blob: 3f333f721170624c44c09918b52676df3e838894 [file] [log] [blame]
Stefan Reinauer9aea04a2012-03-30 12:01:06 -07001/*
2 * This file is part of the coreboot project.
3 *
4 * Copyright (C) 2011 The ChromiumOS Authors. All rights reserved.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; version 2 of the License.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 */
19
20#include <types.h>
21#include <string.h>
22#include <console/console.h>
23#include <pc80/mc146818rtc.h>
24#include <cpu/x86/car.h>
25#include "chromeos.h"
26
27#define VBNV_BLOCK_SIZE 16 /* Size of NV storage block in bytes */
28
29/* Constants for NV storage. We use this rather than structs and
30 * bitfields so the data format is consistent across platforms and
31 * compilers.
32 */
33#define HEADER_OFFSET 0
34#define HEADER_MASK 0xC0
35#define HEADER_SIGNATURE 0x40
36#define HEADER_FIRMWARE_SETTINGS_RESET 0x20
37#define HEADER_KERNEL_SETTINGS_RESET 0x10
38
39#define BOOT_OFFSET 1
40#define BOOT_DEBUG_RESET_MODE 0x80
Bill Richardson0a405ba2012-06-26 16:33:45 -070041#define BOOT_DISABLE_DEV_REQUEST 0x40
42#define BOOT_OPROM_NEEDED 0x20
Stefan Reinauer9aea04a2012-03-30 12:01:06 -070043#define BOOT_TRY_B_COUNT_MASK 0x0F
44
45#define RECOVERY_OFFSET 2
46#define LOCALIZATION_OFFSET 3
47
48#define DEV_FLAGS_OFFSET 4
49#define DEV_BOOT_USB_MASK 0x01
Bill Richardson0a405ba2012-06-26 16:33:45 -070050#define DEV_BOOT_SIGNED_ONLY_MASK 0x02
Stefan Reinauer9aea04a2012-03-30 12:01:06 -070051
52#define KERNEL_FIELD_OFFSET 11
53#define CRC_OFFSET 15
54
55static int vbnv_initialized CAR_GLOBAL;
56uint8_t vbnv[CONFIG_VBNV_SIZE] CAR_GLOBAL;
57
58/* Return CRC-8 of the data, using x^8 + x^2 + x + 1 polynomial. A
59 * table-based algorithm would be faster, but for only 15 bytes isn't
60 * worth the code size.
61 */
62
63static uint8_t crc8(const uint8_t * data, int len)
64{
65 unsigned crc = 0;
66 int i, j;
67
68 for (j = len; j; j--, data++) {
69 crc ^= (*data << 8);
70 for (i = 8; i; i--) {
71 if (crc & 0x8000)
72 crc ^= (0x1070 << 3);
73 crc <<= 1;
74 }
75 }
76
77 return (uint8_t) (crc >> 8);
78}
79
80static void vbnv_setup(void)
81{
82 int i;
83
84 for (i = 0; i < CONFIG_VBNV_SIZE; i++)
85 vbnv[i] = cmos_read(CONFIG_VBNV_OFFSET + 14 + i);
86
87 /* Check data for consistency */
88 if ((HEADER_SIGNATURE != (vbnv[HEADER_OFFSET] & HEADER_MASK))
89 || (crc8(vbnv, CRC_OFFSET) != vbnv[CRC_OFFSET])) {
90
91 /* Data is inconsistent (bad CRC or header),
92 * so reset to defaults
93 */
94 memset(vbnv, 0, VBNV_BLOCK_SIZE);
95 vbnv[HEADER_OFFSET] =
96 (HEADER_SIGNATURE | HEADER_FIRMWARE_SETTINGS_RESET |
97 HEADER_KERNEL_SETTINGS_RESET);
98 }
99 vbnv_initialized = 1;
100}
101
102int get_recovery_mode_from_vbnv(void)
103{
104 if (!vbnv_initialized)
105 vbnv_setup();
106 return vbnv[RECOVERY_OFFSET];
107}
Bill Richardson0a405ba2012-06-26 16:33:45 -0700108
109int vboot_wants_oprom(void)
110{
111 if (!vbnv_initialized)
112 vbnv_setup();
113
114 /* FIXME(crosbug.com/p/8789). The following commented-out line does the
115 * right thing, assuming that vboot has requested the option ROM and
116 * rebooted if it finds that it's needed but not loaded. At the moment,
117 * it doesn't yet do that, so we must always say we want it. */
118
119 /* return (vbnv[BOOT_OFFSET] & BOOT_OPROM_NEEDED) ? 1 : 0; */
120 return 1;
121}