The DT overlay code will need to manipulate nodes and properties while
already holding the devicetree lock, or on nodes that are not yet
attached to the tree, but the current helper functions don't allow that.
Extract the core behaviour from the accessors and create the following
unlocked variants.

The unlocked variants require either the lock to already be held or for
the nodes to be detached from the tree. Changes to live nodes will not
get updated in sysfs, so the caller must arrange for housekeeping to
take place after dropping the lock.

The new functions are: __of_add_property(), __of_remove_property(),
__of_update_property(), __of_attach_node() and __of_detach_node().
Signed-off-by: NPantelis Antoniou <pantelis.antoniou@konsulko.com>
[Remove unnecessary diff hunks and rewrite commit text]
Signed-off-by: NGrant Likely <grant.likely@linaro.org>

Introduce helper functions for working with the live DT tree,
all of them related to dynamically adding/removing nodes and
properties.

__of_prop_dup() copies a property dynamically
__of_node_alloc() creates an empty node

Bug fix about prop->len == 0 by Ionut Nicu <ioan.nicu.ext@nsn.com>
Signed-off-by: NPantelis Antoniou <pantelis.antoniou@konsulko.com>
[glikely: Added unittest for of_copy_property and dropped fine-grained allocations]
[glikely: removed name, type and phandle arguments from __of_node_alloc]
Signed-off-by: NGrant Likely <grant.likely@linaro.org>

Split the dynamic device tree code into a separate file to make it
really clear what features CONFIF_OF_DYNAMIC add to the kernel. Without
CONFIG_OF_DYNAMIC only properties can be changed, and notifiers do not
get sent. Enabling it turns on reference counting, notifiers and the
ability to add and remove nodes.

v2: Moved of_node_release() into dynamic.c
Signed-off-by: NGrant Likely <grant.likely@linaro.org>
Signed-off-by: NPantelis Antoniou <pantelis.antoniou@konsulko.com>
Cc: Rob Herring <robh+dt@kernel.org>

We're overloading usage of of_aliases_mutex for sysfs changes,
so rename to something that is more generic.
Signed-off-by: NPantelis Antoniou <pantelis.antoniou@konsulko.com>
Signed-off-by: NGrant Likely <grant.likely@linaro.org>

In some situations, userspace may want to resolve a
device by function and logical number (ie, "serial0")
rather than by the base address or full device path. Being
able to resolve a device by alias frees userspace from the
burden of otherwise having to maintain a mapping between
device addresses and their logical assignments on each
platform when multiple instances of the same hardware block
are present in the system.

Although the uevent device attribute contains devicetree
compatible information and the full device path, the uevent
does not list the alises that may have been defined for the
device.
Signed-off-by: NStepan Moskovchenko <stepanm@codeaurora.org>
[grant.likely: Removed OF_ALIAS_N field; I don't think it's needed]
[grant.likely: Added #ifndef _LINUX_OF_PRIVATE_H wrapper]
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>