[meta-rockchip][PATCH] KERNEL_DEVICETREE: 32-bit re-org

[meta-rockchip][PATCH] KERNEL_DEVICETREE: 32-bit re-org

[Trevor Woerner]

The upstream kernel reorganized the 32-bit arch/arm device-tree directory structure
to separate out the device-trees by manufacturer (similar to the organization
of the arch/arm64 device-trees). Update the references to 32-bit arm
device-trees to match.

Signed-off-by: Trevor Woerner <twoerner@gmail.com>
---
 conf/machine/firefly-rk3288.conf   | 2 +-
 conf/machine/marsboard-rk3066.conf | 2 +-
 conf/machine/radxarock.conf        | 2 +-
 conf/machine/rock2-square.conf     | 2 +-
 conf/machine/tinker-board-s.conf   | 2 +-
 conf/machine/tinker-board.conf     | 2 +-
 6 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/conf/machine/firefly-rk3288.conf b/conf/machine/firefly-rk3288.conf
index 3270bb9f1657..6ff1be822008 100644
--- a/conf/machine/firefly-rk3288.conf
+++ b/conf/machine/firefly-rk3288.conf
@@ -9,5 +9,5 @@
 require conf/machine/include/rk3288.inc
 require conf/machine/include/rockchip-wic.inc
 
-KERNEL_DEVICETREE = "rk3288-firefly.dtb"
+KERNEL_DEVICETREE = "rockchip/rk3288-firefly.dtb"
 UBOOT_MACHINE = "firefly-rk3288_defconfig"
diff --git a/conf/machine/marsboard-rk3066.conf b/conf/machine/marsboard-rk3066.conf
index 52fd256a3445..36945e8e407b 100644
--- a/conf/machine/marsboard-rk3066.conf
+++ b/conf/machine/marsboard-rk3066.conf
@@ -8,4 +8,4 @@
 
 require conf/machine/include/rk3066.inc
 
-KERNEL_DEVICETREE = "rk3066a-marsboard.dtb"
+KERNEL_DEVICETREE = "rockchip/rk3066a-marsboard.dtb"
diff --git a/conf/machine/radxarock.conf b/conf/machine/radxarock.conf
index 42d8848e1d09..6ad8474669d0 100644
--- a/conf/machine/radxarock.conf
+++ b/conf/machine/radxarock.conf
@@ -9,4 +9,4 @@
 
 require conf/machine/include/rk3188.inc
 
-KERNEL_DEVICETREE = "rk3188-radxarock.dtb"
+KERNEL_DEVICETREE = "rockchip/rk3188-radxarock.dtb"
diff --git a/conf/machine/rock2-square.conf b/conf/machine/rock2-square.conf
index 46064eebcc67..9468b9a6b559 100644
--- a/conf/machine/rock2-square.conf
+++ b/conf/machine/rock2-square.conf
@@ -9,7 +9,7 @@
 require conf/machine/include/rk3288.inc
 
 SPL_BINARY = "u-boot-spl-dtb.bin"
-KERNEL_DEVICETREE = "rk3288-rock2-square.dtb"
+KERNEL_DEVICETREE = "rockchip/rk3288-rock2-square.dtb"
 UBOOT_MACHINE = "rock2_defconfig"
 
 # This board doesn't support the combined idbloader, so resort to the older
diff --git a/conf/machine/tinker-board-s.conf b/conf/machine/tinker-board-s.conf
index 870b9bcdf8c7..3a656136c554 100644
--- a/conf/machine/tinker-board-s.conf
+++ b/conf/machine/tinker-board-s.conf
@@ -7,5 +7,5 @@
 
 require conf/machine/include/tinker.inc
 
-KERNEL_DEVICETREE = "rk3288-tinker-s.dtb"
+KERNEL_DEVICETREE = "rockchip/rk3288-tinker-s.dtb"
 UBOOT_MACHINE = "tinker-s-rk3288_defconfig"
diff --git a/conf/machine/tinker-board.conf b/conf/machine/tinker-board.conf
index 8fe5f6305d70..ef1a1c1ac098 100644
--- a/conf/machine/tinker-board.conf
+++ b/conf/machine/tinker-board.conf
@@ -7,5 +7,5 @@
 
 require conf/machine/include/tinker.inc
 
-KERNEL_DEVICETREE = "rk3288-tinker.dtb"
+KERNEL_DEVICETREE = "rockchip/rk3288-tinker.dtb"
 UBOOT_MACHINE = "tinker-rk3288_defconfig"
-- 
2.41.0.327.gaa9166bcc0ba

Re: [yocto] [meta-rockchip][PATCH] KERNEL_DEVICETREE: 32-bit re-org

[Quentin Schulz]

Hi Trevor,

On 10/3/23 06:19, Trevor Woerner via lists.yoctoproject.org wrote:
> The upstream kernel reorganized the 32-bit arch/arm device-tree directory structure
> to separate out the device-trees by manufacturer (similar to the organization
> of the arch/arm64 device-trees). Update the references to 32-bit arm
> device-trees to match.
> 

Does this work with linux-yocto and linux-yocto-dev from master or do we 
need to add some logic to support both (do you want to?).

Cheers,
Quentin

Re: [yocto] [meta-rockchip][PATCH] KERNEL_DEVICETREE: 32-bit re-org

[Trevor Woerner]

On Tue 2023-10-03 @ 12:32:08 PM, Quentin Schulz wrote:
> Hi Trevor,
> 
> On 10/3/23 06:19, Trevor Woerner via lists.yoctoproject.org wrote:
> > The upstream kernel reorganized the 32-bit arch/arm device-tree directory structure
> > to separate out the device-trees by manufacturer (similar to the organization
> > of the arch/arm64 device-trees). Update the references to 32-bit arm
> > device-trees to match.
> > 
> 
> Does this work with linux-yocto and linux-yocto-dev from master or do we
> need to add some logic to support both (do you want to?).

This doesn't work at all. I figured this was an easy one, made the tweak,
submitted it, then added it to my jenkins builder to verify overnight. Woke up
to find the do_image_wic() tasks failed. It's the same layout as the 64-bit
machines but I'll have to dig in to figure out why it didn't work.

As for the linux-yocto vs linux-yocto-dev question I'll take a look. This
happened with linux-yocto, so I would assume it is already the case with
linux-yocto-dev. But if oe-core supports multiple versions of linux-yocto,
that might be the tricky bit and yes, I would look into supporting both for
the time-being until the transition period ends.

Although... any BSP layer supporting 32-bit machines will have similar issues,
so perhaps there's a better way to solve this in oe-core?

Best regards,
	Trevor

Re: [yocto] [meta-rockchip][PATCH] KERNEL_DEVICETREE: 32-bit re-org

[Quentin Schulz]

Hi Trevor,

On 10/3/23 15:38, Trevor Woerner wrote:
> On Tue 2023-10-03 @ 12:32:08 PM, Quentin Schulz wrote:
>> Hi Trevor,
>>
>> On 10/3/23 06:19, Trevor Woerner via lists.yoctoproject.org wrote:
>>> The upstream kernel reorganized the 32-bit arch/arm device-tree directory structure
>>> to separate out the device-trees by manufacturer (similar to the organization
>>> of the arch/arm64 device-trees). Update the references to 32-bit arm
>>> device-trees to match.
>>>
>>
>> Does this work with linux-yocto and linux-yocto-dev from master or do we
>> need to add some logic to support both (do you want to?).
> 
> This doesn't work at all. I figured this was an easy one, made the tweak,
> submitted it, then added it to my jenkins builder to verify overnight. Woke up
> to find the do_image_wic() tasks failed. It's the same layout as the 64-bit
> machines but I'll have to dig in to figure out why it didn't work.
> 
> As for the linux-yocto vs linux-yocto-dev question I'll take a look. This
> happened with linux-yocto, so I would assume it is already the case with
> linux-yocto-dev. But if oe-core supports multiple versions of linux-yocto,
> that might be the tricky bit and yes, I would look into supporting both for
> the time-being until the transition period ends.
> 

This was done in v6.5-rc1 so anything before won't work sadly.

master branch of poky supports 6.1 6.4 and 6.5 for linux-yocto 
(linux-yocto-dev being typically newer than the latest linux-yocto and 
the latest linux-yocto already having the change, I'll omit the change 
for linux-yocto-dev).

For reference, denix on IRC suggested you look at 
https://git.openembedded.org/openembedded-core/commit/?id=04ab57d20009d85eb566e83ae6fe1dcea4db7300 
for what we're trying to do here. But I think this isn't applying to how 
the DTB is found but rather where it's put and this is too late for us.

I think we need to modify get_real_dtb_path_in_kernel in 
meta/classes-recipe/kernel-devicetree.bbclass instead.

We could handle it this way for example to allow a fallback:
"""
get_real_dtb_path_in_kernel:arm () {
	dtb="$1"
	dtb_path="${B}/arch/${ARCH}/boot/dts/$dtb"
         # Handle pre-v6.5 layout for Aarch32/ARM DTB
	if [ ! -e "$dtb_path" ]; then
		dtb_path="${B}/arch/${ARCH}/boot/dts/$(basename "$dtb")"
	fi
	if [ ! -e "$dtb_path" ]; then
		dtb_path="${B}/arch/${ARCH}/boot/$dtb"
	fi
         # Handle pre-v6.5 layout for Aarch32/ARM DTB
	if [ ! -e "$dtb_path" ]; then
		dtb_path="${B}/arch/${ARCH}/boot/$(basename "$dtb")"
	fi

	echo "$dtb_path"
}
"""
(to be determined if "arm" is a valid OVERRIDES, otherwise we need to 
check against "ARCH" bb variable; also not sure about the second 
basename if it's necessary at all).

Then you would just have KERNEL_DEVICETREE done the same way as in this 
patch:
KERNEL_DEVICETREE = "rockchip/rk3066a-marsboard.dtb"

and we wouldn't have to handle it on the recipe level.

Otherwise, we could do the following:
RK_KERNEL_DEVICETREE = "rockchip/rk3066a-marsboard.dtb"
KERNEL_DEVICETREE ?= "${RK_KERNEL_DEVICETREE}"

then have a bbappend for all old-layout recipes:
linux-yocto-rt_6.1.bbappend
linux-yocto-tiny_6.1.bbappend
linux-yocto_6.1.bbappend
linux-yocto-rt_6.4.bbappend
linux-yocto-tiny_6.4.bbappend
linux-yocto_6.4.bbappend

KERNEL_DEVICETREE:arm = "${@' '.join(os.path.basename(dtb) for dtb in 
d.getVar('RK_KERNEL_DEVICETREE').split())}"

or something like that. We probably want to have something a bit more 
precise than just arm to avoid breaking other arm machine conf files 
which do not define RK_KERNEL_DEVICETREE, maybe 
KERNEL_DEVICETREE:rockchip:arm if that is even resolving properly.

> Although... any BSP layer supporting 32-bit machines will have similar issues,
> so perhaps there's a better way to solve this in oe-core?
> 
Adding Bruce in Cc, I hope he doesn't mind being summoned like this. 
Maybe you have an idea on how to handle both the new and old layout for 
ARM/Aarch32 DTB in the kernel for the KERNEL_DEVICETREE variable?

Cheers,
Quentin

Re: [yocto] [meta-rockchip][PATCH] KERNEL_DEVICETREE: 32-bit re-org

[Quentin Schulz]

With Bruce in Cc for real this time :)

On 10/4/23 15:45, Quentin Schulz wrote:
> Hi Trevor,
> 
> On 10/3/23 15:38, Trevor Woerner wrote:
>> On Tue 2023-10-03 @ 12:32:08 PM, Quentin Schulz wrote:
>>> Hi Trevor,
>>>
>>> On 10/3/23 06:19, Trevor Woerner via lists.yoctoproject.org wrote:
>>>> The upstream kernel reorganized the 32-bit arch/arm device-tree 
>>>> directory structure
>>>> to separate out the device-trees by manufacturer (similar to the 
>>>> organization
>>>> of the arch/arm64 device-trees). Update the references to 32-bit arm
>>>> device-trees to match.
>>>>
>>>
>>> Does this work with linux-yocto and linux-yocto-dev from master or do we
>>> need to add some logic to support both (do you want to?).
>>
>> This doesn't work at all. I figured this was an easy one, made the tweak,
>> submitted it, then added it to my jenkins builder to verify overnight. 
>> Woke up
>> to find the do_image_wic() tasks failed. It's the same layout as the 
>> 64-bit
>> machines but I'll have to dig in to figure out why it didn't work.
>>
>> As for the linux-yocto vs linux-yocto-dev question I'll take a look. This
>> happened with linux-yocto, so I would assume it is already the case with
>> linux-yocto-dev. But if oe-core supports multiple versions of 
>> linux-yocto,
>> that might be the tricky bit and yes, I would look into supporting 
>> both for
>> the time-being until the transition period ends.
>>
> 
> This was done in v6.5-rc1 so anything before won't work sadly.
> 
> master branch of poky supports 6.1 6.4 and 6.5 for linux-yocto 
> (linux-yocto-dev being typically newer than the latest linux-yocto and 
> the latest linux-yocto already having the change, I'll omit the change 
> for linux-yocto-dev).
> 
> For reference, denix on IRC suggested you look at 
> https://git.openembedded.org/openembedded-core/commit/?id=04ab57d20009d85eb566e83ae6fe1dcea4db7300 for what we're trying to do here. But I think this isn't applying to how the DTB is found but rather where it's put and this is too late for us.
> 
> I think we need to modify get_real_dtb_path_in_kernel in 
> meta/classes-recipe/kernel-devicetree.bbclass instead.
> 
> We could handle it this way for example to allow a fallback:
> """
> get_real_dtb_path_in_kernel:arm () {
>      dtb="$1"
>      dtb_path="${B}/arch/${ARCH}/boot/dts/$dtb"
>          # Handle pre-v6.5 layout for Aarch32/ARM DTB
>      if [ ! -e "$dtb_path" ]; then
>          dtb_path="${B}/arch/${ARCH}/boot/dts/$(basename "$dtb")"
>      fi
>      if [ ! -e "$dtb_path" ]; then
>          dtb_path="${B}/arch/${ARCH}/boot/$dtb"
>      fi
>          # Handle pre-v6.5 layout for Aarch32/ARM DTB
>      if [ ! -e "$dtb_path" ]; then
>          dtb_path="${B}/arch/${ARCH}/boot/$(basename "$dtb")"
>      fi
> 
>      echo "$dtb_path"
> }
> """
> (to be determined if "arm" is a valid OVERRIDES, otherwise we need to 
> check against "ARCH" bb variable; also not sure about the second 
> basename if it's necessary at all).
> 
> Then you would just have KERNEL_DEVICETREE done the same way as in this 
> patch:
> KERNEL_DEVICETREE = "rockchip/rk3066a-marsboard.dtb"
> 
> and we wouldn't have to handle it on the recipe level.
> 
> Otherwise, we could do the following:
> RK_KERNEL_DEVICETREE = "rockchip/rk3066a-marsboard.dtb"
> KERNEL_DEVICETREE ?= "${RK_KERNEL_DEVICETREE}"
> 
> then have a bbappend for all old-layout recipes:
> linux-yocto-rt_6.1.bbappend
> linux-yocto-tiny_6.1.bbappend
> linux-yocto_6.1.bbappend
> linux-yocto-rt_6.4.bbappend
> linux-yocto-tiny_6.4.bbappend
> linux-yocto_6.4.bbappend
> 
> KERNEL_DEVICETREE:arm = "${@' '.join(os.path.basename(dtb) for dtb in 
> d.getVar('RK_KERNEL_DEVICETREE').split())}"
> 
> or something like that. We probably want to have something a bit more 
> precise than just arm to avoid breaking other arm machine conf files 
> which do not define RK_KERNEL_DEVICETREE, maybe 
> KERNEL_DEVICETREE:rockchip:arm if that is even resolving properly.
> 
>> Although... any BSP layer supporting 32-bit machines will have similar 
>> issues,
>> so perhaps there's a better way to solve this in oe-core?
>>
> Adding Bruce in Cc, I hope he doesn't mind being summoned like this. 
> Maybe you have an idea on how to handle both the new and old layout for 
> ARM/Aarch32 DTB in the kernel for the KERNEL_DEVICETREE variable?
> 
> Cheers,
> Quentin

Re: [yocto] [meta-rockchip][PATCH] KERNEL_DEVICETREE: 32-bit re-org

[Bruce Ashfield]

[-- Attachment #1: Type: text/plain, Size: 5748 bytes --]

On Wed, Oct 4, 2023 at 9:59 AM Quentin Schulz via lists.yoctoproject.org
<quentin.schulz=theobroma-systems.com@lists.yoctoproject.org> wrote:

> Hi Trevor,
>
> On 10/3/23 15:38, Trevor Woerner wrote:
> > On Tue 2023-10-03 @ 12:32:08 PM, Quentin Schulz wrote:
> >> Hi Trevor,
> >>
> >> On 10/3/23 06:19, Trevor Woerner via lists.yoctoproject.org wrote:
> >>> The upstream kernel reorganized the 32-bit arch/arm device-tree
> directory structure
> >>> to separate out the device-trees by manufacturer (similar to the
> organization
> >>> of the arch/arm64 device-trees). Update the references to 32-bit arm
> >>> device-trees to match.
> >>>
> >>
> >> Does this work with linux-yocto and linux-yocto-dev from master or do we
> >> need to add some logic to support both (do you want to?).
> >
> > This doesn't work at all. I figured this was an easy one, made the tweak,
> > submitted it, then added it to my jenkins builder to verify overnight.
> Woke up
> > to find the do_image_wic() tasks failed. It's the same layout as the
> 64-bit
> > machines but I'll have to dig in to figure out why it didn't work.
> >
> > As for the linux-yocto vs linux-yocto-dev question I'll take a look. This
> > happened with linux-yocto, so I would assume it is already the case with
> > linux-yocto-dev. But if oe-core supports multiple versions of
> linux-yocto,
> > that might be the tricky bit and yes, I would look into supporting both
> for
> > the time-being until the transition period ends.
> >
>
> This was done in v6.5-rc1 so anything before won't work sadly.
>
> master branch of poky supports 6.1 6.4 and 6.5 for linux-yocto
> (linux-yocto-dev being typically newer than the latest linux-yocto and
> the latest linux-yocto already having the change, I'll omit the change
> for linux-yocto-dev).
>
> For reference, denix on IRC suggested you look at
>
> https://git.openembedded.org/openembedded-core/commit/?id=04ab57d20009d85eb566e83ae6fe1dcea4db7300
> for what we're trying to do here. But I think this isn't applying to how
> the DTB is found but rather where it's put and this is too late for us.
>
> I think we need to modify get_real_dtb_path_in_kernel in
> meta/classes-recipe/kernel-devicetree.bbclass instead.
>
> We could handle it this way for example to allow a fallback:
> """
> get_real_dtb_path_in_kernel:arm () {
>         dtb="$1"
>         dtb_path="${B}/arch/${ARCH}/boot/dts/$dtb"
>          # Handle pre-v6.5 layout for Aarch32/ARM DTB
>         if [ ! -e "$dtb_path" ]; then
>                 dtb_path="${B}/arch/${ARCH}/boot/dts/$(basename "$dtb")"
>         fi
>         if [ ! -e "$dtb_path" ]; then
>                 dtb_path="${B}/arch/${ARCH}/boot/$dtb"
>         fi
>          # Handle pre-v6.5 layout for Aarch32/ARM DTB
>         if [ ! -e "$dtb_path" ]; then
>                 dtb_path="${B}/arch/${ARCH}/boot/$(basename "$dtb")"
>         fi
>
>         echo "$dtb_path"
> }
> """
> (to be determined if "arm" is a valid OVERRIDES, otherwise we need to
> check against "ARCH" bb variable; also not sure about the second
> basename if it's necessary at all).
>
> Then you would just have KERNEL_DEVICETREE done the same way as in this
> patch:
> KERNEL_DEVICETREE = "rockchip/rk3066a-marsboard.dtb"
>
> and we wouldn't have to handle it on the recipe level.
>
> Otherwise, we could do the following:
> RK_KERNEL_DEVICETREE = "rockchip/rk3066a-marsboard.dtb"
> KERNEL_DEVICETREE ?= "${RK_KERNEL_DEVICETREE}"
>
> then have a bbappend for all old-layout recipes:
> linux-yocto-rt_6.1.bbappend
> linux-yocto-tiny_6.1.bbappend
> linux-yocto_6.1.bbappend
> linux-yocto-rt_6.4.bbappend
> linux-yocto-tiny_6.4.bbappend
> linux-yocto_6.4.bbappend
>
> KERNEL_DEVICETREE:arm = "${@' '.join(os.path.basename(dtb) for dtb in
> d.getVar('RK_KERNEL_DEVICETREE').split())}"
>
> or something like that. We probably want to have something a bit more
> precise than just arm to avoid breaking other arm machine conf files
> which do not define RK_KERNEL_DEVICETREE, maybe
> KERNEL_DEVICETREE:rockchip:arm if that is even resolving properly.
>
> > Although... any BSP layer supporting 32-bit machines will have similar
> issues,
> > so perhaps there's a better way to solve this in oe-core?
> >
> Adding Bruce in Cc, I hope he doesn't mind being summoned like this.
> Maybe you have an idea on how to handle both the new and old layout for
> ARM/Aarch32 DTB in the kernel for the KERNEL_DEVICETREE variable?
>

My last run in with this may have been before some of the most recent
device tree handling patches, and/or I may have been doing it wrong.

But my solution was to simply override the variable in a kernel version
specific bbappend, and not do it in the conf files.

But of course, if that variable is being interpreted by a different class in
the global namespace, then the kernel bbappend approach isn't going
to work anymore.

I've stayed away from utilities or searching, etc, rather just a way for the
configuration to specify directly what to find, as anything that searches
ends up being fragile.

Bruce


>
> Cheers,
> Quentin
>
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Re: [yocto] [meta-rockchip][PATCH] KERNEL_DEVICETREE: 32-bit re-org

[Trevor Woerner]

On Wed 2023-10-04 @ 10:39:14 AM, Bruce Ashfield wrote:
> On Wed, Oct 4, 2023 at 9:59 AM Quentin Schulz via lists.yoctoproject.org
> <quentin.schulz=theobroma-systems.com@lists.yoctoproject.org> wrote:
> 
> > Hi Trevor,
> >
> > On 10/3/23 15:38, Trevor Woerner wrote:
> > > On Tue 2023-10-03 @ 12:32:08 PM, Quentin Schulz wrote:
> > >> Hi Trevor,
> > >>
> > >> On 10/3/23 06:19, Trevor Woerner via lists.yoctoproject.org wrote:
> > >>> The upstream kernel reorganized the 32-bit arch/arm device-tree
> > directory structure
> > >>> to separate out the device-trees by manufacturer (similar to the
> > organization
> > >>> of the arch/arm64 device-trees). Update the references to 32-bit arm
> > >>> device-trees to match.
> > >>>
> > >>
> > >> Does this work with linux-yocto and linux-yocto-dev from master or do we
> > >> need to add some logic to support both (do you want to?).
> > >
> > > This doesn't work at all. I figured this was an easy one, made the tweak,
> > > submitted it, then added it to my jenkins builder to verify overnight.
> > Woke up
> > > to find the do_image_wic() tasks failed. It's the same layout as the
> > 64-bit
> > > machines but I'll have to dig in to figure out why it didn't work.
> > >
> > > As for the linux-yocto vs linux-yocto-dev question I'll take a look. This
> > > happened with linux-yocto, so I would assume it is already the case with
> > > linux-yocto-dev. But if oe-core supports multiple versions of
> > linux-yocto,
> > > that might be the tricky bit and yes, I would look into supporting both
> > for
> > > the time-being until the transition period ends.
> > >
> >
> > This was done in v6.5-rc1 so anything before won't work sadly.
> >
> > master branch of poky supports 6.1 6.4 and 6.5 for linux-yocto
> > (linux-yocto-dev being typically newer than the latest linux-yocto and
> > the latest linux-yocto already having the change, I'll omit the change
> > for linux-yocto-dev).
> >
> > For reference, denix on IRC suggested you look at
> >
> > https://git.openembedded.org/openembedded-core/commit/?id=04ab57d20009d85eb566e83ae6fe1dcea4db7300
> > for what we're trying to do here. But I think this isn't applying to how
> > the DTB is found but rather where it's put and this is too late for us.
> >
> > I think we need to modify get_real_dtb_path_in_kernel in
> > meta/classes-recipe/kernel-devicetree.bbclass instead.
> >
> > We could handle it this way for example to allow a fallback:
> > """
> > get_real_dtb_path_in_kernel:arm () {
> >         dtb="$1"
> >         dtb_path="${B}/arch/${ARCH}/boot/dts/$dtb"
> >          # Handle pre-v6.5 layout for Aarch32/ARM DTB
> >         if [ ! -e "$dtb_path" ]; then
> >                 dtb_path="${B}/arch/${ARCH}/boot/dts/$(basename "$dtb")"
> >         fi
> >         if [ ! -e "$dtb_path" ]; then
> >                 dtb_path="${B}/arch/${ARCH}/boot/$dtb"
> >         fi
> >          # Handle pre-v6.5 layout for Aarch32/ARM DTB
> >         if [ ! -e "$dtb_path" ]; then
> >                 dtb_path="${B}/arch/${ARCH}/boot/$(basename "$dtb")"
> >         fi
> >
> >         echo "$dtb_path"
> > }
> > """
> > (to be determined if "arm" is a valid OVERRIDES, otherwise we need to
> > check against "ARCH" bb variable; also not sure about the second
> > basename if it's necessary at all).
> >
> > Then you would just have KERNEL_DEVICETREE done the same way as in this
> > patch:
> > KERNEL_DEVICETREE = "rockchip/rk3066a-marsboard.dtb"
> >
> > and we wouldn't have to handle it on the recipe level.
> >
> > Otherwise, we could do the following:
> > RK_KERNEL_DEVICETREE = "rockchip/rk3066a-marsboard.dtb"
> > KERNEL_DEVICETREE ?= "${RK_KERNEL_DEVICETREE}"
> >
> > then have a bbappend for all old-layout recipes:
> > linux-yocto-rt_6.1.bbappend
> > linux-yocto-tiny_6.1.bbappend
> > linux-yocto_6.1.bbappend
> > linux-yocto-rt_6.4.bbappend
> > linux-yocto-tiny_6.4.bbappend
> > linux-yocto_6.4.bbappend
> >
> > KERNEL_DEVICETREE:arm = "${@' '.join(os.path.basename(dtb) for dtb in
> > d.getVar('RK_KERNEL_DEVICETREE').split())}"
> >
> > or something like that. We probably want to have something a bit more
> > precise than just arm to avoid breaking other arm machine conf files
> > which do not define RK_KERNEL_DEVICETREE, maybe
> > KERNEL_DEVICETREE:rockchip:arm if that is even resolving properly.
> >
> > > Although... any BSP layer supporting 32-bit machines will have similar
> > issues,
> > > so perhaps there's a better way to solve this in oe-core?
> > >
> > Adding Bruce in Cc, I hope he doesn't mind being summoned like this.
> > Maybe you have an idea on how to handle both the new and old layout for
> > ARM/Aarch32 DTB in the kernel for the KERNEL_DEVICETREE variable?
> >
> 
> My last run in with this may have been before some of the most recent
> device tree handling patches, and/or I may have been doing it wrong.
> 
> But my solution was to simply override the variable in a kernel version
> specific bbappend, and not do it in the conf files.
> 
> But of course, if that variable is being interpreted by a different class in
> the global namespace, then the kernel bbappend approach isn't going
> to work anymore.
> 
> I've stayed away from utilities or searching, etc, rather just a way for the
> configuration to specify directly what to find, as anything that searches
> ends up being fragile.

The biggest tangle is that the master branch supports 6.1, 6.4, and 6.5.
Getting something to work with one version at at time isn't hard; getting it
to work simultaneously with all 3 (and others?) is the tricky part.

In a perfect world we could have linux-kernel-version-specific machine conf
sections/files... but that would be crazy!

I've been poking at this from different angles off-and-on for the last couple
days. The more I look at it, the more I like what meta-ti-bsp did. That's
probably what I'm going to do:

conf/machine/MACHINE.conf file has:
- KERNEL_DEVICETREE that just lists the bare dtb file (without directories)
- KERNEL_DEVICETREE_PREFIX that lists possible directory names

recipes-kernel/linux/linux-yocto% bbappends have logic to check combinations
of KERNEL_DEVICETREE_PREFIX+KERNEL_DEVICETREE to find the actual dtb.

Something probably also needs to be added to IMAGE_BOOT_FILES so wic works
too.

NOTE: given that this is meta-rockchip, the KERNEL_DEVICETREE_PREFIX could
simply be known to be "rockchip" a-priori; it doesn't necessarily need to be
that flexible.

And the real catch is that this is only a problem today because a specific OE
branch has both pre- and post- cleanup kernel versions. If the OE branches
didn't mix the two, this wouldn't be a problem. And someday once master has
moved away from having both pre- and post- cleanup kernel versions, we can
throw all this infrastructure out (on master) going forward.

Best regards,
	Trevor