Passing Ratchet Status to Guest OSes
Ratchet fuse burning status is passed to guest OS via the kernel device tree. There are separate nodes for MB1, MTS, and MB1-BCT at the following location under the /proc interface.
/proc/device-tree/chosen/ratchet-status
Each node has two fields: status and error.
- "error" has the appropriate ratchet error value.
- "status" can have following status strings:
Ratcheting Status | Description |
---|---|
not_tried | Default status. Ratchet check path is skipped. |
skipped_a | Active Boot Chain firmware ratchet matches with HW fuses. |
skipped_b | Inactive Boot Chain firmware ratchet matches with HW fuses. |
updated | Ratchet fuses are successfully updated with SW ratchet value. |
failed | Ratchet fuse update(burning) failed. |
no_option | Ratchet update check skipped as Opt-in fuse is not set by OEM |