<div dir="ltr"><div dir="ltr"><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, May 17, 2021 at 10:06 AM Christian MAUDERER <<a href="mailto:christian.mauderer@embedded-brains.de">christian.mauderer@embedded-brains.de</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hello Joel,<br>
<br>
Am 17.05.21 um 14:04 schrieb Joel Sherrill:<br>
> <br>
> <br>
> On Mon, May 17, 2021, 2:35 AM Christian Mauderer <br>
> <<a href="mailto:christian.mauderer@embedded-brains.de" target="_blank">christian.mauderer@embedded-brains.de</a> <br>
> <mailto:<a href="mailto:christian.mauderer@embedded-brains.de" target="_blank">christian.mauderer@embedded-brains.de</a>>> wrote:<br>
> <br>
> The -@ option adds symbols that are used when applying an overlay. RTEMS<br>
> doesn't support overlays or re-parsing of device trees. So the symbols<br>
> only increase the size of the binary.<br>
> <br>
> The same is true for the padding. It would be useful if the device tree<br>
> is changed during run time which is not supported in RTEMS.<br>
> <br>
> Update #4180<br>
> ---<br>
> user/bsps/arm/imxrt.rst | 2 +-<br>
> 1 file changed, 1 insertion(+), 1 deletion(-)<br>
> <br>
> diff --git a/user/bsps/arm/imxrt.rst b/user/bsps/arm/imxrt.rst<br>
> index 1bce6d7..c60b51d 100644<br>
> --- a/user/bsps/arm/imxrt.rst<br>
> +++ b/user/bsps/arm/imxrt.rst<br>
> @@ -118,7 +118,7 @@ with your FDT source names)::<br>
> sh> arm-rtems6-cpp -P -x assembler-with-cpp \<br>
> -I ${PREFIX}/arm-rtems6/imxrt1052/lib/include \<br>
> -include "YOUR.dts" /dev/null | \<br>
> - dtc -@ -O dtb -o "YOUR.dtb" -b 0 -p 1024<br>
> + dtc -O dtb -o "YOUR.dtb" -b 0 -p 64<br>
> sh> rtems-bin2c -C -N imxrt_dtb "YOUR.dtb" "YOUR.c"<br>
> <br>
> Make sure that your new c file is compiled and linked into the<br>
> application.<br>
> <br>
> <br>
> C should be capitalized.<br>
<br>
I'll create an extra commit for that because it's an unrelated change.<br>
<br>
> <br>
> Do you think the command should be explained in the docs like you did in <br>
> the comment?<br>
<br>
From my point of view that is not necessary. I don't see a use case of <br>
the -@ or a bigger padding in the near or even not so near future. <br>
Therefore I don't think it's useful to describe options that are _not_ <br>
used for this BSP.<br>
<br>
<br>
I start to think that we sooner or later will have to add some general <br>
device-tree information to our manual. But I'm not sure yet what and <br>
where. Basically stuff like:<br>
<br>
- What is a device tree. What are the file endings dts and dtb.<br>
- What is a good source for a device tree (most of the time FreeBSD in <br>
our case).<br></blockquote><div><br></div><div>Vivado or the Xilinux github site for the Xilinx BSPs.</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
- How to handle it with U-Boot.<br>
- How to apply overlays with U-Boot.<br>
- How to replace it with a device tree that is compiled into the <br>
application and why it will infect the code with GPL in most cases.<br>
<br>
I think we already start to duplicate some of that stuff in the BSP <br>
documentation. Do you have a suggestion where we could put such a chapter?<br></blockquote><div><br></div><div>It seems like a general topic for the BSPs and Device Drivers</div><div>manual but you want to make a cross manual reference to it. </div><div>And try to cover a lot in there from a general sense so the BSP</div><div>specific sections can say "we use U-Boot with this one detail</div><div>specific to this board" </div><div><br></div><div>Maybe viewing it from a consumer and producer viewpoint is</div><div>helpful. The BSP tends to consume it and that process needs </div><div>to go in the BSP guide. But some details may be BSP specific</div><div>and that needs to be in the BSP specific area. Try to cover as</div><div>much in the general BSP guide as possible.</div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<br>
Best regards<br>
<br>
Christian<br>
<br>
> <br>
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