[Buildroot] [PATCH 2/7] linux: add option to rely on a bootloader-provided DTB

[Yann E. MORIN <yann.morin.1998@free.fr>]

Thomas, All,

On 2015-01-01 22:24 +0100, Thomas Petazzoni spake thusly:
> On Thu,  1 Jan 2015 21:23:48 +0100, Yann E. MORIN wrote:
> > On some platforms (e.g. the Raspberry Pi), the DTB is already bundled
> > with the bootloader, and installed with it. On some other platforms, the
> > DTB might even be stored on the device itself (which is the ultimate
> > goal of the DTB).
> > 
> > So far, when we build a kernel with DT support, we forcibly want a to
> > also build the DTB blob, which goes against the situations described
> > above.
> > 
> > Add a new option in the DT choice, to specify the DTB will be provided
> > by the bootloader or the device itself.
> > 
> > This also means we must be a little bit more selective when we check the
> > validity of the DTS name at build time.
> > 
> > Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
> 
> I don't really see the point of this. If you don't want to build a DTB,
> then don't tell Buildroot that you want to build a DTB, and that's it.
> Why would we want such a patch?
> 
> Enabling CONFIG_OF should be done by the platform defconfig. It really
> is tied to how the platform is supported in the Linux kernel, and is
> not something that Buildroot should touch IMO.

Fact is, the prompt reads:

    [*] Device tree support

So, I take that as "build a kernel with support for the device tree",
not as "build a DTB".

But Now I think of it, this patch is doing two things:

  - enable USE_OF when that option is enabled,

  - add support for bootloader- or board-provided DTB.

Maybe that should be split up in two, then?

Or do you still want that option to mean "build a DTB" ?

Regards,
Yann E. MORIN.

-- 
.-----------------.--------------------.------------------.--------------------.
|  Yann E. MORIN  | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
| +33 662 376 056 | Software  Designer | \ / CAMPAIGN     |  ___               |
| +33 223 225 172 `------------.-------:  X  AGAINST      |  \e/  There is no  |
| http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL    |   v   conspiracy.  |
'------------------------------^-------^------------------^--------------------'