TS-7500

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Revision as of 15:36, 7 October 2010 by Cargoudel (talk | contribs) (initial article on the ts-7500)
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Overview

The TS-7500 is based on a Cavium CNS2132 (aka Star Semi STR8132) which contains a Faraday FA-526 core which basically resembles a ARM920T but has NO thumb or thumb interworking support which makes it not a fully EABI compliant architecture. However, as of GCC-4.4.2 (recommend at least GCC-4.4.4) EABI binaries can be built for ARMv4 architectures like this one. This guide helps you setup a openembedded toolchain and new kernel w/ EABI support. Most major linux distributions have decided to make ARMv4T (not ARMv4) the minimum supported architecture for their packages so OE is the best way to roll your own EABI Linux for this board. see the Debian discussion

Kernel

The kernel that comes default from Technologic Systems TS-7500 only supports OABI, so we first need to recompile the kernel linux-2.6.24-cavium_source_aug052010.tar.gz and see this for a reference for how-to get to kernel on your board.

Only a few changes need to be make to the default TS-7500 kernel .config

 #this first two are the most important options 
 CONFIG_AEABI=y
 #allows old OABI to still work like in the TS-7500's default initrd
 CONFIG_OABI_COMPAT=y
 #lets be able to check our configuration 
 CONFIG_IKCONFIG=y
 CONFIG_IKCONFIG_PROC=y
 #speed up floating point (not for scientific computing)
 # CONFIG_FPE_NWFPE is not set
 CONFIG_FPE_FASTFPE=y

Or you can use the prebuild kernel from here: ts7500/ make sure to cp modules.tar.gz into your initrd partition overwriting the old one.

Machine

A ts75xx.conf and tune-fa526.inc are here ts7500/ but they should be added into OE soon.

Angstrom

There is a couple of changes you need to make to Angstrom in my experience to get it working

distro/include/angstrom.inc

 #comment this line out .. it was adding thumb when it shouldn't have for a armv4 (bug?)
 #DISTRO_FEATURES += ' ${@["", "thumb-interwork"][bb.data.getVar('THUMB_INTERWORK', d, 1) == "yes"]}'
 #force 32-bit at all times
 ARM_INSTRUCTION_SET = "arm" 
 #no BX instructions  (maybe this fixed the above problem)
 THUMB_INTERWORK = "no"

distro/angstrom-2008.1.conf

 #gcc-4.4.4 seems to work better 
 ANGSTROM_GCC_VERSION_armv4              ?= "4.4.4"

an inittab from a base-image that works

 ::sysinit:/etc/init.d/rcS
 ::restart:/sbin/init
 ::ctrlaltdel:/sbin/reboot
 ::shutdown:/bin/umount -a -r
 ttyS0::respawn:/sbin/getty -L ttyS0 115200 vt100

You need to move some scripts out of rc.S get get it working with the standard chroot boot method for this board. Notice the lack of udev using busybox's mdev -s seems to work fine.

 root@ts75xx:/etc/rcS.d# ls
 S02banner       S38devpts.sh    S39hostname.sh