[Buildroot] [PATCH v3] boot/uboot: support custom DTS with CONFIG_OF_UPSTREAM

* [Buildroot] [PATCH v3] boot/uboot: support custom DTS with CONFIG_OF_UPSTREAM
@ 2026-10-03 21:06 Alexander Sverdlin
  2026-10-18 19:32 ` Thomas Petazzoni via buildroot
  0 siblings, 1 reply; 4+ messages in thread
From: Alexander Sverdlin @ 2026-10-03 21:06 UTC (permalink / raw)
  To: buildroot; +Cc: Alexander Sverdlin, Romain Naour, Vincent Jardin

Since U-Boot 2024.07, boards with CONFIG_OF_UPSTREAM build their device
trees from dts/upstream/src/<arch>/<vendor>/ instead of arch/<arch>/dts/,
so the files copied by BR2_TARGET_UBOOT_CUSTOM_DTS_PATH were misplaced.

Derive the destination from the U-Boot configuration, including the vendor
sub-directory taken from CONFIG_DEFAULT_DEVICE_TREE.

Signed-off-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
---
Changelog:
v3:
- reduced verbocity and duplication in the commit message, help text and
  code comments
v2:
- handle *u-boot.dtsi separately
- document the new behaviour with OF_UPSTREAM-enabled U-Boot builds
- https://lore.kernel.org/all/20260913133520.3423773-1-alexander.sverdlin@gmail.com/
v1:
- https://lore.kernel.org/all/20260901145225.579733-1-alexander.sverdlin@gmail.com/

 boot/uboot/Config.in |  5 ++---
 boot/uboot/uboot.mk  | 25 ++++++++++++++++++++++---
 2 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/boot/uboot/Config.in b/boot/uboot/Config.in
index 1eabd10407..c6cddee1a2 100644
--- a/boot/uboot/Config.in
+++ b/boot/uboot/Config.in
@@ -802,9 +802,8 @@ if BR2_TARGET_UBOOT_BUILD_SYSTEM_KCONFIG
 config BR2_TARGET_UBOOT_CUSTOM_DTS_PATH
 	string "Device Tree Source file paths"
 	help
-	  Space-separated list of paths to device tree source files
-	  that will be copied to arch/ARCH/dts/ before starting the
-	  build.
+	  Space-separated paths to device tree source files to copy into
+	  source tree before building.
 
 	  To use this device tree source file, the U-Boot configuration
 	  file must refer to it.
diff --git a/boot/uboot/uboot.mk b/boot/uboot/uboot.mk
index 5b3f46ac74..05972f6a79 100644
--- a/boot/uboot/uboot.mk
+++ b/boot/uboot/uboot.mk
@@ -426,10 +426,29 @@ endif # BR2_TARGET_UBOOT_BUILD_SYSTEM_LEGACY
 
 UBOOT_CUSTOM_DTS_PATH = $(call qstrip,$(BR2_TARGET_UBOOT_CUSTOM_DTS_PATH))
 
+# Linux uses arm64 where UBOOT_ARCH is arm.
+define UBOOT_INSTALL_CUSTOM_DTS
+	arch_dir="arch/$(UBOOT_ARCH)/dts"; \
+	dts_dir="$$arch_dir"; \
+	if grep -q "^CONFIG_OF_UPSTREAM=y" $(@D)/.config; then \
+		if grep -q "^CONFIG_ARM64=y" $(@D)/.config; then \
+			dts_dir="dts/upstream/src/arm64"; \
+		else \
+			dts_dir="dts/upstream/src/$(UBOOT_ARCH)"; \
+		fi; \
+		dt=$$(sed -n 's/^CONFIG_DEFAULT_DEVICE_TREE="\(.*\)"$$/\1/p' $(@D)/.config); \
+		case "$$dt" in */*) dts_dir="$$dts_dir/$${dt%/*}";; esac; \
+	fi; \
+	for dts in $(UBOOT_CUSTOM_DTS_PATH); do \
+		case "$$dts" in \
+		*u-boot.dtsi) cp -f "$$dts" $(@D)/$$arch_dir/;; \
+		*) cp -f "$$dts" $(@D)/$$dts_dir/;; \
+		esac; \
+	done
+endef
+
 define UBOOT_BUILD_CMDS
-	$(if $(UBOOT_CUSTOM_DTS_PATH),
-		cp -f $(UBOOT_CUSTOM_DTS_PATH) $(@D)/arch/$(UBOOT_ARCH)/dts/
-	)
+	$(if $(UBOOT_CUSTOM_DTS_PATH),$(UBOOT_INSTALL_CUSTOM_DTS))
 	$(TARGET_CONFIGURE_OPTS) \
 		PKG_CONFIG="$(PKG_CONFIG_HOST_BINARY)" \
 		PKG_CONFIG_SYSROOT_DIR="/" \
-- 
2.56.0

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