xref: /openbmc/qemu/include/hw/nvram/chrp_nvram.h (revision 09a274d8)
1 /*
2  * Common Hardware Reference Platform NVRAM functions.
3  *
4  * This code is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published
6  * by the Free Software Foundation; either version 2 of the License,
7  * or (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, see <http://www.gnu.org/licenses/>.
16  */
17 
18 #ifndef CHRP_NVRAM_H
19 #define CHRP_NVRAM_H
20 
21 /* OpenBIOS NVRAM partition */
22 typedef struct {
23     uint8_t signature;
24     uint8_t checksum;
25     uint16_t len;       /* Big endian, length divided by 16 */
26     char name[12];
27 } ChrpNvramPartHdr;
28 
29 #define CHRP_NVPART_SYSTEM 0x70
30 #define CHRP_NVPART_FREE 0x7f
31 
32 static inline void
33 chrp_nvram_finish_partition(ChrpNvramPartHdr *header, uint32_t size)
34 {
35     unsigned int i, sum;
36     uint8_t *tmpptr;
37 
38     /* Length divided by 16 */
39     header->len = cpu_to_be16(size >> 4);
40 
41     /* Checksum */
42     tmpptr = (uint8_t *)header;
43     sum = *tmpptr;
44     for (i = 0; i < 14; i++) {
45         sum += tmpptr[2 + i];
46         sum = (sum + ((sum & 0xff00) >> 8)) & 0xff;
47     }
48     header->checksum = sum & 0xff;
49 }
50 
51 int chrp_nvram_create_system_partition(uint8_t *data, int min_len);
52 int chrp_nvram_create_free_partition(uint8_t *data, int len);
53 
54 #endif
55