U-Boot Davinci Bootcount Manager

U-Boot implements a boot count scheme that can be used to detect multiple failed attempts to boot Linux. On Davinci (TI AM 335x) the bootcount is stored in the RTC SCRATCH2 register. However there's no way to read or write this register from userspace. This tool provides a means to read and write the bootcount value.

Usage

If invoked without any args, bootcount will read and print the current value to stdout. When passing the -r flag, it will reset the bootcount value

~ # bootcount
42
~ # bootcount -r     # <-- prints nothing to stdout, exit code 0 means success
~ # bootcount
0
~ #

Building

Assuming you're doing a cross-build from x86 host to ARM target:

./autogen.sh
./configure --host=arm-linux-gnueabihf --prefix=/usr
make
make install DESTDIR=$LOCATION_OF_CHROOT

Further Reading

• http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
• http://git.ti.com/ti-u-boot/ti-u-boot/blobs/master/drivers/bootcount/bootcount_davinci.c