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

[Ryan Eatmon <reatmon@ti.com>]

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?

>>
>> Right now this new DTB is only available on linux-next and has not 
>> made it into any released kernels.
>>
>>
> 

-- 
Ryan Eatmon                reatmon@ti.com
-----------------------------------------
Texas Instruments, Inc.  -  LCPD  -  MGTS