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1 | /* |
2 | * Copyright (C) 2010 Intel Corporation. All rights reserved. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of version 2 of the GNU General | |
6 | * Public License as published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be | |
9 | * useful, but WITHOUT ANY WARRANTY; without even the implied | |
10 | * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR | |
11 | * PURPOSE. See the GNU General Public License for more details. | |
12 | * You should have received a copy of the GNU General Public | |
13 | * License along with this program; if not, write to the Free | |
14 | * Software Foundation, Inc., 59 Temple Place - Suite 330, | |
15 | * Boston, MA 02111-1307, USA. | |
16 | * The full GNU General Public License is included in this | |
17 | * distribution in the file called COPYING. | |
18 | */ | |
19 | ||
20 | #ifndef MEMRAR_ALLOCATOR_H | |
21 | #define MEMRAR_ALLOCATOR_H | |
22 | ||
23 | ||
24 | #include <linux/mutex.h> | |
25 | #include <linux/list.h> | |
26 | #include <linux/types.h> | |
27 | #include <linux/kernel.h> | |
28 | ||
29 | ||
30 | /** | |
31 | * struct memrar_address_range - struct that describes a memory range | |
32 | * @begin: Beginning of available address range. | |
33 | * @end: End of available address range, one past the end, | |
34 | * i.e. [begin, end). | |
35 | */ | |
36 | struct memrar_address_range { | |
37 | /* private: internal use only */ | |
38 | unsigned long begin; | |
39 | unsigned long end; | |
40 | }; | |
41 | ||
42 | /** | |
43 | * struct memrar_address_ranges - list of areas of memory. | |
44 | * @list: Linked list of address ranges. | |
45 | * @range: Memory address range corresponding to given list node. | |
46 | */ | |
47 | struct memrar_address_ranges { | |
48 | /* private: internal use only */ | |
49 | struct list_head list; | |
50 | struct memrar_address_range range; | |
51 | }; | |
52 | ||
53 | /** | |
54 | * struct memrar_allocator - encapsulation of the memory allocator state | |
55 | * @lock: Lock used to synchronize access to the memory | |
56 | * allocator state. | |
57 | * @base: Base (start) address of the allocator memory | |
58 | * space. | |
59 | * @capacity: Size of the allocator memory space in bytes. | |
60 | * @block_size: The size in bytes of individual blocks within | |
61 | * the allocator memory space. | |
62 | * @largest_free_area: Largest free area of memory in the allocator | |
63 | * in bytes. | |
64 | * @allocated_list: List of allocated memory block address | |
65 | * ranges. | |
66 | * @free_list: List of free address ranges. | |
67 | * | |
68 | * This structure contains all memory allocator state, including the | |
69 | * base address, capacity, free list, lock, etc. | |
70 | */ | |
71 | struct memrar_allocator { | |
72 | /* private: internal use only */ | |
73 | struct mutex lock; | |
74 | unsigned long base; | |
75 | size_t capacity; | |
76 | size_t block_size; | |
77 | size_t largest_free_area; | |
78 | struct memrar_address_ranges allocated_list; | |
79 | struct memrar_address_ranges free_list; | |
80 | }; | |
81 | ||
82 | /** | |
83 | * memrar_create_allocator() - create a memory allocator | |
84 | * @base: Address at which the memory allocator begins. | |
85 | * @capacity: Desired size of the memory allocator. This value must | |
86 | * be larger than the block_size, ideally more than twice | |
87 | * as large since there wouldn't be much point in using a | |
88 | * memory allocator otherwise. | |
89 | * @block_size: The size of individual blocks within the memory | |
90 | * allocator. This value must smaller than the | |
91 | * capacity. | |
92 | * | |
93 | * Create a memory allocator with the given capacity and block size. | |
94 | * The capacity will be reduced to be a multiple of the block size, if | |
95 | * necessary. | |
96 | * | |
97 | * Returns an instance of the memory allocator, if creation succeeds, | |
98 | * otherwise zero if creation fails. Failure may occur if not enough | |
99 | * kernel memory exists to create the memrar_allocator instance | |
100 | * itself, or if the capacity and block_size arguments are not | |
101 | * compatible or make sense. | |
102 | */ | |
103 | struct memrar_allocator *memrar_create_allocator(unsigned long base, | |
104 | size_t capacity, | |
105 | size_t block_size); | |
106 | ||
107 | /** | |
108 | * memrar_destroy_allocator() - destroy allocator | |
109 | * @allocator: The allocator being destroyed. | |
110 | * | |
111 | * Reclaim resources held by the memory allocator. The caller must | |
112 | * explicitly free all memory reserved by memrar_allocator_alloc() | |
113 | * prior to calling this function. Otherwise leaks will occur. | |
114 | */ | |
115 | void memrar_destroy_allocator(struct memrar_allocator *allocator); | |
116 | ||
117 | /** | |
118 | * memrar_allocator_alloc() - reserve an area of memory of given size | |
119 | * @allocator: The allocator instance being used to reserve buffer. | |
120 | * @size: The size in bytes of the buffer to allocate. | |
121 | * | |
122 | * This functions reserves an area of memory managed by the given | |
123 | * allocator. It returns zero if allocation was not possible. | |
124 | * Failure may occur if the allocator no longer has space available. | |
125 | */ | |
126 | unsigned long memrar_allocator_alloc(struct memrar_allocator *allocator, | |
127 | size_t size); | |
128 | ||
129 | /** | |
130 | * memrar_allocator_free() - release buffer starting at given address | |
131 | * @allocator: The allocator instance being used to release the buffer. | |
132 | * @address: The address of the buffer being released. | |
133 | * | |
134 | * Release an area of memory starting at the given address. Failure | |
135 | * could occur if the given address is not in the address space | |
136 | * managed by the allocator. Returns zero on success or an errno | |
137 | * (negative value) on failure. | |
138 | */ | |
139 | long memrar_allocator_free(struct memrar_allocator *allocator, | |
140 | unsigned long address); | |
141 | ||
142 | #endif /* MEMRAR_ALLOCATOR_H */ | |
143 | ||
144 | ||
145 | /* | |
146 | Local Variables: | |
147 | c-file-style: "linux" | |
148 | End: | |
149 | */ |