[PATCH v2 0/1] u-boot-tools: drop yaml in DT validation

[PATCH v2 0/1] u-boot-tools: drop yaml in DT validation

[João Marcos Costa]

Hello,

I hope this fixes the DTC build issues once and for all!

Changes since v1:
- The patch was added to SRC_URI_RISCV only, so I replaced it by an append
  straight to SRC_URI

João Marcos Costa (1):
  u-boot-tools: drop yaml in DT validation

 ...ripts-dtc-drop-yaml-in-DT-validation.patch | 85 +++++++++++++++++++
 meta/recipes-bsp/u-boot/u-boot-tools.inc      |  2 +-
 meta/recipes-bsp/u-boot/u-boot_2026.04.bb     |  1 +
 3 files changed, 87 insertions(+), 1 deletion(-)
 create mode 100644 meta/recipes-bsp/u-boot/files/0001-scripts-dtc-drop-yaml-in-DT-validation.patch

-- 
2.47.0

[PATCH v2 1/1] u-boot-tools: drop yaml in DT validation

[João Marcos Costa]

Since yamltree was dropped from upstream dtc (i.e., in Linux), a patch was
sent to U-Boot to backport the corresponding changes.

Apply this patch in u-boot's sources.

Overall, this fixes the build-time issues with DTC (and so in
u-boot-tools).

Considering libyaml is no longer used, the dependency on libyaml-native can be
dropped as well (thus reverting the change below):

02e09e036e: u-boot-tools: Add dependency on libyaml for dtschema validation

Signed-off-by: João Marcos Costa <joaomarcos.costa@bootlin.com>
---
 ...ripts-dtc-drop-yaml-in-DT-validation.patch | 85 +++++++++++++++++++
 meta/recipes-bsp/u-boot/u-boot-tools.inc      |  2 +-
 meta/recipes-bsp/u-boot/u-boot_2026.04.bb     |  1 +
 3 files changed, 87 insertions(+), 1 deletion(-)
 create mode 100644 meta/recipes-bsp/u-boot/files/0001-scripts-dtc-drop-yaml-in-DT-validation.patch

diff --git a/meta/recipes-bsp/u-boot/files/0001-scripts-dtc-drop-yaml-in-DT-validation.patch b/meta/recipes-bsp/u-boot/files/0001-scripts-dtc-drop-yaml-in-DT-validation.patch
new file mode 100644
index 0000000000..4913366102
--- /dev/null
+++ b/meta/recipes-bsp/u-boot/files/0001-scripts-dtc-drop-yaml-in-DT-validation.patch
@@ -0,0 +1,85 @@
+From e77402000f978561ff2afe405aa9e5c9037a8717 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Jo=C3=A3o=20Marcos=20Costa?= <joaomarcos.costa@bootlin.com>
+Date: Wed, 29 Apr 2026 15:22:25 +0200
+Subject: [PATCH] scripts/dtc: drop yaml in DT validation
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+The build issues found in dtc/yamltree were partially mitigated by a
+previous commit (807bcd844a: "scripts/dtc: Fix pkg-config behavior under
+sysroot"), but upstream dtc simply disabled yaml, and the same should be
+done here in order to permanently avoid those issues.
+
+Backport the change below from Linux v5.18 [1]:
+
+ef8795f3f1c ("dt-bindings: kbuild: Use DTB files for validation")
+
+I tested this patch with a couple Yocto builds: u-boot and u-boot-tools,
+using the current master branch (rev. "c53b0708f9"), having removed
+libyaml-native from u-boot-tools's dependencies.
+
+[1] https://git.kernel.org/linus/ef8795f3f1ce
+
+Signed-off-by: João Marcos Costa <joaomarcos.costa@bootlin.com>
+
+Upstream-Status: Submitted [https://lore.kernel.org/u-boot/20260429144615.142350-1-joaomarcos.costa@bootlin.com/]
+---
+ scripts/Makefile.lib             | 6 ------
+ scripts/dtc/Makefile             | 8 --------
+ scripts/dtc/update-dtc-source.sh | 2 +-
+ 3 files changed, 1 insertion(+), 15 deletions(-)
+
+diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
+index b8969b7de54..d66f1ed13b1 100644
+--- a/scripts/Makefile.lib
++++ b/scripts/Makefile.lib
+@@ -86,12 +86,6 @@ base-dtb-y := $(foreach m, $(multi-dtb-y), $(firstword $(call suffix-search, $m,
+ extra-y				+= $(dtb-y)
+ extra-$(CONFIG_OF_ALL_DTBS)	+= $(dtb-)
+ 
+-# U-Boot specific
+-ifneq ($(CHECK_DTBS),)
+-extra-y += $(patsubst %.dtb,%.dt.yaml, $(dtb-y))
+-extra-$(CONFIG_OF_ALL_DTBS) += $(patsubst %.dtb,%.dt.yaml, $(dtb-))
+-endif
+-
+ # Add subdir path
+ 
+ extra-y		:= $(addprefix $(obj)/,$(extra-y))
+diff --git a/scripts/dtc/Makefile b/scripts/dtc/Makefile
+index 6f309b37e08..2ba8dba03be 100644
+--- a/scripts/dtc/Makefile
++++ b/scripts/dtc/Makefile
+@@ -17,15 +17,7 @@ fdtoverlay-objs	:= $(libfdt) fdtoverlay.o util.o
+ # Source files need to get at the userspace version of libfdt_env.h to compile
+ HOST_EXTRACFLAGS := -I$(srctree)/$(src)/libfdt
+ 
+-ifeq ($(wildcard $(PKG_CONFIG_SYSROOT_DIR)/usr/include/yaml.h),)
+ HOST_EXTRACFLAGS += -DNO_YAML
+-else
+-dtc-objs	+= yamltree.o
+-# To include <yaml.h> installed in a non-default path
+-HOSTCFLAGS_yamltree.o := $(shell pkg-config --cflags yaml-0.1)
+-# To link libyaml installed in a non-default path
+-HOSTLDLIBS_dtc	:= $(shell pkg-config --libs yaml-0.1)
+-endif
+ 
+ # Generated files need one more search path to include headers in source tree
+ HOSTCFLAGS_dtc-lexer.lex.o := -I$(src)
+diff --git a/scripts/dtc/update-dtc-source.sh b/scripts/dtc/update-dtc-source.sh
+index 32ff17ffd08..94627541533 100755
+--- a/scripts/dtc/update-dtc-source.sh
++++ b/scripts/dtc/update-dtc-source.sh
+@@ -32,7 +32,7 @@ DTC_UPSTREAM_PATH=`pwd`/../dtc
+ DTC_LINUX_PATH=`pwd`/scripts/dtc
+ 
+ DTC_SOURCE="checks.c data.c dtc.c dtc.h flattree.c fstree.c livetree.c srcpos.c \
+-		srcpos.h treesource.c util.c util.h version_gen.h yamltree.c \
++		srcpos.h treesource.c util.c util.h version_gen.h \
+ 		dtc-lexer.l dtc-parser.y"
+ LIBFDT_SOURCE="fdt.c fdt.h fdt_addresses.c fdt_empty_tree.c \
+ 		fdt_overlay.c fdt_ro.c fdt_rw.c fdt_strerror.c fdt_sw.c \
+-- 
+2.47.0
+
diff --git a/meta/recipes-bsp/u-boot/u-boot-tools.inc b/meta/recipes-bsp/u-boot/u-boot-tools.inc
index a055409c2c..4e4f7fa092 100644
--- a/meta/recipes-bsp/u-boot/u-boot-tools.inc
+++ b/meta/recipes-bsp/u-boot/u-boot-tools.inc
@@ -1,5 +1,5 @@
 SUMMARY = "U-Boot bootloader tools"
-DEPENDS += "gnutls openssl util-linux swig-native libyaml-native"
+DEPENDS += "gnutls openssl util-linux swig-native"
 
 inherit python3native
 export STAGING_INCDIR = "${STAGING_INCDIR_NATIVE}"
diff --git a/meta/recipes-bsp/u-boot/u-boot_2026.04.bb b/meta/recipes-bsp/u-boot/u-boot_2026.04.bb
index 5259fd5832..501d59d723 100644
--- a/meta/recipes-bsp/u-boot/u-boot_2026.04.bb
+++ b/meta/recipes-bsp/u-boot/u-boot_2026.04.bb
@@ -16,5 +16,6 @@ SRC_URI_RISCV = "\
     ${@bb.utils.contains    ("TUNE_FEATURES", "zicbom", "file://u-boot-riscv-isa_zicbom.cfg", "", d)} \
     "
 
+SRC_URI:append = " file://0001-scripts-dtc-drop-yaml-in-DT-validation.patch"
 SRC_URI:append:riscv32 = "${SRC_URI_RISCV}"
 SRC_URI:append:riscv64 = "${SRC_URI_RISCV}"
-- 
2.47.0

Re: [OE-core] [PATCH v2 1/1] u-boot-tools: drop yaml in DT validation

[Joao Marcos Costa]

Hello, folks

On 4/29/26 20:06, Joao Marcos Costa via lists.openembedded.org wrote:
> Since yamltree was dropped from upstream dtc (i.e., in Linux), a patch was
> sent to U-Boot to backport the corresponding changes.
> 
> Apply this patch in u-boot's sources.
(...)
> +
> +I tested this patch with a couple Yocto builds: u-boot and u-boot-tools,
> +using the current master branch (rev. "c53b0708f9"), having removed
> +libyaml-native from u-boot-tools's dependencies.
> +
> +[1] https://git.kernel.org/linus/ef8795f3f1ce
> +
> +Signed-off-by: João Marcos Costa <joaomarcos.costa@bootlin.com>
> +
> +Upstream-Status: Submitted [https://lore.kernel.org/u-boot/20260429144615.142350-1-joaomarcos.costa@bootlin.com/]
> +---
(...)

Update: the patch was merged into master [1].

[1] 
https://lore.kernel.org/u-boot/177757652458.1689679.13411123339948819206.b4-ty@konsulko.com/

-- 
Best regards,
João Marcos Costa

Re: [OE-core] [PATCH v2 0/1] u-boot-tools: drop yaml in DT validation

[Ricardo de Araujo (Salveti)]

Hi,

On Wed, Apr 29, 2026 at 3:06 PM Joao Marcos Costa via
lists.openembedded.org
<joaomarcos.costa=bootlin.com@lists.openembedded.org> wrote:
>
> Hello,
>
> I hope this fixes the DTC build issues once and for all!
>
> Changes since v1:
> - The patch was added to SRC_URI_RISCV only, so I replaced it by an append
>   straight to SRC_URI

It seems v1 was merged instead
(https://git.openembedded.org/openembedded-core/commit/?id=5e97f3c1e2cf76f8b810da5a8c591eb6e22586f2),
which is causing build failures for non-riscv targets.

Will send a patch to get that fixed.

Thanks,

Ricardo

Re: [OE-core] [PATCH v2 0/1] u-boot-tools: drop yaml in DT validation

[Michael Opdenacker]

Hi João Marcos

FYI, building the "qemuriscv64" machine is still broken on OE-core 
(master), and it's seems likely to be related to this change;

| /usr/bin/ld: scripts/dtc/yamltree.o: in function `dt_to_yaml':
| yamltree.c:(.text+0x8fa): undefined reference to `yaml_emitter_initialize'
| /usr/bin/ld: yamltree.c:(.text+0x905): undefined reference to 
`yaml_emitter_set_output_file'
| /usr/bin/ld: yamltree.c:(.text+0x912): undefined reference to 
`yaml_stream_start_event_initialize'
| /usr/bin/ld: yamltree.c:(.text+0x91d): undefined reference to 
`yaml_emitter_emit'
| /usr/bin/ld: yamltree.c:(.text+0x936): undefined reference to 
`yaml_document_start_event_initialize'
| /usr/bin/ld: yamltree.c:(.text+0x941): undefined reference to 
`yaml_emitter_emit'
| /usr/bin/ld: yamltree.c:(.text+0x962): undefined reference to 
`yaml_sequence_start_event_initialize'
| /usr/bin/ld: yamltree.c:(.text+0x96d): undefined reference to 
`yaml_emitter_emit'
| /usr/bin/ld: yamltree.c:(.text+0x98a): undefined reference to 
`yaml_sequence_end_event_initialize'
| /usr/bin/ld: yamltree.c:(.text+0x995): undefined reference to 
`yaml_emitter_emit'
| /usr/bin/ld: yamltree.c:(.text+0x9a7): undefined reference to 
`yaml_document_end_event_initialize'
| /usr/bin/ld: yamltree.c:(.text+0x9b2): undefined reference to 
`yaml_emitter_emit'
| /usr/bin/ld: yamltree.c:(.text+0x9be): undefined reference to 
`yaml_stream_end_event_initialize'
| /usr/bin/ld: yamltree.c:(.text+0x9c9): undefined reference to 
`yaml_emitter_emit'
| /usr/bin/ld: yamltree.c:(.text+0x9d5): undefined reference to 
`yaml_emitter_delete'
| collect2: error: ld returned 1 exit status
| make[2]: *** 
[/home/mike/work/kas/qemuriscv64/build/tmp/work/x86_64-linux/u-boot-tools-native/2026.04/sources/u-boot-tools-2026.04/scripts/Makefile.host:105: 
scripts/dtc/dtc] Error 1
| make[2]: *** Waiting for unfinished jobs....
| if [ -f 
/home/mike/work/kas/qemuriscv64/build/tmp/work/x86_64-linux/u-boot-tools-native/2026.04/sources/u-boot-tools-2026.04/.config 
-o -d 
/home/mike/work/kas/qemuriscv64/build/tmp/work/x86_64-linux/u-boot-tools-native/2026.04/sources/u-boot-tools-2026.04/include/config 
]; then \
|     echo >&2 " 
/home/mike/work/kas/qemuriscv64/build/tmp/work/x86_64-linux/u-boot-tools-native/2026.04/sources/u-boot-tools-2026.04 
is not clean, please run 'make mrproper'"; \
|     echo >&2 "  in the 
'/home/mike/work/kas/qemuriscv64/build/tmp/work/x86_64-linux/u-boot-tools-native/2026.04/sources/u-boot-tools-2026.04' 
directory.";\
|     /bin/false; \
| fi;
| set -e; mkdir -p include/generated/; trap "rm -f 
include/generated/.version_autogenerated.h.tmp" EXIT; {     (echo 
\#define PLAIN_VERSION \"2026.04\"; echo \#define U_BOOT_VERSION 
\"U-Boot \" PLAIN_VERSION; echo \#define U_BOOT_VERSION_NUM 2026; echo 
\#define U_BOOT_VERSION_NUM_PATCH $(echo 04 | sed -e "s/^0*//"); echo 
\#define HOST_ARCH 0x8664; echo \#define CC_VERSION_STRING \"$(LC_ALL=C 
gcc 
-isystem/home/mike/work/kas/qemuriscv64/build/tmp/work/x86_64-linux/u-boot-tools-native/2026.04/recipe-sysroot-native/usr/include 
-O2 -pipe 
-L/home/mike/work/kas/qemuriscv64/build/tmp/work/x86_64-linux/u-boot-tools-native/2026.04/recipe-sysroot-native/usr/lib 
  -L/home/mike/work/kas/qemuriscv64/build/tmp/work/x86_64-linux/u-boot-tools-native/2026.04/recipe-sysroot-native/lib 
                        -Wl,--enable-new-dtags 
  -Wl,-rpath-link,/home/mike/work/kas/qemuriscv64/build/tmp/work/x86_64-linux/u-boot-tools-native/2026.04/recipe-sysroot-native/usr/lib 
  -Wl,-rpath-link,/home/mike/work/kas/qemuriscv64/build/tmp/work/x86_64-linux/u-boot-tools-native/2026.04/recipe-sysroot-native/lib 
  -Wl,-rpath,/home/mike/work/kas/qemuriscv64/build/tmp/work/x86_64-linux/u-boot-tools-native/2026.04/recipe-sysroot-native/usr/lib 
  -Wl,-rpath,/home/mike/work/kas/qemuriscv64/build/tmp/work/x86_64-linux/u-boot-tools-native/2026.04/recipe-sysroot-native/lib 
                        -Wl,-O1 -Wl,--allow-shlib-undefined 
-Wl,--dynamic-linker=/home/mike/work/kas/qemuriscv64/build/tmp/sysroots-uninative/x86_64-linux/lib/ld-linux-x86-64.so.2 
-pthread --version | head -n 1)\"; echo \#define LD_VERSION_STRING 
\"$(LC_ALL=C ld --version | head -n 1)\"; ); } > 
include/generated/.version_autogenerated.h.tmp; if [ ! -r 
include/generated/version_autogenerated.h ] || ! cmp -s 
include/generated/version_autogenerated.h 
include/generated/.version_autogenerated.h.tmp; then : '  UPD 
  include/generated/version_autogenerated.h'; mv -f 
include/generated/.version_autogenerated.h.tmp 
include/generated/version_autogenerated.h; fi
| make[1]: *** 
[/home/mike/work/kas/qemuriscv64/build/tmp/work/x86_64-linux/u-boot-tools-native/2026.04/sources/u-boot-tools-2026.04/Makefile:2385: 
scripts_dtc] Error 2
| ERROR: oe_runmake failed
| make: Leaving directory 
'/home/mike/work/kas/qemuriscv64/build/tmp/work/x86_64-linux/u-boot-tools-native/2026.04/sources/u-boot-tools-2026.04'
| WARNING: exit code 1 from a shell command.
| make: *** [Makefile:189: __sub-make] Error 2
ERROR: Task 
(virtual:native:/home/mike/work/kas/qemuriscv64/build/../openembedded-core/meta/recipes-bsp/u-boot/u-boot-tools_2026.04.bb:do_compile) 
failed with exit code '1'
NOTE: Tasks Summary: Attempted 3456 tasks of which 18 didn't need to be 
rerun and 1 failed.

Cheers
Michael.

-- 
Root Commit
Embedded Linux Training and Consulting
https://rootcommit.com

Re: [OE-core] [PATCH v2 0/1] u-boot-tools: drop yaml in DT validation

[Joao Marcos Costa]

Hello,

On 5/18/26 21:12, Michael Opdenacker wrote:
> Hi João Marcos
> 
> FYI, building the "qemuriscv64" machine is still broken on OE-core 
> (master), and it's seems likely to be related to this change;
(...)

I just checked-out on master, and I don't have this linking issue. Could 
you please share your 'Build configuration' so I can try to reproduce it?

P.S.: Regardless of reproducing or not, we still need the fix in 
u-boot-tools' recipe.

-- 
Best regards,
João Marcos Costa

Re: [OE-core] [PATCH v2 0/1] u-boot-tools: drop yaml in DT validation

[Joao Marcos Costa]

Hello again,

On 5/18/26 21:12, Michael Opdenacker wrote:
> Hi João Marcos
> 
> FYI, building the "qemuriscv64" machine is still broken on OE-core 
> (master), and it's seems likely to be related to this change;
> 
> | /usr/bin/ld: scripts/dtc/yamltree.o: in function `dt_to_yaml':
> | yamltree.c:(.text+0x8fa): undefined reference to 
> `yaml_emitter_initialize'
> | /usr/bin/ld: yamltree.c:(.text+0x905): undefined reference to 
> `yaml_emitter_set_output_file'
> | /usr/bin/ld: yamltree.c:(.text+0x912): undefined reference to 
> `yaml_stream_start_event_initialize'
> | /usr/bin/ld: yamltree.c:(.text+0x91d): undefined reference to 
> `yaml_emitter_emit'
(...)

This looks very much as the case described here:

https://github.com/u-boot/u-boot/commit/807bcd844afeadbfe47ac132524cc7e3b699bc46

Which could explain why it wasn't caught in the autobuilder, and why I'm 
not able to reproduce it in my container that does not natively provides 
this lib (i.e., no /usr/include/yaml.h).

-- 
Best regards,
João Marcos Costa

Re: [OE-core] [PATCH v2 0/1] u-boot-tools: drop yaml in DT validation

[Michael Opdenacker]

Hi João Marcos

On 5/19/26 3:51 PM, Joao Marcos Costa wrote:
> Hello again,
>
> On 5/18/26 21:12, Michael Opdenacker wrote:
>> Hi João Marcos
>>
>> FYI, building the "qemuriscv64" machine is still broken on OE-core 
>> (master), and it's seems likely to be related to this change;
>>
>> | /usr/bin/ld: scripts/dtc/yamltree.o: in function `dt_to_yaml':
>> | yamltree.c:(.text+0x8fa): undefined reference to 
>> `yaml_emitter_initialize'
>> | /usr/bin/ld: yamltree.c:(.text+0x905): undefined reference to 
>> `yaml_emitter_set_output_file'
>> | /usr/bin/ld: yamltree.c:(.text+0x912): undefined reference to 
>> `yaml_stream_start_event_initialize'
>> | /usr/bin/ld: yamltree.c:(.text+0x91d): undefined reference to 
>> `yaml_emitter_emit'
> (...)
>
> This looks very much as the case described here:
>
> https://github.com/u-boot/u-boot/commit/807bcd844afeadbfe47ac132524cc7e3b699bc46 
>
>
> Which could explain why it wasn't caught in the autobuilder, and why 
> I'm not able to reproduce it in my container that does not natively 
> provides this lib (i.e., no /usr/include/yaml.h).


Indeed, I had the "libyaml-dev" package on my Debian 13 system, and the 
problem goes away when I remove it.
So, this explains why our autobuilder didn't catch this and I'm the only 
one who seems to be impacted.

So, this is a U-Boot issue. However, I wonder why the problem is still 
there while the above commit (present in 2026.04 that we're using) is 
supposed to fix it...
Thanks again
Cheers
Michael.

-- 
Root Commit
Embedded Linux Training and Consulting
https://rootcommit.com

Re: [OE-core] [PATCH v2 0/1] u-boot-tools: drop yaml in DT validation

[Joao Marcos Costa]

Hello,

On 5/19/26 18:24, Michael Opdenacker wrote:
> Hi João Marcos
> 
> On 5/19/26 3:51 PM, Joao Marcos Costa wrote:
>> Hello again,
>>
>> On 5/18/26 21:12, Michael Opdenacker wrote:
>>> Hi João Marcos
>>>
>>> FYI, building the "qemuriscv64" machine is still broken on OE-core 
>>> (master), and it's seems likely to be related to this change;
>>>
>>> | /usr/bin/ld: scripts/dtc/yamltree.o: in function `dt_to_yaml':
>>> | yamltree.c:(.text+0x8fa): undefined reference to 
>>> `yaml_emitter_initialize'
>>> | /usr/bin/ld: yamltree.c:(.text+0x905): undefined reference to 
>>> `yaml_emitter_set_output_file'
>>> | /usr/bin/ld: yamltree.c:(.text+0x912): undefined reference to 
>>> `yaml_stream_start_event_initialize'
>>> | /usr/bin/ld: yamltree.c:(.text+0x91d): undefined reference to 
>>> `yaml_emitter_emit'
>> (...)
>>
>> This looks very much as the case described here:
>>
>> https://github.com/u-boot/u-boot/commit/807bcd844afeadbfe47ac132524cc7e3b699bc46
>>
>> Which could explain why it wasn't caught in the autobuilder, and why 
>> I'm not able to reproduce it in my container that does not natively 
>> provides this lib (i.e., no /usr/include/yaml.h).
> 
> 
> Indeed, I had the "libyaml-dev" package on my Debian 13 system, and the 
> problem goes away when I remove it.
> So, this explains why our autobuilder didn't catch this and I'm the only 
> one who seems to be impacted.
> 
> So, this is a U-Boot issue. However, I wonder why the problem is still 
> there while the above commit (present in 2026.04 that we're using) is 
> supposed to fix it...
> Thanks again
> Cheers
> Michael.

Well, yes, it was not a definitive solution. In fact, fixing this once 
and for all was originally the point of my patch, which is merged into 
u-boot's master, but not in 2026.04 tag.

-- 
Best regards,
João Marcos Costa