reading files in /proc/device-tree

[Segher Boessenkool]

> 	I am looking for a way to be able to read data files for nodes under
> /proc/device-tree, from userspace.

> 	Basically, I have a requirement to be able to find out System RAM
> addressable ranges from userspace. I was told it could be obtained by 
> reading
> the memory nodes's reg property from under /proc/device-tree.

Just read the file.

segher at victim:~ $ xxd -g4 /proc/device-tree/memory/reg

00000000 00000000 00000000 80000000         ; 2GB at 0
00000001 00000000 00000000 80000000         ; 2GB at 4GB

(comments are mine, data is faked).

There might be more memory nodes; read them all and take
the union.

Also, the format of the entries is dependent on the
#address-cells and #sized-cells properties.

Hope this helps,


Segher

(oh, and _do_ read the OF specs: 
<http://playground.sun.com/1275/home.html>).