Quoting Rob Herring (2024-05-15 15:08:47)
> On Wed, May 15, 2024 at 4:15 PM Stephen Boyd <sboyd@xxxxxxxxxx> wrote:
> > diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> > index 389d4ea6bfc1..acecefcfdba7 100644
> > --- a/drivers/of/platform.c
> > +++ b/drivers/of/platform.c
> > @@ -421,6 +421,7 @@ int of_platform_bus_probe(struct device_node *root,
> > if (of_match_node(matches, root)) {
> > rc = of_platform_bus_create(root, matches, NULL, parent, false);
> > } else for_each_child_of_node(root, child) {
> > + of_node_set_flag(root, OF_POPULATED_BUS);
>
> No, the same spot as of_platform_populate has it. I guess this would
> be the same, but no reason to do this in the for_each_child_of_node
> loop...
Ok. I'm not intending to send this patch.
>
> > if (!of_match_node(matches, child))
> > continue;
> > rc = of_platform_bus_create(child, matches, NULL, parent, false);
> >
> >
> > This doesn't work though. I see that prom_init() is called, which
> > constructs a DTB and flattens it to be unflattened by
> > unflatten_device_tree(). The powerpc machine type used by qemu is
> > PLATFORM_PSERIES_LPAR. It looks like it never calls
> > of_platform_bus_probe() from the pseries platform code.
>
> Huh. Maybe pseries doesn't have any platform devices?
Looks like it.
>
> Ideally, we'd still do it in of_platform_default_populate_init(), but
> if you look at the history, you'll see that broke some PPC boards
> (damn initcall ordering).
>
> > What about skipping the OF_POPULATED_BUS check, or skipping the check
> > when the parent is the root node? This is the if condition that's
> > giving the headache.
>
> I don't think we should just remove it, but a root node check seems fine.
>
Alright. I've added a check to see if the root node is the parent to
allow it. That works well enough, so I'll send that in v5.
