT_SYMBOL(gen_pool_create);
167 
168 /**
169  * gen_pool_add_owner- add a new chunk of special memory to the pool
170  * @pool: pool to add new memory chunk to
171  * @virt: virtual starting address of memory chunk to add to pool
172  * @phys: physical starting address of memory chunk to add to pool
173  * @size: size in bytes of the memory chunk to add to pool
174  * @nid: node id of the node the chunk structure and bitmap should be
175  *       allocated on, or -1
176  * @owner: private data the publisher would like to recall at alloc time
177  *
178  * Add a new chunk of special memory to the specified pool.
179  *
180  * Returns 0 on success or a -ve errno on failure.
181  */
182 int gen_pool_add_owner(struct gen_pool *pool, unsigned long virt, phys_addr_t phys,
183 		 size_t size, int nid, void *owner)
184 {
185 	struct gen_pool_chunk *chunk;
186 	int nbits = size >> pool->min_alloc_order;
187 	int nbytes = sizeof(struct gen_pool_chunk) +
188 				BITS_TO_LONGS(nbits) * sizeof(long);
189 
190 	chunk = vzalloc_node(nbytes, nid);
191 	if (unlikely(chunk == NULL))
192 		return -ENOMEM;
193 
194 	chunk->phys_addr = phys;
195 	chunk->start_addr = virt;
196 	chunk->end_addr = virt + size - 1;
197 	chunk->owner = owner;
198 	atomic_long_set(&chunk->avail, size);
199 
200 	spin_lock(&pool->lock);
201 	list_add_rcu(&chunk->next_chunk, &pool->chunks);
202 	spin_unlock(&pool->lock);
203 
204 	return 0;
205 }
206 EXPORT_SYMBOL(gen_pool_add_owner);
207 
208 /**
209  * gen_pool_virt_to_phys - return the physical address of memory
210  * @pool: pool to allocate from
211  * @addr: starting address of memory
212  *
213  * Returns the physical address on success, or -1 on error.
214  */
215 phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long addr)
216 {
217 	struct gen_pool_chunk *chunk;
218 	phys_addr_t paddr = -1;
219 
220 	rcu_read_lock();
221 	list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
222 		if (addr >= chunk->start_addr && addr <= chunk->end_addr) {
223 			paddr = chunk->phys_addr + (addr - chunk->start_addr);
224 			break;
225 		}
226 	}
227 	rcu_read_unlock();
228 
229 	return paddr;
230 }
231 EXPORT_SYMBOL(gen_pool_virt_to_phys);
232 
233 /**
234  * gen_pool_destroy - destroy a special memory pool
235  * @pool: pool to destroy
236  *
237  * Destroy the specified special memory pool. Verifies that there are no
238  * outstanding allocations.
239  */
240 void gen_pool_destroy(struct gen_pool *pool)
241 {
242 	struct list_head *_chunk, *_next_chunk;
243 	struct gen_pool_chunk *chunk;
244 	int order = pool->min_alloc_order;
245 	int bit, end_bit;
246 
247 	list_for_each_safe(_chunk, _next_chunk, &pool->chunks) {
248 		chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
249 		list_del(&chunk->next_chunk);
250 
251 		end_bit = chunk_size(chunk) >> order;
252 		bit = find_next_bit(chunk->bits, end_bit, 0);
253 		BUG_ON(bit < end_bit);
254 
255 		vfree(chunk);
256 	}
257 	kfree_const(pool->name);
258 	kfree(pool);
259 }
260 EXPORT_SYMBOL(gen_pool_destroy);
261 
262 /**
263  * gen_pool_alloc_algo_owner - allocate special memory from the pool
264  * @pool: pool to allocate from
265  * @size: number of bytes to allocate from the pool
266  * @algo: algorithm passed from caller
267  * @data: data passed to algorithm
268  * @owner: optionally retrieve the chunk owner
269  *
270  * Allocate the requested number of bytes from the specified pool.
271  * Uses the pool allocation function (with first-fit algorithm by default).
272  * Can not be used in NMI handler on architectures without
273  * NMI-safe cmpxchg implementation.
274  */
275 unsigned long gen_pool_alloc_algo_owner(struct gen_pool *pool, size_t size,
276 		genpool_algo_t algo, void *data, void **owner)
277 {
278 	struct gen_pool_chunk *chunk;
279 	unsigned long addr = 0;
280 	int order = pool->min_alloc_order;
281 	int nbits, start_bit, end_bit, remain;
282 
283 #ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
284 	BUG_ON(in_nmi());
285 #endif
286 
287 	if (owner)
288 		*owner = NULL;
289 
290 	if (size == 0)
291 		return 0;
292 
293 	nbits = (size + (1UL << order) - 1) >> order;
294 	rcu_read_lock();
295 	list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
296 		if (size > atomic_long_read(&chunk->avail))
297 			continue;
298 
299 		start_bit = 0;
300 		end_bit = chunk_size(chunk) >> order;
301 retry:
302 		start_bit = algo(chunk->bits, end_bit, start_bit,
303 				 nbits, data, pool, chunk->start_addr);
304 		if (start_bit >= end_bit)
305 			continue;
306 		remain = bitmap_set_ll(chunk->bits, start_bit, nbits);
307 		if (remain) {
308 			remain = bitmap_clear_ll(chunk->bits, start_bit,
309 						 nbits - remain);
310 			BUG_ON(remain);
311 			goto retry;
312 		}
313 
314 		addr = chunk->start_addr + ((unsigned long)start_bit << order);
315 		size = nbits << order;
316 		atomic_long_sub(size, &chunk->avail);
317 		if (owner)
318 			*owner = chunk->owner;
319 		break;
320 	}
321 	rcu_read_unlock();
322 	return addr;
323 }
324 EXPORT_SYMBOL(gen_pool_alloc_algo_owner);
325 
326 /**
327  * gen_pool_dma_alloc - allocate special memory from the pool for DMA usage
328  * @pool: pool to allocate from
329  * @size: number of bytes to allocate from the pool
330  * @dma: dma-view physical address return value.  Use %NULL if unneeded.
331  *
332  * Allocate the requested number of bytes from the specified pool.
333  * Uses the pool allocation function (with first-fit algorithm by default).
334  * Can not be used in NMI handler on architectures without
335  * NMI-safe cmpxchg implementation.
336  *
337  * Return: virtual address of the allocated memory, or %NULL on failure
338  */
339 void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size, dma_addr_t *dma)
340 {
341 	return gen_pool_dma_alloc_algo(pool, size, dma, pool->algo, pool->data);
342 }
343 EXPORT_SYMBOL(gen_pool_dma_alloc);
344 
345 /**
346  * gen_pool_dma_alloc_algo - allocate special memory from the pool for DMA
347  * usage with the given pool algorithm
348  * @pool: pool to allocate from
349  * @size: number of bytes to allocate from the pool
350  * @dma: DMA-view physical address return value. Use %NULL if unneeded.
351  * @algo: algorithm passed from caller
352  * @data: data passed to algorithm
353  *
354  * Allocate the requested number of bytes from the specified pool. Uses the
355  * given pool allocation function. Can not be used in NMI handler on
356  * architectures without NMI-safe cmpxchg implementation.
357  *
358  * Return: virtual address of the allocated memory, or %NULL on failure
359  */
360 void *gen_pool_dma_alloc_algo(struct gen_pool *pool, size_t size,
361 		dma_addr_t *dma, genpool_algo_t algo, void *data)
362 {
363 	unsigned long vaddr;
364 
365 	if (!pool)
366 		return NULL;
367 
368 	vaddr = gen_pool_alloc_algo(pool, size, algo, data);
369 	if (!vaddr)
370 		return NULL;
371 
372 	if (dma)
373 		*dma = gen_pool_virt_to_phys(pool, vaddr);
374 
375 	return (void *)vaddr;
376 }
377 EXPORT_SYMBOL(gen_pool_dma_alloc_algo);
378 
379 /**
380  * gen_pool_dma_alloc_align - allocate special memory from the pool for DMA
381  * usage with the given alignment
382  * @pool: pool to allocate from
383  * @size: number of bytes to allocate from the pool
384  * @dma: DMA-view physical address return value. Use %NULL if unneeded.
385  * @align: alignment in bytes for starting address
386  *
387  * Allocate the requested number bytes from the specified pool, with the given
388  * alignment restriction. Can not be used in NMI handler on architectures
389  * without NMI-safe cmpxchg implementation.
390  *
391  * Return: virtual address of the allocated memory, or %NULL on failure
392  */
393 void *gen_pool_dma_alloc_align(struct gen_pool *pool, size_t size,
394 		dma_addr_t *dma, int align)
395 {
396 	struct genpool_data_align data = { .align = align };
397 
398 	return gen_pool_dma_alloc_algo(pool, size, dma,
399 			gen_pool_first_fit_align, &data);
400 }
401 EXPORT_SYMBOL(gen_pool_dma_alloc_align);
402 
403 /**
404  * gen_pool_dma_zalloc - allocate special zeroed memory from the pool for
405  * DMA usage
406  * @pool: pool to allocate from
407  * @size: number of bytes to allocate from the pool
408  * @dma: dma-view physical address return value.  Use %NULL if unneeded.
409  *
410  * Allocate the requested number of zeroed bytes from the specified pool.
411  * Uses the pool allocation function (with first-fit algorithm by default).
412  * Can not be used in NMI handler on architectures without
413  * NMI-safe cmpxchg implementation.
414  *
415  * Return: virtual address of the allocated zeroed memory, or %NULL on failure
416  */
417 void *gen_pool_dma_zalloc(struct gen_pool *pool, size_t size, dma_addr_t *dma)
418 {
419 	return gen_pool_dma_zalloc_algo(pool, size, dma, pool->algo, pool->data);
420 }
421 EXPORT_SYMBOL(gen_pool_dma_zalloc);
422 
423 /**
424  * gen_pool_dma_zalloc_algo - allocate special zeroed memory from the pool for
425  * DMA usage with the given pool algorithm
426  * @pool: pool to allocate from
427  * @size: number of bytes to allocate from the pool
428  * @dma: DMA-view physical address return value. Use %NULL if unneeded.
429  * @algo: algorithm passed from caller
430  * @data: data passed to algorithm
431  *
432  * Allocate the requested number of zeroed bytes from the specified pool. Uses
433  * the given pool allocation function. Can not be used in NMI handler on
434  * architectures without NMI-safe cmpxchg implementation.
435  *
436  * Return: virtual address of the allocated zeroed memory, or %NULL on failure
437  */
438 void *gen_pool_dma_zalloc_algo(struct gen_pool *pool, size_t size,
439 		dma_addr_t *dma, genpool_algo_t algo, void *data)
440 {
441 	void *vaddr = gen_pool_dma_alloc_algo(pool, size, dma, algo, data);
442 
443 	if (vaddr)
444 		memset(vaddr, 0, size);
445 
446 	return vaddr;
447 }
448 EXPORT_SYMBOL(gen_pool_dma_zalloc_algo);
449 
450 /**
451  * gen_pool_dma_zalloc_align - allocate special zeroed memory from the pool for
452  * DMA usage with the given alignment
453  * @pool: pool to allocate from
454  * @size: number of bytes to allocate from the pool
455  * @dma: DMA-view physical address return value. Use %NULL if unneeded.
456  * @align: alignment in bytes for starting address
457  *
458  * Allocate the requested number of zeroed bytes from the specified pool,
459  * with the given alignment restriction. Can not be used in NMI handler on
460  * architectures without NMI-safe cmpxchg implementation.
461  *
462  * Return: virtual address of the allocated zeroed memory, or %NULL on failure
463  */
464 void *gen_pool_dma_zalloc_align(struct gen_pool *pool, size_t size,
465 		dma_addr_t *dma, int align)
466 {
467 	struct genpool_data_align data = { .align = align };
468 
469 	return gen_pool_dma_zalloc_algo(pool, size, dma,
470 			gen_pool_first_fit_align, &data);
471 }
472 EXPORT_SYMBOL(gen_pool_dma_zalloc_align);
473 
474 /**
475  * gen_pool_free - free allocated special memory back to the pool
476  * @pool: pool to free to
477  * @addr: starting address of memory to free back to pool
478  * @size: size in bytes of memory to free
479  * @owner: private data stashed at gen_pool_add() time
480  *
481  * Free previously allocated special memory back to the specified
482  * pool.  Can not be used in NMI handler on architectures without
483  * NMI-safe cmpxchg implementation.
484  */
485 void gen_pool_free_owner(struct gen_pool *pool, unsigned long addr, size_t size,
486 		void **owner)
487 {
488 	struct gen_pool_chunk *chunk;
489 	int order = pool->min_alloc_order;
490 	int start_bit, nbits, remain;
491 
492 #ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
493 	BUG_ON(in_nmi());
494 #endif
495 
496 	if (owner)
497 		*owner = NULL;
498 
499 	nbits = (size + (1UL << order) - 1) >> order;
500 	rcu_read_lock();
501 	list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
502 		if (addr >= chunk->start_addr && addr <= chunk->end_addr) {
503 			BUG_ON(addr + size - 1 > chunk->end_addr);
504 			start_bit = (addr - chunk->start_addr) >> order;
505 			remain = bitmap_clear_ll(chunk->bits, start_bit, nbits);
506 			BUG_ON(remain);
507 			size = nbits << order;
508 			atomic_long_add(size, &chunk->avail);
509 			if (owner)
510 				*owner = chunk->owner;
511 			rcu_read_unlock();
512 			return;
513 		}
514 	}
515 	rcu_read_unlock();
516 	BUG();
517 }
518 EXPORT_SYMBOL(gen_pool_free_owner);
519 
520 /**
521  * gen_pool_for_each_chunk - call func for every chunk of generic memory pool
522  * @pool:	the generic memory pool
523  * @func:	func to call
524  * @data:	additional data used by @func
525  *
526  * Call @func for every chunk of generic memory pool.  The @func is
527  * called with rcu_read_lock held.
528  */
529 void gen_pool_for_each_chunk(struct gen_pool *pool,
530 	void (*func)(struct gen_pool *pool, struct gen_pool_chunk *chunk, void *data),
531 	void *data)
532 {
533 	struct gen_pool_chunk *chunk;
534 
535 	rcu_read_lock();
536 	list_for_each_entry_rcu(chunk, &(pool)->chunks, next_chunk)
537 		func(pool, chunk, data);
538 	rcu_read_unlock();
539 }
540 EXPORT_SYMBOL(gen_pool_for_each_chunk);
541 
542 /**
543  * addr_in_gen_pool - checks if an address falls within the range of a pool
544  * @pool:	the generic memory pool
545  * @start:	start address
546  * @size:	size of the region
547  *
548  * Check if the range of addresses falls within the specified pool. Returns
549  * true if the entire range is contained in the pool and false otherwise.
550  */
551 bool addr_in_gen_pool(struct gen_pool *pool, unsigned long start,
552 			size_t size)
553 {
554 	bool found = false;
555 	unsigned long end = start + size - 1;
556 	struct gen_pool_chunk *chunk;
557 
558 	rcu_read_lock();
559 	list_for_each_entry_rcu(chunk, &(pool)->chunks, next_chunk) {
560 		if (start >= chunk->start_addr && start <= chunk->end_addr) {
561 			if (end <= chunk->end_addr) {
562 				found = true;
563 				break;
564 			}
565 		}
566 	}
567 	rcu_read_unlock();
568 	return found;
569 }
570 
571 /**
572  * gen_pool_avail - get available free space of the pool
573  * @pool: pool to get available free space
574  *
575  * Return available free space of the specified pool.
576  */
577 size_t gen_pool_avail(struct gen_pool *pool)
578 {
579 	struct gen_pool_chunk *chunk;
580 	size_t avail = 0;
581 
582 	rcu_read_lock();
583 	list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
584 		avail += atomic_long_read(&chunk->avail);
585 	rcu_read_unlock();
586 	return avail;
587 }
588 EXPORT_SYMBOL_GPL(gen_pool_avail);
589 
590 /**
591  * gen_pool_size - get size in bytes of memory managed by the pool
592  * @pool: pool to get size
593  *
594  * Return size in bytes of memory managed by the pool.
595  */
596 size_t gen_pool_size(struct gen_pool *pool)
597 {
598 	struct gen_pool_chunk *chunk;
599 	size_t size = 0;
600 
601 	rcu_read_lock();
602 	list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
603 		size += chunk_size(chunk);
604 	rcu_read_unlock();
605 	return size;
606 }
607 EXPORT_SYMBOL_GPL(gen_pool_size);
608 
609 /**
610  * gen_pool_set_algo - set the allocation algorithm
611  * @pool: pool to change allocation algorithm
612  * @algo: custom algorithm function
613  * @data: additional data used by @algo
614  *
615  * Call @algo for each memory allocation in the pool.
616  * If @algo is NULL use gen_pool_first_fit as default
617  * memory allocation function.
618  */
619 void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo, void *data)
620 {
621 	rcu_read_lock();
622 
623 	pool->algo = algo;
624 	if (!pool->algo)
625 		pool->algo = gen_pool_first_fit;
626 
627 	pool->data = data;
628 
629 	rcu_read_unlock();
630 }
631 EXPORT_SYMBOL(gen_pool_set_algo);
632 
633 /**
634  * gen_pool_first_fit - find the first available region
635  * of memory matching the size requirement (no alignment constraint)
636  * @map: The address to base the search on
637  * @size: The bitmap size in bits
638  * @start: The bitnumber to start searching at
639  * @nr: The number of zeroed bits we're looking for
640  * @data: additional data - unused
641  * @pool: pool to find the fit region memory from
642  */
643 unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size,
644 		unsigned long start, unsigned int nr, void *data,
645 		struct gen_pool *pool, unsigned long start_addr)
646 {
647 	return bitmap_find_next_zero_area(map, size, start, nr, 0);
648 }
649 EXPORT_SYMBOL(gen_pool_first_fit);
650 
651 /**
652  * gen_pool_first_fit_align - find the first available region
653  * of memory matching the size requirement (alignment constraint)
654  * @map: The address to base the search on
655  * @size: The bitmap size in bits
656  * @start: The bitnumber to start searching at
657  * @nr: The number of zeroed bits we're looking for
658  * @data: data for alignment
659  * @pool: pool to get order from
660  */
661 unsigned long gen_pool_first_fit_align(unsigned long *map, unsigned long size,
662 		unsigned long start, unsigned int nr, void *data,
663 		struct gen_pool *pool, unsigned long start_addr)
664 {
665 	struct genpool_data_align *alignment;
666 	unsigned long align_mask, align_off;
667 	int order;
668 
669 	alignment = data;
670 	order = pool->min_alloc_order;
671 	align_mask = ((alignment->align + (1UL << order) - 1) >> order) - 1;
672 	align_off = (start_addr & (alignment->align - 1)) >> order;
673 
674 	return bitmap_find_next_zero_area_off(map, size, start, nr,
675 					      align_mask, align_off);
676 }
677 EXPORT_SYMBOL(gen_pool_first_fit_align);
678 
679 /**
680  * gen_pool_fixed_alloc - reserve a specific region
681  * @map: The address to base the search on
682  * @size: The bitmap size in bits
683  * @start: The bitnumber to start searching at
684  * @nr: The number of zeroed bits we're looking for
685  * @data: data for alignment
686  * @pool: pool to get order from
687  */
688 unsigned long gen_pool_fixed_alloc(unsigned long *map, unsigned long size,
689 		unsigned long start, unsigned int nr, void *data,
690 		struct gen_pool *pool, unsigned long start_addr)
691 {
692 	struct genpool_data_fixed *fixed_data;
693 	int order;
694 	unsigned long offset_bit;
695 	unsigned long start_bit;
696 
697 	fixed_data = data;
698 	order = pool->min_alloc_order;
699 	offset_bit = fixed_data->offset >> order;
700 	if (WARN_ON(fixed_data->offset & ((1UL << order) - 1)))
701 		return size;
702 
703 	start_bit = bitmap_find_next_zero_area(map, size,
704 			start + offset_bit, nr, 0);
705 	if (start_bit != offset_bit)
706 		start_bit = size;
707 	return start_bit;
708 }
709 EXPORT_SYMBOL(gen_pool_fixed_alloc);
710 
711 /**
712  * gen_pool_first_fit_order_align - find the first available region
713  * of memory matching the size requirement. The region will be aligned
714  * to the order of the size specified.
715  * @map: The address to base the search on
716  * @size: The bitmap size in bits
717  * @start: The bitnumber to start searching at
718  * @nr: The number of zeroed bits we're looking for
719  * @data: additional data - unused
720  * @pool: pool to find the fit region memory from
721  */
722 unsigned long gen_pool_first_fit_order_align(unsigned long *map,
723 		unsigned long size, unsigned long start,
724 		unsigned int nr, void *data, struct gen_pool *pool,
725 		unsigned long start_addr)
726 {
727 	unsigned long align_mask = roundup_pow_of_two(nr) - 1;
728 
729 	return bitmap_find_next_zero_area(map, size, start, nr, align_mask);
730 }
731 EXPORT_SYMBOL(gen_pool_first_fit_order_align);
732 
733 /**
734  * gen_pool_best_fit - find the best fitting region of memory
735  * macthing the size requirement (no alignment constraint)
736  * @map: The address to base the search on
737  * @size: The bitmap size in bits
738  * @start: The bitnumber to start searching at
739  * @nr: The number of zeroed bits we're looking for
740  * @data: additional data - unused
741  * @pool: pool to find the fit region memory from
742  *
743  * Iterate over the bitmap to find the smallest free region
744  * which we can allocate the memory.
745  */
746 unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
747 		unsigned long start, unsigned int nr, void *data,
748 		struct gen_pool *pool, unsigned long start_addr)
749 {
750 	unsigned long start_bit = size;
751 	unsigned long len = size + 1;
752 	unsigned long index;
753 
754 	index = bitmap_find_next_zero_area(map, size, start, nr, 0);
755 
756 	while (index < size) {
757 		int next_bit = find_next_bit(map, size, index + nr);
758 		if ((next_bit - index) < len) {
759 			len = next_bit - index;
760 			start_bit = index;
761 			if (len == nr)
762 				return start_bit;
763 		}
764 		index = bitmap_find_next_zero_area(map, size,
765 						   next_bit + 1, nr, 0);
766 	}
767 
768 	return start_bit;
769 }
770 EXPORT_SYMBOL(gen_pool_best_fit);
771 
772 static void devm_gen_pool_release(struct device *dev, void *res)
773 {
774 	gen_pool_destroy(*(struct gen_pool **)res);
775 }
776 
777 static int devm_gen_pool_match(struct device *dev, void *res, void *data)
778 {
779 	struct gen_pool **p = res;
780 
781 	/* NULL data matches only a pool without an assigned name */
782 	if (!data && !(*p)->name)
783 		return 1;
784 
785 	if (!data || !(*p)->name)
786 		return 0;
787 
788 	return !strcmp((*p)->name, data);
789 }
790 
791 /**
792  * gen_pool_get - Obtain the gen_pool (if any) for a device
793  * @dev: device to retrieve the gen_pool from
794  * @name: name of a gen_pool or NULL, identifies a particular gen_pool on device
795  *
796  * Returns the gen_pool for the device if one is present, or NULL.
797  */
798 struct gen_pool *gen_pool_get(struct device *dev, const char *name)
799 {
800 	struct gen_pool **p;
801 
802 	p = devres_find(dev, devm_gen_pool_release, devm_gen_pool_match,
803 			(void *)name);
804 	if (!p)
805 		return NULL;
806 	return *p;
807 }
808 EXPORT_SYMBOL_GPL(gen_pool_get);
809 
810 /**
811  * devm_gen_pool_create - managed gen_pool_create
812  * @dev: device that provides the gen_pool
813  * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
814  * @nid: node selector for allocated gen_pool, %NUMA_NO_NODE for all nodes
815  * @name: name of a gen_pool or NULL, identifies a particular gen_pool on device
816  *
817  * Create a new special memory pool that can be used to manage special purpose
818  * memory not managed by the regular kmalloc/kfree interface. The pool will be
819  * automatically destroyed by the device management code.
820  */
821 struct gen_pool *devm_gen_pool_create(struct device *dev, int min_alloc_order,
822 				      int nid, const char *name)
823 {
824 	struct gen_pool **ptr, *pool;
825 	const char *pool_name = NULL;
826 
827 	/* Check that genpool to be created is uniquely addressed on device */
828 	if (gen_pool_get(dev, name))
829 		return ERR_PTR(-EINVAL);
830 
831 	if (name) {
832 		pool_name = kstrdup_const(name, GFP_KERNEL);
833 		if (!pool_name)
834 			return ERR_PTR(-ENOMEM);
835 	}
836 
837 	ptr = devres_alloc(devm_gen_pool_release, sizeof(*ptr), GFP_KERNEL);
838 	if (!ptr)
839 		goto free_pool_name;
840 
841 	pool = gen_pool_create(min_alloc_order, nid);
842 	if (!pool)
843 		goto free_devres;
844 
845 	*ptr = pool;
846 	pool->name = pool_name;
847 	devres_add(dev, ptr);
848 
849 	return pool;
850 
851 free_devres:
852 	devres_free(ptr);
853 free_pool_name:
854 	kfree_const(pool_name);
855 
856 	return ERR_PTR(-ENOMEM);
857 }
858 EXPORT_SYMBOL(devm_gen_pool_create);
859 
860 #ifdef CONFIG_OF
861 /**
862  * of_gen_pool_get - find a pool by phandle property
863  * @np: device node
864  * @propname: property name containing phandle(s)
865  * @index: index into the phandle array
866  *
867  * Returns the pool that contains the chunk starting at the physical
868  * address of the device tree node pointed at by the phandle property,
869  * or NULL if not found.
870  */
871 struct gen_pool *of_gen_pool_get(struct device_node *np,
872 	const char *propname, int index)
873 {
874 	struct platform_device *pdev;
875 	struct device_node *np_pool, *parent;
876 	const char *name = NULL;
877 	struct gen_pool *pool = NULL;
878 
879 	np_pool = of_parse_phandle(np, propname, index);
880 	if (!np_pool)
881 		return NULL;
882 
883 	pdev = of_find_device_by_node(np_pool);
884 	if (!pdev) {
885 		/* Check if named gen_pool is created by parent node device */
886 		parent = of_get_parent(np_pool);
887 		pdev = of_find_device_by_node(parent);
888 		of_node_put(parent);
889 
890 		of_property_read_string(np_pool, "label", &name);
891 		if (!name)
892 			name = np_pool->name;
893 	}
894 	if (pdev)
895 		pool = gen_pool_get(&pdev->dev, name);
896 	of_node_put(np_pool);
897 
898 	return pool;
899 }
900 EXPORT_SYMBOL_GPL(of_gen_pool_get);
901 #endif /* CONFIG_OF */
902