diff options
Diffstat (limited to 'src/vendorcode/google/chromeos/vbnv.c')
-rw-r--r-- | src/vendorcode/google/chromeos/vbnv.c | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/src/vendorcode/google/chromeos/vbnv.c b/src/vendorcode/google/chromeos/vbnv.c new file mode 100644 index 0000000000..2129461fc1 --- /dev/null +++ b/src/vendorcode/google/chromeos/vbnv.c @@ -0,0 +1,109 @@ +/* + * This file is part of the coreboot project. + * + * Copyright (C) 2011 The ChromiumOS Authors. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include <types.h> +#include <string.h> +#include <console/console.h> +#include <pc80/mc146818rtc.h> +#include <cpu/x86/car.h> +#include "chromeos.h" + +#define VBNV_BLOCK_SIZE 16 /* Size of NV storage block in bytes */ + +/* Constants for NV storage. We use this rather than structs and + * bitfields so the data format is consistent across platforms and + * compilers. + */ +#define HEADER_OFFSET 0 +#define HEADER_MASK 0xC0 +#define HEADER_SIGNATURE 0x40 +#define HEADER_FIRMWARE_SETTINGS_RESET 0x20 +#define HEADER_KERNEL_SETTINGS_RESET 0x10 + +#define BOOT_OFFSET 1 +#define BOOT_DEBUG_RESET_MODE 0x80 +#define BOOT_TRY_B_COUNT_MASK 0x0F + +#define RECOVERY_OFFSET 2 +#define LOCALIZATION_OFFSET 3 + +#define DEV_FLAGS_OFFSET 4 +#define DEV_BOOT_USB_MASK 0x01 + +#define FIRMWARE_FLAGS_OFFSET 5 +#define FIRMWARE_TEST_ERR_FUNC_MASK 0x38 +#define FIRMWARE_TEST_ERR_FUNC_SHIFT 3 +#define FIRMWARE_TEST_ERR_NUM_MASK 0x07 + +#define KERNEL_FIELD_OFFSET 11 +#define CRC_OFFSET 15 + +static int vbnv_initialized CAR_GLOBAL; +uint8_t vbnv[CONFIG_VBNV_SIZE] CAR_GLOBAL; + +/* Return CRC-8 of the data, using x^8 + x^2 + x + 1 polynomial. A + * table-based algorithm would be faster, but for only 15 bytes isn't + * worth the code size. + */ + +static uint8_t crc8(const uint8_t * data, int len) +{ + unsigned crc = 0; + int i, j; + + for (j = len; j; j--, data++) { + crc ^= (*data << 8); + for (i = 8; i; i--) { + if (crc & 0x8000) + crc ^= (0x1070 << 3); + crc <<= 1; + } + } + + return (uint8_t) (crc >> 8); +} + +static void vbnv_setup(void) +{ + int i; + + for (i = 0; i < CONFIG_VBNV_SIZE; i++) + vbnv[i] = cmos_read(CONFIG_VBNV_OFFSET + 14 + i); + + /* Check data for consistency */ + if ((HEADER_SIGNATURE != (vbnv[HEADER_OFFSET] & HEADER_MASK)) + || (crc8(vbnv, CRC_OFFSET) != vbnv[CRC_OFFSET])) { + + /* Data is inconsistent (bad CRC or header), + * so reset to defaults + */ + memset(vbnv, 0, VBNV_BLOCK_SIZE); + vbnv[HEADER_OFFSET] = + (HEADER_SIGNATURE | HEADER_FIRMWARE_SETTINGS_RESET | + HEADER_KERNEL_SETTINGS_RESET); + } + vbnv_initialized = 1; +} + +int get_recovery_mode_from_vbnv(void) +{ + if (!vbnv_initialized) + vbnv_setup(); + return vbnv[RECOVERY_OFFSET]; +} |