1 /* 2 * Implement primitive realloc(3) functionality. 3 * 4 * Author: Mark A. Greer <mgreer@mvista.com> 5 * 6 * 2006 (c) MontaVista, Software, Inc. This file is licensed under 7 * the terms of the GNU General Public License version 2. This program 8 * is licensed "as is" without any warranty of any kind, whether express 9 * or implied. 10 */ 11 12 #include <stddef.h> 13 #include "types.h" 14 #include "page.h" 15 #include "string.h" 16 #include "ops.h" 17 18 #define ENTRY_BEEN_USED 0x01 19 #define ENTRY_IN_USE 0x02 20 21 static struct alloc_info { 22 u32 flags; 23 u32 base; 24 u32 size; 25 } *alloc_tbl; 26 27 static u32 tbl_entries; 28 static u32 alloc_min; 29 static u32 next_base; 30 static u32 space_left; 31 32 /* 33 * First time an entry is used, its base and size are set. 34 * An entry can be freed and re-malloc'd but its base & size don't change. 35 * Should be smart enough for needs of bootwrapper. 36 */ 37 static void *simple_malloc(u32 size) 38 { 39 u32 i; 40 struct alloc_info *p = alloc_tbl; 41 42 if (size == 0) 43 goto err_out; 44 45 size = _ALIGN_UP(size, alloc_min); 46 47 for (i=0; i<tbl_entries; i++, p++) 48 if (!(p->flags & ENTRY_BEEN_USED)) { /* never been used */ 49 if (size <= space_left) { 50 p->base = next_base; 51 p->size = size; 52 p->flags = ENTRY_BEEN_USED | ENTRY_IN_USE; 53 next_base += size; 54 space_left -= size; 55 return (void *)p->base; 56 } 57 goto err_out; /* not enough space left */ 58 } 59 /* reuse an entry keeping same base & size */ 60 else if (!(p->flags & ENTRY_IN_USE) && (size <= p->size)) { 61 p->flags |= ENTRY_IN_USE; 62 return (void *)p->base; 63 } 64 err_out: 65 return NULL; 66 } 67 68 static struct alloc_info *simple_find_entry(void *ptr) 69 { 70 u32 i; 71 struct alloc_info *p = alloc_tbl; 72 73 for (i=0; i<tbl_entries; i++,p++) { 74 if (!(p->flags & ENTRY_BEEN_USED)) 75 break; 76 if ((p->flags & ENTRY_IN_USE) && (p->base == (u32)ptr)) 77 return p; 78 } 79 return NULL; 80 } 81 82 static void simple_free(void *ptr) 83 { 84 struct alloc_info *p = simple_find_entry(ptr); 85 86 if (p != NULL) 87 p->flags &= ~ENTRY_IN_USE; 88 } 89 90 /* 91 * Change size of area pointed to by 'ptr' to 'size'. 92 * If 'ptr' is NULL, then its a malloc(). If 'size' is 0, then its a free(). 93 * 'ptr' must be NULL or a pointer to a non-freed area previously returned by 94 * simple_realloc() or simple_malloc(). 95 */ 96 static void *simple_realloc(void *ptr, unsigned long size) 97 { 98 struct alloc_info *p; 99 void *new; 100 101 if (size == 0) { 102 simple_free(ptr); 103 return NULL; 104 } 105 106 if (ptr == NULL) 107 return simple_malloc(size); 108 109 p = simple_find_entry(ptr); 110 if (p == NULL) /* ptr not from simple_malloc/simple_realloc */ 111 return NULL; 112 if (size <= p->size) /* fits in current block */ 113 return ptr; 114 115 new = simple_malloc(size); 116 memcpy(new, ptr, p->size); 117 simple_free(ptr); 118 return new; 119 } 120 121 /* 122 * Returns addr of first byte after heap so caller can see if it took 123 * too much space. If so, change args & try again. 124 */ 125 void *simple_alloc_init(char *base, u32 heap_size, u32 granularity, 126 u32 max_allocs) 127 { 128 u32 heap_base, tbl_size; 129 130 heap_size = _ALIGN_UP(heap_size, granularity); 131 alloc_min = granularity; 132 tbl_entries = max_allocs; 133 134 tbl_size = tbl_entries * sizeof(struct alloc_info); 135 136 alloc_tbl = (struct alloc_info *)_ALIGN_UP((unsigned long)base, 8); 137 memset(alloc_tbl, 0, tbl_size); 138 139 heap_base = _ALIGN_UP((u32)alloc_tbl + tbl_size, alloc_min); 140 141 next_base = heap_base; 142 space_left = heap_size; 143 144 platform_ops.malloc = simple_malloc; 145 platform_ops.free = simple_free; 146 platform_ops.realloc = simple_realloc; 147 148 return (void *)(heap_base + heap_size); 149 } 150