Building linux for psp - busybox

Busybox provides many core linux utilities in a single package. Get a busybox 1.7.0 version from http://busybox.net/ .
Untar it and apply the busybox-0.21 patch from here http://jacksonm88.googlepages.com/linuxonpsp.htm
and copy the config file to /path/to/busybox/.config
use this command to customize the tools u need
make CROSS_COMPILE=mipsel-linux- LDFLAGS="-static -Wl,-elf2flt" CFLAGS="-fno-jump-tables" menuconfig
The -static option is because mmu-less systems dont support shared libraries, -Wl,-elf2flt says the compiler to convert the elf executable to flat which is supported by mmu-less systems. I didn't quite understand the use of -fno-jump-tables, but as it is mentioned in jacksons site "-fno-jump-tables is essential too as it tells gcc not to generate relocation entries of GPREL32 frequently used in jump tables".
Do the below command to locally install busybox into /path/to/busybo/_install
make CROSS_COMPILE=mipsel-linux- LDFLAGS="-static -Wl,-elf2flt" CFLAGS="-fno-jump-tables" install
If u want to install in another directory edit the install options for busybox with menuconfig.
next is we compile kernel and specify the busybox install

Building linux for psp - getting toolchain / crosscompiler

Here i will explain how to get the psp-linux toolchain. Not that this is not the same toolchain which is used to compile homebrew applications.

1) Get the buildroot sutable for the patches 20071216 version ; but if u go to buildroot website u will not find this , so checkout a version from svn close to this

svn co --revision 20650 svn://uclibc.org/trunk/buildroot

2) Get the patches from http://jacksonm88.googlepages.com/linuxonpsp.htm

3) Edit the patches to match the location of the buildroot (where you save it)
for example if my location of build root is /home/vijay/stuff/embeddedsystems/psplinux/buildroot/buildroot
u need to change the following in the patch file
/usr/src/buildroot/./toolchain_build_mipsel/gcc-4.2.1/libgomp/configure
to
/home/vijay/stuff/embeddedsystems/psplinux/buildroot/buildroot/toolchain_build_mipsel/gcc-4.2.1/libgomp/configure
edit all the patches as above

4) Now as mentioned here http://jacksonm88.googlepages.com/linuxonpsp.htm
add $(BUILDROOT)/build_mipsel/staging_dir/usr/bin/ to your search PATH by
PATH=$PATH:/path/to/buidroot/build_mipsel/staging_dir/usr/bin
This is during compilation of uclibc libraries. It searches the PATH variable for the mipsel-linux-gcc command. Basically when u type a command in terminal; linux system searches for that command in the locations defined in PATH variable.
Place the gcc,uclibc and elf2flt patches to
$(BUILDROOT)/toolchain/gcc/4.2.1/
$(BUILDROOT)/toolchain/uClibc/
$(BUILDROOT)/toolchain/elf2flt/
Buildroot applies these patches during build time.

5)Apply the buildroot patch
cd /path/to/buildroot/
patch -p1 < /path/to/buildroot-20071216.linuxonpsppatch
Now it may compile that a particular file has not found manually enter the path, just give the complete path to the file

6) configuring builroot
copy the buildroot-20071216-linuxonpsp.config to $(BUILDROOT)/
U need to change the .config file in the /path/to/buildroot folder with the above file ; this file contains the information about wht to build and all
cp /path/to/buildroot-20071216-linuxonpsp.config /path/to/buildroot/.config
use the below command from /path/to/buildroot directory to customize the options
cd /path/to/buildroot
make menuconfig

7) configuring uclibc c library
use
make uclibc-menuconfig
this will download the uclibc-0.9.29 and start menuconfig for customizing the option; just exit menuconfig for now. and copy the uclibc-0.9.29-linuxonpsp.config to the $(BUILDROOT)/toolchain_build_mipsel/uClibc-0.9.29 folder
cp /path/to/uclibc-0.9.29-linuxonpsp.config /path/to/buildroot/toolchain_build_mipsel/uClibc-0.9.29/.config
We will now again issue the make uclibc-menuconfig for customizing,
Select the below options

Target Architecture Features and Options --->
(/path/to/buildroot/toolchain_build_mipsel/linux/include)
String and Stdio Support --->
[*] Support Signed Characters In 'ctype.h' Functions.
ctype argument checking (Do not check -- unsafe) --->
uClibc development/debugging options --->
(/path/to/buildroot/build_mipsel/staging_dir/usr/bin/mipsel-linux-uclibc-)

This a resolves a error later, Enable any other options/support u require and exit the menuconfig
Now u are ready for buildind the toolchain.

8) Start building toolchain/cross compiler
cd /path/to/buildroot make source make

9) Possible problems and solutions
As mentioned here http://jacksonm88.googlepages.com/linuxonpsp.htm u may encounter one of the following problems

1) Possible issue 1:
make[4]: *** [bfd.info] Error 1
make[4]: Leaving directory `/usr/src/buildroot-20071216/toolchain_build_mipsel/binutils-2.18-build/bfd/doc'
...
make[4]: Leaving directory `/usr/src/buildroot-20071216/toolchain_build_mipsel/binutils-2.18-build/bfd'
make[3]: *** [info-recursive] Error 1
make[3]: Leaving directory `/usr/src/buildroot-20071216/toolchain_build_mipsel/binutils-2.18-build/bfd'
make[2]: *** [all-bfd] Error 2
make[2]: Leaving directory `/usr/src/buildroot-20071216/toolchain_build_mipsel/binutils-2.18-build'
make[1]: *** [all] Error 2
make[1]: Leaving directory `/usr/src/buildroot-20071216/toolchain_build_mipsel/binutils-2.18-build'
make: *** [/usr/src/buildroot-20071216/toolchain_build_mipsel/binutils-2.18-build/binutils/objdump] Error 2

Workaround:
cd /usr/src/buildroot-20071216/toolchain_build_mipsel/binutils-2.18-build/bfd/doc
makeinfo --split-size=5000000 --split-size=5000000   -I /usr/src/buildroot-20071216/toolchain_build_mipsel/binutils-2.18/bfd/doc -o bfd.info `test -f 'bfd.texinfo' || echo '/usr/src/buildroot-20071216/toolchain_build_mipsel/binutils-2.18/bfd/doc/'`bfd.texinfo
continue to run make under $(BUILDROOT)/

2) Possible issue 2:
if [ ! -e /usr/src/buildroot-20071216/build_mipsel/staging_dir/mipsel-linux-uclibc/bin/cc ]; then \
ln -snf gcc /usr/src/buildroot-20071216/build_mipsel/staging_dir/mipsel-linux-uclibc/bin/cc; \
fi
ln: creating symbolic link `/usr/src/buildroot-20071216/build_mipsel/staging_dir/mipsel-linux-uclibc/bin/cc' to `gcc': No such file or directory
make: *** [/usr/src/buildroot-20071216/toolchain_build_mipsel/gcc-4.2.1-final/.installed] Error 1

Workaround:
cd $(BUILDROOT)/build_mipsel/staging_dir/
ln -s usr/mipsel-linux-uclibc/ mipsel-linux-uclibc
continue to run make under $(BUILDROOT)/

3) Possible issue 3:
install -c /usr/src/buildroot-20071216/project_build_mipsel/linuxonpsp/root/usr/bin/ldd \
/usr/src/buildroot-20071216/build_mipsel/staging_dir/mipsel-linux-uclibc/target_utils/ldd
install: cannot stat `/usr/src/buildroot-20071216/project_build_mipsel/linuxonpsp/root/usr/bin/ldd': No such file or directory
make: *** [/usr/src/buildroot-20071216/project_build_mipsel/linuxonpsp/root/usr/bin/ldd] Error 1

Workaround:
touch $(BUILDROOT)/project_build_mipsel/linuxonpsp/root/usr/bin/ldd
continue to run make under $(BUILDROOT)/

4) Possible issue 4:
[ -f /usr/src/buildroot-20071216/build_mipsel/staging_dir/bin/mipsel-linux-uclibc-ld.real ] || \
mv /usr/src/buildroot-20071216/build_mipsel/staging_dir/bin/mipsel-linux-uclibc-ld /usr/src/buildroot-20071216/build_mipsel/staging_dir/bin/mipsel-linux-uclibc-ld.real
mv: can't stat source /usr/src/buildroot-20071216/build_mipsel/staging_dir/bin/mipsel-linux-uclibc-ld
make[1]: *** [install] Error 1
make[1]: Leaving directory `/usr/src/buildroot-20071216/toolchain_build_mipsel/elf2flt'
make: *** [/usr/src/buildroot-20071216/toolchain_build_mipsel/elf2flt/elf2flt] Error 2

Workaround:
cd $(BUILDROOT)/build_mipsel/staging_dir/bin/
ln -s `find .. -name 'mipsel-linux-uclibc-ld'` mipsel-linux-uclibc-ld
cd $(BUILDROOT)/toolchain_build_mipsel/elf2flt/
make install
continue to run make under $(BUILDROOT)/

10) Remeber if u needed to do a ( make clean and make )in the buildroot directory for rebuilding the toolchain with extra options; Issue the Steps in possible issue :4 otherwise -elf2flt support will be broken in toolchain
11) now add the /path/tp/buildroot/build_mipsel/staging_dir/usr/bin to ur PATH variable permanently by editing the .bashrc file in home directory
echo "export PATH=$PATH:/path/tp/buildroot/build_mipsel/staging_dir/usr/bin" >> ~/.bashrc
12) Now u r up with the toolchain for psp linux development :)

Building linux for psp - Introduction

Hi recently i was looking at getting linux on to my psp and found this site.
http://jacksonm88.googlepages.com/linuxonpsp.htm
The information provided here is not enough for a noob like me to get it up from start ; I had to do a lot of twiking around, google alot ask about my problem at http://ps2.dev.org to get it up and in the process i learned alot about linux :) .

Basically getting linux on psp or embedded system for that matter, Involves the following steps

1) Get a cross compiler / toolchain
2) Get a bootloader
3) Compile a kernel with drivers
4) Get a rootfs

Before going further i would like to mentions some details about the psp hardware and its limitations for running linux. PSP has a mips microcontroller / arch mips32, mmu-less. The mmu is a important unit for any OS. Fortunately there is a branch of linux which can be run on a mmu-less processors called uClinux. But it is very limited.
The limitations of a mmu-less system as far as i understood are
- No glibc
- It does not support shared libraries.
- The executable file format should be flat, ELF is not supported.

Qtopia phone edition on fedora-arm / arm arch

I wanted to test qtopia, but since i dont have real hardware that support embedded linux i compiled it for arm arch and tested on the fedora-arm running on qemu. have a look here
http://montamer.blogspot.com/2008/08/fedora-arm-distribution-on-qemu.html
I compiled qtopia with the following configuration options, have a look at the doc files provided with the source , the options are straight forward.
../qtopia-opensource-src-4.3.2-snapshot-20080801/configure -separate-debug-info -little-endian -arch arm -no-telephony -no-modem -no-bluetooth -no-infrared -displaysize 170mmx130mm -prefix /opt/qtopia -extra-qtopiacore-config "-embedded arm -qt-gfx-linuxfb "
edit the qtopia-opensource-src/qtopiacore/qconfig-qpe.h if u want cursor, simply comment out the no cursor options in Qtopia core section.
do "make" and "make install" which will generate a folder called "Image" where u compiled; transfer the contents in the image folder to "/opt/qtopia" directory in fedora-arm linux ; remember that i compiled with prefix "/opt/qtopia".
start the qtopia phone edition (qpe) by issuing
/opt/qtopia/bin/qpe -qws
command in fedora-arm. Play around a little with the interface :).

Porting it to a real device may be difficult maybe a little tough (i have not tried yet) . U have to adjust the parameters like which /dev/xxx to use for what; shortcut keys etc ........ have a look at "/qtopia-opensource-src/device" folder create a new folder there with custom files and adjust the '-xplatform nameoffolder' to the name of that folder.

X on fedora-arm

Im trying to get Xserver running on fedora-arm for some time to test GUI applications that i compile for arm . I didn't have that much experience with yum. I have used fedora-5 for 6 monthsand then shifted to ubuntu. I tried "yum groupinstall "X Window System"", but it didn't work as it supposed to so i have to manually select the xorg packages i have to install to get X windows running. Here is the list of packages i installed
xorg-x11-xauth
xorg-x11-apps
xorg-x11-xinit
xorg-x11-utils
xorg-x11-server-utils
xorg-x11-drv-fbdev
xorg-x11-drv-vga
xorg-x11-drv-cirrus
xorg-x11-fonts-misc
xorg-x11-fonts-75dpi
xorg-x11-server-Xvfb
xorg-x11-twm
I don't exactly know what to install and what not from above; Im just making trail and error. twm is the minimistinc window-manager. u can also install fluxbox. Remember if u issue startx it will start twm, if u want to start fluxbox instead of twm edit the xinitrc file.

Fedora-arm distribution on qemu

Qemu can emulate almost every processor. You can emulate a arm processor on qemu and install fedora-arm linux distribution on it. Look at this link for further details on how to setup.
http://fedoraproject.org/wiki/Architectures/ARM/HowToQemu .
and here is repo whr u can get arm rpm packages
http://ftp.linux.org.uk/pub/linux/arm/fedora/pub/fedora/linux/releases/8/Everything/arm/os/Packages/
It has an gcc 4.1.2 arm5vtel installed in it, so u can compile applications and test for arm, But the compilation is very slow, On my core2duo 2.13 GHz it took one and half day to compile gcc-4.2.2. :-/ .