TS-7600 kernel compile guide

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:

sudo apt-get install build-essential libncurses5-dev libncursesw5-dev git
## If you are on a 64-bit system then 32-bit libraries will be required for the toolchain
# sudo apt-get install ia32-libs

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

Download sources and configure

git clone https://github.com/embeddedarm/linux-2.6.35.3-imx28.git

# This sets up the default configuration that we ship with
make ts7600_defconfig
ln -sf initramfs.cpio-ts7600 initramfs.cpio

Once you have the configuration ready you can make your changes to the kernel. Commonly a reason for recompiling is to add support that was not built into the standard image's kernel. You can get a menu to browse available options by running:

make menuconfig

You can use the "/" key to search for specific terms through the kernel.

Build the kernel

Once you have it configured you can begin building the kernel. This usually takes about 5-10 minutes.

make

Build bootstream

The i.MX28 utilizes what Freescale calls a "bootstream," this is a series of "bootlets" that are all put together in a binary blob. The default bootstream sets up RAM, power, and contains the kernel to be run. Every time a kernel is rebuilt, a new bootstream must be compiled containing the new kernel image. The following script is used to take the newly built kernel and output a bootstream for an SPI device as well as an SD card:

./build_bootstream

This will create two files in imx-bootlets-src-10.12.01/ imx28_ivt_linux.sb and imx28_ivt_linux.spi. The .sb file is the standard image used for the SD card, while the .spi is meant to be imaged to the SPI flash device on the TS-7600.

Building External Wireless Modules

In order to support the wide range of USB wifi modules that Technologic Systems has offered over the years, the compat-wireless project is used to build all compatible modules. A simple command is used to build them:

./build_wireless

Install the bootstream (kernel/initramfs) and Modules

Next you need to install the kernel and modules to the SD card. Freescale uses a specialized booting mechanism for their processor, so to simplify installation we provide two scripts to handle installation of the kernel+bootstream, kernel modules, headers, and compat-wireless modules.

For example, if your workstation's SD card is /dev/mmcblk0:

./install_bootstream imx-bootlets-src-10.12.01/imx28_ivt_linux.sb mmcblk0 p1
./install_hdr_mod mmcblk0p2

Note:

On newer linux distributions, the output of 'fdisk' has changed. If the unit fails to boot after a compile, take a look at the output of the './install_bootstream ... ' command. If the line ./install_bootstream: line 122: [: !=: unary operator expected is printed, then you need to apply the patch to fix this. Use the following command to apply the patch: patch -p1 < install_bootstream-newer-fdisk.patch

Install the bootstream (kernel/initramfs) to SPI flash

The `./build_bootstream` command creates the file "imx-bootlets-src-10.12.01/imx28_ivt_linux.spi" that can be used to program the SPI flash, see the SPI Flash section for more information. The `./install_hdr_mod` command copies both the SPI bootstream and the stock bootstream to /lib/modules so they may be used to program SPI devices or NAND.

This bootstream is the exact same kernel/initramfs that is made for the SD card, it has the exact same init script.. Note that the SPI flash is bootable by itself, with or without an SD card. However, if an SD card is not used, there will be no Debian libraries to use or a Debian filesystem to boot to, only the busybox/uclibc environment that is in the initramfs.