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.h>
36  #include <linux/of_platform.h>
37  #include <linux/platform_device.h>
38  #include <linux/vmalloc.h>
39  
chunk_size(const struct gen_pool_chunk * chunk)40  static inline size_t chunk_size(const struct gen_pool_chunk *chunk)
41  {
42  	return chunk->end_addr - chunk->start_addr + 1;
43  }
44  
45  static inline int
set_bits_ll(unsigned long * addr,unsigned long mask_to_set)46  set_bits_ll(unsigned long *addr, unsigned long mask_to_set)
47  {
48  	unsigned long val = READ_ONCE(*addr);
49  
50  	do {
51  		if (val & mask_to_set)
52  			return -EBUSY;
53  		cpu_relax();
54  	} while (!try_cmpxchg(addr, &val, val | mask_to_set));
55  
56  	return 0;
57  }
58  
59  static inline int
clear_bits_ll(unsigned long * addr,unsigned long mask_to_clear)60  clear_bits_ll(unsigned long *addr, unsigned long mask_to_clear)
61  {
62  	unsigned long val = READ_ONCE(*addr);
63  
64  	do {
65  		if ((val & mask_to_clear) != mask_to_clear)
66  			return -EBUSY;
67  		cpu_relax();
68  	} while (!try_cmpxchg(addr, &val, val & ~mask_to_clear));
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 unsigned long
bitmap_set_ll(unsigned long * map,unsigned long start,unsigned long nr)85  bitmap_set_ll(unsigned long *map, unsigned long start, unsigned long nr)
86  {
87  	unsigned long *p = map + BIT_WORD(start);
88  	const unsigned long size = start + nr;
89  	int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
90  	unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
91  
92  	while (nr >= bits_to_set) {
93  		if (set_bits_ll(p, mask_to_set))
94  			return nr;
95  		nr -= bits_to_set;
96  		bits_to_set = BITS_PER_LONG;
97  		mask_to_set = ~0UL;
98  		p++;
99  	}
100  	if (nr) {
101  		mask_to_set &= BITMAP_LAST_WORD_MASK(size);
102  		if (set_bits_ll(p, mask_to_set))
103  			return nr;
104  	}
105  
106  	return 0;
107  }
108  
109  /*
110   * bitmap_clear_ll - clear the specified number of bits at the specified position
111   * @map: pointer to a bitmap
112   * @start: a bit position in @map
113   * @nr: number of bits to set
114   *
115   * Clear @nr bits start from @start in @map lock-lessly. Several users
116   * can set/clear the same bitmap simultaneously without lock. If two
117   * users clear the same bit, one user will return remain bits,
118   * otherwise return 0.
119   */
120  static unsigned long
bitmap_clear_ll(unsigned long * map,unsigned long start,unsigned long nr)121  bitmap_clear_ll(unsigned long *map, unsigned long start, unsigned long nr)
122  {
123  	unsigned long *p = map + BIT_WORD(start);
124  	const unsigned long size = start + nr;
125  	int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
126  	unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
127  
128  	while (nr >= bits_to_clear) {
129  		if (clear_bits_ll(p, mask_to_clear))
130  			return nr;
131  		nr -= bits_to_clear;
132  		bits_to_clear = BITS_PER_LONG;
133  		mask_to_clear = ~0UL;
134  		p++;
135  	}
136  	if (nr) {
137  		mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
138  		if (clear_bits_ll(p, mask_to_clear))
139  			return nr;
140  	}
141  
142  	return 0;
143  }
144  
145  /**
146   * gen_pool_create - create a new special memory pool
147   * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
148   * @nid: node id of the node the pool structure should be allocated on, or -1
149   *
150   * Create a new special memory pool that can be used to manage special purpose
151   * memory not managed by the regular kmalloc/kfree interface.
152   */
gen_pool_create(int min_alloc_order,int nid)153  struct gen_pool *gen_pool_create(int min_alloc_order, int nid)
154  {
155  	struct gen_pool *pool;
156  
157  	pool = kmalloc_node(sizeof(struct gen_pool), GFP_KERNEL, nid);
158  	if (pool != NULL) {
159  		spin_lock_init(&pool->lock);
160  		INIT_LIST_HEAD(&pool->chunks);
161  		pool->min_alloc_order = min_alloc_order;
162  		pool->algo = gen_pool_first_fit;
163  		pool->data = NULL;
164  		pool->name = NULL;
165  	}
166  	return pool;
167  }
168  EXPORT_SYMBOL(gen_pool_create);
169  
170  /**
171   * gen_pool_add_owner- add a new chunk of special memory to the pool
172   * @pool: pool to add new memory chunk to
173   * @virt: virtual starting address of memory chunk to add to pool
174   * @phys: physical starting address of memory chunk to add to pool
175   * @size: size in bytes of the memory chunk to add to pool
176   * @nid: node id of the node the chunk structure and bitmap should be
177   *       allocated on, or -1
178   * @owner: private data the publisher would like to recall at alloc time
179   *
180   * Add a new chunk of special memory to the specified pool.
181   *
182   * Returns 0 on success or a -ve errno on failure.
183   */
gen_pool_add_owner(struct gen_pool * pool,unsigned long virt,phys_addr_t phys,size_t size,int nid,void * owner)184  int gen_pool_add_owner(struct gen_pool *pool, unsigned long virt, phys_addr_t phys,
185  		 size_t size, int nid, void *owner)
186  {
187  	struct gen_pool_chunk *chunk;
188  	unsigned long nbits = size >> pool->min_alloc_order;
189  	unsigned long nbytes = sizeof(struct gen_pool_chunk) +
190  				BITS_TO_LONGS(nbits) * sizeof(long);
191  
192  	chunk = vzalloc_node(nbytes, nid);
193  	if (unlikely(chunk == NULL))
194  		return -ENOMEM;
195  
196  	chunk->phys_addr = phys;
197  	chunk->start_addr = virt;
198  	chunk->end_addr = virt + size - 1;
199  	chunk->owner = owner;
200  	atomic_long_set(&chunk->avail, size);
201  
202  	spin_lock(&pool->lock);
203  	list_add_rcu(&chunk->next_chunk, &pool->chunks);
204  	spin_unlock(&pool->lock);
205  
206  	return 0;
207  }
208  EXPORT_SYMBOL(gen_pool_add_owner);
209  
210  /**
211   * gen_pool_virt_to_phys - return the physical address of memory
212   * @pool: pool to allocate from
213   * @addr: starting address of memory
214   *
215   * Returns the physical address on success, or -1 on error.
216   */
gen_pool_virt_to_phys(struct gen_pool * pool,unsigned long addr)217  phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long addr)
218  {
219  	struct gen_pool_chunk *chunk;
220  	phys_addr_t paddr = -1;
221  
222  	rcu_read_lock();
223  	list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
224  		if (addr >= chunk->start_addr && addr <= chunk->end_addr) {
225  			paddr = chunk->phys_addr + (addr - chunk->start_addr);
226  			break;
227  		}
228  	}
229  	rcu_read_unlock();
230  
231  	return paddr;
232  }
233  EXPORT_SYMBOL(gen_pool_virt_to_phys);
234  
235  /**
236   * gen_pool_destroy - destroy a special memory pool
237   * @pool: pool to destroy
238   *
239   * Destroy the specified special memory pool. Verifies that there are no
240   * outstanding allocations.
241   */
gen_pool_destroy(struct gen_pool * pool)242  void gen_pool_destroy(struct gen_pool *pool)
243  {
244  	struct list_head *_chunk, *_next_chunk;
245  	struct gen_pool_chunk *chunk;
246  	int order = pool->min_alloc_order;
247  	unsigned long bit, end_bit;
248  
249  	list_for_each_safe(_chunk, _next_chunk, &pool->chunks) {
250  		chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
251  		list_del(&chunk->next_chunk);
252  
253  		end_bit = chunk_size(chunk) >> order;
254  		bit = find_first_bit(chunk->bits, end_bit);
255  		BUG_ON(bit < end_bit);
256  
257  		vfree(chunk);
258  	}
259  	kfree_const(pool->name);
260  	kfree(pool);
261  }
262  EXPORT_SYMBOL(gen_pool_destroy);
263  
264  /**
265   * gen_pool_alloc_algo_owner - allocate special memory from the pool
266   * @pool: pool to allocate from
267   * @size: number of bytes to allocate from the pool
268   * @algo: algorithm passed from caller
269   * @data: data passed to algorithm
270   * @owner: optionally retrieve the chunk owner
271   *
272   * Allocate the requested number of bytes from the specified pool.
273   * Uses the pool allocation function (with first-fit algorithm by default).
274   * Can not be used in NMI handler on architectures without
275   * NMI-safe cmpxchg implementation.
276   */
gen_pool_alloc_algo_owner(struct gen_pool * pool,size_t size,genpool_algo_t algo,void * data,void ** owner)277  unsigned long gen_pool_alloc_algo_owner(struct gen_pool *pool, size_t size,
278  		genpool_algo_t algo, void *data, void **owner)
279  {
280  	struct gen_pool_chunk *chunk;
281  	unsigned long addr = 0;
282  	int order = pool->min_alloc_order;
283  	unsigned long nbits, start_bit, end_bit, remain;
284  
285  #ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
286  	BUG_ON(in_nmi());
287  #endif
288  
289  	if (owner)
290  		*owner = NULL;
291  
292  	if (size == 0)
293  		return 0;
294  
295  	nbits = (size + (1UL << order) - 1) >> order;
296  	rcu_read_lock();
297  	list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
298  		if (size > atomic_long_read(&chunk->avail))
299  			continue;
300  
301  		start_bit = 0;
302  		end_bit = chunk_size(chunk) >> order;
303  retry:
304  		start_bit = algo(chunk->bits, end_bit, start_bit,
305  				 nbits, data, pool, chunk->start_addr);
306  		if (start_bit >= end_bit)
307  			continue;
308  		remain = bitmap_set_ll(chunk->bits, start_bit, nbits);
309  		if (remain) {
310  			remain = bitmap_clear_ll(chunk->bits, start_bit,
311  						 nbits - remain);
312  			BUG_ON(remain);
313  			goto retry;
314  		}
315  
316  		addr = chunk->start_addr + ((unsigned long)start_bit << order);
317  		size = nbits << order;
318  		atomic_long_sub(size, &chunk->avail);
319  		if (owner)
320  			*owner = chunk->owner;
321  		break;
322  	}
323  	rcu_read_unlock();
324  	return addr;
325  }
326  EXPORT_SYMBOL(gen_pool_alloc_algo_owner);
327  
328  /**
329   * gen_pool_dma_alloc - allocate special memory from the pool for DMA usage
330   * @pool: pool to allocate from
331   * @size: number of bytes to allocate from the pool
332   * @dma: dma-view physical address return value.  Use %NULL if unneeded.
333   *
334   * Allocate the requested number of bytes from the specified pool.
335   * Uses the pool allocation function (with first-fit algorithm by default).
336   * Can not be used in NMI handler on architectures without
337   * NMI-safe cmpxchg implementation.
338   *
339   * Return: virtual address of the allocated memory, or %NULL on failure
340   */
gen_pool_dma_alloc(struct gen_pool * pool,size_t size,dma_addr_t * dma)341  void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size, dma_addr_t *dma)
342  {
343  	return gen_pool_dma_alloc_algo(pool, size, dma, pool->algo, pool->data);
344  }
345  EXPORT_SYMBOL(gen_pool_dma_alloc);
346  
347  /**
348   * gen_pool_dma_alloc_algo - allocate special memory from the pool for DMA
349   * usage with the given pool algorithm
350   * @pool: pool to allocate from
351   * @size: number of bytes to allocate from the pool
352   * @dma: DMA-view physical address return value. Use %NULL if unneeded.
353   * @algo: algorithm passed from caller
354   * @data: data passed to algorithm
355   *
356   * Allocate the requested number of bytes from the specified pool. Uses the
357   * given pool allocation function. Can not be used in NMI handler on
358   * architectures without NMI-safe cmpxchg implementation.
359   *
360   * Return: virtual address of the allocated memory, or %NULL on failure
361   */
gen_pool_dma_alloc_algo(struct gen_pool * pool,size_t size,dma_addr_t * dma,genpool_algo_t algo,void * data)362  void *gen_pool_dma_alloc_algo(struct gen_pool *pool, size_t size,
363  		dma_addr_t *dma, genpool_algo_t algo, void *data)
364  {
365  	unsigned long vaddr;
366  
367  	if (!pool)
368  		return NULL;
369  
370  	vaddr = gen_pool_alloc_algo(pool, size, algo, data);
371  	if (!vaddr)
372  		return NULL;
373  
374  	if (dma)
375  		*dma = gen_pool_virt_to_phys(pool, vaddr);
376  
377  	return (void *)vaddr;
378  }
379  EXPORT_SYMBOL(gen_pool_dma_alloc_algo);
380  
381  /**
382   * gen_pool_dma_alloc_align - allocate special memory from the pool for DMA
383   * usage with the given alignment
384   * @pool: pool to allocate from
385   * @size: number of bytes to allocate from the pool
386   * @dma: DMA-view physical address return value. Use %NULL if unneeded.
387   * @align: alignment in bytes for starting address
388   *
389   * Allocate the requested number bytes from the specified pool, with the given
390   * alignment restriction. Can not be used in NMI handler on architectures
391   * without NMI-safe cmpxchg implementation.
392   *
393   * Return: virtual address of the allocated memory, or %NULL on failure
394   */
gen_pool_dma_alloc_align(struct gen_pool * pool,size_t size,dma_addr_t * dma,int align)395  void *gen_pool_dma_alloc_align(struct gen_pool *pool, size_t size,
396  		dma_addr_t *dma, int align)
397  {
398  	struct genpool_data_align data = { .align = align };
399  
400  	return gen_pool_dma_alloc_algo(pool, size, dma,
401  			gen_pool_first_fit_align, &data);
402  }
403  EXPORT_SYMBOL(gen_pool_dma_alloc_align);
404  
405  /**
406   * gen_pool_dma_zalloc - allocate special zeroed memory from the pool for
407   * DMA usage
408   * @pool: pool to allocate from
409   * @size: number of bytes to allocate from the pool
410   * @dma: dma-view physical address return value.  Use %NULL if unneeded.
411   *
412   * Allocate the requested number of zeroed bytes from the specified pool.
413   * Uses the pool allocation function (with first-fit algorithm by default).
414   * Can not be used in NMI handler on architectures without
415   * NMI-safe cmpxchg implementation.
416   *
417   * Return: virtual address of the allocated zeroed memory, or %NULL on failure
418   */
gen_pool_dma_zalloc(struct gen_pool * pool,size_t size,dma_addr_t * dma)419  void *gen_pool_dma_zalloc(struct gen_pool *pool, size_t size, dma_addr_t *dma)
420  {
421  	return gen_pool_dma_zalloc_algo(pool, size, dma, pool->algo, pool->data);
422  }
423  EXPORT_SYMBOL(gen_pool_dma_zalloc);
424  
425  /**
426   * gen_pool_dma_zalloc_algo - allocate special zeroed memory from the pool for
427   * DMA usage with the given pool algorithm
428   * @pool: pool to allocate from
429   * @size: number of bytes to allocate from the pool
430   * @dma: DMA-view physical address return value. Use %NULL if unneeded.
431   * @algo: algorithm passed from caller
432   * @data: data passed to algorithm
433   *
434   * Allocate the requested number of zeroed bytes from the specified pool. Uses
435   * the given pool allocation function. Can not be used in NMI handler on
436   * architectures without NMI-safe cmpxchg implementation.
437   *
438   * Return: virtual address of the allocated zeroed memory, or %NULL on failure
439   */
gen_pool_dma_zalloc_algo(struct gen_pool * pool,size_t size,dma_addr_t * dma,genpool_algo_t algo,void * data)440  void *gen_pool_dma_zalloc_algo(struct gen_pool *pool, size_t size,
441  		dma_addr_t *dma, genpool_algo_t algo, void *data)
442  {
443  	void *vaddr = gen_pool_dma_alloc_algo(pool, size, dma, algo, data);
444  
445  	if (vaddr)
446  		memset(vaddr, 0, size);
447  
448  	return vaddr;
449  }
450  EXPORT_SYMBOL(gen_pool_dma_zalloc_algo);
451  
452  /**
453   * gen_pool_dma_zalloc_align - allocate special zeroed memory from the pool for
454   * DMA usage with the given alignment
455   * @pool: pool to allocate from
456   * @size: number of bytes to allocate from the pool
457   * @dma: DMA-view physical address return value. Use %NULL if unneeded.
458   * @align: alignment in bytes for starting address
459   *
460   * Allocate the requested number of zeroed bytes from the specified pool,
461   * with the given alignment restriction. Can not be used in NMI handler on
462   * architectures without NMI-safe cmpxchg implementation.
463   *
464   * Return: virtual address of the allocated zeroed memory, or %NULL on failure
465   */
gen_pool_dma_zalloc_align(struct gen_pool * pool,size_t size,dma_addr_t * dma,int align)466  void *gen_pool_dma_zalloc_align(struct gen_pool *pool, size_t size,
467  		dma_addr_t *dma, int align)
468  {
469  	struct genpool_data_align data = { .align = align };
470  
471  	return gen_pool_dma_zalloc_algo(pool, size, dma,
472  			gen_pool_first_fit_align, &data);
473  }
474  EXPORT_SYMBOL(gen_pool_dma_zalloc_align);
475  
476  /**
477   * gen_pool_free_owner - free allocated special memory back to the pool
478   * @pool: pool to free to
479   * @addr: starting address of memory to free back to pool
480   * @size: size in bytes of memory to free
481   * @owner: private data stashed at gen_pool_add() time
482   *
483   * Free previously allocated special memory back to the specified
484   * pool.  Can not be used in NMI handler on architectures without
485   * NMI-safe cmpxchg implementation.
486   */
gen_pool_free_owner(struct gen_pool * pool,unsigned long addr,size_t size,void ** owner)487  void gen_pool_free_owner(struct gen_pool *pool, unsigned long addr, size_t size,
488  		void **owner)
489  {
490  	struct gen_pool_chunk *chunk;
491  	int order = pool->min_alloc_order;
492  	unsigned long start_bit, nbits, remain;
493  
494  #ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
495  	BUG_ON(in_nmi());
496  #endif
497  
498  	if (owner)
499  		*owner = NULL;
500  
501  	nbits = (size + (1UL << order) - 1) >> order;
502  	rcu_read_lock();
503  	list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
504  		if (addr >= chunk->start_addr && addr <= chunk->end_addr) {
505  			BUG_ON(addr + size - 1 > chunk->end_addr);
506  			start_bit = (addr - chunk->start_addr) >> order;
507  			remain = bitmap_clear_ll(chunk->bits, start_bit, nbits);
508  			BUG_ON(remain);
509  			size = nbits << order;
510  			atomic_long_add(size, &chunk->avail);
511  			if (owner)
512  				*owner = chunk->owner;
513  			rcu_read_unlock();
514  			return;
515  		}
516  	}
517  	rcu_read_unlock();
518  	BUG();
519  }
520  EXPORT_SYMBOL(gen_pool_free_owner);
521  
522  /**
523   * gen_pool_for_each_chunk - call func for every chunk of generic memory pool
524   * @pool:	the generic memory pool
525   * @func:	func to call
526   * @data:	additional data used by @func
527   *
528   * Call @func for every chunk of generic memory pool.  The @func is
529   * called with rcu_read_lock held.
530   */
gen_pool_for_each_chunk(struct gen_pool * pool,void (* func)(struct gen_pool * pool,struct gen_pool_chunk * chunk,void * data),void * data)531  void gen_pool_for_each_chunk(struct gen_pool *pool,
532  	void (*func)(struct gen_pool *pool, struct gen_pool_chunk *chunk, void *data),
533  	void *data)
534  {
535  	struct gen_pool_chunk *chunk;
536  
537  	rcu_read_lock();
538  	list_for_each_entry_rcu(chunk, &(pool)->chunks, next_chunk)
539  		func(pool, chunk, data);
540  	rcu_read_unlock();
541  }
542  EXPORT_SYMBOL(gen_pool_for_each_chunk);
543  
544  /**
545   * gen_pool_has_addr - checks if an address falls within the range of a pool
546   * @pool:	the generic memory pool
547   * @start:	start address
548   * @size:	size of the region
549   *
550   * Check if the range of addresses falls within the specified pool. Returns
551   * true if the entire range is contained in the pool and false otherwise.
552   */
gen_pool_has_addr(struct gen_pool * pool,unsigned long start,size_t size)553  bool gen_pool_has_addr(struct gen_pool *pool, unsigned long start,
554  			size_t size)
555  {
556  	bool found = false;
557  	unsigned long end = start + size - 1;
558  	struct gen_pool_chunk *chunk;
559  
560  	rcu_read_lock();
561  	list_for_each_entry_rcu(chunk, &(pool)->chunks, next_chunk) {
562  		if (start >= chunk->start_addr && start <= chunk->end_addr) {
563  			if (end <= chunk->end_addr) {
564  				found = true;
565  				break;
566  			}
567  		}
568  	}
569  	rcu_read_unlock();
570  	return found;
571  }
572  EXPORT_SYMBOL(gen_pool_has_addr);
573  
574  /**
575   * gen_pool_avail - get available free space of the pool
576   * @pool: pool to get available free space
577   *
578   * Return available free space of the specified pool.
579   */
gen_pool_avail(struct gen_pool * pool)580  size_t gen_pool_avail(struct gen_pool *pool)
581  {
582  	struct gen_pool_chunk *chunk;
583  	size_t avail = 0;
584  
585  	rcu_read_lock();
586  	list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
587  		avail += atomic_long_read(&chunk->avail);
588  	rcu_read_unlock();
589  	return avail;
590  }
591  EXPORT_SYMBOL_GPL(gen_pool_avail);
592  
593  /**
594   * gen_pool_size - get size in bytes of memory managed by the pool
595   * @pool: pool to get size
596   *
597   * Return size in bytes of memory managed by the pool.
598   */
gen_pool_size(struct gen_pool * pool)599  size_t gen_pool_size(struct gen_pool *pool)
600  {
601  	struct gen_pool_chunk *chunk;
602  	size_t size = 0;
603  
604  	rcu_read_lock();
605  	list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
606  		size += chunk_size(chunk);
607  	rcu_read_unlock();
608  	return size;
609  }
610  EXPORT_SYMBOL_GPL(gen_pool_size);
611  
612  /**
613   * gen_pool_set_algo - set the allocation algorithm
614   * @pool: pool to change allocation algorithm
615   * @algo: custom algorithm function
616   * @data: additional data used by @algo
617   *
618   * Call @algo for each memory allocation in the pool.
619   * If @algo is NULL use gen_pool_first_fit as default
620   * memory allocation function.
621   */
gen_pool_set_algo(struct gen_pool * pool,genpool_algo_t algo,void * data)622  void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo, void *data)
623  {
624  	rcu_read_lock();
625  
626  	pool->algo = algo;
627  	if (!pool->algo)
628  		pool->algo = gen_pool_first_fit;
629  
630  	pool->data = data;
631  
632  	rcu_read_unlock();
633  }
634  EXPORT_SYMBOL(gen_pool_set_algo);
635  
636  /**
637   * gen_pool_first_fit - find the first available region
638   * of memory matching the size requirement (no alignment constraint)
639   * @map: The address to base the search on
640   * @size: The bitmap size in bits
641   * @start: The bitnumber to start searching at
642   * @nr: The number of zeroed bits we're looking for
643   * @data: additional data - unused
644   * @pool: pool to find the fit region memory from
645   * @start_addr: not used in this function
646   */
gen_pool_first_fit(unsigned long * map,unsigned long size,unsigned long start,unsigned int nr,void * data,struct gen_pool * pool,unsigned long start_addr)647  unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size,
648  		unsigned long start, unsigned int nr, void *data,
649  		struct gen_pool *pool, unsigned long start_addr)
650  {
651  	return bitmap_find_next_zero_area(map, size, start, nr, 0);
652  }
653  EXPORT_SYMBOL(gen_pool_first_fit);
654  
655  /**
656   * gen_pool_first_fit_align - find the first available region
657   * of memory matching the size requirement (alignment constraint)
658   * @map: The address to base the search on
659   * @size: The bitmap size in bits
660   * @start: The bitnumber to start searching at
661   * @nr: The number of zeroed bits we're looking for
662   * @data: data for alignment
663   * @pool: pool to get order from
664   * @start_addr: start addr of alloction chunk
665   */
gen_pool_first_fit_align(unsigned long * map,unsigned long size,unsigned long start,unsigned int nr,void * data,struct gen_pool * pool,unsigned long start_addr)666  unsigned long gen_pool_first_fit_align(unsigned long *map, unsigned long size,
667  		unsigned long start, unsigned int nr, void *data,
668  		struct gen_pool *pool, unsigned long start_addr)
669  {
670  	struct genpool_data_align *alignment;
671  	unsigned long align_mask, align_off;
672  	int order;
673  
674  	alignment = data;
675  	order = pool->min_alloc_order;
676  	align_mask = ((alignment->align + (1UL << order) - 1) >> order) - 1;
677  	align_off = (start_addr & (alignment->align - 1)) >> order;
678  
679  	return bitmap_find_next_zero_area_off(map, size, start, nr,
680  					      align_mask, align_off);
681  }
682  EXPORT_SYMBOL(gen_pool_first_fit_align);
683  
684  /**
685   * gen_pool_fixed_alloc - reserve a specific region
686   * @map: The address to base the search on
687   * @size: The bitmap size in bits
688   * @start: The bitnumber to start searching at
689   * @nr: The number of zeroed bits we're looking for
690   * @data: data for alignment
691   * @pool: pool to get order from
692   * @start_addr: not used in this function
693   */
gen_pool_fixed_alloc(unsigned long * map,unsigned long size,unsigned long start,unsigned int nr,void * data,struct gen_pool * pool,unsigned long start_addr)694  unsigned long gen_pool_fixed_alloc(unsigned long *map, unsigned long size,
695  		unsigned long start, unsigned int nr, void *data,
696  		struct gen_pool *pool, unsigned long start_addr)
697  {
698  	struct genpool_data_fixed *fixed_data;
699  	int order;
700  	unsigned long offset_bit;
701  	unsigned long start_bit;
702  
703  	fixed_data = data;
704  	order = pool->min_alloc_order;
705  	offset_bit = fixed_data->offset >> order;
706  	if (WARN_ON(fixed_data->offset & ((1UL << order) - 1)))
707  		return size;
708  
709  	start_bit = bitmap_find_next_zero_area(map, size,
710  			start + offset_bit, nr, 0);
711  	if (start_bit != offset_bit)
712  		start_bit = size;
713  	return start_bit;
714  }
715  EXPORT_SYMBOL(gen_pool_fixed_alloc);
716  
717  /**
718   * gen_pool_first_fit_order_align - find the first available region
719   * of memory matching the size requirement. The region will be aligned
720   * to the order of the size specified.
721   * @map: The address to base the search on
722   * @size: The bitmap size in bits
723   * @start: The bitnumber to start searching at
724   * @nr: The number of zeroed bits we're looking for
725   * @data: additional data - unused
726   * @pool: pool to find the fit region memory from
727   * @start_addr: not used in this function
728   */
gen_pool_first_fit_order_align(unsigned long * map,unsigned long size,unsigned long start,unsigned int nr,void * data,struct gen_pool * pool,unsigned long start_addr)729  unsigned long gen_pool_first_fit_order_align(unsigned long *map,
730  		unsigned long size, unsigned long start,
731  		unsigned int nr, void *data, struct gen_pool *pool,
732  		unsigned long start_addr)
733  {
734  	unsigned long align_mask = roundup_pow_of_two(nr) - 1;
735  
736  	return bitmap_find_next_zero_area(map, size, start, nr, align_mask);
737  }
738  EXPORT_SYMBOL(gen_pool_first_fit_order_align);
739  
740  /**
741   * gen_pool_best_fit - find the best fitting region of memory
742   * matching the size requirement (no alignment constraint)
743   * @map: The address to base the search on
744   * @size: The bitmap size in bits
745   * @start: The bitnumber to start searching at
746   * @nr: The number of zeroed bits we're looking for
747   * @data: additional data - unused
748   * @pool: pool to find the fit region memory from
749   * @start_addr: not used in this function
750   *
751   * Iterate over the bitmap to find the smallest free region
752   * which we can allocate the memory.
753   */
gen_pool_best_fit(unsigned long * map,unsigned long size,unsigned long start,unsigned int nr,void * data,struct gen_pool * pool,unsigned long start_addr)754  unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
755  		unsigned long start, unsigned int nr, void *data,
756  		struct gen_pool *pool, unsigned long start_addr)
757  {
758  	unsigned long start_bit = size;
759  	unsigned long len = size + 1;
760  	unsigned long index;
761  
762  	index = bitmap_find_next_zero_area(map, size, start, nr, 0);
763  
764  	while (index < size) {
765  		unsigned long next_bit = find_next_bit(map, size, index + nr);
766  		if ((next_bit - index) < len) {
767  			len = next_bit - index;
768  			start_bit = index;
769  			if (len == nr)
770  				return start_bit;
771  		}
772  		index = bitmap_find_next_zero_area(map, size,
773  						   next_bit + 1, nr, 0);
774  	}
775  
776  	return start_bit;
777  }
778  EXPORT_SYMBOL(gen_pool_best_fit);
779  
devm_gen_pool_release(struct device * dev,void * res)780  static void devm_gen_pool_release(struct device *dev, void *res)
781  {
782  	gen_pool_destroy(*(struct gen_pool **)res);
783  }
784  
devm_gen_pool_match(struct device * dev,void * res,void * data)785  static int devm_gen_pool_match(struct device *dev, void *res, void *data)
786  {
787  	struct gen_pool **p = res;
788  
789  	/* NULL data matches only a pool without an assigned name */
790  	if (!data && !(*p)->name)
791  		return 1;
792  
793  	if (!data || !(*p)->name)
794  		return 0;
795  
796  	return !strcmp((*p)->name, data);
797  }
798  
799  /**
800   * gen_pool_get - Obtain the gen_pool (if any) for a device
801   * @dev: device to retrieve the gen_pool from
802   * @name: name of a gen_pool or NULL, identifies a particular gen_pool on device
803   *
804   * Returns the gen_pool for the device if one is present, or NULL.
805   */
gen_pool_get(struct device * dev,const char * name)806  struct gen_pool *gen_pool_get(struct device *dev, const char *name)
807  {
808  	struct gen_pool **p;
809  
810  	p = devres_find(dev, devm_gen_pool_release, devm_gen_pool_match,
811  			(void *)name);
812  	if (!p)
813  		return NULL;
814  	return *p;
815  }
816  EXPORT_SYMBOL_GPL(gen_pool_get);
817  
818  /**
819   * devm_gen_pool_create - managed gen_pool_create
820   * @dev: device that provides the gen_pool
821   * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
822   * @nid: node selector for allocated gen_pool, %NUMA_NO_NODE for all nodes
823   * @name: name of a gen_pool or NULL, identifies a particular gen_pool on device
824   *
825   * Create a new special memory pool that can be used to manage special purpose
826   * memory not managed by the regular kmalloc/kfree interface. The pool will be
827   * automatically destroyed by the device management code.
828   */
devm_gen_pool_create(struct device * dev,int min_alloc_order,int nid,const char * name)829  struct gen_pool *devm_gen_pool_create(struct device *dev, int min_alloc_order,
830  				      int nid, const char *name)
831  {
832  	struct gen_pool **ptr, *pool;
833  	const char *pool_name = NULL;
834  
835  	/* Check that genpool to be created is uniquely addressed on device */
836  	if (gen_pool_get(dev, name))
837  		return ERR_PTR(-EINVAL);
838  
839  	if (name) {
840  		pool_name = kstrdup_const(name, GFP_KERNEL);
841  		if (!pool_name)
842  			return ERR_PTR(-ENOMEM);
843  	}
844  
845  	ptr = devres_alloc(devm_gen_pool_release, sizeof(*ptr), GFP_KERNEL);
846  	if (!ptr)
847  		goto free_pool_name;
848  
849  	pool = gen_pool_create(min_alloc_order, nid);
850  	if (!pool)
851  		goto free_devres;
852  
853  	*ptr = pool;
854  	pool->name = pool_name;
855  	devres_add(dev, ptr);
856  
857  	return pool;
858  
859  free_devres:
860  	devres_free(ptr);
861  free_pool_name:
862  	kfree_const(pool_name);
863  
864  	return ERR_PTR(-ENOMEM);
865  }
866  EXPORT_SYMBOL(devm_gen_pool_create);
867  
868  #ifdef CONFIG_OF
869  /**
870   * of_gen_pool_get - find a pool by phandle property
871   * @np: device node
872   * @propname: property name containing phandle(s)
873   * @index: index into the phandle array
874   *
875   * Returns the pool that contains the chunk starting at the physical
876   * address of the device tree node pointed at by the phandle property,
877   * or NULL if not found.
878   */
of_gen_pool_get(struct device_node * np,const char * propname,int index)879  struct gen_pool *of_gen_pool_get(struct device_node *np,
880  	const char *propname, int index)
881  {
882  	struct platform_device *pdev;
883  	struct device_node *np_pool, *parent;
884  	const char *name = NULL;
885  	struct gen_pool *pool = NULL;
886  
887  	np_pool = of_parse_phandle(np, propname, index);
888  	if (!np_pool)
889  		return NULL;
890  
891  	pdev = of_find_device_by_node(np_pool);
892  	if (!pdev) {
893  		/* Check if named gen_pool is created by parent node device */
894  		parent = of_get_parent(np_pool);
895  		pdev = of_find_device_by_node(parent);
896  		of_node_put(parent);
897  
898  		of_property_read_string(np_pool, "label", &name);
899  		if (!name)
900  			name = of_node_full_name(np_pool);
901  	}
902  	if (pdev)
903  		pool = gen_pool_get(&pdev->dev, name);
904  	of_node_put(np_pool);
905  
906  	return pool;
907  }
908  EXPORT_SYMBOL_GPL(of_gen_pool_get);
909  #endif /* CONFIG_OF */
910