It is very inconvenient to maintain an application that both runs on a
Zephyr board and an out-of-tree board.
It forces one to write build scripts like this in the app:
if(BOARD STREQUAL my_out_of_tree_board)
set(BOARD_ROOT some/out/of/tree/board/path)
endif()
To avoid this we change the semantics of BOARD_ROOT. Instead of it
being a path to the board root it is now a prioritized list of board
root directories. Zephyr will append ZEPHYR_BASE to BOARD_ROOT.
This ensures that Zephyr boards can be used when the out-of-tree board
directory can not supply the requested board.
Signed-off-by: Sebastian Bøe <sebastian.boe@nordicsemi.no>
This is one way we can support out of tree board definitions. Basically
all this needs is a board definition in the application source directory
that follows the same structure we have in the main Zephyr tree (also
allowing multiple custom boards). An application tree would look like
this for example:
boards/
CMakeLists.txt
prj.conf
README.rst
src/
with boards following the same structure as in Zephyr:
.
├── boards
│ └── x86
│ └── arduino_101
│ ├── doc
│ │ └── img
│ └── support
└── src
To use this, you need to specify the BOARD_ROOT variable on the command
line when building:
cmake -DBOARD=<board name> -DBOARD_ROOT=<path to boards> ..
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
Introducing CMake is an important step in a larger effort to make
Zephyr easy to use for application developers working on different
platforms with different development environment needs.
Simplified, this change retains Kconfig as-is, and replaces all
Makefiles with CMakeLists.txt. The DSL-like Make language that KBuild
offers is replaced by a set of CMake extentions. These extentions have
either provided simple one-to-one translations of KBuild features or
introduced new concepts that replace KBuild concepts.
This is a breaking change for existing test infrastructure and build
scripts that are maintained out-of-tree. But for FW itself, no porting
should be necessary.
For users that just want to continue their work with minimal
disruption the following should suffice:
Install CMake 3.8.2+
Port any out-of-tree Makefiles to CMake.
Learn the absolute minimum about the new command line interface:
$ cd samples/hello_world
$ mkdir build && cd build
$ cmake -DBOARD=nrf52_pca10040 ..
$ cd build
$ make
PR: zephyrproject-rtos#4692
docs: http://docs.zephyrproject.org/getting_started/getting_started.html
Signed-off-by: Sebastian Boe <sebastian.boe@nordicsemi.no>
Sebastian Bøe