| /* |
| * Basic general purpose allocator for managing special purpose |
| * memory, for example, memory that is not managed by the regular |
| * kmalloc/kfree interface. Uses for this includes on-device special |
| * memory, uncached memory etc. |
| * |
| * It is safe to use the allocator in NMI handlers and other special |
| * unblockable contexts that could otherwise deadlock on locks. This |
| * is implemented by using atomic operations and retries on any |
| * conflicts. The disadvantage is that there may be livelocks in |
| * extreme cases. For better scalability, one allocator can be used |
| * for each CPU. |
| * |
| * The lockless operation only works if there is enough memory |
| * available. If new memory is added to the pool a lock has to be |
| * still taken. So any user relying on locklessness has to ensure |
| * that sufficient memory is preallocated. |
| * |
| * The basic atomic operation of this allocator is cmpxchg on long. |
| * On architectures that don't have NMI-safe cmpxchg implementation, |
| * the allocator can NOT be used in NMI handler. So code uses the |
| * allocator in NMI handler should depend on |
| * CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG. |
| * |
| * Copyright 2005 (C) Jes Sorensen <jes@trained-monkey.org> |
| * |
| * This source code is licensed under the GNU General Public License, |
| * Version 2. See the file COPYING for more details. |
| */ |
| |
| #include <linux/slab.h> |
| #include <linux/export.h> |
| #include <linux/bitmap.h> |
| #include <linux/rculist.h> |
| #include <linux/interrupt.h> |
| #include <linux/genalloc.h> |
| #include <linux/of_address.h> |
| #include <linux/of_device.h> |
| |
| static inline size_t chunk_size(const struct gen_pool_chunk *chunk) |
| { |
| return chunk->end_addr - chunk->start_addr + 1; |
| } |
| |
| static int set_bits_ll(unsigned long *addr, unsigned long mask_to_set) |
| { |
| unsigned long val, nval; |
| |
| nval = *addr; |
| do { |
| val = nval; |
| if (val & mask_to_set) |
| return -EBUSY; |
| cpu_relax(); |
| } while ((nval = cmpxchg(addr, val, val | mask_to_set)) != val); |
| |
| return 0; |
| } |
| |
| static int clear_bits_ll(unsigned long *addr, unsigned long mask_to_clear) |
| { |
| unsigned long val, nval; |
| |
| nval = *addr; |
| do { |
| val = nval; |
| if ((val & mask_to_clear) != mask_to_clear) |
| return -EBUSY; |
| cpu_relax(); |
| } while ((nval = cmpxchg(addr, val, val & ~mask_to_clear)) != val); |
| |
| return 0; |
| } |
| |
| /* |
| * bitmap_set_ll - set the specified number of bits at the specified position |
| * @map: pointer to a bitmap |
| * @start: a bit position in @map |
| * @nr: number of bits to set |
| * |
| * Set @nr bits start from @start in @map lock-lessly. Several users |
| * can set/clear the same bitmap simultaneously without lock. If two |
| * users set the same bit, one user will return remain bits, otherwise |
| * return 0. |
| */ |
| static int bitmap_set_ll(unsigned long *map, int start, int nr) |
| { |
| unsigned long *p = map + BIT_WORD(start); |
| const int size = start + nr; |
| int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG); |
| unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start); |
| |
| while (nr - bits_to_set >= 0) { |
| if (set_bits_ll(p, mask_to_set)) |
| return nr; |
| nr -= bits_to_set; |
| bits_to_set = BITS_PER_LONG; |
| mask_to_set = ~0UL; |
| p++; |
| } |
| if (nr) { |
| mask_to_set &= BITMAP_LAST_WORD_MASK(size); |
| if (set_bits_ll(p, mask_to_set)) |
| return nr; |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * bitmap_clear_ll - clear the specified number of bits at the specified position |
| * @map: pointer to a bitmap |
| * @start: a bit position in @map |
| * @nr: number of bits to set |
| * |
| * Clear @nr bits start from @start in @map lock-lessly. Several users |
| * can set/clear the same bitmap simultaneously without lock. If two |
| * users clear the same bit, one user will return remain bits, |
| * otherwise return 0. |
| */ |
| static int bitmap_clear_ll(unsigned long *map, int start, int nr) |
| { |
| unsigned long *p = map + BIT_WORD(start); |
| const int size = start + nr; |
| int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG); |
| unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start); |
| |
| while (nr - bits_to_clear >= 0) { |
| if (clear_bits_ll(p, mask_to_clear)) |
| return nr; |
| nr -= bits_to_clear; |
| bits_to_clear = BITS_PER_LONG; |
| mask_to_clear = ~0UL; |
| p++; |
| } |
| if (nr) { |
| mask_to_clear &= BITMAP_LAST_WORD_MASK(size); |
| if (clear_bits_ll(p, mask_to_clear)) |
| return nr; |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * gen_pool_create - create a new special memory pool |
| * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents |
| * @nid: node id of the node the pool structure should be allocated on, or -1 |
| * |
| * Create a new special memory pool that can be used to manage special purpose |
| * memory not managed by the regular kmalloc/kfree interface. |
| */ |
| struct gen_pool *gen_pool_create(int min_alloc_order, int nid) |
| { |
| struct gen_pool *pool; |
| |
| pool = kmalloc_node(sizeof(struct gen_pool), GFP_KERNEL, nid); |
| if (pool != NULL) { |
| spin_lock_init(&pool->lock); |
| INIT_LIST_HEAD(&pool->chunks); |
| pool->min_alloc_order = min_alloc_order; |
| pool->algo = gen_pool_first_fit; |
| pool->data = NULL; |
| } |
| return pool; |
| } |
| EXPORT_SYMBOL(gen_pool_create); |
| |
| /** |
| * gen_pool_add_virt - add a new chunk of special memory to the pool |
| * @pool: pool to add new memory chunk to |
| * @virt: virtual starting address of memory chunk to add to pool |
| * @phys: physical starting address of memory chunk to add to pool |
| * @size: size in bytes of the memory chunk to add to pool |
| * @nid: node id of the node the chunk structure and bitmap should be |
| * allocated on, or -1 |
| * |
| * Add a new chunk of special memory to the specified pool. |
| * |
| * Returns 0 on success or a -ve errno on failure. |
| */ |
| int gen_pool_add_virt(struct gen_pool *pool, unsigned long virt, phys_addr_t phys, |
| size_t size, int nid) |
| { |
| struct gen_pool_chunk *chunk; |
| int nbits = size >> pool->min_alloc_order; |
| int nbytes = sizeof(struct gen_pool_chunk) + |
| BITS_TO_LONGS(nbits) * sizeof(long); |
| |
| chunk = kmalloc_node(nbytes, GFP_KERNEL | __GFP_ZERO, nid); |
| if (unlikely(chunk == NULL)) |
| return -ENOMEM; |
| |
| chunk->phys_addr = phys; |
| chunk->start_addr = virt; |
| chunk->end_addr = virt + size - 1; |
| atomic_set(&chunk->avail, size); |
| |
| spin_lock(&pool->lock); |
| list_add_rcu(&chunk->next_chunk, &pool->chunks); |
| spin_unlock(&pool->lock); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL(gen_pool_add_virt); |
| |
| /** |
| * gen_pool_virt_to_phys - return the physical address of memory |
| * @pool: pool to allocate from |
| * @addr: starting address of memory |
| * |
| * Returns the physical address on success, or -1 on error. |
| */ |
| phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long addr) |
| { |
| struct gen_pool_chunk *chunk; |
| phys_addr_t paddr = -1; |
| |
| rcu_read_lock(); |
| list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) { |
| if (addr >= chunk->start_addr && addr <= chunk->end_addr) { |
| paddr = chunk->phys_addr + (addr - chunk->start_addr); |
| break; |
| } |
| } |
| rcu_read_unlock(); |
| |
| return paddr; |
| } |
| EXPORT_SYMBOL(gen_pool_virt_to_phys); |
| |
| /** |
| * gen_pool_destroy - destroy a special memory pool |
| * @pool: pool to destroy |
| * |
| * Destroy the specified special memory pool. Verifies that there are no |
| * outstanding allocations. |
| */ |
| void gen_pool_destroy(struct gen_pool *pool) |
| { |
| struct list_head *_chunk, *_next_chunk; |
| struct gen_pool_chunk *chunk; |
| int order = pool->min_alloc_order; |
| int bit, end_bit; |
| |
| list_for_each_safe(_chunk, _next_chunk, &pool->chunks) { |
| chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk); |
| list_del(&chunk->next_chunk); |
| |
| end_bit = chunk_size(chunk) >> order; |
| bit = find_next_bit(chunk->bits, end_bit, 0); |
| BUG_ON(bit < end_bit); |
| |
| kfree(chunk); |
| } |
| kfree(pool); |
| return; |
| } |
| EXPORT_SYMBOL(gen_pool_destroy); |
| |
| /** |
| * gen_pool_alloc - allocate special memory from the pool |
| * @pool: pool to allocate from |
| * @size: number of bytes to allocate from the pool |
| * |
| * Allocate the requested number of bytes from the specified pool. |
| * Uses the pool allocation function (with first-fit algorithm by default). |
| * Can not be used in NMI handler on architectures without |
| * NMI-safe cmpxchg implementation. |
| */ |
| unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size) |
| { |
| struct gen_pool_chunk *chunk; |
| unsigned long addr = 0; |
| int order = pool->min_alloc_order; |
| int nbits, start_bit = 0, end_bit, remain; |
| |
| #ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG |
| BUG_ON(in_nmi()); |
| #endif |
| |
| if (size == 0) |
| return 0; |
| |
| nbits = (size + (1UL << order) - 1) >> order; |
| rcu_read_lock(); |
| list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) { |
| if (size > atomic_read(&chunk->avail)) |
| continue; |
| |
| end_bit = chunk_size(chunk) >> order; |
| retry: |
| start_bit = pool->algo(chunk->bits, end_bit, start_bit, nbits, |
| pool->data); |
| if (start_bit >= end_bit) |
| continue; |
| remain = bitmap_set_ll(chunk->bits, start_bit, nbits); |
| if (remain) { |
| remain = bitmap_clear_ll(chunk->bits, start_bit, |
| nbits - remain); |
| BUG_ON(remain); |
| goto retry; |
| } |
| |
| addr = chunk->start_addr + ((unsigned long)start_bit << order); |
| size = nbits << order; |
| atomic_sub(size, &chunk->avail); |
| break; |
| } |
| rcu_read_unlock(); |
| return addr; |
| } |
| EXPORT_SYMBOL(gen_pool_alloc); |
| |
| /** |
| * gen_pool_dma_alloc - allocate special memory from the pool for DMA usage |
| * @pool: pool to allocate from |
| * @size: number of bytes to allocate from the pool |
| * @dma: dma-view physical address |
| * |
| * Allocate the requested number of bytes from the specified pool. |
| * Uses the pool allocation function (with first-fit algorithm by default). |
| * Can not be used in NMI handler on architectures without |
| * NMI-safe cmpxchg implementation. |
| */ |
| void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size, dma_addr_t *dma) |
| { |
| unsigned long vaddr; |
| |
| if (!pool) |
| return NULL; |
| |
| vaddr = gen_pool_alloc(pool, size); |
| if (!vaddr) |
| return NULL; |
| |
| *dma = gen_pool_virt_to_phys(pool, vaddr); |
| |
| return (void *)vaddr; |
| } |
| EXPORT_SYMBOL(gen_pool_dma_alloc); |
| |
| /** |
| * gen_pool_free - free allocated special memory back to the pool |
| * @pool: pool to free to |
| * @addr: starting address of memory to free back to pool |
| * @size: size in bytes of memory to free |
| * |
| * Free previously allocated special memory back to the specified |
| * pool. Can not be used in NMI handler on architectures without |
| * NMI-safe cmpxchg implementation. |
| */ |
| void gen_pool_free(struct gen_pool *pool, unsigned long addr, size_t size) |
| { |
| struct gen_pool_chunk *chunk; |
| int order = pool->min_alloc_order; |
| int start_bit, nbits, remain; |
| |
| #ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG |
| BUG_ON(in_nmi()); |
| #endif |
| |
| nbits = (size + (1UL << order) - 1) >> order; |
| rcu_read_lock(); |
| list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) { |
| if (addr >= chunk->start_addr && addr <= chunk->end_addr) { |
| BUG_ON(addr + size - 1 > chunk->end_addr); |
| start_bit = (addr - chunk->start_addr) >> order; |
| remain = bitmap_clear_ll(chunk->bits, start_bit, nbits); |
| BUG_ON(remain); |
| size = nbits << order; |
| atomic_add(size, &chunk->avail); |
| rcu_read_unlock(); |
| return; |
| } |
| } |
| rcu_read_unlock(); |
| BUG(); |
| } |
| EXPORT_SYMBOL(gen_pool_free); |
| |
| /** |
| * gen_pool_for_each_chunk - call func for every chunk of generic memory pool |
| * @pool: the generic memory pool |
| * @func: func to call |
| * @data: additional data used by @func |
| * |
| * Call @func for every chunk of generic memory pool. The @func is |
| * called with rcu_read_lock held. |
| */ |
| void gen_pool_for_each_chunk(struct gen_pool *pool, |
| void (*func)(struct gen_pool *pool, struct gen_pool_chunk *chunk, void *data), |
| void *data) |
| { |
| struct gen_pool_chunk *chunk; |
| |
| rcu_read_lock(); |
| list_for_each_entry_rcu(chunk, &(pool)->chunks, next_chunk) |
| func(pool, chunk, data); |
| rcu_read_unlock(); |
| } |
| EXPORT_SYMBOL(gen_pool_for_each_chunk); |
| |
| /** |
| * gen_pool_avail - get available free space of the pool |
| * @pool: pool to get available free space |
| * |
| * Return available free space of the specified pool. |
| */ |
| size_t gen_pool_avail(struct gen_pool *pool) |
| { |
| struct gen_pool_chunk *chunk; |
| size_t avail = 0; |
| |
| rcu_read_lock(); |
| list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) |
| avail += atomic_read(&chunk->avail); |
| rcu_read_unlock(); |
| return avail; |
| } |
| EXPORT_SYMBOL_GPL(gen_pool_avail); |
| |
| /** |
| * gen_pool_size - get size in bytes of memory managed by the pool |
| * @pool: pool to get size |
| * |
| * Return size in bytes of memory managed by the pool. |
| */ |
| size_t gen_pool_size(struct gen_pool *pool) |
| { |
| struct gen_pool_chunk *chunk; |
| size_t size = 0; |
| |
| rcu_read_lock(); |
| list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) |
| size += chunk_size(chunk); |
| rcu_read_unlock(); |
| return size; |
| } |
| EXPORT_SYMBOL_GPL(gen_pool_size); |
| |
| /** |
| * gen_pool_set_algo - set the allocation algorithm |
| * @pool: pool to change allocation algorithm |
| * @algo: custom algorithm function |
| * @data: additional data used by @algo |
| * |
| * Call @algo for each memory allocation in the pool. |
| * If @algo is NULL use gen_pool_first_fit as default |
| * memory allocation function. |
| */ |
| void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo, void *data) |
| { |
| rcu_read_lock(); |
| |
| pool->algo = algo; |
| if (!pool->algo) |
| pool->algo = gen_pool_first_fit; |
| |
| pool->data = data; |
| |
| rcu_read_unlock(); |
| } |
| EXPORT_SYMBOL(gen_pool_set_algo); |
| |
| /** |
| * gen_pool_first_fit - find the first available region |
| * of memory matching the size requirement (no alignment constraint) |
| * @map: The address to base the search on |
| * @size: The bitmap size in bits |
| * @start: The bitnumber to start searching at |
| * @nr: The number of zeroed bits we're looking for |
| * @data: additional data - unused |
| */ |
| unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size, |
| unsigned long start, unsigned int nr, void *data) |
| { |
| return bitmap_find_next_zero_area(map, size, start, nr, 0); |
| } |
| EXPORT_SYMBOL(gen_pool_first_fit); |
| |
| /** |
| * gen_pool_best_fit - find the best fitting region of memory |
| * macthing the size requirement (no alignment constraint) |
| * @map: The address to base the search on |
| * @size: The bitmap size in bits |
| * @start: The bitnumber to start searching at |
| * @nr: The number of zeroed bits we're looking for |
| * @data: additional data - unused |
| * |
| * Iterate over the bitmap to find the smallest free region |
| * which we can allocate the memory. |
| */ |
| unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size, |
| unsigned long start, unsigned int nr, void *data) |
| { |
| unsigned long start_bit = size; |
| unsigned long len = size + 1; |
| unsigned long index; |
| |
| index = bitmap_find_next_zero_area(map, size, start, nr, 0); |
| |
| while (index < size) { |
| int next_bit = find_next_bit(map, size, index + nr); |
| if ((next_bit - index) < len) { |
| len = next_bit - index; |
| start_bit = index; |
| if (len == nr) |
| return start_bit; |
| } |
| index = bitmap_find_next_zero_area(map, size, |
| next_bit + 1, nr, 0); |
| } |
| |
| return start_bit; |
| } |
| EXPORT_SYMBOL(gen_pool_best_fit); |
| |
| static void devm_gen_pool_release(struct device *dev, void *res) |
| { |
| gen_pool_destroy(*(struct gen_pool **)res); |
| } |
| |
| /** |
| * devm_gen_pool_create - managed gen_pool_create |
| * @dev: device that provides the gen_pool |
| * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents |
| * @nid: node id of the node the pool structure should be allocated on, or -1 |
| * |
| * Create a new special memory pool that can be used to manage special purpose |
| * memory not managed by the regular kmalloc/kfree interface. The pool will be |
| * automatically destroyed by the device management code. |
| */ |
| struct gen_pool *devm_gen_pool_create(struct device *dev, int min_alloc_order, |
| int nid) |
| { |
| struct gen_pool **ptr, *pool; |
| |
| ptr = devres_alloc(devm_gen_pool_release, sizeof(*ptr), GFP_KERNEL); |
| |
| pool = gen_pool_create(min_alloc_order, nid); |
| if (pool) { |
| *ptr = pool; |
| devres_add(dev, ptr); |
| } else { |
| devres_free(ptr); |
| } |
| |
| return pool; |
| } |
| |
| /** |
| * dev_get_gen_pool - Obtain the gen_pool (if any) for a device |
| * @dev: device to retrieve the gen_pool from |
| * @name: Optional name for the gen_pool, usually NULL |
| * |
| * Returns the gen_pool for the device if one is present, or NULL. |
| */ |
| struct gen_pool *dev_get_gen_pool(struct device *dev) |
| { |
| struct gen_pool **p = devres_find(dev, devm_gen_pool_release, NULL, |
| NULL); |
| |
| if (!p) |
| return NULL; |
| return *p; |
| } |
| EXPORT_SYMBOL_GPL(dev_get_gen_pool); |
| |
| #ifdef CONFIG_OF |
| /** |
| * of_get_named_gen_pool - find a pool by phandle property |
| * @np: device node |
| * @propname: property name containing phandle(s) |
| * @index: index into the phandle array |
| * |
| * Returns the pool that contains the chunk starting at the physical |
| * address of the device tree node pointed at by the phandle property, |
| * or NULL if not found. |
| */ |
| struct gen_pool *of_get_named_gen_pool(struct device_node *np, |
| const char *propname, int index) |
| { |
| struct platform_device *pdev; |
| struct device_node *np_pool; |
| |
| np_pool = of_parse_phandle(np, propname, index); |
| if (!np_pool) |
| return NULL; |
| pdev = of_find_device_by_node(np_pool); |
| if (!pdev) |
| return NULL; |
| return dev_get_gen_pool(&pdev->dev); |
| } |
| EXPORT_SYMBOL_GPL(of_get_named_gen_pool); |
| #endif /* CONFIG_OF */ |