tree 51a4d7c45ab129fb1eeb1f1f4261a6d463c7f8bd
parent 91cfaea6ebd8dc30e56ad742c560956556544956
author Andrew Fuller <abf@google.com> 1435101195 -0700
committer Andrew Fuller <abf@google.com> 1435139758 +0000

windcharger: enable wdt before loading kernel

This allows us to recover from many kinds of upgrade issues, including corrupt
kernel images, rootfs problems, and incompatibilities between uboot and the
selected kernel (for example, DVT board 2.6 kernel will panic with current
uboot).

With this patch, a successful boot must go from uboot to linux userland
(/etc/init.d/S01watchdog) within 171 seconds, or the wdt will trigger and the
failsafe counter will increment. It may take up to 171*3 seconds to switch
back to the previous working partition (since we allow 3 failsafe attempts).

This is implemented in uboot variables so that we can manually disable this
during development if necessary.

b/22012423
b/22034225

Change-Id: Id28dd058cebf2ad1addeeaaaae3b6cfb8bb1c380