[U-Boot] [PATCH v2 8/9] dm: core: Add ofnode to represent device tree nodes

[Masahiro Yamada <yamada.masahiro@socionext.com>]

Hi Simon,


2017-05-20 11:29 GMT+09:00 Simon Glass <sjg@chromium.org>:
> Hi Masahiro,
>
> On 16 May 2017 at 04:35, Masahiro Yamada <yamada.masahiro@socionext.com> wrote:
>>
>> Hi Simon,
>>
>>
>> 2017-05-02 0:18 GMT+09:00 Simon Glass <sjg@chromium.org>:
>> > With live tree we need a struct device_node * to reference a node. With
>> > the existing flat tree, we need an int offset. We need to unify these into
>> > a single value which can represent both.
>> >
>> > Add an ofnode union for this and adjust existing code to move to this.
>> >
>> > Signed-off-by: Simon Glass <sjg@chromium.org>
>> > ---
>> >
>> > Changes in v2: None
>> >
>> >  drivers/core/device.c |   2 +-
>> >  drivers/core/root.c   |   2 +-
>> >  include/dm.h          |   1 +
>> >  include/dm/device.h   |  14 +++++--
>> >  include/dm/ofnode.h   | 100 ++++++++++++++++++++++++++++++++++++++++++++++++++
>> >  5 files changed, 113 insertions(+), 6 deletions(-)
>> >  create mode 100644 include/dm/ofnode.h
>
>> When you add a new header, please make sure it is self-contained.
>>
>> You use bool for offset_toofnode() and ofnode_equal().
>> So you need to include <stdbool.h> from this header.
>>
>> (or, use "int" for the return type.)
>
> I'm wondering about this problem:
>
> In general we want to minimise the size of headers included by U-Boot.
> For something like ofnode which is used by several header files we end
> up including it many times, once per header.

It is no problem if the header body is surrounded by an include guard.

With include guards, each header is
_parsed_ only once even if _included_ multiple times.


> With dm.h we avoid this since the header is only included ones (and in
> the correct order).

Generally, we should not rely on a specific include order.

Even if we compel drivers to include dm.h,
each of dm/{device.h, platdata.h, uclass.h} should be self-contained.


We usually sort includes alphabetically,
but technically it should work in any order.
It would be possible if each header is self-contained.



> What is the best solution to this?


-- 
Best Regards
Masahiro Yamada