Nikita: /* Snapshot download */

2016-02-14T14:23:02Z

‎Snapshot download

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== Overview ==
CM-T43 firmware consists of two components: Secondary Program Loader (SPL) and U-Boot.
Both components are based on [http://www.denx.de/wiki/U-Boot/WebHome U-Boot] source code.
SPL is the bootstrap utility invoked by the CPU internal boot ROM code of the AM437x SoC.
SPL performs minimal hardware initialization and loads U-Boot from the same boot device.
U-Boot initializes hardware modules necessary for system boot and loads the operating system.

== Building Firmware images for CM-T43 ==
=== Getting U-Boot sources ===
There are various ways to get U-Boot sources that can be used as a baseline for CM-T43 SPL and U-Boot.
For instance, a copy of the U-Boot mainline git tree can be created or a the sources snapshot can be downloaded.
We assume that you have created {{filename|/home/development/cm-t43/u-boot}} directory for CM-T43 U-Boot development.

==== Snapshot download ====
* Download [http://git.denx.de/?p=u-boot.git;a=snapshot;h=fa85e826c16b9ce1ad302a57e9c4b24db0d8b930 v2016.01] snapshot with your web browser.
* Extract the downloaded archive {{filename|u-boot-fa85e82.tar.gz}}
<pre>
cd /home/development/cm-t43/u-boot
tar xvf /path/to/downloaded/u-boot-fa85e82.tar.gz
mv u-boot u-boot-cm-t43
</pre>
: This will create {{filename|/home/development/cm-t43/u-boot/u-boot-cm-t43}} directory containing U-Boot source code tree.
* Apply the CM-T43 patch
<pre>
cd /home/development/cm-t43/u-boot/u-boot-cm-t43
patch -p1 < /path/to/cm-t43-u-boot-package/u-boot/u-boot-v2016.01-cm-t43-1.patch
</pre>

==== Git clone ====
* Install [http://git-scm.com/ git] version control system.
* Create a clone of U-Boot tree
<pre>
cd /home/development/cm-t43/u-boot
git clone git://git.denx.de/u-boot.git u-boot-cm-t43
cd /home/development/cm-t43/u-boot/u-boot-cm-t43
</pre>
* Create a branch for CM-T43 development. The CM-T43 patches are generated vs. v2016.01 tag (fa85e826c16b9ce1ad302a57e9c4b24db0d8b930 commit) in the U-Boot tree. It is recommended to use exactly the same baseline to avoid merge conflicts.
<pre>
git checkout -b cm-t43-dev v2016.01
</pre>
* Apply the CM-T43 patch
<pre>
git apply /path/to/cm-t43-u-boot-package/u-boot/u-boot-v2016.01-cm-t43-1.patch
</pre>

=== Building the firmware images ===
* First, compile both SPL and U-Boot. The following commands create the {{filename|MLO}}, {{filename|MLO.byteswap}}, and {{filename|u-boot.img}} binaries (along with other image types):
<pre>
export ARCH=arm
export CROSS_COMPILE=arm-none-linux-eabi-
make mrproper
make cm_t43_defconfig && make
</pre>
* Create the combined image for SPI-flash installation by creating a 0xFF initialized 768KB {{filename|cm-t43-firmware-sf}} file, and writing the {{filename|MLO.byteswap}}, {{filename|MLO}}, and {{filename|u-boot.img}} data to the appropriate offsets within the {{filename|cm-t43-firmware}} file. The {{filename|MLO.byteswap}} file will be written into the first 3 64KB segments to allow the bootROM to find it in 3 different places, thus improving reliability. The non-byteswapped {{filename|MLO}} will occupy the 4th 64KB segment, thus allowing the same {{filename|cm-t43-firmware}} to be written into SD-card, for which the bootROM requires non-byteswapped data. Finally, {{filename|u-boot.img}} is written to the 256KB offset, right at the end of the 4 MLO segments.
<pre>
dd if=/dev/zero count=768 bs=1K | tr '\000' '\377' > cm-t43-firmware
dd if=MLO.byteswap of=cm-t43-firmware bs=1k seek=0 conv=notrunc
dd if=MLO.byteswap of=cm-t43-firmware bs=1k seek=64 conv=notrunc
dd if=MLO.byteswap of=cm-t43-firmware bs=1k seek=128 conv=notrunc
dd if=MLO of=cm-t43-firmware bs=1k seek=192 conv=notrunc
dd if=u-boot.img of=cm-t43-firmware bs=1k seek=256 conv=notrunc
</pre>
* You can now install the {{filename|cm-t43-firmware}} file into the CM-T43 SPI flash or SD-card.

== See also ==

* [[CM-T43: U-Boot: Firmware Overview]]
* [[CM-T43: U-Boot: Firmware Update]]
* [[U-Boot quick reference]]
* [[U-Boot images]]
* [http://www.denx.de/wiki/U-Boot/Documentation U-Boot documentation]

[[Category:U-Boot]]
[[Category:CM-T43]]

CM-T43: U-Boot: Building Images - Revision history

Nikita: /* Snapshot download */