path: root/linux
diff options
authorGravatar Philipp Wagner <philipp.wagner@tum.de>2018-11-16 16:45:01 +0100
committerGravatar Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>2019-08-01 16:08:01 +0200
commit869773d6683fc5bc0d8b3a7240a3dd95e17e659d (patch)
tree346c77298e626b213a7c344845d3897361e97aac /linux
parent6120b02494064acda300b4531bf7337912359ee5 (diff)
Currently the BR2_LINUX_KERNEL_DTB_IS_SELF_BUILT option is only available to be selected by another config option. This option controls if the Linux build system should build the DTB itself, or if buildroot explicitly calls the Linux Makefile like "make something.dtb". My use case: I want to build an OpenRISC image with a custom device tree file. OpenRISC does not support appended DTBs, and I'm not using a bootloader, but link everything into a single kernel (vmlinux) image. The kernel option CONFIG_OPENRISC_BUILTIN_DTB allows me to specify a dtb file, which is typically located in the kernel source tree in arch/openrisc/boot/dts/NAME.dts. Since my dts file is not part of the upstream kernel, I have two options: either patch the kernel to include the DTS file, and then specify it using the CONFIG_OPENRISC_BUILTIN_DTB option. Or use buildroot's BR2_LINUX_KERNEL_CUSTOM_DTS_PATH config option to copy any DTS file to the kernel source tree, and then specify this file with CONFIG_OPENRISC_BUILTIN_DTB as before. However, the second option also requries the buildroot option BR2_LINUX_KERNEL_DTB_IS_SELF_BUILT to be set, otherwise I end up with a "make -C kerneldir NAME.dts" call, which doesn't work (no such target exists). Currently the BR2_LINUX_KERNEL_DTB_IS_SELF_BUILT option exists, but it's not visible/available. Simply making it available solves the problem for me nicely. Signed-off-by: Philipp Wagner <mail@philipp-wagner.com> [Arnout: add help text] Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Diffstat (limited to 'linux')
1 files changed, 7 insertions, 1 deletions
diff --git a/linux/Config.in b/linux/Config.in
index 871141fdcd..e275b8ad4f 100644
--- a/linux/Config.in
+++ b/linux/Config.in
@@ -375,7 +375,13 @@ if BR2_LINUX_KERNEL_DTS_SUPPORT
# The variable below address the second case, were you only want
# limited actions from buildroot.
- bool
+ bool "DTB is built by kernel itself"
+ help
+ Normally, the device tree(s) to be built have to be passed
+ explicitly to the kernel build system. For some binary
+ formats, however, the kernel build system links in the
+ device tree directly in the kernel binary. Select this option
+ if you have such a kernel binary format.