1 /* SPDX-License-Identifier: GPL-2.0-only */
2
3 #include <commonlib/bsd/ipchksum.h>
4 #include <console/console.h>
5 #include <pc80/mc146818rtc.h>
6 #include <stdint.h>
7 #include <elog.h>
8
9 /*
10 * We need a region in CMOS to store the boot counter.
11 *
12 * This can either be declared as part of the option
13 * table or statically defined in the board config.
14 */
15 #if CONFIG(USE_OPTION_TABLE)
16 # include "option_table.h"
17 # define BOOT_COUNT_CMOS_OFFSET (CMOS_VSTART_boot_count_offset >> 3)
18 #else
19 # if (CONFIG_ELOG_BOOT_COUNT_CMOS_OFFSET != 0)
20 # define BOOT_COUNT_CMOS_OFFSET CONFIG_ELOG_BOOT_COUNT_CMOS_OFFSET
21 # else
22 # error "Must configure CONFIG_ELOG_BOOT_COUNT_CMOS_OFFSET"
23 # endif
24 #endif
25
26 #define BOOT_COUNT_SIGNATURE 0x4342 /* 'BC' */
27
28 struct boot_count {
29 u16 signature;
30 u32 count;
31 u16 checksum;
32 } __packed;
33
34 /* Read and validate boot count structure from CMOS */
boot_count_cmos_read(struct boot_count * bc)35 static int boot_count_cmos_read(struct boot_count *bc)
36 {
37 u8 i, *p;
38 u16 csum;
39
40 for (p = (u8 *)bc, i = 0; i < sizeof(*bc); i++, p++)
41 *p = cmos_read(BOOT_COUNT_CMOS_OFFSET + i);
42
43 /* Verify signature */
44 if (bc->signature != BOOT_COUNT_SIGNATURE) {
45 printk(BIOS_DEBUG, "Boot Count invalid signature\n");
46 return -1;
47 }
48
49 /* Verify checksum over signature and counter only */
50 csum = ipchksum(bc, offsetof(struct boot_count, checksum));
51
52 if (csum != bc->checksum) {
53 printk(BIOS_DEBUG, "Boot Count checksum mismatch\n");
54 return -1;
55 }
56
57 return 0;
58 }
59
60 /* Write boot count structure to CMOS */
boot_count_cmos_write(struct boot_count * bc)61 static void boot_count_cmos_write(struct boot_count *bc)
62 {
63 u8 i, *p;
64
65 /* Checksum over signature and counter only */
66 bc->checksum = ipchksum(
67 bc, offsetof(struct boot_count, checksum));
68
69 for (p = (u8 *)bc, i = 0; i < sizeof(*bc); i++, p++)
70 cmos_write(*p, BOOT_COUNT_CMOS_OFFSET + i);
71 }
72
73 /* Increment boot count and return the new value */
boot_count_increment(void)74 u32 boot_count_increment(void)
75 {
76 struct boot_count bc;
77
78 /* Read and increment boot count */
79 if (boot_count_cmos_read(&bc) < 0) {
80 /* Structure invalid, re-initialize */
81 bc.signature = BOOT_COUNT_SIGNATURE;
82 bc.count = 0;
83 }
84
85 /* Increment boot counter */
86 bc.count++;
87
88 /* Write the new count to CMOS */
89 boot_count_cmos_write(&bc);
90
91 printk(BIOS_DEBUG, "Boot Count incremented to %u\n", bc.count);
92 return bc.count;
93 }
94
95 /* Return the current boot count */
boot_count_read(void)96 u32 boot_count_read(void)
97 {
98 struct boot_count bc;
99
100 if (boot_count_cmos_read(&bc) < 0)
101 return 0;
102
103 return bc.count;
104 }
105