env: fix potential stack overflow in environment functions
[platform/kernel/u-boot.git] / common / env_eeprom.c
1 /*
2  * (C) Copyright 2000-2010
3  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
4  *
5  * (C) Copyright 2001 Sysgo Real-Time Solutions, GmbH <www.elinos.com>
6  * Andreas Heppel <aheppel@sysgo.de>
7  *
8  * See file CREDITS for list of people who contributed to this
9  * project.
10  *
11  * This program is free software; you can redistribute it and/or
12  * modify it under the terms of the GNU General Public License as
13  * published by the Free Software Foundation; either version 2 of
14  * the License, or (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with this program; if not, write to the Free Software
23  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
24  * MA 02111-1307 USA
25  */
26
27 #include <common.h>
28 #include <command.h>
29 #include <environment.h>
30 #include <linux/stddef.h>
31 #if defined(CONFIG_I2C_ENV_EEPROM_BUS)
32 #include <i2c.h>
33 #endif
34 #include <search.h>
35 #include <errno.h>
36 #include <linux/compiler.h>     /* for BUG_ON */
37
38 DECLARE_GLOBAL_DATA_PTR;
39
40 env_t *env_ptr;
41 static char env_buf[CONFIG_ENV_SIZE];
42
43 char *env_name_spec = "EEPROM";
44 int env_eeprom_bus = -1;
45
46 static int eeprom_bus_read(unsigned dev_addr, unsigned offset,
47                            uchar *buffer, unsigned cnt)
48 {
49         int rcode;
50 #if defined(CONFIG_I2C_ENV_EEPROM_BUS)
51         int old_bus = i2c_get_bus_num();
52
53         if (gd->flags & GD_FLG_RELOC) {
54                 if (env_eeprom_bus == -1) {
55                         I2C_MUX_DEVICE *dev = NULL;
56                         dev = i2c_mux_ident_muxstring(
57                                 (uchar *)CONFIG_I2C_ENV_EEPROM_BUS);
58                         if (dev != NULL)
59                                 env_eeprom_bus = dev->busid;
60                         else
61                                 printf("error adding env eeprom bus.\n");
62                 }
63                 if (old_bus != env_eeprom_bus) {
64                         i2c_set_bus_num(env_eeprom_bus);
65                         old_bus = env_eeprom_bus;
66                 }
67         } else {
68                 rcode = i2c_mux_ident_muxstring_f(
69                                 (uchar *)CONFIG_I2C_ENV_EEPROM_BUS);
70         }
71 #endif
72
73         rcode = eeprom_read(dev_addr, offset, buffer, cnt);
74
75 #if defined(CONFIG_I2C_ENV_EEPROM_BUS)
76         if (old_bus != env_eeprom_bus)
77                 i2c_set_bus_num(old_bus);
78 #endif
79         return rcode;
80 }
81
82 static int eeprom_bus_write(unsigned dev_addr, unsigned offset,
83                             uchar *buffer, unsigned cnt)
84 {
85         int rcode;
86 #if defined(CONFIG_I2C_ENV_EEPROM_BUS)
87         int old_bus = i2c_get_bus_num();
88
89         rcode = i2c_mux_ident_muxstring_f((uchar *)CONFIG_I2C_ENV_EEPROM_BUS);
90 #endif
91         rcode = eeprom_write(dev_addr, offset, buffer, cnt);
92 #if defined(CONFIG_I2C_ENV_EEPROM_BUS)
93         i2c_set_bus_num(old_bus);
94 #endif
95         return rcode;
96 }
97
98 uchar env_get_char_spec(int index)
99 {
100         uchar c;
101         unsigned int off = CONFIG_ENV_OFFSET;
102
103 #ifdef CONFIG_ENV_OFFSET_REDUND
104         if (gd->env_valid == 2)
105                 off = CONFIG_ENV_OFFSET_REDUND;
106 #endif
107         eeprom_bus_read(CONFIG_SYS_DEF_EEPROM_ADDR,
108                         off + index + offsetof(env_t, data), &c, 1);
109
110         return c;
111 }
112
113 void env_relocate_spec(void)
114 {
115         char *buf = env_buf;
116         unsigned int off = CONFIG_ENV_OFFSET;
117
118 #ifdef CONFIG_ENV_OFFSET_REDUND
119         if (gd->env_valid == 2)
120                 off = CONFIG_ENV_OFFSET_REDUND;
121 #endif
122         eeprom_bus_read(CONFIG_SYS_DEF_EEPROM_ADDR,
123                         off, (uchar *)buf, CONFIG_ENV_SIZE);
124
125         env_import(buf, 1);
126 }
127
128 int saveenv(void)
129 {
130         env_t   *env_new = (env_t *)env_buf;
131         ssize_t len;
132         char    *res;
133         int     rc;
134         unsigned int off        = CONFIG_ENV_OFFSET;
135 #ifdef CONFIG_ENV_OFFSET_REDUND
136         unsigned int off_red    = CONFIG_ENV_OFFSET_REDUND;
137         char flag_obsolete      = OBSOLETE_FLAG;
138 #endif
139
140         BUG_ON(env_ptr != NULL);
141
142         res = (char *)env_new->data;
143         len = hexport_r(&env_htab, '\0', 0, &res, ENV_SIZE, 0, NULL);
144         if (len < 0) {
145                 error("Cannot export environment: errno = %d\n", errno);
146                 return 1;
147         }
148         env_new->crc = crc32(0, env_new->data, ENV_SIZE);
149
150 #ifdef CONFIG_ENV_OFFSET_REDUND
151         if (gd->env_valid == 1) {
152                 off     = CONFIG_ENV_OFFSET_REDUND;
153                 off_red = CONFIG_ENV_OFFSET;
154         }
155
156         env_new->flags = ACTIVE_FLAG;
157 #endif
158
159         rc = eeprom_bus_write(CONFIG_SYS_DEF_EEPROM_ADDR,
160                               off, (uchar *)env_new, CONFIG_ENV_SIZE);
161
162 #ifdef CONFIG_ENV_OFFSET_REDUND
163         if (rc == 0) {
164                 eeprom_bus_write(CONFIG_SYS_DEF_EEPROM_ADDR,
165                                  off_red + offsetof(env_t, flags),
166                                  (uchar *)&flag_obsolete, 1);
167
168                 if (gd->env_valid == 1)
169                         gd->env_valid = 2;
170                 else
171                         gd->env_valid = 1;
172         }
173 #endif
174         return rc;
175 }
176
177 /*
178  * Initialize Environment use
179  *
180  * We are still running from ROM, so data use is limited.
181  * Use a (moderately small) buffer on the stack
182  */
183 #ifdef CONFIG_ENV_OFFSET_REDUND
184 int env_init(void)
185 {
186         ulong len, crc[2], crc_tmp;
187         unsigned int off, off_env[2];
188         uchar buf[64], flags[2];
189         int i, crc_ok[2] = {0, 0};
190
191         eeprom_init();  /* prepare for EEPROM read/write */
192
193         off_env[0] = CONFIG_ENV_OFFSET;
194         off_env[1] = CONFIG_ENV_OFFSET_REDUND;
195
196         for (i = 0; i < 2; i++) {
197                 /* read CRC */
198                 eeprom_bus_read(CONFIG_SYS_DEF_EEPROM_ADDR,
199                                 off_env[i] + offsetof(env_t, crc),
200                                 (uchar *)&crc[i], sizeof(ulong));
201                 /* read FLAGS */
202                 eeprom_bus_read(CONFIG_SYS_DEF_EEPROM_ADDR,
203                                 off_env[i] + offsetof(env_t, flags),
204                                 (uchar *)&flags[i], sizeof(uchar));
205
206                 crc_tmp = 0;
207                 len = ENV_SIZE;
208                 off = off_env[i] + offsetof(env_t, data);
209                 while (len > 0) {
210                         int n = (len > sizeof(buf)) ? sizeof(buf) : len;
211
212                         eeprom_bus_read(CONFIG_SYS_DEF_EEPROM_ADDR, off,
213                                         buf, n);
214
215                         crc_tmp = crc32(crc_tmp, buf, n);
216                         len -= n;
217                         off += n;
218                 }
219
220                 if (crc_tmp == crc[i])
221                         crc_ok[i] = 1;
222         }
223
224         if (!crc_ok[0] && !crc_ok[1]) {
225                 gd->env_addr    = 0;
226                 gd->env_valid   = 0;
227
228                 return 0;
229         } else if (crc_ok[0] && !crc_ok[1]) {
230                 gd->env_valid = 1;
231         } else if (!crc_ok[0] && crc_ok[1]) {
232                 gd->env_valid = 2;
233         } else {
234                 /* both ok - check serial */
235                 if (flags[0] == ACTIVE_FLAG && flags[1] == OBSOLETE_FLAG)
236                         gd->env_valid = 1;
237                 else if (flags[0] == OBSOLETE_FLAG && flags[1] == ACTIVE_FLAG)
238                         gd->env_valid = 2;
239                 else if (flags[0] == 0xFF && flags[1] == 0)
240                         gd->env_valid = 2;
241                 else if (flags[1] == 0xFF && flags[0] == 0)
242                         gd->env_valid = 1;
243                 else /* flags are equal - almost impossible */
244                         gd->env_valid = 1;
245         }
246
247         if (gd->env_valid == 2)
248                 gd->env_addr = off_env[1] + offsetof(env_t, data);
249         else if (gd->env_valid == 1)
250                 gd->env_addr = off_env[0] + offsetof(env_t, data);
251
252         return 0;
253 }
254 #else
255 int env_init(void)
256 {
257         ulong crc, len, new;
258         unsigned off;
259         uchar buf[64];
260
261         eeprom_init();  /* prepare for EEPROM read/write */
262
263         /* read old CRC */
264         eeprom_bus_read(CONFIG_SYS_DEF_EEPROM_ADDR,
265                         CONFIG_ENV_OFFSET + offsetof(env_t, crc),
266                         (uchar *)&crc, sizeof(ulong));
267
268         new = 0;
269         len = ENV_SIZE;
270         off = offsetof(env_t, data);
271
272         while (len > 0) {
273                 int n = (len > sizeof(buf)) ? sizeof(buf) : len;
274
275                 eeprom_bus_read(CONFIG_SYS_DEF_EEPROM_ADDR,
276                                 CONFIG_ENV_OFFSET + off, buf, n);
277                 new = crc32(new, buf, n);
278                 len -= n;
279                 off += n;
280         }
281
282         if (crc == new) {
283                 gd->env_addr    = offsetof(env_t, data);
284                 gd->env_valid   = 1;
285         } else {
286                 gd->env_addr    = 0;
287                 gd->env_valid   = 0;
288         }
289
290         return 0;
291 }
292 #endif