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1 /*
2  * libfdt - Flat Device Tree manipulation
3  * Copyright (C) 2006 David Gibson, IBM Corporation.
4  *
5  * libfdt is dual licensed: you can use it either under the terms of
6  * the GPL, or the BSD license, at your option.
7  *
8  *  a) This library is free software; you can redistribute it and/or
9  *     modify it under the terms of the GNU General Public License as
10  *     published by the Free Software Foundation; either version 2 of the
11  *     License, or (at your option) any later version.
12  *
13  *     This library is distributed in the hope that it will be useful,
14  *     but WITHOUT ANY WARRANTY; without even the implied warranty of
15  *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  *     GNU General Public License for more details.
17  *
18  *     You should have received a copy of the GNU General Public
19  *     License along with this library; if not, write to the Free
20  *     Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
21  *     MA 02110-1301 USA
22  *
23  * Alternatively,
24  *
25  *  b) Redistribution and use in source and binary forms, with or
26  *     without modification, are permitted provided that the following
27  *     conditions are met:
28  *
29  *     1. Redistributions of source code must retain the above
30  *        copyright notice, this list of conditions and the following
31  *        disclaimer.
32  *     2. Redistributions in binary form must reproduce the above
33  *        copyright notice, this list of conditions and the following
34  *        disclaimer in the documentation and/or other materials
35  *        provided with the distribution.
36  *
37  *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
38  *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
39  *     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
40  *     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
41  *     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
42  *     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
43  *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
44  *     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
45  *     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
46  *     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
47  *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
48  *     OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
49  *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
50  */
51 #include "libfdt_env.h"
52 
53 #include <fdt.h>
54 #include <libfdt.h>
55 
56 #include "libfdt_internal.h"
57 
_fdt_sw_check_header(void * fdt)58 static int _fdt_sw_check_header(void *fdt)
59 {
60 	if (fdt_magic(fdt) != FDT_SW_MAGIC)
61 		return -FDT_ERR_BADMAGIC;
62 	/* FIXME: should check more details about the header state */
63 	return 0;
64 }
65 
66 #define FDT_SW_CHECK_HEADER(fdt) \
67 	{ \
68 		int err; \
69 		if ((err = _fdt_sw_check_header(fdt)) != 0) \
70 			return err; \
71 	}
72 
_fdt_grab_space(void * fdt,size_t len)73 static void *_fdt_grab_space(void *fdt, size_t len)
74 {
75 	int offset = fdt_size_dt_struct(fdt);
76 	int spaceleft;
77 
78 	spaceleft = fdt_totalsize(fdt) - fdt_off_dt_struct(fdt)
79 		- fdt_size_dt_strings(fdt);
80 
81 	if ((offset + len < offset) || (offset + len > spaceleft))
82 		return NULL;
83 
84 	fdt_set_size_dt_struct(fdt, offset + len);
85 	return _fdt_offset_ptr_w(fdt, offset);
86 }
87 
fdt_create(void * buf,int bufsize)88 int fdt_create(void *buf, int bufsize)
89 {
90 	void *fdt = buf;
91 
92 	if (bufsize < sizeof(struct fdt_header))
93 		return -FDT_ERR_NOSPACE;
94 
95 	memset(buf, 0, bufsize);
96 
97 	fdt_set_magic(fdt, FDT_SW_MAGIC);
98 	fdt_set_version(fdt, FDT_LAST_SUPPORTED_VERSION);
99 	fdt_set_last_comp_version(fdt, FDT_FIRST_SUPPORTED_VERSION);
100 	fdt_set_totalsize(fdt,  bufsize);
101 
102 	fdt_set_off_mem_rsvmap(fdt, FDT_ALIGN(sizeof(struct fdt_header),
103 					      sizeof(struct fdt_reserve_entry)));
104 	fdt_set_off_dt_struct(fdt, fdt_off_mem_rsvmap(fdt));
105 	fdt_set_off_dt_strings(fdt, bufsize);
106 
107 	return 0;
108 }
109 
fdt_resize(void * fdt,void * buf,int bufsize)110 int fdt_resize(void *fdt, void *buf, int bufsize)
111 {
112 	size_t headsize, tailsize;
113 	char *oldtail, *newtail;
114 
115 	FDT_SW_CHECK_HEADER(fdt);
116 
117 	headsize = fdt_off_dt_struct(fdt);
118 	tailsize = fdt_size_dt_strings(fdt);
119 
120 	if ((headsize + tailsize) > bufsize)
121 		return -FDT_ERR_NOSPACE;
122 
123 	oldtail = (char *)fdt + fdt_totalsize(fdt) - tailsize;
124 	newtail = (char *)buf + bufsize - tailsize;
125 
126 	/* Two cases to avoid clobbering data if the old and new
127 	 * buffers partially overlap */
128 	if (buf <= fdt) {
129 		memmove(buf, fdt, headsize);
130 		memmove(newtail, oldtail, tailsize);
131 	} else {
132 		memmove(newtail, oldtail, tailsize);
133 		memmove(buf, fdt, headsize);
134 	}
135 
136 	fdt_set_off_dt_strings(buf, bufsize);
137 	fdt_set_totalsize(buf, bufsize);
138 
139 	return 0;
140 }
141 
fdt_add_reservemap_entry(void * fdt,uint64_t addr,uint64_t size)142 int fdt_add_reservemap_entry(void *fdt, uint64_t addr, uint64_t size)
143 {
144 	struct fdt_reserve_entry *re;
145 	int offset;
146 
147 	FDT_SW_CHECK_HEADER(fdt);
148 
149 	if (fdt_size_dt_struct(fdt))
150 		return -FDT_ERR_BADSTATE;
151 
152 	offset = fdt_off_dt_struct(fdt);
153 	if ((offset + sizeof(*re)) > fdt_totalsize(fdt))
154 		return -FDT_ERR_NOSPACE;
155 
156 	re = (struct fdt_reserve_entry *)((char *)fdt + offset);
157 	re->address = cpu_to_fdt64(addr);
158 	re->size = cpu_to_fdt64(size);
159 
160 	fdt_set_off_dt_struct(fdt, offset + sizeof(*re));
161 
162 	return 0;
163 }
164 
fdt_finish_reservemap(void * fdt)165 int fdt_finish_reservemap(void *fdt)
166 {
167 	return fdt_add_reservemap_entry(fdt, 0, 0);
168 }
169 
fdt_begin_node(void * fdt,const char * name)170 int fdt_begin_node(void *fdt, const char *name)
171 {
172 	struct fdt_node_header *nh;
173 	int namelen = strlen(name) + 1;
174 
175 	FDT_SW_CHECK_HEADER(fdt);
176 
177 	nh = _fdt_grab_space(fdt, sizeof(*nh) + FDT_TAGALIGN(namelen));
178 	if (! nh)
179 		return -FDT_ERR_NOSPACE;
180 
181 	nh->tag = cpu_to_fdt32(FDT_BEGIN_NODE);
182 	memcpy(nh->name, name, namelen);
183 	return 0;
184 }
185 
fdt_end_node(void * fdt)186 int fdt_end_node(void *fdt)
187 {
188 	fdt32_t *en;
189 
190 	FDT_SW_CHECK_HEADER(fdt);
191 
192 	en = _fdt_grab_space(fdt, FDT_TAGSIZE);
193 	if (! en)
194 		return -FDT_ERR_NOSPACE;
195 
196 	*en = cpu_to_fdt32(FDT_END_NODE);
197 	return 0;
198 }
199 
_fdt_find_add_string(void * fdt,const char * s)200 static int _fdt_find_add_string(void *fdt, const char *s)
201 {
202 	char *strtab = (char *)fdt + fdt_totalsize(fdt);
203 	const char *p;
204 	int strtabsize = fdt_size_dt_strings(fdt);
205 	int len = strlen(s) + 1;
206 	int struct_top, offset;
207 
208 	p = _fdt_find_string(strtab - strtabsize, strtabsize, s);
209 	if (p)
210 		return p - strtab;
211 
212 	/* Add it */
213 	offset = -strtabsize - len;
214 	struct_top = fdt_off_dt_struct(fdt) + fdt_size_dt_struct(fdt);
215 	if (fdt_totalsize(fdt) + offset < struct_top)
216 		return 0; /* no more room :( */
217 
218 	memcpy(strtab + offset, s, len);
219 	fdt_set_size_dt_strings(fdt, strtabsize + len);
220 	return offset;
221 }
222 
fdt_property(void * fdt,const char * name,const void * val,int len)223 int fdt_property(void *fdt, const char *name, const void *val, int len)
224 {
225 	struct fdt_property *prop;
226 	int nameoff;
227 
228 	FDT_SW_CHECK_HEADER(fdt);
229 
230 	nameoff = _fdt_find_add_string(fdt, name);
231 	if (nameoff == 0)
232 		return -FDT_ERR_NOSPACE;
233 
234 	prop = _fdt_grab_space(fdt, sizeof(*prop) + FDT_TAGALIGN(len));
235 	if (! prop)
236 		return -FDT_ERR_NOSPACE;
237 
238 	prop->tag = cpu_to_fdt32(FDT_PROP);
239 	prop->nameoff = cpu_to_fdt32(nameoff);
240 	prop->len = cpu_to_fdt32(len);
241 	memcpy(prop->data, val, len);
242 	return 0;
243 }
244 
fdt_finish(void * fdt)245 int fdt_finish(void *fdt)
246 {
247 	char *p = (char *)fdt;
248 	fdt32_t *end;
249 	int oldstroffset, newstroffset;
250 	uint32_t tag;
251 	int offset, nextoffset;
252 
253 	FDT_SW_CHECK_HEADER(fdt);
254 
255 	/* Add terminator */
256 	end = _fdt_grab_space(fdt, sizeof(*end));
257 	if (! end)
258 		return -FDT_ERR_NOSPACE;
259 	*end = cpu_to_fdt32(FDT_END);
260 
261 	/* Relocate the string table */
262 	oldstroffset = fdt_totalsize(fdt) - fdt_size_dt_strings(fdt);
263 	newstroffset = fdt_off_dt_struct(fdt) + fdt_size_dt_struct(fdt);
264 	memmove(p + newstroffset, p + oldstroffset, fdt_size_dt_strings(fdt));
265 	fdt_set_off_dt_strings(fdt, newstroffset);
266 
267 	/* Walk the structure, correcting string offsets */
268 	offset = 0;
269 	while ((tag = fdt_next_tag(fdt, offset, &nextoffset)) != FDT_END) {
270 		if (tag == FDT_PROP) {
271 			struct fdt_property *prop =
272 				_fdt_offset_ptr_w(fdt, offset);
273 			int nameoff;
274 
275 			nameoff = fdt32_to_cpu(prop->nameoff);
276 			nameoff += fdt_size_dt_strings(fdt);
277 			prop->nameoff = cpu_to_fdt32(nameoff);
278 		}
279 		offset = nextoffset;
280 	}
281 	if (nextoffset < 0)
282 		return nextoffset;
283 
284 	/* Finally, adjust the header */
285 	fdt_set_totalsize(fdt, newstroffset + fdt_size_dt_strings(fdt));
286 	fdt_set_magic(fdt, FDT_MAGIC);
287 	return 0;
288 }
289