of: move of_get_cpu_node implementation to DT core library

This patch moves the generalized implementation of of_get_cpu_node from
PowerPC to DT core library, thereby adding support for retrieving cpu
node for a given logical cpu index on any architecture.

The CPU subsystem can now use this function to assign of_node in the
cpu device while registering CPUs.

It is recommended to use these helper function only in pre-SMP/early
initialisation stages to retrieve CPU device node pointers in logical
ordering. Once the cpu devices are registered, it can be retrieved easily
from cpu device of_node which avoids unnecessary parsing and matching.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Grant Likely <grant.likely@linaro.org>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
Signed-off-by: Dan Trifan <jimsth@gmail.com>
dt: introduce for_each_available_child_of_node, of_get_next_available_child

Macro for_each_child_of_node() makes it easy to iterate over all of the
children for a given device tree node, including those nodes that are
marked as unavailable (i.e. status = "disabled").

Introduce for_each_available_child_of_node(), which is like
for_each_child_of_node(), but it automatically skips unavailable nodes.
This also requires the introduction of helper function
of_get_next_available_child(), which returns the next available child
node.

Change-Id: I811ff03886518989373a69240c35a9d7de23a2c6
Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Dan Trifan <jimsth@gmail.com>
dt: introduce of_get_child_by_name to get child node by name

This patch introduces of_get_child_by_name function to get a child node
by its name in a given parent node.

Without this patch each driver code has to iterate the parent and do
a string compare, However having of_get_child_by_name libary function would
avoid code duplication, errors and is more convenient.

Change-Id: Id33184bb9f4b494e7121d7dde719d29206dcad52
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@st.com>
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Dan Trifan <jimsth@gmail.com>