Specifications

This variable will be automatically created if it does not exist, and it will be updated at each reset of
the processor. After a power-on reset, it will be initialized with 1, and each reboot will increment the
value by 1.
bootlimit:
If this variable exists, its contents are taken as the maximum number of reboot cycles allowed.
altbootcmd:
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 altbootcmd will be executed.
If the variable bootlimit is not defined in the environment, the Boot Count 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.
At the moment, the Boot Count Limit feature is available only for MPC8xx, MPC82xx and MPC5200
Power Architecture® processors.
ubootBootcountAccess.c: C-source: bootcount access through /proc file system•
6. Embedded Linux Configuration
6.1. Download and Unpack the Linux Kernel Sources♦
6.2. Kernel Configuration and Compilation♦
6.3. Installation♦
•
6. Embedded Linux Configuration
6.1. Download and Unpack the Linux Kernel Sources
You can download the Linux Kernel Sources from our anonymous git server at http://git.denx.de/. To
checkout the module for the first time, proceed as follows:
bash$ cd /opt/eldk/usr/src
bash$ git clone git://git.denx.de/linux-denx.git linux-denx
bash$ cd linux-denx
bash$ git checkout -b duts remotes/origin/m28
Branch duts set up to track remote branch m28 from origin.
Switched to a new branch 'duts'
bash$
6.2. Kernel Configuration and Compilation
The m28 board is fully supported by DENX Software Engineering. This means that you will always be able to
build a working default configuration with just minimal interaction.
Please be aware that you will need the "arm" cross development tools for the following steps. Make sure that
the directory which contains the binaries of your ELDK are in your PATH.
To be sure that no intermediate results of previous builds are left in your Linux kernel source tree you can
clean it up as follows:
bash$ make mrproper
6. Embedded Linux Configuration 85