include/hw/nvram/chrp_nvram.h

   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