| .. SPDX-License-Identifier: GPL-2.0+ |
| |
| cbcmos |
| ====== |
| |
| Synopis |
| ------- |
| |
| :: |
| |
| cbcmos check [<dev>] |
| cbcmos update [<dev>] |
| |
| |
| Description |
| ----------- |
| |
| This checks or updates the CMOS-RAM checksum value against the CMOS-RAM |
| contents. It is used with coreboot, which provides information about where to |
| find the checksum and what part of the CMOS RAM it covers. |
| |
| If `<dev>` is provided then the named real-time clock (RTC) device is used. |
| Otherwise the default RTC is used. |
| |
| Example |
| ------- |
| |
| This shows checking and updating a checksum across bytes 38 and 39 of the |
| CMOS RAM:: |
| |
| => rtc read 38 2 |
| 00000038: 71 00 q. |
| => cbc check |
| => rtc write 38 66 |
| => rtc read 38 2 |
| 00000038: 66 00 f. |
| => cbc check |
| Checksum 7100 error: calculated 6600 |
| => cbc update |
| Checksum 6600 written |
| => cbc check |
| => |