Re: [PATCH 1/2] conf: machine: add BeagleBone Green Eco to KERNEL_DEVICETREE

[Miguel Gazquez <miguel.gazquez@bootlin.com>]

Le 21/07/2025 à 18:49, Ryan Eatmon a écrit :
> 
> 
> On 7/18/2025 10:48 AM, Miguel Gazquez wrote:
>>
>>
>> Le 18/07/2025 à 16:35, Ryan Eatmon a écrit :
>>>
>>>
>>> On 7/18/2025 4:54 AM, Miguel Gazquez wrote:
>>>>
>>>>
>>>> Le 17/07/2025 à 20:01, Ryan Eatmon a écrit :
>>>>>
>>>>>
>>>>> On 7/17/2025 12:55 PM, Miguel Gazquez wrote:
>>>>>>
>>>>>>
>>>>>> Le 15/07/2025 à 15:52, Ryan Eatmon a écrit :
>>>>>>>
>>>>>>>
>>>>>>> On 7/15/2025 6:34 AM, Miguel Gazquez wrote:
>>>>>>>> Add am335x-bonegreen-eco devicetree to KERNEL_DEVICETREE in 
>>>>>>>> ti33x.inc
>>>>>>>>
>>>>>>>> Signed-off-by: Miguel Gazquez <miguel.gazquez@bootlin.com>
>>>>>>>> ---
>>>>>>>>   meta-ti-bsp/conf/machine/include/ti33x.inc | 1 +
>>>>>>>>   1 file changed, 1 insertion(+)
>>>>>>>>
>>>>>>>> diff --git a/meta-ti-bsp/conf/machine/include/ti33x.inc b/meta- 
>>>>>>>> ti- bsp/ conf/machine/include/ti33x.inc
>>>>>>>> index 
>>>>>>>> 7e9eb48c52737e74750565e639956334162432e2..0a0730eae104371d65548588b3333839857a3a50 100644
>>>>>>>> --- a/meta-ti-bsp/conf/machine/include/ti33x.inc
>>>>>>>> +++ b/meta-ti-bsp/conf/machine/include/ti33x.inc
>>>>>>>> @@ -28,6 +28,7 @@ KERNEL_DEVICETREE = " \
>>>>>>>>       ti/omap/am335x-boneblack.dtb \
>>>>>>>>       ti/omap/am335x-boneblue.dtb \
>>>>>>>>       ti/omap/am335x-bonegreen-wireless.dtb \
>>>>>>>> +    ti/omap/am335x-bonegreen-eco.dtb \
>>>>>>>>       ti/omap/am335x-bonegreen.dtb \
>>>>>>>>       ti/omap/am335x-chiliboard.dtb \
>>>>>>>>       ti/omap/am335x-cm-t335.dtb \
>>>>>>>
>>>>>>> NAK.  As has been mentioned several times on this list, we do not 
>>>>>>> update KERNEL_DEVICETREE directly.  As we support multiple kernel 
>>>>>>> versions with each branch, we cannot have a single 
>>>>>>> KERNEL_DEVICETREE that works for all kernel versions.
>>>>>>>
>>>>>>> To that end we setup the KERNEL_DEVICETREE_PREFIX variable that 
>>>>>>> will pattern match and change the value for KERNEL_DEVICETREE 
>>>>>>> based on the available matching DTBs in the given kernel.  The 
>>>>>>> only kernel version that uses KERNEL_DEVICETREE is the mainline 
>>>>>>> (aka latest stable) kernel. And the value for this variable is 
>>>>>>> automatically updated to include all of the available DTBs in the 
>>>>>>> mainline kernel at the time we update the recipe to that version.
>>>>>>>
>>>>>>> As the KERNEL_DEVICETREE_PREFIX already has an entry that will 
>>>>>>> pick up this new DTB when it is available, this change is not 
>>>>>>> needed.
>>>>>>
>>>>>> When building for the am335x_evm without this patch, the 
>>>>>> devicetree for the beaglebone green eco is not included in the wic 
>>>>>> image, so the kernel can't boot.
>>>>>>
>>>>>> As you said, in the linux-ti-staging recipe, KERNEL_DEVICETREE 
>>>>>> does contains the dtb for the bbg eco.
>>>>>>
>>>>>> But core-image-minimal (which create the wic image) uses the value 
>>>>>> of KERNEL_DEVICETREE from ti33x.inc, and not the one generated 
>>>>>> from KERNEL_DEVICETREE_PREFIX, so it doesn't contains the 
>>>>>> devicetree for the bbge. This can be checked with `bitbake-getvar 
>>>>>> -r core-image- minimal KERNEL_DEVICETREE`.
>>>>>>
>>>>>> It probably works for others boards because, apart from the bbge, 
>>>>>> there isn't any board supported in ti-linux-6.12.y but not in 
>>>>>> mainline.
>>>>>>
>>>>>> If we can't modify KERNEL_DEVICETREE here, what should I do to 
>>>>>> include the devicetree into the final image ?
>>>>>
>>>>> Are you talking about a poky build with a poky kernel?  Or a poky 
>>>>> build with the TI kernel?
>>>>>
>>>>> If you are talking about the TI kernel, then the mainline recipe 
>>>>> does not point to a kernel that has this DTB.  So are you trying to 
>>>>> use the mainline recipe but change the SRCREV to point a commit 
>>>>> that does contain this new DTB file?
>>>>
>>>> I'm using a poky build with the TI kernel, which by default uses the 
>>>> branch "ti-linux-6.12.y", with the SRCREV equal to 
>>>> "78e6abff322081d53c5a685d927476086c9b2846" (on the scarthgap branch, 
>>>> I forgot to mention it). And on this branch there is the commit 
>>>> "ab7f0d695e9a3268deb760dcd0fa58812a614cd8" adding the devicetree for 
>>>> the beaglebone green eco.
>>>
>>> If you are on scarthgap and using linux-ti-staging_6.12, then you 
>>> should just need to point to the appropriate SRCREV for the patch you 
>>> want and build am335x-evm.  That should build the deploy the dtb you 
>>> are looking for.  It is in our nightly builds.
>>>
>>> In fact, we just promoted our CICD and I can see the file of interest 
>>> in our build.  So you should not even need to change the SRCREV if 
>>> you use the latest scarthgap.
>>
>> Indeed, the dtb is build and deployed in the kernel workdir. However, 
>> it's not present in the final wic image.
>> I checked the image from your CICD [0], and the dtb doesn't seem to be 
>> there either.
>>
>> IIUC, the list of dtbs deployed into the final image depends on 
>> KERNEL_DEVICETREE, and it seems like the recipe building the wic file 
>> uses the value hardcoded in ti33x.inc.
> 
> 
> Good point.  We don't do any automated nightly testing with the wic 
> image at the moment.  Most of our testing is done over the UART.
> 
> I sent two patches to the meta-ti mailing list and on scarthgap-wip that 
> correctly handle setting KERNEL_DEVICETREE for the Poky and Arago images 
> so that the .wic files have the correct files in the boot partition.
> 
> We will work on getting this patch through our CICD, but in the meantime 
> you can point to the scarthgap-wip branch for your testing.  I'll send 
> reply to this thread once this is on on scarthgap proper.

I tested using the scarthgap-wip branch, and it works perfectly, I can 
boot the BeagleBone Green Eco with the am335x_evm image without any issues.

Thanks !

> 
>>
>> [0] https://software-dl.ti.com/cicd-report/linux/index.html? 
>> section=snapshot&platform=am335x&snapshot=cicd.scarthgap.202507051251
>>>>>>>
>>>>>>> Right now this new DTB is only available on linux-next and has 
>>>>>>> not made it into any released kernels.
>>>>>>>
>>
>> Please let me know what you think,
>>
>> Thanks,
>>
> 

-- 
Miguel Gazquez, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com