[RFC][PATCH 15/30] powerpc/85xx: Rework P1022DS device tree

[Kumar Gala]

On Nov 10, 2011, at 11:30 AM, Tabi Timur-B04825 wrote:

> On Thu, Nov 10, 2011 at 10:13 AM, Kumar Gala <galak at kernel.crashing.org> wrote:
>> 
>>  arch/powerpc/boot/dts/fsl/p1022si-post.dtsi |  235 +++++++++++++++
>>  arch/powerpc/boot/dts/fsl/p1022si-pre.dtsi  |   68 +++++
>>  arch/powerpc/boot/dts/p1022ds.dts           |  431 +--------------------------
>>  3 files changed, 318 insertions(+), 416 deletions(-)
>>  create mode 100644 arch/powerpc/boot/dts/fsl/p1022si-post.dtsi
>>  create mode 100644 arch/powerpc/boot/dts/fsl/p1022si-pre.dtsi
> 
> I understand the value of removing duplication of DTS contents, so
> that we don't copy-paste the same nodes over and over again, but now
> that you've added pre- and post- dtsi files, I wonder if you're not
> jumping out of the frying pan and into the flame.  It seems that the
> DTS files are more fragile than ever, and it's more difficult now to
> figure out which files go where.

I hope that is not true, as the template is the same.

BOARD.dts:

include "fsl/SOCsi-pre.dtsi"

…

include "fsl/SOCsi-post.dtsi"

[ some boards may do more complicated things like we do on MPC8572DS to deal with 32-bit vs 36-bit addr maps, or CAMP use examples ]

All BOARD dts's should follow this pattern given the knowledge of which SoC you are utilizing.  For a board port, you should NEVER have to touch anything in the 'fsl/' directory.  That assumes, we've done a good job with the .dts struct in general.  From time to time I'm sure we'll find some pattern or IP block we need to fix.

> Another concern I have is whether this will force all Pxxxx boards to
> have the same CCSR address.  I don't think so, because I didn't see
> it, but I just want to make sure.


Nope, we can have as many boards for the same SoC w/different address maps and share the same SOC.dtsi files

- k