Legacy libevl build
The information contained in this document only applies to libevl
prior to release #29 (r29), with a build system based on mere
Makefiles. These days, the meson build
system is used instead, as described in this document.
The generic command for building libevl prior to release 29 was:
$ make [-C $SRCDIR] [ARCH=$cpu_arch] [CROSS_COMPILE=$toolchain] UAPI=$uapi_dir [OTHER_BUILD_VARS] [goal...]
Main build variables
| Variable | Description |
|---|---|
| $SRCDIR | Path to this source tree |
| $cpu_arch | CPU architecture you build for (‘arm’, ‘arm64’, ‘x86’) |
| $toolchain | Optional prefix of the binutils filename (e.g. ‘arm-linux-gnueabihf-’, ‘aarch64-linux-gnu-’) |
Other build variables
| Variable | Description | Default |
|---|---|---|
| D={0|1} | Disable or enable debug build, i.e. -g -O0 vs -O2 | 0 |
| O=$output_dir | Generate binary output files into $output_dir | . |
| V={0|1} | Set build verbosity level, 0 is terse | 0 |
| DESTDIR=$install_dir | Install library and binaries into $install_dir | /usr/evl |
Make goals
| Goal | Action |
|---|---|
| all | generate all binaries (library, utilities and tests) |
| clean | remove the build files |
| install | do all, copying the generated system binaries to $DESTDIR in the process |
| install_all | install, copying all the generated binaries including the tidbits |
Cross-compiling EVL
Let’s say the library source code is located at ~/git/libevl, and the kernel sources featuring the EVL core is located at ~/git/linux-evl.
Cross-compiling EVL and installing the resulting library and utilities to a staging directory located at /nfsroot/<machine>/usr/evl would amount to this:
Cross-compiling from a separate build directory
# First create a build directory the where output files should go
$ mkdir /tmp/build-imx6q && cd /tmp/build-imx6q
# Then start the build+install process
$ make -C ~/git/libevl O=$PWD ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- UAPI=~/git/linux-evl DESTDIR=/nfsroot/imx6q/usr/evl install
or,
Cross-compiling from the EVL library source tree
$ mkdir /tmp/build-hikey
$ cd ~/git/libevl
$ make O=/tmp/build-hikey ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- UAPI=~/git/linux-evl DESTDIR=/nfsroot/hikey/usr/evl install
This is good practice to always generate the build output files to a separate build directory using the O= directive on the make command line, not to clutter your source tree with those. Generating output to a separate directory also creates convenience Makefiles on the fly in the output tree, which you can use to run subsequent builds without having to mention the whole series of variables and options on the make command line again.
Native EVL build
Conversely, you may want to build EVL natively on the target system. Installing the resulting library and utilities directly to their final home located at e.g. /usr/evl can be done as follows:
Building natively from a build directory
$ mkdir /tmp/build-native && cd /tmp/build-native
$ make -C ~/git/libevl O=$PWD UAPI=~/git/linux-evl DESTDIR=/usr/evl install
or,
Building natively from the EVL library source tree
$ mkdir /tmp/build-native
$ cd ~/git/libevl
$ make O=/tmp/build-native UAPI=~/git/linux-evl DESTDIR=/usr/evl install
