[SOLVED] Compile for LibreELEC / SDK (RPi3) ?

V10lator · Jun 6th 2016

Sorry if this might sound stupid but finding documentation on this doesn't seem to be easy.

I'm searching for a way to compile my own binaries for LibreELEC / Raspberry Pi 3. These binaries should not be Kodi addons as I want to start them with the help of .config/autostart.sh (or systemd) and said binaries should handle things like fan control, LED control and so on.
So I'm simply searching a way to cross-compile for LibreELEC. Is there any good entry point for documentation?

Side question: This is my (quick&dirty) Makefile, is there anything to do better (i.e. CFLAGS, I guess -march=native won't work while cross compiling) ?

Code

#
# Makefile
#


# compiler to use
CC = gcc
AR = "gcc-ar"
NM = "gcc-nm"
RANLIB = "gcc-ranlib"


# flags to pass compiler
CFLAGS = -march=native -O2 -pipe -fno-ident -flto=8 -fuse-linker-plugin -floop-interchange -ftree-loop-distribution -floop-strip-mine -floop-block -fgraphite-identity -std=c99 -Wall -Werror
LDFLAGS = "-Wl,-O1 -Wl,--as-needed ${CFLAGS}"


# name for executable
EXE = testbinary


# space-separated list of header files
HDRS = gpio.h strtonum.h


# space-separated list of libraries, if any,
# each of which should be prefixed with -l
LIBS =


# space-separated list of source files
SRCS = gpio.c strtonum.c main.c


# automatically generated list of object files
OBJS = $(SRCS:.c=.o)


# default target
$(EXE): $(OBJS) $(HDRS) Makefile
    $(CC) $(CFLAGS) -o [email protected] $(OBJS) $(LIBS)


# dependencies
$(OBJS): $(HDRS) Makefile


# housekeeping
clean:
    rm -f core $(EXE) $(OBJS)

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**chewitt** · Jun 6th 2016

I normally copy simple x86_64 binary things over from an Ubuntu VM .. which generally works unless something is kernel specific or has a bunch of lib dependencies that aren't accounted for. If you really do need to compile things you're best off using the build-system and creating packages for them.

V10lator · Jun 6th 2016

Quote from chewitt

I normally copy simple x86_64 binary things over from an Ubuntu VM .. which generally works unless something is kernel specific or has a bunch of lib dependencies that aren't accounted for. If you really do need to compile things you're best off using the build-system and creating packages for them.

Sorry, I forgot to say that this is for the Raspberry Pi 3, so x86_64 binaries won't work.

**vpeter** · Jun 6th 2016

V10lator, why don't you create proper package for your programs and compile them as everything else is done in librelec?

V10lator · Jun 6th 2016

Quote from vpeter

V10lator, why don't you create proper package for your programs and compile them as everything else is done in librelec?

Cause I don't know how to "create proper package for your programs and compile them as everything else is done in librelec". Also I guess that means creating Kodi addons which isn't what I want.

Anyway, I found this: Kernel building - Raspberry Pi Documentation - It's not only usefull to compile kernels. In a nutshell:

Code

git clone https://github.com/raspberrypi/tools
PATH="${PATH}:$(pwd)/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian-x64/bin" /bin/bash

This opens a bash with a altered PATH including cross-compile tools. In that bash the following Makefile worked:

Code

#
# Makefile
#


# compiler to use
CC = arm-linux-gnueabihf-gcc
AR = arm-linux-gnueabihf-ar
NM = arm-linux-gnueabihf-nm
RANLIB = arm-linux-gnueabihf-ranlib
STRIP = arm-linux-gnueabihf-strip


# flags to pass compiler
#CFLAGS = -march=armv8-a -pipe -ggdb -std=c99 -Wall -Werror
CFLAGS = -march=armv8-a -O2 -pipe -fno-ident -flto=8 -floop-interchange -ftree-loop-distribution -floop-strip-mine -floop-block -fgraphite-identity -std=c99 -Wall -Werror
LDFLAGS = -Wl,-O1 -Wl,--as-needed $(CFLAGS)


# name for executable
EXE = testbinary


# space-separated list of header files
HDRS = gpio.h strtonum.h


# space-separated list of libraries, if any,
# each of which should be prefixed with -l
LIBS = 


# space-separated list of source files
SRCS = gpio.c strtonum.c main.c


# automatically generated list of object files
OBJS = $(SRCS:.c=.o)


# default target
$(EXE): $(OBJS) $(HDRS) Makefile
	$(CC) $(CFLAGS) -o [email protected] $(OBJS) $(LIBS)
#	$(STRIP) -s [email protected]


# dependencies
$(OBJS): $(HDRS) Makefile


# housekeeping
clean:
	rm -f core $(EXE) $(OBJS)

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While this is great progress there's one thing that annoys me: The gcc version used is from 2014. Does anyone know where to get a more modern toolchain?

**vpeter** · Jun 6th 2016

Clone Libreelec repo and build libreelec.
Then you will get toolchain build too. You can use it to build somethig outside libreelec build environment.

Code

user:~/LibreELEC/LibreELEC.tv$ ./build.LibreELEC-RPi2.arm-7.0.1/toolchain/bin/armv7ve-libreelec-linux-gnueabi-gcc -v
Using built-in specs.
COLLECT_GCC=/home/user/LibreELEC/LibreELEC.tv/build.LibreELEC-RPi2.arm-7.0.1/toolchain/bin/armv7ve-libreelec-linux-gnueabi-gcc-5.3.0
COLLECT_LTO_WRAPPER=/home/user/LibreELEC/LibreELEC.tv/build.LibreELEC-RPi2.arm-7.0.1/toolchain/lib/gcc/armv7ve-libreelec-linux-gnueabi/5.3.0/lto-wrapper
Target: armv7ve-libreelec-linux-gnueabi
Configured with: /home/user/LibreELEC/LibreELEC.tv/build.LibreELEC-RPi2.arm-7.0.1/gcc-5.3.0/configure --host=i686-linux-gnu --build=i686-linux-gnu --prefix=/home/user/LibreELEC/LibreELEC.tv/build.LibreELEC-RPi2.arm-7.0.1/toolchain ...........
Thread model: posix
gcc version 5.3.0 (GCC)

You create package with looking into one another.

**lrusak** · Jun 6th 2016

Creating a package doesn't mean it has to be an add-on. It's simply an easy way of cross compiling. You can then just copy the binary over.

tbob · Sep 14th 2016

Quote from vpeter

Clone Libreelec repo and build libreelec.
Then you will get toolchain build too. You can use it to build somethig outside libreelec build environment.

Code

user:~/LibreELEC/LibreELEC.tv$ ./build.LibreELEC-RPi2.arm-7.0.1/toolchain/bin/armv7ve-libreelec-linux-gnueabi-gcc -v
Using built-in specs.
COLLECT_GCC=/home/user/LibreELEC/LibreELEC.tv/build.LibreELEC-RPi2.arm-7.0.1/toolchain/bin/armv7ve-libreelec-linux-gnueabi-gcc-5.3.0
COLLECT_LTO_WRAPPER=/home/user/LibreELEC/LibreELEC.tv/build.LibreELEC-RPi2.arm-7.0.1/toolchain/lib/gcc/armv7ve-libreelec-linux-gnueabi/5.3.0/lto-wrapper
Target: armv7ve-libreelec-linux-gnueabi
Configured with: /home/user/LibreELEC/LibreELEC.tv/build.LibreELEC-RPi2.arm-7.0.1/gcc-5.3.0/configure --host=i686-linux-gnu --build=i686-linux-gnu --prefix=/home/user/LibreELEC/LibreELEC.tv/build.LibreELEC-RPi2.arm-7.0.1/toolchain ...........
Thread model: posix
gcc version 5.3.0 (GCC)

You create package with looking into one another.

Once you've built libreelec for your architecture, how do you get another project's build system to be aware of the toolchain you've installed. I can't imagine you just run ./configure and make and end up with the correct binary.

[SOLVED] Compile for LibreELEC / SDK (RPi3) ?

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