Ts75xx kernel compile guide

The TS kernel is built from the same Linux sources Cavium Networks has tested and used on their CPU evaluation boards. There are no Technologic Systems specific drivers or kernel support implemented. Instead, there has been userspace driver support implemented for the SPI NOR flash, MicroSD cards, XNAND drive, battery-backed real-time clock, XUART serial port channels, watchdog, and GPIO pins. This allows easy migration to newer kernels when either Cavium or the mainline Linux kernel community creates them. In the past, constant Linux-internal API redesign required rewriting and revisiting custom drivers with each new kernel revision, in effect locking customers in to whatever kernel version was released and tested during initial product release. Being free to update to newer kernels in the future allows easier support of the new USB devices as those drivers tend to only be developed for the newest kernel sources.

We provide Linux 2.6.24 as the supported kernel.

WARNING:

Backup any important data on the board before replacing the kernel.

For adding new support to the kernel, or recompiling with more specific options you will need to have an X86 compatible linux host available that can handle the cross compiling. Compiling the kernel on the board is not supported or recommended. Before building the kernel you will need to install a few support libraries on your workstation:

Prerequisites

RHEL/Fedora/CentOS:

yum install ncurses-devel ncurses
yum groupinstall "Development Tools" "Development Libraries"

Ubuntu/Debian:

apt-get install build-essential libncurses5-dev libncursesw5-dev

For other distributions, please refer to their documentation to find equivalent tools.

Set up the Sources and Toolchain

# Download the cross compile toolchain (OABI)from Technologic Systems:
wget ftp://ftp.embeddedTS.com/ts-arm-sbc/ts-7500-linux/cross-toolchains/crosstool-linux-arm-uclibc-3.4.6.tar.gz

#Extract to current working directory:
tar xvf crosstool-linux-arm-uclibc-3.4.6.tar.gz

#Download the Cavium Sources
wget ftp://ftp.embeddedTS.com/ts-arm-sbc/ts-7500-linux/sources/linux-2.6.24-ts-src-aug102009.tar.gz

#Extract the Kernel Sources
gzip -dc linux-2.6.24-ts-src-aug102009.tar.gz | tar xf -

cd linux-2.6.24-cavium/

export ARCH=arm
export CROSS_COMPILE=../arm-uclibc-3.4.6/bin/arm-linux-

# This sets up the default configuration for the Cavium CPU
make ts7500_defconfig

Note:

If you get the message "Make: *** mixed implicit and normal rules. Stop." Then you may need to downgrade your version of make.

make menuconfig

This will bring up a graphical menu where you can edit the configuration to include support for new devices. For Example, to include CIFS support, use the arrow and Enter keys to navigate to Filesystems -> Network File Systems -> CIFS Support. Press "y" to include CIFS support into the kernel (alternatively, you could modularize the feature with "m" so you can enable or disable the module on demand which will also enable you to simply copy/paste the cifs.ko into the correct path in the kernel instead of copying the entire kernel (outlined below in appendix)). Keep hitting "exit" until you're prompted to save changes, choose "yes".

Once you have it configured, start building. This usually takes a few minutes.

make && make modules

The new kernel will be at "arch/arm/boot" in a compressed format called "zImage". The uncompressed version is simply called "Image". With the default partitioning scheme it is REQUIRED that the kernel be < 2096640 bytes in size. If you need to shorten the size, try including your changes to the kernel as modules instead. Otherwise you will need to resize the kernel partition to account for the size difference.

Now that you have a kernel you can install it as you would our stock. See the #Backup / Restore section for examples on writing this to disk.

Now we need to install the modules.

mkdir newmodules
INSTALL_MOD_PATH=newmodules make modules_install

#Replace /dev/sdb with your sd card
mkdir /mnt/miniSD4
mount /dev/sdb4 /mnt/miniSD4/

#Remove existing modules:
rm -r /mnt/miniSD4/lib/modules/*
cp -r newmodules/* /mnt/miniSD4/

umount /mnt/miniSD4

After you install the new modules, you will need to boot the kernel and run "depmod -a" to rebuild the dependency map. You can them use modprobe to load the individual modules.

You can also copy individual modules to your existing kernel assuming the kernel is the exact same version as the installed one.

If you require functionality from a newer kernel, we also provide sources for the 2.6.36 kernel patched with support as-is. You can find the sources here. You will need to also use this toolchain. The rest of the steps for building the kernel are the same. This kernel should function the same as the other, however the USB device driver is not implemented. We strongly suggest using the 2.6.24 kernel unless you have a requirement for a later kernel as the 2.6.24 is supported and has gone through much more testing through various productions.

We also now have a copy of a 3.4.0 kernel source here. These same instructions are applicable but you will need to use this toolchain instead of the one used with 2.6.24.