A Raspberry Pi emulated environment on OSX Lion

To set up an emulated environment of the Raspberry Pi software on OSX one will need:

• A Cross-Compiling Tool for the CPU architecture of RPi. ( eg. ARM EABI Toolchain )
  
• The RPi Kernel.
  
• The RPi root filesystem.
  
• The Emulator (QEMU).

• The Cross-Compiling Tool for the ARM architecture.

Assuming one already have the latest Xcode and command line tools from Apple Developer and homebrew installed, then should install the dependencies:

brew install mpfr gmp libmpc libelf texinfo

Grab and compile the tool:

mkdir ~/rpi
mkdir ~/rpi/arm-cs-tools
git clone https://github.com/jsnyder/arm-eabi-toolchain.git
cd arm-eabi-toolchain
PREFIX=$HOME/rpi/arm-cs-tools make install-cross
make clean
echo “export PATH=$HOME/rpi/arm-cs-tools/bin:$PATH” » ~/.bash_profile

• The RPi Kernel Compilation

mkdir ~/rpi/kernel
cd ~/rpi/kernel
git clone https://github.com/raspberrypi/linux.git
cd linux

Grab the config file and configure the kernel:

cp arch/arm/configs/bcmrpi_cutdown_defconfig .config
make ARCH=arm CROSS_COMPILE=~/rpi/arm-cs-tools/bin/arm-none-eabi- menuconfig

Save the configuration and let’s build the kernel afterwards. Note that the compilation should fail and complain about an <elf.h> inclusion in scripts/mod/mk_elfconfig. If it does, one must create the file:

sudo touch /usr/local/include/elf.h

Edit it and write the following:

#include <libelf.h>

#define R_386_NONE 0
#define R_386_32 1
#define R_386_PC32 2
#define R_ARM_NONE 0
#define R_ARM_PC24 1
#define R_ARM_ABS32 2
#define R_MIPS_NONE 0
#define R_MIPS_16 1
#define R_MIPS_32 2
#define R_MIPS_REL32 3
#define R_MIPS_26 4
#define R_MIPS_HI16 5
#define R_MIPS_LO16 6

and follow through the building process:

make ARCH=arm CROSS_COMPILE=~/rpi/arm-cs-tools/bin/arm-none-eabi- -k

The image file is created and located as arch/arm/boot/zImage.

• The Emulator

Due to a bug of a white screen hanging QEMU if compiled with llvm one must install the package apple-gcc42 from the homebrew’s dupes repository.

brew install homebrew/dupes/apple-gcc42

And then compile and install qemu like:

brew install qemu —use-gcc

Now we’re left with all we need to start the RPi distribution so let’s start it like:

qemu-system-arm -M versatilepb -cpu arm1176 -hda debian6-19-04-2012.img -kernel zImage -append “root=/dev/sda2” -serial stdio -usbdevice tablet

and...



Happy hacking kids!