Need help on APM for gumstix

Hi,

I am trying to get APM to work on the gumstix. I was able to put it to
sleep, validated by measuring the current (normal ~200mA, sleep ~10mA)
by using command "apm -s". Where the code is downloaded from
http://alumnit.ca/~apenwarr/apmd/ and modified slightly to run on the
gumstix.

I have a switch that sends the wake up signal to the PXA255 and it
seems to be valid since the current jumps back to about 130mA from
10mA. However, there is nothing showing at the serial console. My
guess is that the APM driver was not initialized properly. Just a
note, the current is about 300mA when the unit is booting up from
reset.

My questions:
1. Can anyone point me to the source code or the directory where thing
are set up during boot time? I am new to the Linux kernel and not
familiar with the directory structure.

1.1 Would the code be in u-boot or kernel?

2. BTW, is there documentation on how the kernel source files are
organized? I have the book title "Understanding the Linux Kernel" but
it does not have enough details on page 539.

Any help will be much appreciated.

Regards,
Podi