[SOLVED] how to write the compiler command or in Makefile to ARMv6

I was trying to compile a kernel module for my raspberry pi which runs 3.6.11+ Linux kerne. The kernel source on my development host is as same as the one running on rpi. When I do "modinfo spidev.ko" which is compiled on my host machine,
it shows "vermagic: 3.6.11+ preempt mod_unload modversions ARMv5".

However when I do "modinfo spidev.ko"(this module which comes with the image I downloaded from internet is under /lib/modules/kernel/drivers/spidev.ko in my raspberry pi), it shows "3.6.11+ preempt mod_unload modversions ARMv6".

Becasue the first one is ARMv5 so that it cannot be insmod to raspberry.

So does anybody know how to specify ARMv6 when I cross-compile the module on my host?

You should review the documentation for how configure tools to build the RPi kernel, here's one option:

http://elinux.org/RPi_Kernel_Compilation

Originally Posted by rtmistler You should review the documentation for how configure tools to build the RPi kernel, here's one option: http://elinux.org/RPi_Kernel_Compilation

Hi rtmistler, thanks for your help. I did add the extra flag in my Makefile as the website said. My Makefile is like below

**********************************************************
obj-m += hello.o
HOSTCFLAGS=-march=armv6zk -mtune=arm1176jzf-s
all:
make -C /home/gwang/raspi_tool/kernel M=$(PWD) modules
clean:
make -C /home/gwang/raspi_tool/kernel M=$(PWD) clean
**********************************************************

But however I did "modinfo hello.ko" after I compiled it. It still shows the arch is ARMv5.

Here below is compile message it gives:

****************************************************************
gwang@george-dell:~/Dropbox/modules$ make ARCH=arm CROSS_COMPILE=arm-bcm2708-linux-gnueabi-
make -C /home/gwang/raspi_tool/kernel M=/home/gwang/Dropbox/modules modules
make[1]: Entering directory `/home/gwang/raspi_tool/kernel'
CC [M] /home/gwang/Dropbox/modules/hello.o
/home/gwang/Dropbox/modules/hello.c:1:0: warning: "MODULE" redefined [enabled by default]
this is the location of the previous definition
/home/gwang/Dropbox/modules/hello.c:3:0: warning: "__KERNEL__" redefined [enabled by default]
<command-line>:0:0: note: this is the location of the previous definition
Building modules, stage 2.
MODPOST 1 modules
WARNING: "__gnu_mcount_nc" [/home/gwang/Dropbox/modules/hello.ko] undefined!
CC /home/gwang/Dropbox/modules/hello.mod.o
LD [M] /home/gwang/Dropbox/modules/hello.ko
make[1]: Leaving directory `/home/gwang/raspi_tool/kernel

gwang@george-dell:~/Dropbox/modules$ modinfo hello.ko
filename: hello.ko
license: GPL
srcversion: 81534A67BAB6D41BF92CCE5
depends:
vermagic: 3.6.11+ mod_unload modversions ARMv5 p2v8

***********************************************************************************

I think the proper term is "CFLAGS" not "HOSTCFLAGS", but those are the correct terms to use.

Another option which I didn't think of before is to build the module "on" the raspberry pi. That will clearly use the on system libraries an produce a result which will work on that machine.

I changed to CFLAGS but I still get the ARMv5 version module.
Did you mean build the module directly on ras pi? I guess that's possible gonna work but I still want to try out on host machine...

Originally Posted by rtmistler I think the proper term is "CFLAGS" not "HOSTCFLAGS", but those are the correct terms to use. Another option which I didn't think of before is to build the module "on" the raspberry pi. That will clearly use the on system libraries an produce a result which will work on that machine.

Originally Posted by rtmistler I think the proper term is "CFLAGS" not "HOSTCFLAGS", but those are the correct terms to use. Another option which I didn't think of before is to build the module "on" the raspberry pi. That will clearly use the on system libraries an produce a result which will work on that machine.

Hey man, I got it works, just change CONFIG_CPU_32v5 to CONFIG_CPU_32v6 in ./include/config/auto.conf and it will become armv6, but I still have to figure out how to add "preempt" option.

Congrats! I've not mucked with the kernel preempt option if that's what you're referring too. Pretty sure there's info on that available via some general web searching.