xref: /openbmc/qemu/hw/nvram/chrp_nvram.c (revision 5b2ecaba)
1 /*
2  * Common Hardware Reference Platform NVRAM helper functions.
3  *
4  * The CHRP NVRAM layout is used by OpenBIOS and SLOF. See CHRP
5  * specification, chapter 8, or the LoPAPR specification for details
6  * about the NVRAM layout.
7  *
8  * This code is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published
10  * by the Free Software Foundation; either version 2 of the License,
11  * or (at your option) any later version.
12  *
13  * This program 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 License
19  * along with this program; if not, see <http://www.gnu.org/licenses/>.
20  */
21 
22 #include "qemu/osdep.h"
23 #include "qemu/cutils.h"
24 #include "hw/hw.h"
25 #include "hw/nvram/chrp_nvram.h"
26 #include "sysemu/sysemu.h"
27 
28 static int chrp_nvram_set_var(uint8_t *nvram, int addr, const char *str)
29 {
30     int len;
31 
32     len = strlen(str) + 1;
33     memcpy(&nvram[addr], str, len);
34 
35     return addr + len;
36 }
37 
38 /**
39  * Create a "system partition", used for the Open Firmware
40  * environment variables.
41  */
42 int chrp_nvram_create_system_partition(uint8_t *data, int min_len)
43 {
44     ChrpNvramPartHdr *part_header;
45     unsigned int i;
46     int end;
47 
48     part_header = (ChrpNvramPartHdr *)data;
49     part_header->signature = CHRP_NVPART_SYSTEM;
50     pstrcpy(part_header->name, sizeof(part_header->name), "system");
51 
52     end = sizeof(ChrpNvramPartHdr);
53     for (i = 0; i < nb_prom_envs; i++) {
54         end = chrp_nvram_set_var(data, end, prom_envs[i]);
55     }
56 
57     /* End marker */
58     data[end++] = '\0';
59 
60     end = (end + 15) & ~15;
61     /* XXX: OpenBIOS is not able to grow up a partition. Leave some space for
62        new variables. */
63     if (end < min_len) {
64         end = min_len;
65     }
66     chrp_nvram_finish_partition(part_header, end);
67 
68     return end;
69 }
70 
71 /**
72  * Create a "free space" partition
73  */
74 int chrp_nvram_create_free_partition(uint8_t *data, int len)
75 {
76     ChrpNvramPartHdr *part_header;
77 
78     part_header = (ChrpNvramPartHdr *)data;
79     part_header->signature = CHRP_NVPART_FREE;
80     pstrcpy(part_header->name, sizeof(part_header->name), "free");
81 
82     chrp_nvram_finish_partition(part_header, len);
83 
84     return len;
85 }
86