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/* Copyright (c) 2012,2014, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <soc/qcom/ocmem.h>
#include "ocmem_priv.h"
#include <linux/genalloc.h>
/* All allocator operations are serialized by ocmem driver */
/* The allocators work as follows:
Constraints:
1) There is no IOMMU access to OCMEM hence successive allocations
in the zone must be physically contiguous
2) Allocations must be freed in reverse order within a zone.
z->z_start: Fixed pointer to the start of a zone
z->z_end: Fixed pointer to the end of a zone
z->z_head: Movable pointer to the next free area when growing at head
Fixed on zones that grow from tail
z->z_tail: Movable pointer to the next free area when growing at tail
Fixed on zones that grow from head
z->z_free: Free space in a zone that is updated on an allocation/free
reserve: Enable libgenpool to simulate tail allocations
*/
int allocate_head(struct ocmem_zone *z, unsigned long size,
unsigned long *offset)
{
*offset = gen_pool_alloc(z->z_pool, size);
if (!(*offset))
return -ENOMEM;
z->z_head += size;
z->z_free -= size;
return 0;
}
int allocate_tail(struct ocmem_zone *z, unsigned long size,
unsigned long *offset)
{
unsigned long reserve;
unsigned long head;
if (z->z_tail < (z->z_head + size))
return -ENOMEM;
reserve = z->z_tail - z->z_head - size;
if (reserve) {
head = gen_pool_alloc(z->z_pool, reserve);
*offset = gen_pool_alloc(z->z_pool, size);
gen_pool_free(z->z_pool, head, reserve);
} else
*offset = gen_pool_alloc(z->z_pool, size);
if (!(*offset))
return -ENOMEM;
z->z_tail -= size;
z->z_free -= size;
return 0;
}
int free_head(struct ocmem_zone *z, unsigned long offset,
unsigned long size)
{
if (offset > z->z_head) {
pr_err("ocmem: Detected out of order free "
"leading to fragmentation\n");
return -EINVAL;
}
gen_pool_free(z->z_pool, offset, size);
z->z_head -= size;
z->z_free += size;
return 0;
}
int free_tail(struct ocmem_zone *z, unsigned long offset,
unsigned long size)
{
if (offset > z->z_tail) {
pr_err("ocmem: Detected out of order free "
"leading to fragmentation\n");
return -EINVAL;
}
gen_pool_free(z->z_pool, offset, size);
z->z_tail += size;
z->z_free += size;
return 0;
}
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