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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* 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.
*/
#ifndef __GENALLOC_H__
#define __GENALLOC_H__
#include <linux/types.h>
#include <linux/spinlock_types.h>
#include <linux/atomic.h>
struct device;
struct device_node;
struct gen_pool;
/**
* typedef genpool_algo_t: Allocation callback function type definition
* @map: Pointer to bitmap
* @size: The bitmap size in bits
* @start: The bitnumber to start searching at
* @nr: The number of zeroed bits we're looking for
* @data: optional additional data used by the callback
* @pool: the pool being allocated from
*/
typedef unsigned long (*genpool_algo_t)(unsigned long *map,
unsigned long size,
unsigned long start,
unsigned int nr,
void *data, struct gen_pool *pool,
unsigned long start_addr);
/*
* General purpose special memory pool descriptor.
*/
struct gen_pool {
spinlock_t lock;
struct list_head chunks; /* list of chunks in this pool */
int min_alloc_order; /* minimum allocation order */
genpool_algo_t algo; /* allocation function */
void *data;
const char *name;
};
/*
* General purpose special memory pool chunk descriptor.
*/
struct gen_pool_chunk {
struct list_head next_chunk; /* next chunk in pool */
atomic_long_t avail;
phys_addr_t phys_addr; /* physical starting address of memory chunk */
void *owner; /* private data to retrieve at alloc time */
unsigned long start_addr; /* start address of memory chunk */
unsigned long end_addr; /* end address of memory chunk (inclusive) */
unsigned long bits[0]; /* bitmap for allocating memory chunk */
};
/*
* gen_pool data descriptor for gen_pool_first_fit_align.
*/
struct genpool_data_align {
int align; /* alignment by bytes for starting address */
};
/*
* gen_pool data descriptor for gen_pool_fixed_alloc.
*/
struct genpool_data_fixed {
unsigned long offset; /* The offset of the specific region */
};
extern struct gen_pool *gen_pool_create(int, int);
extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long);
extern int gen_pool_add_owner(struct gen_pool *, unsigned long, phys_addr_t,
size_t, int, void *);
static inline int gen_pool_add_virt(struct gen_pool *pool, unsigned long addr,
phys_addr_t phys, size_t size, int nid)
{
return gen_pool_add_owner(pool, addr, phys, size, nid, NULL);
}
/**
* gen_pool_add - add a new chunk of special memory to the pool
* @pool: pool to add new memory chunk to
* @addr: 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.
*/
static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr,
size_t size, int nid)
{
return gen_pool_add_virt(pool, addr, -1, size, nid);
}
extern void gen_pool_destroy(struct gen_pool *);
unsigned long gen_pool_alloc_algo_owner(struct gen_pool *pool, size_t size,
genpool_algo_t algo, void *data, void **owner);
static inline unsigned long gen_pool_alloc_owner(struct gen_pool *pool,
size_t size, void **owner)
{
return gen_pool_alloc_algo_owner(pool, size, pool->algo, pool->data,
owner);
}
static inline unsigned long gen_pool_alloc_algo(struct gen_pool *pool,
size_t size, genpool_algo_t algo, void *data)
{
return gen_pool_alloc_algo_owner(pool, size, algo, data, NULL);
}
/**
* 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.
*/
static inline unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size)
{
return gen_pool_alloc_algo(pool, size, pool->algo, pool->data);
}
extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size,
dma_addr_t *dma);
extern void gen_pool_free_owner(struct gen_pool *pool, unsigned long addr,
size_t size, void **owner);
static inline void gen_pool_free(struct gen_pool *pool, unsigned long addr,
size_t size)
{
gen_pool_free_owner(pool, addr, size, NULL);
}
extern void gen_pool_for_each_chunk(struct gen_pool *,
void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *);
extern size_t gen_pool_avail(struct gen_pool *);
extern size_t gen_pool_size(struct gen_pool *);
extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo,
void *data);
extern unsigned long 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);
extern unsigned long 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);
extern unsigned long 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);
extern unsigned long 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);
extern unsigned long 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);
extern struct gen_pool *devm_gen_pool_create(struct device *dev,
int min_alloc_order, int nid, const char *name);
extern struct gen_pool *gen_pool_get(struct device *dev, const char *name);
bool addr_in_gen_pool(struct gen_pool *pool, unsigned long start,
size_t size);
#ifdef CONFIG_OF
extern struct gen_pool *of_gen_pool_get(struct device_node *np,
const char *propname, int index);
#else
static inline struct gen_pool *of_gen_pool_get(struct device_node *np,
const char *propname, int index)
{
return NULL;
}
#endif
#endif /* __GENALLOC_H__ */
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