CM-T3517: Linux: Kernel - Revision history

Grinberg: /* Overview */

2013-03-11T13:02:06Z

‎Overview

Lifshitz at 16:42, 14 January 2013

2013-01-14T16:42:18Z

Show changes

Lifshitz: /* Bluetooth */

2012-10-17T09:54:19Z

‎Bluetooth

Show changes

Grinberg: /* Kernel command line */

2011-07-10T14:27:15Z

‎Kernel command line

Ilya: /* See also */

2011-04-11T13:54:11Z

‎See also

Igor: /* Building the kernel */

2010-12-27T13:19:12Z

‎Building the kernel

New page

== Overview ==
Linux kernel for CM-T3517 modules provides support for on-board peripherals and abstracts the functionality provided by the hardware. Current support coverage is specified at [http://www.compulab.co.il/t3517/html/t3517-os-support.htm O/S support coverage map] page. CompuLab provides ready-to-run binary kernel images, and source code of the modifications and additions made to the Linux kernel to work properly with CM-T3517 modules.

== Kernel command line ==
The Linux kernel for CM-T3517 is shipped with built-in command line parameters:
ubi.mtd=fs,2048 root=ubi0:rootfs rootfstype=ubifs console=ttyS2,115200 \
omapfb.mode=dvi:1024x768-24@60 omapfb.vram=1:4M vram=8M omapdss.def_disp=lcd

The default kernel command line defines primary console, default display settings, root device and root filesystem type.

Setting U-Boot {{parameter|bootargs}} environment variable overrides default kernel command line and can be used to set desired kernel parameters.

== Building kernel for CM-T3517 ==
=== Cross-Compiler ===
There are several options for cross-compilation toolchain setup. You can either compile your cross-compiler or use an already built cross-compiler. The cross-compiler should support the ARM embedded-application binary interface ("[http://en.wikipedia.org/wiki/Application_binary_interface#EABI EABI]")
* Pre-built toolchain:
** [http://www.codesourcery.com/sgpp/lite/arm/portal/release324 CodeSourcery]
* Tools for creating cross-compilers:
** [http://ymorin.is-a-geek.org/dokuwiki/projects/crosstool Crosstool-ng]: Builds a cross-compiler from source. Non-distribution specific.
** [http://www.gentoo.org/proj/en/base/embedded/handbook/index.xml?part=1&chap=4 Crossdev]: Gentoo's cross-compiler builder. Needs Gentoo.

=== U-Boot mkimage tool ===
U-Boot {{cmd|mkimage}} utility is required in order to create kernel images that can be loaded by the CM-T3517 bootloader.
You can download prebuilt [[media:mkimage.tar.gz|{{cmd|mkimage}} binary]] or build it yourself:
<pre>
mkdir ~/tmp
cd tmp
wget ftp://ftp.denx.de/pub/u-boot/u-boot-latest.tar.bz2
tar -xjvf u-boot-latest.tar.bz2
cd u-boot-20xx.xx
touch include/config.{h,mk}
make tools
sudo install tools/mkimage /usr/local/bin
</pre>

=== Getting kernel sources ===
There are two ways to get Linux kernel sources that can be used as a baseline for CM-T3517 kernel. You can create a copy of linux-omap git tree or download a snapshot and extract it. We assume that you have created {{filename|/home/development/cm-t3517/kernel}} directory for CM-T3517 kernel development.
==== Snapshot download ====
* Download [http://git.kernel.org/?p=linux/kernel/git/tmlind/linux-omap-2.6.git;a=snapshot;h=3fd5969a81a9324b58a1c19cf510c0da97c99565;sf=tgz snapshot] with your web browser. Note, that tools like {{cmd|wget}} and {{cmd|curl}} will not work here.
* Extract the downloaded archive {{filename|linux-omap-2.6-3fd5969.tar.gz}}
<pre>
cd /home/development/cm-t3517/kernel
tar xzvf /path/to/downloaded/linux-omap-2.6-3fd5969.tar.gz
</pre>
: This will create {{filename|/home/development/cm-t3517/kernel/linux-omap-2.6}} directory containing linux-omap kernel tree.
* Apply the CM-T3517 patch
<pre>
cd /home/development/cm-t3517/kernel/linux-omap-2.6
patch -p1 < /path/to/t3517-linux/kernel/linux-2.6.32-3fd5969a81a9324b58a1c19cf510c0da97c99565-cm-t3517.patch
</pre>

==== Git clone ====
* Install [http://git-scm.com/ git] version control system.
* Create a clone of linux-omap kernel tree
<pre>
cd /home/development/cm-t3517/kernel
git clone git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2.6.git linux-omap-2.6
</pre>
* Create a branch for CM-T3517 development. The CM-T3517 patches are generated vs. commit 3fd5969a81a9324b58a1c19cf510c0da97c99565 in the linux-omap tree. It is recommended to use exactly the same baseline to avoid merge conflicts.
<pre>
git checkout -b cm-t3517-dev 3fd5969a81a9324b58a1c19cf510c0da97c99565
</pre>
* Apply the CM-T3517 patch
<pre>
cd /home/development/cm-t3517/kernel/linux-omap-2.6
git apply /path/to/t3517-linux/kernel/linux-2.6.32-3fd5969a81a9324b58a1c19cf510c0da97c99565-cm-t3517.patch
</pre>

=== Building the kernel ===
<pre>
export ARCH=arm
export CROSS_COMPILE=arm-none-linux-eabi-
make cm_t3517_defconfig
make menuconfig
make && make uImage && \
INSTALL_MOD_PATH=/home/development/cm-t3517/rootfs make modules_install
</pre>

In the example above, the Linux kernel image ({{filename|uImage}}) will be created in {{filename|/home/development/cm-t3517/kernel/linux-omap-2.6/arch/arm/boot}}, and the loadable kernel modules will be installed into the {{filename|/home/development/cm-t3517/rootfs/lib/modules}} directory.

When the CM-T3517 is booted with the kernel image created as described above and with networked root filesystem at {{filename|/home/development/cm-t3517/rootfs/}}, the system will be able to load the kernel modules properly, thus avoiding module version problems.

== See also ==
* [[CM-T3517: Linux: Getting started]]
* [[CM-T3517: Linux: Debian]]
* [[U-Boot for CM-T3517]]

[[Category:Linux]]
[[Category:CM-T3517]]

@@ Line 1: / Line 1: @@
 == Overview ==
-Linux kernel for CM-T3517 modules provides support for on-board peripherals and abstracts the functionality provided by the hardware. Current support coverage is specified at [http://www.compulab.co.il/t3517/html/t3517-os-support.htm O/S support coverage map] page. CompuLab provides ready-to-run binary kernel images, and source code of the modifications and additions made to the Linux kernel to work properly with CM-T3517 modules.
+Linux kernel for CM-T3517 modules provides support for on-board peripherals and abstracts the functionality provided by the hardware. Current support coverage is specified at [http://compulab.co.il/products/availability-of-os-and-drivers-for-cm-t3517-sbc-t3517/ O/S support coverage map] page. CompuLab provides ready-to-run binary kernel images, and source code of the modifications and additions made to the Linux kernel to work properly with CM-T3517 modules.
 == Kernel command line ==

@@ Line 4: / Line 4: @@
 == Kernel command line ==
 The Linux kernel for CM-T3517 is shipped with built-in command line parameters:
-  ubi.mtd=fs,2048 root=ubi0:rootfs rootfstype=ubifs console=ttyS2,115200 \
+  ubi.mtd=rootfs,2048 root=ubi0:rootfs rootfstype=ubifs console=ttyS2,115200 \
   omapfb.mode=dvi:1024x768-24@60 omapfb.vram=1:4M vram=8M omapdss.def_disp=lcd

@@ Line 80: / Line 80: @@
 When the CM-T3517 is booted with the kernel image created as described above and with networked root filesystem at {{filename|/home/development/cm-t3517/rootfs/}}, the system will be able to load the kernel modules properly, thus avoiding module version problems.
 == See also ==
@@ Line 85: / Line 174: @@
 * [[CM-T3517: Linux: Debian]]
 * [[U-Boot for CM-T3517]]
 [[Category:Linux]]
 [[Category:CM-T3517]]