Simon Glass | e25c34d | 2024-10-14 16:32:10 -0600 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0+ |
| 2 | /* |
| 3 | * Support for booting from coreboot |
| 4 | * |
| 5 | * Copyright 2021 Google LLC |
| 6 | */ |
| 7 | |
| 8 | #define LOG_CATEGORY UCLASS_RTC |
| 9 | |
| 10 | #include <command.h> |
| 11 | #include <dm.h> |
| 12 | #include <rtc.h> |
| 13 | #include <asm/cb_sysinfo.h> |
| 14 | #include <asm/global_data.h> |
| 15 | |
| 16 | DECLARE_GLOBAL_DATA_PTR; |
| 17 | |
| 18 | const struct sysinfo_t *get_table(void) |
| 19 | { |
| 20 | if (!gd->arch.coreboot_table) { |
| 21 | printf("No coreboot sysinfo table found\n"); |
| 22 | return NULL; |
| 23 | } |
| 24 | |
| 25 | return &lib_sysinfo; |
| 26 | } |
| 27 | |
| 28 | static int calc_sum(struct udevice *dev, uint start_bit, uint bit_count) |
| 29 | { |
| 30 | uint start_byte = start_bit / 8; |
| 31 | uint byte_count = bit_count / 8; |
| 32 | int ret, i; |
| 33 | uint sum; |
| 34 | |
| 35 | log_debug("Calc sum from %x: %x bytes\n", start_byte, byte_count); |
| 36 | sum = 0; |
| 37 | for (i = 0; i < bit_count / 8; i++) { |
| 38 | ret = rtc_read8(dev, start_bit / 8 + i); |
| 39 | if (ret < 0) |
| 40 | return ret; |
| 41 | sum += ret; |
| 42 | } |
| 43 | |
| 44 | return (sum & 0xff) << 8 | (sum & 0xff00) >> 8; |
| 45 | } |
| 46 | |
| 47 | /** |
| 48 | * prep_cbcmos() - Prepare for a CMOS-RAM command |
| 49 | * |
| 50 | * @tab: coreboot table |
| 51 | * @devnum: RTC device name to use, or NULL for the first one |
| 52 | * @dep: Returns RTC device on success |
| 53 | * Return: calculated checksum for CMOS RAM or -ve on error |
| 54 | */ |
| 55 | static int prep_cbcmos(const struct sysinfo_t *tab, const char *devname, |
| 56 | struct udevice **devp) |
| 57 | { |
| 58 | struct udevice *dev; |
| 59 | int ret; |
| 60 | |
| 61 | if (!tab) |
| 62 | return CMD_RET_FAILURE; |
| 63 | if (devname) |
| 64 | ret = uclass_get_device_by_name(UCLASS_RTC, devname, &dev); |
| 65 | else |
| 66 | ret = uclass_first_device_err(UCLASS_RTC, &dev); |
| 67 | if (ret) { |
| 68 | printf("Failed to get RTC device: %dE\n", ret); |
| 69 | return ret; |
| 70 | } |
| 71 | |
| 72 | ret = calc_sum(dev, tab->cmos_range_start, |
| 73 | tab->cmos_range_end + 1 - tab->cmos_range_start); |
| 74 | if (ret < 0) { |
| 75 | printf("Failed to read RTC device: %dE\n", ret); |
| 76 | return ret; |
| 77 | } |
| 78 | *devp = dev; |
| 79 | |
| 80 | return ret; |
| 81 | } |
| 82 | |
| 83 | static int do_cbcmos_check(struct cmd_tbl *cmdtp, int flag, int argc, |
| 84 | char *const argv[]) |
| 85 | { |
| 86 | const struct sysinfo_t *tab = get_table(); |
| 87 | struct udevice *dev; |
| 88 | u16 cur, sum; |
| 89 | int ret; |
| 90 | |
| 91 | ret = prep_cbcmos(tab, argv[1], &dev); |
| 92 | if (ret < 0) |
| 93 | return CMD_RET_FAILURE; |
| 94 | sum = ret; |
| 95 | |
| 96 | ret = rtc_read16(dev, tab->cmos_checksum_location / 8, &cur); |
| 97 | if (ret < 0) { |
| 98 | printf("Failed to read RTC device: %dE\n", ret); |
| 99 | return CMD_RET_FAILURE; |
| 100 | } |
| 101 | if (sum != cur) { |
| 102 | printf("Checksum %04x error: calculated %04x\n", cur, sum); |
| 103 | return CMD_RET_FAILURE; |
| 104 | } |
| 105 | |
| 106 | return 0; |
| 107 | } |
| 108 | |
| 109 | static int do_cbcmos_update(struct cmd_tbl *cmdtp, int flag, int argc, |
| 110 | char *const argv[]) |
| 111 | { |
| 112 | const struct sysinfo_t *tab = get_table(); |
| 113 | struct udevice *dev; |
| 114 | u16 sum; |
| 115 | int ret; |
| 116 | |
| 117 | ret = prep_cbcmos(tab, argv[1], &dev); |
| 118 | if (ret < 0) |
| 119 | return CMD_RET_FAILURE; |
| 120 | sum = ret; |
| 121 | |
| 122 | ret = rtc_write16(dev, tab->cmos_checksum_location / 8, sum); |
| 123 | if (ret < 0) { |
| 124 | printf("Failed to read RTC device: %dE\n", ret); |
| 125 | return CMD_RET_FAILURE; |
| 126 | } |
| 127 | printf("Checksum %04x written\n", sum); |
| 128 | |
| 129 | return 0; |
| 130 | } |
| 131 | |
| 132 | U_BOOT_LONGHELP(cbcmos, |
| 133 | "check - check CMOS RAM\n" |
| 134 | "cbcmos update - Update CMOS-RAM checksum"; |
| 135 | ); |
| 136 | |
| 137 | U_BOOT_CMD_WITH_SUBCMDS(cbcmos, "coreboot CMOS RAM", cbcmos_help_text, |
| 138 | U_BOOT_SUBCMD_MKENT(check, 2, 1, do_cbcmos_check), |
| 139 | U_BOOT_SUBCMD_MKENT(update, 2, 1, do_cbcmos_update)); |