[PATCH rtems-docs] bsps/imxrt: Remove superfluous options from dtc

[Christian MAUDERER]

Hello Joel,

Am 17.05.21 um 14:04 schrieb Joel Sherrill:
> 
> 
> On Mon, May 17, 2021, 2:35 AM Christian Mauderer 
> <christian.mauderer at embedded-brains.de 
> <mailto:christian.mauderer at embedded-brains.de>> wrote:
> 
>     The -@ option adds symbols that are used when applying an overlay. RTEMS
>     doesn't support overlays or re-parsing of device trees. So the symbols
>     only increase the size of the binary.
> 
>     The same is true for the padding. It would be useful if the device tree
>     is changed during run time which is not supported in RTEMS.
> 
>     Update #4180
>     ---
>       user/bsps/arm/imxrt.rst | 2 +-
>       1 file changed, 1 insertion(+), 1 deletion(-)
> 
>     diff --git a/user/bsps/arm/imxrt.rst b/user/bsps/arm/imxrt.rst
>     index 1bce6d7..c60b51d 100644
>     --- a/user/bsps/arm/imxrt.rst
>     +++ b/user/bsps/arm/imxrt.rst
>     @@ -118,7 +118,7 @@ with your FDT source names)::
>         sh> arm-rtems6-cpp -P -x assembler-with-cpp \
>                            -I ${PREFIX}/arm-rtems6/imxrt1052/lib/include \
>                            -include "YOUR.dts" /dev/null | \
>     -            dtc -@ -O dtb -o "YOUR.dtb" -b 0 -p 1024
>     +            dtc -O dtb -o "YOUR.dtb" -b 0 -p 64
>         sh> rtems-bin2c -C -N imxrt_dtb "YOUR.dtb" "YOUR.c"
> 
>       Make sure that your new c file is compiled and linked into the
>     application.
> 
> 
> C should be capitalized.

I'll create an extra commit for that because it's an unrelated change.

> 
> Do you think the command should be explained in the docs like you did in 
> the comment?

 From my point of view that is not necessary. I don't see a use case of 
the -@ or a bigger padding in the near or even not so near future. 
Therefore I don't think it's useful to describe options that are _not_ 
used for this BSP.


I start to think that we sooner or later will have to add some general 
device-tree information to our manual. But I'm not sure yet what and 
where. Basically stuff like:

- What is a device tree. What are the file endings dts and dtb.
- What is a good source for a device tree (most of the time FreeBSD in 
our case).
- How to handle it with U-Boot.
- How to apply overlays with U-Boot.
- How to replace it with a device tree that is compiled into the 
application and why it will infect the code with GPL in most cases.

I think we already start to duplicate some of that stuff in the BSP 
documentation. Do you have a suggestion where we could put such a chapter?

Best regards

Christian

> 
>     -- 
>     2.26.2
> 
>     _______________________________________________
>     devel mailing list
>     devel at rtems.org <mailto:devel at rtems.org>
>     http://lists.rtems.org/mailman/listinfo/devel
>     <http://lists.rtems.org/mailman/listinfo/devel>
> 

-- 
--------------------------------------------
embedded brains GmbH
Herr Christian MAUDERER
Dornierstr. 4
82178 Puchheim
Germany
email: christian.mauderer at embedded-brains.de
phone: +49-89-18 94 741 - 18
fax:   +49-89-18 94 741 - 08

Registergericht: Amtsgericht München
Registernummer: HRB 157899
Vertretungsberechtigte Geschäftsführer: Peter Rasmussen, Thomas Dörfler
Unsere Datenschutzerklärung finden Sie hier:
https://embedded-brains.de/datenschutzerklaerung/