1 /* 2 * libfdt - Flat Device Tree manipulation 3 * Copyright (C) 2006 David Gibson, IBM Corporation. 4 * SPDX-License-Identifier: GPL-2.0+ BSD-2-Clause 5 */ 6 #include "libfdt_env.h" 7 8 #include <fdt.h> 9 #include <libfdt.h> 10 11 #include "libfdt_internal.h" 12 13 static int _fdt_sw_check_header(void *fdt) 14 { 15 if (fdt_magic(fdt) != FDT_SW_MAGIC) 16 return -FDT_ERR_BADMAGIC; 17 /* FIXME: should check more details about the header state */ 18 return 0; 19 } 20 21 #define FDT_SW_CHECK_HEADER(fdt) \ 22 { \ 23 int err; \ 24 if ((err = _fdt_sw_check_header(fdt)) != 0) \ 25 return err; \ 26 } 27 28 static void *_fdt_grab_space(void *fdt, size_t len) 29 { 30 int offset = fdt_size_dt_struct(fdt); 31 int spaceleft; 32 33 spaceleft = fdt_totalsize(fdt) - fdt_off_dt_struct(fdt) 34 - fdt_size_dt_strings(fdt); 35 36 if ((offset + len < offset) || (offset + len > spaceleft)) 37 return NULL; 38 39 fdt_set_size_dt_struct(fdt, offset + len); 40 return _fdt_offset_ptr_w(fdt, offset); 41 } 42 43 int fdt_create(void *buf, int bufsize) 44 { 45 void *fdt = buf; 46 47 if (bufsize < sizeof(struct fdt_header)) 48 return -FDT_ERR_NOSPACE; 49 50 memset(buf, 0, bufsize); 51 52 fdt_set_magic(fdt, FDT_SW_MAGIC); 53 fdt_set_version(fdt, FDT_LAST_SUPPORTED_VERSION); 54 fdt_set_last_comp_version(fdt, FDT_FIRST_SUPPORTED_VERSION); 55 fdt_set_totalsize(fdt, bufsize); 56 57 fdt_set_off_mem_rsvmap(fdt, FDT_ALIGN(sizeof(struct fdt_header), 58 sizeof(struct fdt_reserve_entry))); 59 fdt_set_off_dt_struct(fdt, fdt_off_mem_rsvmap(fdt)); 60 fdt_set_off_dt_strings(fdt, bufsize); 61 62 return 0; 63 } 64 65 int fdt_add_reservemap_entry(void *fdt, uint64_t addr, uint64_t size) 66 { 67 struct fdt_reserve_entry *re; 68 int offset; 69 70 FDT_SW_CHECK_HEADER(fdt); 71 72 if (fdt_size_dt_struct(fdt)) 73 return -FDT_ERR_BADSTATE; 74 75 offset = fdt_off_dt_struct(fdt); 76 if ((offset + sizeof(*re)) > fdt_totalsize(fdt)) 77 return -FDT_ERR_NOSPACE; 78 79 re = (struct fdt_reserve_entry *)((char *)fdt + offset); 80 re->address = cpu_to_fdt64(addr); 81 re->size = cpu_to_fdt64(size); 82 83 fdt_set_off_dt_struct(fdt, offset + sizeof(*re)); 84 85 return 0; 86 } 87 88 int fdt_finish_reservemap(void *fdt) 89 { 90 return fdt_add_reservemap_entry(fdt, 0, 0); 91 } 92 93 int fdt_begin_node(void *fdt, const char *name) 94 { 95 struct fdt_node_header *nh; 96 int namelen = strlen(name) + 1; 97 98 FDT_SW_CHECK_HEADER(fdt); 99 100 nh = _fdt_grab_space(fdt, sizeof(*nh) + FDT_TAGALIGN(namelen)); 101 if (! nh) 102 return -FDT_ERR_NOSPACE; 103 104 nh->tag = cpu_to_fdt32(FDT_BEGIN_NODE); 105 memcpy(nh->name, name, namelen); 106 return 0; 107 } 108 109 int fdt_end_node(void *fdt) 110 { 111 fdt32_t *en; 112 113 FDT_SW_CHECK_HEADER(fdt); 114 115 en = _fdt_grab_space(fdt, FDT_TAGSIZE); 116 if (! en) 117 return -FDT_ERR_NOSPACE; 118 119 *en = cpu_to_fdt32(FDT_END_NODE); 120 return 0; 121 } 122 123 static int _fdt_find_add_string(void *fdt, const char *s) 124 { 125 char *strtab = (char *)fdt + fdt_totalsize(fdt); 126 const char *p; 127 int strtabsize = fdt_size_dt_strings(fdt); 128 int len = strlen(s) + 1; 129 int struct_top, offset; 130 131 p = _fdt_find_string(strtab - strtabsize, strtabsize, s); 132 if (p) 133 return p - strtab; 134 135 /* Add it */ 136 offset = -strtabsize - len; 137 struct_top = fdt_off_dt_struct(fdt) + fdt_size_dt_struct(fdt); 138 if (fdt_totalsize(fdt) + offset < struct_top) 139 return 0; /* no more room :( */ 140 141 memcpy(strtab + offset, s, len); 142 fdt_set_size_dt_strings(fdt, strtabsize + len); 143 return offset; 144 } 145 146 int fdt_property(void *fdt, const char *name, const void *val, int len) 147 { 148 struct fdt_property *prop; 149 int nameoff; 150 151 FDT_SW_CHECK_HEADER(fdt); 152 153 nameoff = _fdt_find_add_string(fdt, name); 154 if (nameoff == 0) 155 return -FDT_ERR_NOSPACE; 156 157 prop = _fdt_grab_space(fdt, sizeof(*prop) + FDT_TAGALIGN(len)); 158 if (! prop) 159 return -FDT_ERR_NOSPACE; 160 161 prop->tag = cpu_to_fdt32(FDT_PROP); 162 prop->nameoff = cpu_to_fdt32(nameoff); 163 prop->len = cpu_to_fdt32(len); 164 memcpy(prop->data, val, len); 165 return 0; 166 } 167 168 int fdt_finish(void *fdt) 169 { 170 char *p = (char *)fdt; 171 fdt32_t *end; 172 int oldstroffset, newstroffset; 173 uint32_t tag; 174 int offset, nextoffset; 175 176 FDT_SW_CHECK_HEADER(fdt); 177 178 /* Add terminator */ 179 end = _fdt_grab_space(fdt, sizeof(*end)); 180 if (! end) 181 return -FDT_ERR_NOSPACE; 182 *end = cpu_to_fdt32(FDT_END); 183 184 /* Relocate the string table */ 185 oldstroffset = fdt_totalsize(fdt) - fdt_size_dt_strings(fdt); 186 newstroffset = fdt_off_dt_struct(fdt) + fdt_size_dt_struct(fdt); 187 memmove(p + newstroffset, p + oldstroffset, fdt_size_dt_strings(fdt)); 188 fdt_set_off_dt_strings(fdt, newstroffset); 189 190 /* Walk the structure, correcting string offsets */ 191 offset = 0; 192 while ((tag = fdt_next_tag(fdt, offset, &nextoffset)) != FDT_END) { 193 if (tag == FDT_PROP) { 194 struct fdt_property *prop = 195 _fdt_offset_ptr_w(fdt, offset); 196 int nameoff; 197 198 nameoff = fdt32_to_cpu(prop->nameoff); 199 nameoff += fdt_size_dt_strings(fdt); 200 prop->nameoff = cpu_to_fdt32(nameoff); 201 } 202 offset = nextoffset; 203 } 204 if (nextoffset < 0) 205 return nextoffset; 206 207 /* Finally, adjust the header */ 208 fdt_set_totalsize(fdt, newstroffset + fdt_size_dt_strings(fdt)); 209 fdt_set_magic(fdt, FDT_MAGIC); 210 return 0; 211 } 212