[Gumstix-users] Trouble compiling kernel module

[Mike F. <fra...@or...>]

Hi,

I have recently started using OpenEmbedded for a project I'm doing on
a gumstix overo board. I'm trying to cross-compile a kernel module
using a bitbake recipe and keep running up against a wall. I'm
starting with a helloworld module and could not compile that.

So I tried to build the char-driver module in the OE recipes, that
also failed. I'm currently using the overo OE branch. I have managed
to successfully build the console-image I got the following output
from bitbake when building the char-driver with the command:

bitbake char-driver

NOTE: Psyco JIT Compiler (http://psyco.sf.net) not available. Install
it to increase performance.
NOTE: Handling BitBake files: / (7156/7156) [100 %]
NOTE: Parsing finished. 6877 cached, 0 parsed, 279 skipped, 2 masked.
NOTE: Cache is clean, not saving.
NOTE: Resolving any missing task queue dependencies
NOTE: Preparing runqueue
NOTE: Executing runqueue
NOTE: Running task 408 of 574 (ID: 8, /home/mike/courses/enel675/
org.openembedded.dev/recipes/char-driver/char-driver.bb, do_compile)
ERROR: function do_compile failed
ERROR: log data follows (/home/mike/courses/enel675/build/tmp/work/
overo-angstrom-linux-gnueabi/char-driver-1.0-r45/temp/log.do_compile.
5306)
| NOTE: make CROSS_COMPILE=arm-angstrom-linux-gnueabi- KERNELDIR=/home/
mike/courses/enel675/build/tmp/work/overo-angstrom-linux-gnueabi/linux-
omap3-2.6.30-r45/git CC=arm-angstrom-linux-gnueabi-gcc -march=armv7-a -
mtune=cortex-a8 -mfpu=neon -mfloat-abi=softfp
| make -C /home/mike/courses/enel675/build/tmp/work/overo-angstrom-
linux-gnueabi/linux-omap3-2.6.30-r45/git M=/home/mike/courses/enel675/
build/tmp/work/overo-angstrom-linux-gnueabi/char-driver-1.0-r45/char-
driver ARCH=arm CROSS_COMPILE=arm-angstrom-linux-gnueabi- modules
| make[1]: Entering directory `/home/mike/courses/enel675/build/tmp/
work/overo-angstrom-linux-gnueabi/linux-omap3-2.6.30-r45/git'
| scripts/Makefile.build:49: *** CFLAGS was changed in "/home/mike/
courses/enel675/build/tmp/work/overo-angstrom-linux-gnueabi/char-
driver-1.0-r45/char-driver/Makefile". Fix it to use EXTRA_CFLAGS.
Stop.
| make[1]: *** [_module_/home/mike/courses/enel675/build/tmp/work/
overo-angstrom-linux-gnueabi/char-driver-1.0-r45/char-driver] Error 2
| make[1]: Leaving directory `/home/mike/courses/enel675/build/tmp/
work/overo-angstrom-linux-gnueabi/linux-omap3-2.6.30-r45/git'
| make: *** [kernel-module] Error 2
| FATAL: oe_runmake failed
NOTE: Task failed: /home/mike/courses/enel675/build/tmp/work/overo-
angstrom-linux-gnueabi/char-driver-1.0-r45/temp/log.do_compile.5306
ERROR: TaskFailed event exception, aborting
ERROR: Build of /home/mike/courses/enel675/org.openembedded.dev/
recipes/char-driver/char-driver.bb do_compile failed

It seems that the bitbake recipe is calling the makefile with:
CC=arm-angstrom-linux-gnueabi-gcc -march=armv7-a -mtune=cortex-a8 -
mfpu=neon -mfloat-abi=softfp
which doesnt make sense to me. Shouldn't the compiler flags be passed
as a separate variable? Any help would be really appreciated.

Cheers,

Mike