On Thu, 2023-03-09 at 09:12 -0600, Rob Herring wrote:
> On Wed, Mar 8, 2023 at 3:17 AM Qun-Wei Lin <qun-wei.lin@xxxxxxxxxxxx>
> wrote:
> >
> > The overlay fragment is a special case where some properties are
> > not
> > present in the overlay source file, but in the base file.
> >
> > example:
> > +-----------------------------+--------------------+
> > > base.dts | overlay.dts |
> >
> > +-----------------------------+--------------------+
> > > /dts-v1/; | /dts-v1/; |
> > > | /plugin/; |
> > > /{ | |
> > > parent: test { | &parent { |
> > > #address-cells = <1>; | child@0 { |
> > > #size-cells = <0>; | reg = <0x0>; |
> > > }; | }; |
> > > }; | }; |
> >
> > +-----------------------------+--------------------+
> >
> > It will cause the following false alarms when compiling the overlay
> > dts.
> >
> > 1. /fragment@0/__overlay__: Character '_' not recommended in node
> > name
> > 2. /fragment@0/__overlay__: Relying on default #address-cells value
> > 3. /fragment@0/__overlay__: Relying on default #size-cells value
> > 4. /fragment@0/__overlay__:reg: property has invalid length (4
> > bytes)
> > (#address-cells == 2, #size-cells == 1)
> >
> > This workaround will fix them by skip checking for node named
> > __overlay__.
> >
> > Signed-off-by: Qun-Wei Lin <qun-wei.lin@xxxxxxxxxxxx>
> > ---
> > V1 -> V2:
> > - Add is_overlay_node() helper
> > - Skip anything starting with "__" in
> > check_node_name_chars_strict()
> >
> > checks.c | 18 ++++++++++++++++++
> > 1 file changed, 18 insertions(+)
>
> Reviewed-by: Rob Herring <robh@xxxxxxxxxx>
>
> Though I do wonder if as a matter of policy on overlay structure, if
> we should require an overlay to have the parent node with
> #address-cells/#size-cells. In the end that would be duplicated data,
> but without it there's no way to parse and validate reg/ranges in an
> unapplied overlay. That's just one example issue in being able to
> validate overlays.
>
> Rob
Hi Rob,
Thank you for your review.
I think I've found another problem:
+-------------------------+----------------+
| base.dts | overlay.dts |
+-------------------------+----------------+
| /dts-v1/; | /dts-v1/; |
| /{ | /plugin/; |
| #address-cells = <1>; | |
| #size-cells = <0>; | &test { |
| test: example@0 { | reg = <0x1>; |
| reg = <0x0>; | }; |
| }; | |
| }; | |
+-------------------------+----------------+
The following error message is printed when compiling:
Warning (reg_format): /fragment@0/__overlay__:reg: property has invalid
length (4 bytes) (#address-cells == 2, #size-cells == 1)
Warning (unit_address_vs_reg): /fragment@0/__overlay__: node has a reg
or ranges property, but no unit name
Warning (avoid_default_addr_size): /fragment@0/__overlay__: Relying on
default #address-cells value
Warning (avoid_default_addr_size): /fragment@0/__overlay__: Relying on
default #size-cells value
We can't get the #address-cells/#size-cells of the parent of the
example node in the overlay structure.
Do you think we should change it to is_overlay_node(node) instead of
is_overlay_node(node->parent)?
Or we just need to skip checking for node names starting with "__" in
check_node_name_chars_strict()?
Qun-Wei
