Grinberg: /* See also */

2017-06-19T11:31:02Z

‎See also

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== Overview ==
The Linux kernel for UCM-iMX7 provides support for on-board peripherals/interfaces of UCM-iMX7 system-on-module (SoM) and SBC-UCM-iMX7 Single Board Computer.
It is recommended to use the most recent Linux package released. It can be downloaded from the product [http://www.compulab.com/products/computer-on-modules/ucm-imx7-nxp-i-mx-7-ultra-miniature-system-on-module/#devres web page].
Unzip the downloaded Linux package to a directory on your host workstation. The following discussion uses {{filename|/path/to/ucm-imx7-linux/}} template for this location. Please use the real path to the Linux package instead.

== Building kernel for UCM-iMX7 ==

=== Getting kernel sources ===
Linux git tree can be cloned or downloaded as a tarball from [http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/ Freescale public git repository].
The instructions below assume that the {{filename|/home/development/ucm-imx7/kernel}} directory has been created for UCM-iMX7 kernel development.
==== Snapshot download ====
* Download [http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/snapshot/linux-2.6-imx-rel_imx_4.1.15_1.2.0_ga.tar.gz rel_imx_4.1.15_1.2.0_ga] snapshot with your web browser.

* Extract the downloaded archive {{filename|linux-2.6-imx-rel_imx_4.1.15_1.2.0_ga.tar.gz}}
<pre>
cd /home/development/ucm-imx7/kernel
tar xpf /path/to/downloaded/linux-2.6-imx-rel_imx_4.1.15_1.2.0_ga.tar.gz
mv linux-2.6-imx-rel_imx_4.1.15_1.2.0_ga linux-ucm-imx7
</pre>
* Apply the UCM-iMX7 patch
<pre>
cd /home/development/ucm-imx7/kernel/linux-ucm-imx7
patch -p1 < /path/to/ucm-imx7-linux/kernel/linux-4.1.15-ucm-imx7-*.patch
</pre>

==== Git clone ====
* Install [http://git-scm.com/ git] version control system.
* Create a clone of the FreeScale Linux kernel tree
<pre>
cd /home/development/ucm-imx7/kernel
git clone git://git.freescale.com/imx/linux-2.6-imx.git linux-ucm-imx7
</pre>
* Create a branch for UCM-iMX7 development. The UCM-iMX7 patches are generated vs. [http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/commit/?id=77f61547834c4f127b44b13e43c59133a35880dc rel_imx_4.1.15_1.2.0_ga] tag in the Linux tree. It is recommended to use exactly the same baseline to avoid merge conflicts.
<pre>
cd /home/development/ucm-imx7/kernel/linux-ucm-imx7
git checkout -b development rel_imx_4.1.15_1.2.0_ga
</pre>
* Apply the UCM-iMX7 patch
<pre>
git am /path/to/ucm-imx7-linux/kernel/patches/*.patch
</pre>

=== Building the kernel ===
The following discussion assumes a [[Linux: Setting up a development environment|development environment]] is set up on your host workstation and Linaro GCC 5 crosstoolchain with the prefix '''arm-linux-gnueabihf-''' is installed on on it and its location is found in the '''PATH'''.

<pre>
cd /home/development/ucm-imx7/kernel/linux-ucm-imx7
export ARCH=arm
export CROSS_COMPILE=arm-linux-gnueabihf-
export DTB="imx7d-*ucm-imx7.dtb"
make ucm_imx7_defconfig
make menuconfig
make zImage modules ${DTB} && INSTALL_MOD_PATH=/home/development/ucm-imx7/rootfs make modules_install
</pre>

In the example above:
* Linux kernel image ({{filename|zImage}}) will be created in {{filename|/home/development/ucm-imx7/kernel/linux-ucm-imx7/arch/arm/boot}}
* device tree blobs will be created in {{filename|/home/development/ucm-imx7/kernel/linux-ucm-imx7/arch/arm/boot/dts}}
* loadable kernel modules will be installed into the {{filename|/home/development/ucm-imx7/rootfs/lib/modules}} directory.
<br>
When the UCM-iMX7 is booted with the kernel image created as described above and with networked root filesystem at {{filename|/home/development/ucm-imx7/rootfs/}}, the system will be able to load the kernel modules properly, thus avoiding module version problems.

==== zImage, DTB files and modules locations ====

* In the example above, the Linux kernel image ({{filename|zImage}}) will be created in the {{filename|/home/development/ucm-imx7/kernel/linux-ucm-imx7/arch/arm/boot}} directory.
<pre>
# ls -al /home/development/ucm-imx7/kernel/linux-ucm-imx7/arch/arm/boot/zImage
</pre>
* DTB files
<pre>
# cd /home/development/ucm-imx7/kernel/linux-ucm-imx7/arch/arm/boot/dts/
# ls -al ${DTB}
# cd -
</pre>
* The loadable kernel modules will be installed into the {{filename|/home/development/ucm-imx7/rootfs/lib/modules}} directory.
<pre>
# ls -al /home/development/ucm-imx7/rootfs/lib/modules
</pre>

==== Kernel Version ====

* In the example above, the Linux kernel release version number will be saved in {{filename|/home/development/ucm-imx7/kernel/linux-ucm-imx7/include/config/kernel.release}}
<pre>
# cat /home/development/ucm-imx7/kernel/linux-ucm-imx7/include/config/kernel.release
</pre>

==== Prepare kernel and modules tarball ====

* In the example below, the Linux kernel and modules are packed into the tar archive for deploying onto the UCM-iMX7.
<pre>
# mkdir -p /home/development/ucm-imx7/rootfs/boot
# cp -v /home/development/ucm-imx7/kernel/linux-ucm-imx7/arch/arm/boot/zImage /home/development/ucm-imx7/rootfs/boot/
# cd /home/development/ucm-imx7/kernel/linux-ucm-imx7/arch/arm/boot/dts/
# cp -v ${DTB} /home/development/ucm-imx7/rootfs/boot/
# cd -
# tar -C /home/development/ucm-imx7/rootfs -czvf /home/development/ucm-imx7/linux-image-ucm-imx7.tar.gz .
</pre>

== Basic platform support ==

The UCM-iMX7 basic platform support is implemented in the {{filename|imx7d-ucm-imx7.dtb}} file of the Linux kernel source tree.
The extended interface support depends on carrier board used and thus is implemented in the Single Board Computer device tree files:
* {{filename|imx7d-sbc-ucm-imx7.dtb}} - for SBC-UCM-iMX7 Single Board Computer

These files contain:
* default setup of multi-functional pins;
* registration of the devices integrated in the UCM-iMX7 module;
* definitions of platform-specific configuration for these devices.

== Deploying the UCM-iMX7 kernel and modules ==

* Boot up the UCM-iMX7 computer.
* Copy the previously created {{filename|linux-image-ucm-imx7.tar.gz}} to {{filename|/root}} directory of the UCM-iMX7.

==== Mount boot partition ====
* Use the below command to mount the boot partition for installing the UCM-iMX7 Linux kernel binary:
<pre>
# boot_partition=`cat /proc/cmdline | awk '{ for (i=1;i<=NF;i++) { if($i~/^root=/) { print substr($i,6,length($i)-6)"1" } } }'`
# mount $boot_partition /boot
</pre>

==== Back up old kernel ====
* It is essential to backup the old (known to work) kernel binary.
<pre>
# mkdir /boot/`uname -r`
# mv /boot/zImage* /boot/*.dtb /boot/`uname -r`/
</pre>

==== Installing kernel and modules ====
Assuming that the {{filename|linux-image-ucm-imx7.tar.gz}} tar ball has been copied to the UCM-iMX7 {{filename|/root}} directory.
* Extract and install the Linux kernel binary:
<pre>
# tar -C / -xvf /root/linux-image-ucm-imx7.tar.gz
</pre>

== U-Boot Environment ==
=== MMC Boot Parameters ===
To boot from MMC/SD card type:
<pre>
setenv mmcdev 0
setenv mmcblk mmcblk0p2
</pre>
Continue to the [[#Common Boot Parameters | Common Boot Parameters]].

=== eMMC Boot Parameters ===
To boot from internal eMMC storage type:
<pre>
setenv mmcdev 2
setenv mmcblk mmcblk2p2
</pre>
Continue to the [[#Common Boot Parameters | Common Boot Parameters]].

=== Device Tree Blob ===
* For SBC-UCM-iMX7 Single Board computer type:
<pre>
setenv fdt_file imx7d-sbc-ucm-imx7.dtb
</pre>

=== Common Boot Parameters ===
To boot Linux type:
<pre>
setenv loadaddr 0x80800000
setenv fdt_addr 0x83000000
setenv image zImage
setenv bootargs console=ttymxc0,115200 root=/dev/${mmcblk} rw rootwait
mmc dev ${mmcdev}
load mmc ${mmcdev} ${loadaddr} ${image}
load mmc ${mmcdev} ${fdt_addr} ${fdt_file}
bootz ${loadaddr} - ${fdt_addr}
</pre>

=== NFS Boot Parameters ===
To boot via network interface type:
<pre>
dhcp
setenv loadaddr 0x80800000
setenv fdt_addr 0x83000000
setenv image zImage
setenv nfsserver <nfs server ip address>
setenv tftpserver <tftp server ip address>
setenv bootargs console=ttymxc0,115200 root=/dev/nfs rw ip=dhcp nfsroot=${nfsserver}:${nfsroot}
tftpboot ${loadaddr} ${tftpserver}:${image}
tftpboot ${fdt_addr} ${tftpserver}:${fdt_file}
bootz ${loadaddr} - ${fdt_addr}
</pre>

== See also ==
* [[UCM-iMX7: Evaluation Kit: Getting Started]]
* [[UCM-iMX7: Evaluation Kit: Hardware Guide]]
* [[UCM-iMX7: Linux: Automatic Installation]]
* [[UCM-iMX7: Linux: Manual Installation]]
* [[UCM-iMX7: Linux: Debian]]
* [[Linux: Development for ARM modules]]
* [[Linux: Debian: Minimal ARM filesystem]]
* [http://www.debian.org/doc/manuals/reference/index.en.html Debian Reference]

[[Category:Linux]]
[[Category:UCM-iMX7]]

UCM-iMX7: Linux: Kernel - Revision history

Grinberg: /* See also */