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author | Michael Opdenacker <michael.opdenacker@bootlin.com> | 2022-03-02 18:56:02 +0300 |
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committer | Heiko Schocher <hs@denx.de> | 2022-03-23 09:27:38 +0300 |
commit | fc1383ae2b5ca69e51bee68e4047589a5ee7b386 (patch) | |
tree | 131b94ca8a39c5bb58b2b0f34e0ba4654d4df8e2 /doc/README.bootcount | |
parent | e3c2042ae7d188e00e48d984e373a2de505d8b77 (diff) | |
download | u-boot-fc1383ae2b5ca69e51bee68e4047589a5ee7b386.tar.xz |
bootcount: clarify documentation
- Grammar fixes
- Clarify explanations
Signed-off-by: Michael Opdenacker <michael.opdenacker@bootlin.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
Diffstat (limited to 'doc/README.bootcount')
-rw-r--r-- | doc/README.bootcount | 34 |
1 files changed, 18 insertions, 16 deletions
diff --git a/doc/README.bootcount b/doc/README.bootcount index b1c22905c6..f6c5f82f98 100644 --- a/doc/README.bootcount +++ b/doc/README.bootcount @@ -3,14 +3,16 @@ Boot Count Limit ================ +This is enabled by CONFIG_BOOTCOUNT_LIMIT. + This allows to detect multiple failed attempts to boot Linux. -After a power-on reset, "bootcount" variable will be initialized with 1, and +After a power-on reset, the "bootcount" variable will be initialized to 1, and each reboot will increment the value by 1. If, after a reboot, the new value of "bootcount" exceeds the value of "bootlimit", then instead of the standard boot action (executing the contents of -"bootcmd") an alternate boot action will be performed, and the contents of +"bootcmd"), an alternate boot action will be performed, and the contents of "altbootcmd" will be executed. If the variable "bootlimit" is not defined in the environment, the Boot Count @@ -18,18 +20,18 @@ Limit feature is disabled. If it is enabled, but "altbootcmd" is not defined, then U-Boot will drop into interactive mode and remain there. It is the responsibility of some application code (typically a Linux -application) to reset the variable "bootcount", thus allowing for more boot -cycles. +application) to reset the variable "bootcount" to 0 when the system booted +successfully, thus allowing for more boot cycles. -BOOTCOUNT_EXT -------------- +CONFIG_BOOTCOUNT_EXT +-------------------- This adds support for maintaining boot count in a file on an EXT filesystem. -The file to use is define by: +The file to use is defined by: -SYS_BOOTCOUNT_EXT_INTERFACE -SYS_BOOTCOUNT_EXT_DEVPART -SYS_BOOTCOUNT_EXT_NAME +CONFIG_SYS_BOOTCOUNT_EXT_INTERFACE +CONFIG_SYS_BOOTCOUNT_EXT_DEVPART +CONFIG_SYS_BOOTCOUNT_EXT_NAME The format of the file is: @@ -42,10 +44,10 @@ u8 bootcount u8 upgrade_available ==== ================= -To prevent unattended usage of "altbootcmd" the "upgrade_available" variable is +To prevent unattended usage of "altbootcmd", the "upgrade_available" variable is used. -If "upgrade_available" is 0, "bootcount" is not saved, if "upgrade_available" is -1 "bootcount" is save. -So the Userspace Application must set the "upgrade_available" and "bootcount" -variables to 0, if a boot was successfully. -This also prevents writes on all reboots. +If "upgrade_available" is 0, "bootcount" is not saved. +If "upgrade_available" is 1, "bootcount" is saved. +So a userspace application should take care of setting the "upgrade_available" +and "bootcount" variables to 0, if the system boots successfully. +This also avoids writing the "bootcount" information on all reboots. |