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