CM-A510: Linux: Kernel - Revision history

Grinberg: /* Custom kernel command line options */

2015-08-31T13:15:14Z

‎Custom kernel command line options

Mike at 15:53, 25 January 2011

2011-01-25T15:53:31Z

Dimitry: 1 revision(s)

2010-11-03T11:35:49Z

1 revision(s)

Igor at 15:40, 27 October 2010

2010-10-27T15:40:10Z

New page

== Overview ==
The CM-A510 Linux kernel 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/a510/html/a510-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-A510 modules.

== Kernel command line ==
The CM-A510 Linux kernel is shipped with built-in command line parameters:
ubi.mtd=1,2048 root=ubi0_0 rootfstype=ubifs useNandHal=4bitecc pm_disable console=ttyS0,115200

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-A510 ==
=== 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-A510 boot-loader.
You can download pre-built [[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-2009.08
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-A510 kernel. You can create a copy of linux-2.6.32.y git tree or download a snapshot and extract it. We assume that you have created {{filename|/home/development/cm-a510/kernel}} directory for CM-A510 kernel development.
==== Snapshot download ====
* Download [http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.32.9.tar.bz2 linux-v2.6.32.9] snapshot with your web browser.
* Extract the downloaded archive {{filename|linux-2.6.32.9.tar.bz2}}
<pre>
cd /home/development/cm-a510/kernel
tar xzvf /path/to/downloaded/linux-2.6.32.9.tar.bz2
</pre>
: This will create {{filename|/home/development/cm-a510/kernel/linux-2.6.32.9}} directory containing linux-2.6.32.9 kernel tree.
* Apply the CM-A510 patch
<pre>
cd /home/development/cm-a510/kernel/linux-2.6.32.9
patch -p1 < /path/to/cm-a510-linux/kernel/linux-2.6.32.9-cm-a510.patch
</pre>

==== Git clone ====
* Install [http://git-scm.com/ git] version control system.
* Create a clone of linux-2.6.32.y kernel tree
<pre>
cd /home/development/cm-a510/kernel
git clone git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-2.6.32.y.git linux-2.6.32.9
</pre>
* Create a branch for CM-A510 development. The CM-A510 patches are generated vs. tag v2.6.32.9 in the linux-2.6.32.y tree. It is recommended to use exactly the same baseline to avoid merge conflicts.
<pre>
git checkout -b cm-a510-dev v2.6.32.9
</pre>
* Apply the CM-A510 patch
<pre>
cd /home/development/cm_a510/kernel/linux-2.6.32.9
git apply /path/to/cma510-linux/kernel/linux-2.6.32.9-cm-a510.patch
</pre>

=== Building the kernel ===
<pre>
export ARCH=arm
export CROSS_COMPILE=arm-none-linux-eabi-
make cm_a510_defconfig
make menuconfig
make && make uImage && \
INSTALL_MOD_PATH=/home/development/cm-a510/rootfs make modules_install
</pre>

In the example above, the Linux kernel image ({{filename|uImage}}) will be created in {{filename|/home/development/cm-a510/kernel/linux-2.6.32.9/arch/arm/boot}}, and the loadable kernel modules will be installed into the {{filename|/home/development/cm-a510/rootfs/lib/modules}} directory.

Now, if you boot CM-A510 with newly created kernel image and with networked root filesysem at {{filename|/home/development/cm-a510/rootfs/}} the system will be able to properly load kernel modules and you avoid modules versioning problems.

== See also ==
* [[CM-A510: Linux: Getting started]]

[[Category:Linux]]
[[Category:CM-A510]]

@@ Line 15: / Line 15: @@
 * Enable VGA output:
-{{cmd|1=video=dovefb:lcd1:1024x768-16@60-edid clcd.lcd1_enable=1 clcd.lcd0_enable=0}}
+{{parameter|1=video=dovefb:lcd1:1024x768-16@60-edid clcd.lcd1_enable=1 clcd.lcd0_enable=0}}
 * Enable DVI output (default):
-{{cmd|1=video=dovefb:lcd0:1024x768-16@60-edid clcd.lcd0_enable=1 clcd.lcd1_enable=0}}
+{{parameter|1=video=dovefb:lcd0:1024x768-16@60-edid clcd.lcd0_enable=1 clcd.lcd1_enable=0}}
 * Enable USB0 device functionality:
-{{cmd|1=usb0Mode=device}}
+{{parameter|1=usb0Mode=device}}
 * Enable USB0 host functionality (default):
-{{cmd|1=usb0Mode=host}}
+{{parameter|1=usb0Mode=host}}
 {{Note| Current kernel release does not support dual head output. Ensure that only one interface (VGA or DVI) is active.}}
@@ Line 61: / Line 61: @@
 <pre>
 cd /home/development/cm-a510/kernel/linux-2.6.32.9
-patch -p1 < /path/to/cm-a510-linux/kernel/linux-2.6.32.9-cm-a510.patch
+patch -p1 < /path/to/cm-a510-linux/kernel/linux-2.6.32.9-dove-5.4.2-cm-a510-2.patch
 </pre>
@@ Line 78: / Line 78: @@
 <pre>
 cd /home/development/cm_a510/kernel/linux-2.6.32.9
-git apply /path/to/cma510-linux/kernel/linux-2.6.32.9-cm-a510.patch
+git apply /path/to/cma510-linux/kernel/linux-2.6.32.9-dove-5.4.2-cm-a510-2.patch
 </pre>
@@ Line 93: / Line 93: @@
 Now, if you boot CM-A510 with newly created kernel image and with networked root filesysem at {{filename|/home/development/cm-a510/rootfs/}} the system will be able to properly load kernel modules and you avoid modules versioning problems.
 == See also ==

@@ Line 6: / Line 6: @@
   ubi.mtd=1,2048 root=ubi0_0 rootfstype=ubifs useNandHal=4bitecc pm_disable console=ttyS0,115200
-The default kernel command line defines primary console, default display settings, root device and root filesystem type.
+The default kernel command line defines primary console, default DVI 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-A510 ==
@@ Line 40: / Line 55: @@
 <pre>
 cd /home/development/cm-a510/kernel
-tar xzvf /path/to/downloaded/linux-2.6.32.9.tar.bz2
+tar xjvf /path/to/downloaded/linux-2.6.32.9.tar.bz2
 </pre>
 : This will create {{filename|/home/development/cm-a510/kernel/linux-2.6.32.9}} directory containing linux-2.6.32.9 kernel tree.
@@ Line 69: / Line 84: @@
 <pre>
 export ARCH=arm
-export CROSS_COMPILE=arm-none-linux-eabi-
+export CROSS_COMPILE=/path/to/cross-compiler/arm-none-linux-gnueabi-
 make cm_a510_defconfig
-make menuconfig
+make uImage && make modules && \
       INSTALL_MOD_PATH=/home/development/cm-a510/rootfs make modules_install
 </pre>

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