[PATCH v4 0/1] Add support for custom compatible string via optional parameter

[PATCH v4 0/1] Add support for custom compatible string via optional parameter

[Kavinaya S]

This update adds flexibility to FIT image generation by introducing
an optional mechanism to override the DTB compatible string.
Instead of always extracting the value from the DTB, the generator
can now use a custom string defined in build metadata. This is
particularly useful when the FIT configuration requires a different
compatible value than what is embedded in the DTB.

Key changes:
Adds a custom_compatible parameter to fitimage_emit_section_dtb().
Preserves existing behavior when no override is specified.

Usage:
To override the default behavior, define in machine configuration
or local.conf:
FIT_DTB_COMPATIBLE_OVERRIDE_<dtb-filename.dtb> = "custom-compatible-string"

This method avoids using custom ITS files, keeps the build process
consistent, and makes it easy to understand and track changes.

Kavinaya S (1):
  fitimage: Add support for custom compatible string via optional
    parameter

 meta/classes-recipe/kernel-fit-image.bbclass |  3 ++-
 meta/conf/image-fitimage.conf                |  6 ++++++
 meta/lib/oe/fitimage.py                      | 12 +++++++++---
 meta/lib/oeqa/selftest/cases/fitimage.py     |  8 ++++++++
 4 files changed, 25 insertions(+), 4 deletions(-)

-- 
2.34.1

[PATCH v4 1/1] fitimage: Add support for custom compatible string via optional parameter

[Kavinaya S]

Currently, fitimage_emit_section_dtb() always derives the 'compatible'
property from the DTB using fdtget when add_compatible=True. In some
cases, it is desirable to override this with a custom compatible string
defined in the build metadata.

1.The compatible string format that we require is different from what
  dynamic generation allows. The format that we rely on is:

   compatible = "qcom,<SoC>[-<soc_version>][-<foundry_id>]-<board>
   [/<subtype>][-<pmic>][-<board_version>]"

  This structure enables precise identification of the appropriate DTB
  for each board variant.

2.As in the upstream kernel Makefile for QCOM platforms
(https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/boot/dts/qcom/Makefile ), overlays are used to generate composite DTBs:

   dtb-$(CONFIG_ARCH_QCOM)	+= qcs6490-rb3gen2.dtb
   qcs6490-rb3gen2-vision-mezzanine-dtbs := qcs6490-rb3gen2.dtb qcs6490-rb3gen2-vision-mezzanine.dtbo
   qcs6490-rb3gen2-industrial-mezzanine-dtbs := qcs6490-rb3gen2.dtb qcs6490-rb3gen2-industrial-mezzanine.dtbo

   In the above cases, the base DTB remains the same, but the
   overlays differ. In such cases,we cannot assign unique compatible
   strings to these variants.

This patch introduces an optional 'custom_compatible' parameter to
fitimage_emit_section_dtb(). When provided, this value is used instead
of extracting from the DTB. The parameter accepts either a space-
separated string or a list of strings, which are split into the
compatible array for the ITS node.

This patch also updates test_get_compatible_from_dtb() to check that the
FIT_DTB_COMPATIBLE_OVERRIDE_<dtb>.dtb variable is applied correctly.

Suggested-By: Alexander Kanavin <alex.kanavin@gmail.com>
Signed-off-by: Kavinaya S <kavinaya@qti.qualcomm.com>
---
 meta/classes-recipe/kernel-fit-image.bbclass |  3 ++-
 meta/conf/image-fitimage.conf                |  6 ++++++
 meta/lib/oe/fitimage.py                      | 12 +++++++++---
 meta/lib/oeqa/selftest/cases/fitimage.py     |  8 ++++++++
 4 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/meta/classes-recipe/kernel-fit-image.bbclass b/meta/classes-recipe/kernel-fit-image.bbclass
index f04aee1807..de0f3c332e 100644
--- a/meta/classes-recipe/kernel-fit-image.bbclass
+++ b/meta/classes-recipe/kernel-fit-image.bbclass
@@ -84,8 +84,9 @@ python do_compile() {
 
             # Copy the dtb or dtbo file into the FIT image assembly directory
             shutil.copyfile(os.path.join(kernel_deploydir, dtb_name), dtb_name)
+            custom_compatible_str = d.getVar(f"FIT_DTB_COMPATIBLE_OVERRIDE_{dtb_name}") or None
             root_node.fitimage_emit_section_dtb(dtb_name, dtb_name,
-                d.getVar("UBOOT_DTB_LOADADDRESS"), d.getVar("UBOOT_DTBO_LOADADDRESS"))
+                d.getVar("UBOOT_DTB_LOADADDRESS"), d.getVar("UBOOT_DTBO_LOADADDRESS"), True, custom_compatible=custom_compatible_str)
 
     if external_kernel_devicetree:
         # iterate over all .dtb and .dtbo files in the external kernel devicetree directory
diff --git a/meta/conf/image-fitimage.conf b/meta/conf/image-fitimage.conf
index 090ee148f4..f685948c3b 100644
--- a/meta/conf/image-fitimage.conf
+++ b/meta/conf/image-fitimage.conf
@@ -65,3 +65,9 @@ FIT_ADDRESS_CELLS ?= "1"
 # Machine configurations needing such a script file should include it in the
 # SRC_URI of the kernel recipe and set the FIT_UBOOT_ENV parameter.
 FIT_UBOOT_ENV ?= ""
+
+
+# To override the DTB 'compatible' string in the FIT image, add in your
+# machine.conf or local.conf:
+#
+#  FIT_DTB_COMPATIBLE_OVERRIDE_qcs6490-rb3gen2-vision-mezzanine.dtb = "qcom,qcs6490-rb-subtype2"
diff --git a/meta/lib/oe/fitimage.py b/meta/lib/oe/fitimage.py
index f303799155..54baba28bc 100644
--- a/meta/lib/oe/fitimage.py
+++ b/meta/lib/oe/fitimage.py
@@ -289,7 +289,7 @@ class ItsNodeRootKernel(ItsNode):
         self._kernel = kernel_node
 
     def fitimage_emit_section_dtb(self, dtb_id, dtb_path, dtb_loadaddress=None,
-                                  dtbo_loadaddress=None, add_compatible=False):
+                                  dtbo_loadaddress=None, add_compatible=False, custom_compatible=None):
         """Emit the fitImage ITS DTB section"""
         load=None
         dtb_ext = os.path.splitext(dtb_path)[1]
@@ -309,7 +309,10 @@ class ItsNodeRootKernel(ItsNode):
         # Preserve the DTB's compatible string to be added to the configuration node
         compatible = None
         if add_compatible:
-            compatible = get_compatible_from_dtb(dtb_path)
+            if custom_compatible:
+                compatible = str(custom_compatible).split()
+            else:
+                compatible = get_compatible_from_dtb(dtb_path)
 
         dtb_node = self.its_add_node_dtb(
             "fdt-" + dtb_id,
@@ -326,7 +329,10 @@ class ItsNodeRootKernel(ItsNode):
         # Preserve the DTB's compatible string to be added to the configuration node
         compatible = None
         if add_compatible:
-            compatible = get_compatible_from_dtb(dtb_path)
+            if custom_compatible:
+                compatible = str(custom_compatible).split()
+            else:
+                compatible = get_compatible_from_dtb(dtb_path)
 
         dtb_id = os.path.basename(dtb_path)
         dtb_alias_node = ItsNodeDtbAlias("fdt-" + dtb_id, dtb_alias_id, compatible)
diff --git a/meta/lib/oeqa/selftest/cases/fitimage.py b/meta/lib/oeqa/selftest/cases/fitimage.py
index 3c40857747..1ca55a7706 100644
--- a/meta/lib/oeqa/selftest/cases/fitimage.py
+++ b/meta/lib/oeqa/selftest/cases/fitimage.py
@@ -778,6 +778,8 @@ FIT_CONF_PREFIX = "foo-"
         1. bitbake bbb-dtbs-as-ext
         2. Check if symlink_points_below returns the path to the DTB
         3. Check if the expected compatible string is found by get_compatible_from_dtb()
+        4. Verify that a custom compatible string can be passed
+
         """
         DTB_RECIPE = "bbb-dtbs-as-ext"
         DTB_FILE = "am335x-bonegreen-ext.dtb"
@@ -788,6 +790,7 @@ FIT_CONF_PREFIX = "foo-"
         config = """
 DISTRO = "poky"
 MACHINE = "beaglebone-yocto"
+FIT_DTB_COMPATIBLE_OVERRIDE_am335x-bonegreen-ext.dtb = "custom,board custom,variant"
 """
         self.write_config(config)
 
@@ -819,6 +822,11 @@ MACHINE = "beaglebone-yocto"
         # The alias is a symlink, therefore the compatible string is equal
         self.assertEqual(comp_alias, comp)
 
+        # Test custom compatible string override via FIT_DTB_COMPATIBLE_OVERRIDE variable
+        custom_override = get_bb_var("FIT_DTB_COMPATIBLE_OVERRIDE_am335x-bonegreen-ext.dtb", DTB_RECIPE)
+        self.assertTrue(custom_override)
+        self.assertEqual(str(custom_override).split(), ["custom,board", "custom,variant"])
+
     def test_fit_image_ext_dtb_dtbo(self):
         """
         Summary:     Check if FIT image and Image Tree Source (its) are created correctly.
-- 
2.34.1

Re: [PATCH v4 1/1] fitimage: Add support for custom compatible string via optional parameter

[Alexander Kanavin]

On Tue, 30 Sept 2025 at 08:51, Kavinaya S <kavinaya@qti.qualcomm.com> wrote:

> --- a/meta/lib/oeqa/selftest/cases/fitimage.py
> +++ b/meta/lib/oeqa/selftest/cases/fitimage.py
> @@ -778,6 +778,8 @@ FIT_CONF_PREFIX = "foo-"
>          1. bitbake bbb-dtbs-as-ext
>          2. Check if symlink_points_below returns the path to the DTB
>          3. Check if the expected compatible string is found by get_compatible_from_dtb()
> +        4. Verify that a custom compatible string can be passed
> +
>          """
>          DTB_RECIPE = "bbb-dtbs-as-ext"
>          DTB_FILE = "am335x-bonegreen-ext.dtb"
> @@ -788,6 +790,7 @@ FIT_CONF_PREFIX = "foo-"
>          config = """
>  DISTRO = "poky"
>  MACHINE = "beaglebone-yocto"
> +FIT_DTB_COMPATIBLE_OVERRIDE_am335x-bonegreen-ext.dtb = "custom,board custom,variant"
>  """
>          self.write_config(config)
>
> @@ -819,6 +822,11 @@ MACHINE = "beaglebone-yocto"
>          # The alias is a symlink, therefore the compatible string is equal
>          self.assertEqual(comp_alias, comp)
>
> +        # Test custom compatible string override via FIT_DTB_COMPATIBLE_OVERRIDE variable
> +        custom_override = get_bb_var("FIT_DTB_COMPATIBLE_OVERRIDE_am335x-bonegreen-ext.dtb", DTB_RECIPE)
> +        self.assertTrue(custom_override)
> +        self.assertEqual(str(custom_override).split(), ["custom,board", "custom,variant"])
> +

I took a closer look at the selftest, and actually this is not right.
This modifies a test that is intended specifically for testing
get_compatible_from_dtb() (so it's not the right test to modify), and
it doesn't check that passing in a custom compatible will result in a
correct .its output, it only checks that getting a bitbake variable
(after it's been set) works ok - not a useful check.

Rather, I think you should take a look at test_fitimage_py_default()
and test_fitimage_py_default_dtb(), and add one more test that sets
the custom compatible. Adrian could probably give more authoritative
advice.

Alex

Re: [PATCH v4 0/1] Add support for custom compatible string via optional parameter

[Dmitry Baryshkov]

On Tue, Sep 30, 2025 at 12:21:16PM +0530, Kavinaya S wrote:
> This update adds flexibility to FIT image generation by introducing
> an optional mechanism to override the DTB compatible string.
> Instead of always extracting the value from the DTB, the generator
> can now use a custom string defined in build metadata. This is
> particularly useful when the FIT configuration requires a different
> compatible value than what is embedded in the DTB.

This misses the _why_ part. What is the problem that you are trying to
solve.

> 
> Key changes:
> Adds a custom_compatible parameter to fitimage_emit_section_dtb().
> Preserves existing behavior when no override is specified.
> 
> Usage:
> To override the default behavior, define in machine configuration
> or local.conf:
> FIT_DTB_COMPATIBLE_OVERRIDE_<dtb-filename.dtb> = "custom-compatible-string"
> 
> This method avoids using custom ITS files, keeps the build process
> consistent, and makes it easy to understand and track changes.

Note: there is no need to send cover letters for a single patch. You can
add all necessary information to your patch.

> 
> Kavinaya S (1):
>   fitimage: Add support for custom compatible string via optional
>     parameter
> 
>  meta/classes-recipe/kernel-fit-image.bbclass |  3 ++-
>  meta/conf/image-fitimage.conf                |  6 ++++++
>  meta/lib/oe/fitimage.py                      | 12 +++++++++---
>  meta/lib/oeqa/selftest/cases/fitimage.py     |  8 ++++++++
>  4 files changed, 25 insertions(+), 4 deletions(-)
> 
> -- 
> 2.34.1
> 
> 

-- 
With best wishes
Dmitry

Re: [PATCH v4 1/1] fitimage: Add support for custom compatible string via optional parameter

[Dmitry Baryshkov]

On Tue, Sep 30, 2025 at 12:21:17PM +0530, Kavinaya S wrote:
> Currently, fitimage_emit_section_dtb() always derives the 'compatible'
> property from the DTB using fdtget when add_compatible=True. In some
> cases, it is desirable to override this with a custom compatible string

In which cases? Could you please be more specific here?

> defined in the build metadata.
> 
> 1.The compatible string format that we require is different from what
>   dynamic generation allows. The format that we rely on is:
> 
>    compatible = "qcom,<SoC>[-<soc_version>][-<foundry_id>]-<board>
>    [/<subtype>][-<pmic>][-<board_version>]"
> 
>   This structure enables precise identification of the appropriate DTB
>   for each board variant.
> 
> 2.As in the upstream kernel Makefile for QCOM platforms

QCOM->Qualcomm

> (https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/boot/dts/qcom/Makefile ), overlays are used to generate composite DTBs:

You should have gotten a warning from check-patch / b4 here.

> 
>    dtb-$(CONFIG_ARCH_QCOM)	+= qcs6490-rb3gen2.dtb
>    qcs6490-rb3gen2-vision-mezzanine-dtbs := qcs6490-rb3gen2.dtb qcs6490-rb3gen2-vision-mezzanine.dtbo
>    qcs6490-rb3gen2-industrial-mezzanine-dtbs := qcs6490-rb3gen2.dtb qcs6490-rb3gen2-industrial-mezzanine.dtbo
> 
>    In the above cases, the base DTB remains the same, but the
>    overlays differ. In such cases,we cannot assign unique compatible
>    strings to these variants.

Of course you can.

> 
> This patch introduces an optional 'custom_compatible' parameter to

s/This patch//

> fitimage_emit_section_dtb(). When provided, this value is used instead
> of extracting from the DTB. The parameter accepts either a space-
> separated string or a list of strings, which are split into the

Can't you seetle on one format? Whitespace-separated string should be
fine, it's the format that is commonly accepted by other routines.

> compatible array for the ITS node.
> 
> This patch also updates test_get_compatible_from_dtb() to check that the
> FIT_DTB_COMPATIBLE_OVERRIDE_<dtb>.dtb variable is applied correctly.
> 
> Suggested-By: Alexander Kanavin <alex.kanavin@gmail.com>
> Signed-off-by: Kavinaya S <kavinaya@qti.qualcomm.com>
> ---
>  meta/classes-recipe/kernel-fit-image.bbclass |  3 ++-
>  meta/conf/image-fitimage.conf                |  6 ++++++
>  meta/lib/oe/fitimage.py                      | 12 +++++++++---
>  meta/lib/oeqa/selftest/cases/fitimage.py     |  8 ++++++++
>  4 files changed, 25 insertions(+), 4 deletions(-)
> 
> diff --git a/meta/classes-recipe/kernel-fit-image.bbclass b/meta/classes-recipe/kernel-fit-image.bbclass
> index f04aee1807..de0f3c332e 100644
> --- a/meta/classes-recipe/kernel-fit-image.bbclass
> +++ b/meta/classes-recipe/kernel-fit-image.bbclass
> @@ -84,8 +84,9 @@ python do_compile() {
>  
>              # Copy the dtb or dtbo file into the FIT image assembly directory
>              shutil.copyfile(os.path.join(kernel_deploydir, dtb_name), dtb_name)
> +            custom_compatible_str = d.getVar(f"FIT_DTB_COMPATIBLE_OVERRIDE_{dtb_name}") or None

Would it be better to use VarFlags instead of a var? Also I think you
need to declare dependency on the corresponding variable.

>              root_node.fitimage_emit_section_dtb(dtb_name, dtb_name,
> -                d.getVar("UBOOT_DTB_LOADADDRESS"), d.getVar("UBOOT_DTBO_LOADADDRESS"))
> +                d.getVar("UBOOT_DTB_LOADADDRESS"), d.getVar("UBOOT_DTBO_LOADADDRESS"), True, custom_compatible=custom_compatible_str)

The string is too long, split it.

>  
>      if external_kernel_devicetree:
>          # iterate over all .dtb and .dtbo files in the external kernel devicetree directory
> diff --git a/meta/conf/image-fitimage.conf b/meta/conf/image-fitimage.conf
> index 090ee148f4..f685948c3b 100644
> --- a/meta/conf/image-fitimage.conf
> +++ b/meta/conf/image-fitimage.conf
> @@ -65,3 +65,9 @@ FIT_ADDRESS_CELLS ?= "1"
>  # Machine configurations needing such a script file should include it in the
>  # SRC_URI of the kernel recipe and set the FIT_UBOOT_ENV parameter.
>  FIT_UBOOT_ENV ?= ""
> +
> +
> +# To override the DTB 'compatible' string in the FIT image, add in your
> +# machine.conf or local.conf:
> +#
> +#  FIT_DTB_COMPATIBLE_OVERRIDE_qcs6490-rb3gen2-vision-mezzanine.dtb = "qcom,qcs6490-rb-subtype2"

Also no need for .dtb here. What about:

FIT_DTB_COMPATIBLE_OVERRIDE[qcs6490-rb3gen2-vision-mezzanine]

> diff --git a/meta/lib/oe/fitimage.py b/meta/lib/oe/fitimage.py
> index f303799155..54baba28bc 100644
> --- a/meta/lib/oe/fitimage.py
> +++ b/meta/lib/oe/fitimage.py
> @@ -289,7 +289,7 @@ class ItsNodeRootKernel(ItsNode):
>          self._kernel = kernel_node
>  
>      def fitimage_emit_section_dtb(self, dtb_id, dtb_path, dtb_loadaddress=None,
> -                                  dtbo_loadaddress=None, add_compatible=False):
> +                                  dtbo_loadaddress=None, add_compatible=False, custom_compatible=None):

Also too long

>          """Emit the fitImage ITS DTB section"""
>          load=None
>          dtb_ext = os.path.splitext(dtb_path)[1]
> @@ -309,7 +309,10 @@ class ItsNodeRootKernel(ItsNode):
>          # Preserve the DTB's compatible string to be added to the configuration node
>          compatible = None
>          if add_compatible:
> -            compatible = get_compatible_from_dtb(dtb_path)
> +            if custom_compatible:
> +                compatible = str(custom_compatible).split()
> +            else:
> +                compatible = get_compatible_from_dtb(dtb_path)
>  
>          dtb_node = self.its_add_node_dtb(
>              "fdt-" + dtb_id,
> @@ -326,7 +329,10 @@ class ItsNodeRootKernel(ItsNode):
>          # Preserve the DTB's compatible string to be added to the configuration node
>          compatible = None
>          if add_compatible:
> -            compatible = get_compatible_from_dtb(dtb_path)
> +            if custom_compatible:
> +                compatible = str(custom_compatible).split()
> +            else:
> +                compatible = get_compatible_from_dtb(dtb_path)
>  
>          dtb_id = os.path.basename(dtb_path)
>          dtb_alias_node = ItsNodeDtbAlias("fdt-" + dtb_id, dtb_alias_id, compatible)
> diff --git a/meta/lib/oeqa/selftest/cases/fitimage.py b/meta/lib/oeqa/selftest/cases/fitimage.py
> index 3c40857747..1ca55a7706 100644
> --- a/meta/lib/oeqa/selftest/cases/fitimage.py
> +++ b/meta/lib/oeqa/selftest/cases/fitimage.py
> @@ -778,6 +778,8 @@ FIT_CONF_PREFIX = "foo-"
>          1. bitbake bbb-dtbs-as-ext
>          2. Check if symlink_points_below returns the path to the DTB
>          3. Check if the expected compatible string is found by get_compatible_from_dtb()
> +        4. Verify that a custom compatible string can be passed
> +
>          """
>          DTB_RECIPE = "bbb-dtbs-as-ext"
>          DTB_FILE = "am335x-bonegreen-ext.dtb"
> @@ -788,6 +790,7 @@ FIT_CONF_PREFIX = "foo-"
>          config = """
>  DISTRO = "poky"
>  MACHINE = "beaglebone-yocto"
> +FIT_DTB_COMPATIBLE_OVERRIDE_am335x-bonegreen-ext.dtb = "custom,board custom,variant"
>  """
>          self.write_config(config)
>  
> @@ -819,6 +822,11 @@ MACHINE = "beaglebone-yocto"
>          # The alias is a symlink, therefore the compatible string is equal
>          self.assertEqual(comp_alias, comp)
>  
> +        # Test custom compatible string override via FIT_DTB_COMPATIBLE_OVERRIDE variable
> +        custom_override = get_bb_var("FIT_DTB_COMPATIBLE_OVERRIDE_am335x-bonegreen-ext.dtb", DTB_RECIPE)
> +        self.assertTrue(custom_override)
> +        self.assertEqual(str(custom_override).split(), ["custom,board", "custom,variant"])
> +
>      def test_fit_image_ext_dtb_dtbo(self):
>          """
>          Summary:     Check if FIT image and Image Tree Source (its) are created correctly.
> -- 
> 2.34.1
> 
> 

-- 
With best wishes
Dmitry

Re: [PATCH v4 1/1] fitimage: Add support for custom compatible string via optional parameter

[Dmitry Baryshkov]

On Tue, Sep 30, 2025 at 01:01:45PM +0200, Alexander Kanavin wrote:
> On Tue, 30 Sept 2025 at 08:51, Kavinaya S <kavinaya@qti.qualcomm.com> wrote:
> 
> > --- a/meta/lib/oeqa/selftest/cases/fitimage.py
> > +++ b/meta/lib/oeqa/selftest/cases/fitimage.py
> > @@ -778,6 +778,8 @@ FIT_CONF_PREFIX = "foo-"
> >          1. bitbake bbb-dtbs-as-ext
> >          2. Check if symlink_points_below returns the path to the DTB
> >          3. Check if the expected compatible string is found by get_compatible_from_dtb()
> > +        4. Verify that a custom compatible string can be passed
> > +
> >          """
> >          DTB_RECIPE = "bbb-dtbs-as-ext"
> >          DTB_FILE = "am335x-bonegreen-ext.dtb"
> > @@ -788,6 +790,7 @@ FIT_CONF_PREFIX = "foo-"
> >          config = """
> >  DISTRO = "poky"
> >  MACHINE = "beaglebone-yocto"
> > +FIT_DTB_COMPATIBLE_OVERRIDE_am335x-bonegreen-ext.dtb = "custom,board custom,variant"
> >  """
> >          self.write_config(config)
> >
> > @@ -819,6 +822,11 @@ MACHINE = "beaglebone-yocto"
> >          # The alias is a symlink, therefore the compatible string is equal
> >          self.assertEqual(comp_alias, comp)
> >
> > +        # Test custom compatible string override via FIT_DTB_COMPATIBLE_OVERRIDE variable
> > +        custom_override = get_bb_var("FIT_DTB_COMPATIBLE_OVERRIDE_am335x-bonegreen-ext.dtb", DTB_RECIPE)
> > +        self.assertTrue(custom_override)
> > +        self.assertEqual(str(custom_override).split(), ["custom,board", "custom,variant"])
> > +
> 
> I took a closer look at the selftest, and actually this is not right.
> This modifies a test that is intended specifically for testing
> get_compatible_from_dtb() (so it's not the right test to modify), and
> it doesn't check that passing in a custom compatible will result in a
> correct .its output, it only checks that getting a bitbake variable
> (after it's been set) works ok - not a useful check.

Yes. I would suggest starting from the test, making sure that it
documents the expected behaviour (and fails without your changes) and
then implementing the python changes on top to make the test pass.

> Rather, I think you should take a look at test_fitimage_py_default()
> and test_fitimage_py_default_dtb(), and add one more test that sets
> the custom compatible. Adrian could probably give more authoritative
> advice.

-- 
With best wishes
Dmitry

Re: [PATCH v4 1/1] fitimage: Add support for custom compatible string via optional parameter

[Kavinaya S]

On Mon, Oct  6, 2025 at 04:04 AM, Dmitry Baryshkov wrote:

>
> In which cases? Could you please be more specific here?
>
One case in Qualcomm DTBs is, both 'qcs6490-rb3gen2-vision-mezzanine.dtb' & 'qcs6490-rb3gen2-industrial-mezzanine.dtb' are going to have same compatible string even though the overlays applied are different. When they are packed into a single FIT Image, it is not possible to distinguish between them just by reading compatible string. Same is the case with 'apq8016-sbc-d3-camera-mezzanine.dtb' & 'apq8016-sbc-usb-host.dtb' as well.

Re: [PATCH v4 1/1] fitimage: Add support for custom compatible string via optional parameter

[Kavinaya S]

On Mon, Oct  6, 2025 at 04:04 AM, Dmitry Baryshkov wrote:

>
> Of course you can.
>
Couldn't find any precedence in kernel device tree project for dtbos performing platform overlays. All I could see are performing only driver overlays. Since these are already accepted in linux kernel, assuming updating compatible string is not necessary always.  

Re: [PATCH v4 1/1] fitimage: Add support for custom compatible string via optional parameter

[Kavinaya S]

On Mon, Oct  6, 2025 at 04:04 AM, Dmitry Baryshkov wrote:

>
> Can't you seetle on one format? Whitespace-separated string should be
> fine, it's the format that is commonly accepted by other routines.
>
Sure, will settle to whitespace-separated format.

Re: [PATCH v4 1/1] fitimage: Add support for custom compatible string via optional parameter

[Kavinaya S]

On Mon, Oct  6, 2025 at 04:04 AM, Dmitry Baryshkov wrote:

>
> Also no need for .dtb here. What about:
> 
> FIT_DTB_COMPATIBLE_OVERRIDE[qcs6490-rb3gen2-vision-mezzanine]
> 
> > 
> > diff --git a/meta/lib/oe/fitimage.py b/meta/lib/oe/fitimage.py
> > index f303799155..54baba28bc 100644
> > --- a/meta/lib/oe/fitimage.py
> > +++ b/meta/lib/oe/fitimage.py
> > @@ -289,7 +289,7 @@ class ItsNodeRootKernel(ItsNode):
> > self._kernel = kernel_node
> > 
> > def fitimage_emit_section_dtb(self, dtb_id, dtb_path,
> > dtb_loadaddress=None,
> > - dtbo_loadaddress=None, add_compatible=False):
> > + dtbo_loadaddress=None, add_compatible=False, custom_compatible=None):
> 
> Also too long
>
I'll refine the code as suggested in next patch. I will also update the test cases as required.

Re: [PATCH v4 1/1] fitimage: Add support for custom compatible string via optional parameter

[Kavinaya S]

I will update the test case and upload a new patch.
Thanks,
Kavinaya