Re: [PATCH] Implements new features for updating existing device tree nodes.

[David Gibson <david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org>]

On Fri, Oct 15, 2010 at 08:35:56PM -0600, Grant Likely wrote:
> Hi John.
> 
> On Fri, Oct 15, 2010 at 7:07 PM, John Bonesio <bones-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org> wrote:
> > This is interesting when the /include/ "<filename>" feature is used. This way
> > we can create base device tree source files for a family of systems and modify
> > the device tree for a specific system.
> >
> > The current sytem allows an existing node to be extended with new properties
> > and subnodes.
> >
> > The new features allow an existing node to be replaced completely by the new
> > properties and subnodes. The new features also allow an existing node to be
> > deleted.
> >
> > This patch does not yet provide a way to remove properties.
> >
> > - John
> 
> Also need s-o-b line, and anything that doesn't belong as part of the
> commit message, such as '- John', needs to be below the '---' line so
> that git will ignore it.
> 
> The patch looks pretty good, but I cannot comment fully until the
> keyword handling works when deeper in the tree (see below).

[snip]
> > +       struct property *prop;
> > +       struct node *child, *parent;
> > +
> > +       while (node->proplist) {
> > +               /* Pop the property off the list */
> > +               prop = node->proplist;
> > +               node->proplist = prop->next;
> > +               prop->next = NULL;
> > +
> > +               free(prop);
> > +       }
> 
> It would be useful to have a 'pop_property()' macro so this could be
> simplified to:
> 
> 	while (prop = pop_child_node(&node->proplist))
> 		free(prop);
> 
> But then on the other hand, most of the list management is open coded
> in dtc. It would be nice to use the list_head macros like used in the
> kernel, but that is probably work for another day. (if it is even worth
> the effort).

I had a look into this at one point.  The way we build up the tree in
a kinda-sorta functional programming like way in dts parsing actually
makes using the list.h form kind of hard.  At least without a fancier
allocator (maybe I should bite the bullet and do a talloc conversion).

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson