| Simon Glass | 47f3652 | 2024-10-14 16:32:10 -0600 | [diff] [blame] | 1 | .. SPDX-License-Identifier: GPL-2.0+ |
| 2 | |
| 3 | cbcmos |
| 4 | ====== |
| 5 | |
| 6 | Synopis |
| 7 | ------- |
| 8 | |
| 9 | :: |
| 10 | |
| 11 | cbcmos check [<dev>] |
| 12 | cbcmos update [<dev>] |
| 13 | |
| 14 | |
| 15 | Description |
| 16 | ----------- |
| 17 | |
| 18 | This checks or updates the CMOS-RAM checksum value against the CMOS-RAM |
| 19 | contents. It is used with coreboot, which provides information about where to |
| 20 | find the checksum and what part of the CMOS RAM it covers. |
| 21 | |
| 22 | If `<dev>` is provided then the named real-time clock (RTC) device is used. |
| 23 | Otherwise the default RTC is used. |
| 24 | |
| 25 | Example |
| 26 | ------- |
| 27 | |
| 28 | This shows checking and updating a checksum across bytes 38 and 39 of the |
| 29 | CMOS RAM:: |
| 30 | |
| 31 | => rtc read 38 2 |
| 32 | 00000038: 71 00 q. |
| 33 | => cbc check |
| 34 | => rtc write 38 66 |
| 35 | => rtc read 38 2 |
| 36 | 00000038: 66 00 f. |
| 37 | => cbc check |
| 38 | Checksum 7100 error: calculated 6600 |
| 39 | => cbc update |
| 40 | Checksum 6600 written |
| 41 | => cbc check |
| 42 | => |
| Simon Glass | 3434420 | 2024-10-14 16:32:11 -0600 | [diff] [blame] | 43 | |
| 44 | See also :ref:`cedit_cb_load` which shows an example that includes the |
| 45 | configuration editor. |