linux: add option to enable support for Device Tree overlays

Add an option to compile device trees in Linux with symbol generation
such that device tree overlays can be loaded on the target system

Signed-off-by: Titouan Christophe <titouan.christophe@railnova.eu>
[Arnout: remove "default n" and move setting of LINUX_MAKE_ENV to the
 place where the rest is set.]
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
This commit is contained in:
Titouan Christophe 2019-01-15 15:15:48 +01:00 committed by Arnout Vandecappelle (Essensium/Mind)
parent 4c8760bdc5
commit eb37deb670
2 changed files with 12 additions and 0 deletions

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@ -394,6 +394,14 @@ config BR2_LINUX_KERNEL_CUSTOM_DTS_PATH
You can provide a list of dts paths to copy and You can provide a list of dts paths to copy and
build, separated by spaces. build, separated by spaces.
config BR2_LINUX_KERNEL_DTB_OVERLAY_SUPPORT
bool "Build Device Tree with overlay support"
help
If enabled, pass the "-@" option to dtc, such that
symbols are generated in the compiled Device Tree.
Choose this option to support Device Tree overlays
on the target system.
endif endif
config BR2_LINUX_KERNEL_INSTALL_TARGET config BR2_LINUX_KERNEL_INSTALL_TARGET

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@ -143,6 +143,10 @@ ifeq ($(BR2_TOOLCHAIN_GCC_AT_LEAST_8),y)
LINUX_MAKE_ENV += KCFLAGS=-Wno-attribute-alias LINUX_MAKE_ENV += KCFLAGS=-Wno-attribute-alias
endif endif
ifeq ($(BR2_LINUX_KERNEL_DTB_OVERLAY_SUPPORT),y)
LINUX_MAKE_ENV += DTC_FLAGS=-@
endif
# Get the real Linux version, which tells us where kernel modules are # Get the real Linux version, which tells us where kernel modules are
# going to be installed in the target filesystem. # going to be installed in the target filesystem.
LINUX_VERSION_PROBED = `$(MAKE) $(LINUX_MAKE_FLAGS) -C $(LINUX_DIR) --no-print-directory -s kernelrelease 2>/dev/null` LINUX_VERSION_PROBED = `$(MAKE) $(LINUX_MAKE_FLAGS) -C $(LINUX_DIR) --no-print-directory -s kernelrelease 2>/dev/null`