Here you will find information about how to edit, customize and test the uBoot, Kernel and YOCTO meta layer.

Content

Prepare a host machine
Edit uBoot
Edit Linux Kernel
Edit YOCTO meta layer
Compile YOCTO, Create SD card and Test it
Edit Filesystem

Prepare a host machine

Before you start doing any changes, you may want to go through: How to start with Software >

Edit uBoot

Get the source code

You have two options to get the source code. You can download it directly from github or you can edit the uBoot files in your YOCTO OpenRex project.

Option 1: Get the uBoot source code from github

git clone -b jethro https://github.com/FEDEVEL/openrex-uboot-v2015.10.git
cd openrex-uboot-v2015.10

Option 2: Find uBoot source code located inside your YOCTO project

Usualy the uBoot source code is located inside your build directory. The path may look like this:

cd ~/fsl-community-bsp/build-openrex/tmp/work/imx6q_openrex-poky-linux-gnueabi/u-boot-openrex/v2015.10+gitAUTOINC+d542ed07a4-r0/git

Install & select cross compiler

If you do not have any compiler installed (or you are not sure)

apt-get install gcc-arm-linux-gnueabihf
export CROSS_COMPILE=arm-linux-gnueabihf-
export ARCH=arm

If you have a compiler installed

export CROSS_COMPILE=/opt/freescale/usr/local/gcc-4.6.2-glibc-2.13-linaro-multilib-2011.12/fsl-linaro-toolchain/bin/arm-none-linux-gnueabi-
export ARCH=arm

Edit files

Here are the files what we normally edit:

gedit configs/mx6qopenrex_defconfig
gedit include/configs/mx6openrex.h
gedit include/configs/mx6openrex_common.h
gedit board/fedevel/mx6openrex/mx6openrex.c
gedit board/fedevel/mx6openrex/mx6q_4x_mt41j256.cfg

Compile uBoot

make distclean
make mx6qopenrex_config
make
cp u-boot.imx /tftp/imx6/u-boot-imx6q-openrex.imx

*Note: If you get error like "lib/asm-offsets.c:1:0: error: bad value (armv5) for -march= switch", then run the "Select cross compiler" again (these are the commands "export CROSS_COMPILE=..." and "export ARCH=arm")

Reflash uBoot

Switch on your OpenRex board, go to uBoot and run following command:

run update_spi_uboot

In case you would like to update it manually, here are the commands:

mw.b 0x10800000 0xFF 0x80000;tftp 0x10800000 imx6/u-boot-imx6q-openrex.imx;sf probe;sf erase 0x0 0x80000;sf write 0x10800000 0x400 0x80000

*Note: If you have updated environmental variables inside uBoot source code, after you reboot uBoot, you may want to run:

env default -a
run set_ethernet
setenv serverip 192.168.0.37 //use your Linux host IP
saveenv

Upload the new uBoot to Github

When you are happy with the new uBoot, run following commands to update uBoot github:

git remote -v //check the origin, should point to your github
//git remote add origin https://github.com/FEDEVEL/openrex-uboot-v2015.10.git //run this if you get error about no origin
//git remote set-url origin https://github.com/FEDEVEL/openrex-uboot-v2015.10.git //run this if you get error, that "git://" is read only
git checkout jethro //set the current active branch to jethro
git branch //check if you are on jethro branch
git status  //have a look what files were changed
//based on the status command, add the files you would like to upload to github
//you could also use "git add .", but that occasionally cause problems
//sometimes "add ." wants to upload also files which you have not changed, that's why I use "git add filename"
git add filename1
git add filename2
git diff origin/jethro //check if it shows correct differences
//in case differences are not what you expected or you find a mistake, you can use "git reset". Then repeat the procedure again
//if you are happy with the differences, upload the changes to github
git commit -m 'Fixed SD card: CD and RW pin definition' //use a comment describing the changes
git push origin jethro

Edit Linux Kernel

Get the source code

You have two options to get the source code. You can download it directly from github or you can edit the Kernel files in your YOCTO OpenRex project.

Option 1: Get the Kernel source code from github

git clone -b jethro https://github.com/FEDEVEL/openrex-linux-3.14.git
cd openrex-linux-3.14

Option 2: Find Kernel source code located inside your YOCTO project

Usualy the Kernel source code is located inside your build directory. The path may look like this:

cd ~/fsl-community-bsp/build-openrex/tmp/work/imx6q_openrex-poky-linux-gnueabi/linux-openrex/3.14-r0/git

Install & select cross compiler

If you do not have any compiler installed (or you are not sure)

apt-get install gcc-arm-linux-gnueabihf
export CROSS_COMPILE=arm-linux-gnueabihf-
export ARCH=arm

If you have a compiler installed

export CROSS_COMPILE=/opt/freescale/usr/local/gcc-4.6.2-glibc-2.13-linaro-multilib-2011.12/fsl-linaro-toolchain/bin/arm-none-linux-gnueabi-
export ARCH=arm

Edit files

Here are the files what we normally edit:

gedit arch/arm/boot/dts/imx6q-openrex.dts
gedit arch/arm/boot/dts/imx6qdl-openrex.dtsi
gedit arch/arm/configs/imx_v7_defconfig

Compile Kernel

make clean
make imx_v7_defconfig
make -j4 zImage imx6q-openrex.dtb
cp arch/arm/boot/zImage /tftp/imx6/zImage-imx6q-openrex
cp arch/arm/boot/dts/imx6q-openrex.dtb /tftp/imx6/imx6q-openrex.dtb

Test the Kernel

In case you run OpenRex from SD card, switch on your OpenRex board, go to uBoot and run following commands:

run update_kernel;run update_fdt;reset

In case you boot from SATA, you can use these commands:

run set_ethernet;run update_set_filename;sata init;tftp ${tftp_dir}/${upd_kernel};fatwrite sata ${satadev}:${satapart} ${loadaddr} ${image} ${filesize};
run set_ethernet;run update_set_filename;sata init;tftp ${tftp_dir}/${upd_fdt};fatwrite sata ${satadev}:${satapart} ${loadaddr} ${fdt_file} ${filesize};
reset

Important: fatwrite error
There is a bug in some versions of uBoot where fatwrite may not work properly. To go around the fatwrite problem, re-format the FAT partion on your SD card. Here is how you can do it: insert SD card into your host machine and run following commands:

umount /dev/sdb?
sudo mkfs.vfat -F16 -s 2 /dev/sdb1
sudo mount /dev/sdb1 /media/fedevel/
sudo cp ~/fsl-community-bsp/build-openrex/tmp/deploy/images/imx6q-openrex/zImage-imx6q-openrex.bin /media/fedevel/zImage
sudo cp ~/fsl-community-bsp/build-openrex/tmp/deploy/images/imx6q-openrex/zImage-imx6q-openrex.dtb /media/fedevel/imx6q-openrex.dtb
sudo umount /media/fedevel

If you would like to test the kernel without saving it to SD card, go to uBoot and use following commands:

tftp 0x12000000 imx6/zImage-imx6q-openrex; tftp 0x18000000 imx6/imx6q-openrex.dtb;bootz 0x12000000 - 0x18000000

Upload the new Kernel to Github

When you are happy with the new Kernel, run following commands to update Kernel github:

git remote add origin https://github.com/FEDEVEL/openrex-linux-3.14.git
//git remote set-url origin https://github.com/FEDEVEL/openrex-linux-3.14.git //run this if you get error, that "git://" is read only
git checkout jethro //set the current active branch to jethro
git branch //check if you are on jethro branch
git status  //have a look what files were changed
//based on the status, add the files you would like to upload to github
//you could also use "git add .", but that occasionally cause problems
//sometimes "add ." wants to upload also files which you have not changed, that's why I use "git add filename"
git add filename1
git add filename2
git diff origin/jethro //check if it shows correct differences
//in case differences are not what you expected or you find a mistake, you can use "git reset". Then repeat the procedure again
//if you are happy with the differences, upload the changes to github
git commit -m 'Fixed SD card: CD and RW pin definition' //use a comment describing the changes
git push origin jethro

Edit YOCTO meta layer

In case you have updated uBoot or Kernel github, you will need to update also your meta layer.

If you have updated uBoot

In case you have updated uBoot and uploaded changes to github, you have to update also meta-openrex. Run:

gedit ~/fsl-community-bsp/sources/meta-openrex/recipes-bsp/u-boot/u-boot-openrex_2015.10.bb

and edit commit number. It may look like this:

Before

...
SRC_URI = "git://github.com/FEDEVEL/openrex-uboot-v2015.10.git;branch=${SRCBRANCH}"

#SRCREV is the commit number, must be always changed for a new version
SRCREV = "b17a70691ea4ec77561c4532ec777338f3b0758a" 

S = "${WORKDIR}/git"
...

After

...
SRC_URI = "git://github.com/FEDEVEL/openrex-uboot-v2015.10.git;branch=${SRCBRANCH}"

#SRCREV is the commit number, must be always changed for a new version
SRCREV = "d542ed07a4398d53e12bf89e14abd169343cef64" 

S = "${WORKDIR}/git"
...

If you have updated Kernel

In case you have updated Kernel and uploaded changes to github, you have to update also meta-openrex. Run:

gedit ~/fsl-community-bsp/sources/meta-openrex/recipes-kernel/linux/linux-openrex_3.14.bb

and edit commit number. It may look like this:

Before

...
#Always update SRCREV based on your last commit
SRCREV = "58f44dd3178b7a9878298bd948082e01f4fe28fb"

KERNEL_SRC ?= "git://github.com/FEDEVEL/openrex-linux-3.14.git;protocol=git"
...

After

...
LOCALVERSION = "-yocto"

#Always update SRCREV based on your last commit
SRCREV = "cc643ef3144090d5b78906361561c6170243e5c8"

KERNEL_SRC ?= "git://github.com/FEDEVEL/openrex-linux-3.14.git;protocol=git"
...

Important: Now, test the new meta layer. See: Compile YOCTO, Create SD card and Test it

Upload the new Meta Layer to Github

If everything works oki, upload the new meta layer to github:

git remote add origin https://github.com/FEDEVEL/meta-openrex.git //run this if you get error, that "git://" is read only
//git remote set-url origin https://github.com/FEDEVEL/meta-openrex.git //run this if you get error, that "git://" is read only
git checkout jethro //set the current active branch to jethro
git branch //check if you are on jethro branch
git status  //have a look what files were changed
//based on the status, add the files you would like to upload to github
//you could also use "git add .", but that occasionally cause problems
//sometimes "add ." wants to upload also files which you have not changed, that's why I use "git add filename"
git add filename1
git add filename2
git diff origin/jethro //check if it shows correct differences
//in case differences are not what you expected or you find a mistake, you can use "git reset". Then repeat the procedure again
//if you are happy with the differences, upload the changes to github
git commit -m 'Fixed SD card: CD and RW pin definition' //use a comment describing the changes
git push origin jethro

Compile YOCTO, Create SD card and Test it

Compile

cd ~/fsl-community-bsp/
MACHINE=imx6q-openrex source setup-environment build-openrex
MACHINE=imx6q-openrex bitbake core-image-base

*Note: If you would like to completely recompile all the files, delete build-openrex directory.

Create SD Card

Check the time & date of the files, just to be sure you have just generated them and they are the recent files:

ls -la ~/fsl-community-bsp/build-openrex/tmp/deploy/images/imx6q-openrex/

Insert an SD card into your host machine. Check under what /dev/? it was recognized:

dmesg | tail

Note: The SD card in my system is recognized as "/dev/sdb". This is what I will be using in the examples below.

Make the SD card

umount /dev/sdb?
gunzip -c ~/fsl-community-bsp/build-openrex/tmp/deploy/images/imx6q-openrex/core-image-base-imx6q-openrex.sdcard.gz > ~/fsl-community-bsp/build-openrex/tmp/deploy/images/imx6q-openrex/core-image-base-imx6q-openrex.sdcard
sudo dd if=~/fsl-community-bsp/build-openrex/tmp/deploy/images/imx6q-openrex/core-image-base-imx6q-openrex.sdcard of=/dev/sdb
umount /dev/sdb?

Work around of the fatwrite issue. Re-format the fat partition and upload the zImage + dtb again. Run following commands:

sudo mkfs.vfat -F16 -s 2 /dev/sdb1
sudo mount /dev/sdb1 /media/fedevel/
sudo cp ~/fsl-community-bsp/build-openrex/tmp/deploy/images/imx6q-openrex/zImage-imx6q-openrex.bin /media/fedevel/zImage
sudo cp ~/fsl-community-bsp/build-openrex/tmp/deploy/images/imx6q-openrex/zImage-imx6q-openrex.dtb /media/fedevel/imx6q-openrex.dtb
sudo umount /media/fedevel

Extend root disk size to SD card size (default size of the root is very small):

fedevel@ubuntu:~/fsl-community-bsp/build-openrex$ sudo fdisk /dev/sdb

Command (m for help): p

Disk /dev/sdb: 7948 MB, 7948206080 bytes
4 heads, 32 sectors/track, 121280 cylinders, total 15523840 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xe9358ca2

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1            8192       24575        8192    c  W95 FAT32 (LBA)
/dev/sdb2           24576      204799       90112   83  Linux

Command (m for help): d
Partition number (1-4): 2

Command (m for help): p

Disk /dev/sdb: 7948 MB, 7948206080 bytes
4 heads, 32 sectors/track, 121280 cylinders, total 15523840 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xe9358ca2

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1            8192       24575        8192    c  W95 FAT32 (LBA)

Command (m for help): n
Partition type:
   p   primary (1 primary, 0 extended, 3 free)
   e   extended
Select (default p): p
Partition number (1-4, default 2): 2
First sector (2048-15523839, default 2048): 24576
Last sector, +sectors or +size{K,M,G} (24576-15523839, default 15523839): 
Using default value 15523839

Command (m for help): p

Disk /dev/sdb: 7948 MB, 7948206080 bytes
4 heads, 32 sectors/track, 121280 cylinders, total 15523840 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xe9358ca2

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1            8192       24575        8192    c  W95 FAT32 (LBA)
/dev/sdb2           24576    15523839     7749632   83  Linux

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.
fedevel@ubuntu:~/fsl-community-bsp/build-openrex$

*Note: As the First sector number use the same number where partition 2 originally started. In the example above, it's 24576.

Then run:

sudo e2fsck -f /dev/sdb2
sudo resize2fs /dev/sdb2
umount /dev/sdb?

Test the new SD card

Remove the card and plug it into OpenRex. Press "RESET" button and wait until it boots up.

*Note: If you resized the partition, you may want to double check if it worked oki:

root@imx6q-openrex:~# df -h
Filesystem                Size      Used Available Use% Mounted on
/dev/root                 7.2G     59.3M      6.7G   1% /
devtmpfs                849.3M         0    849.3M   0% /dev
tmpfs                  1009.5M    188.0K   1009.3M   0% /run
tmpfs                  1009.5M     76.0K   1009.4M   0% /var/volatile
root@imx6q-openrex:~#

THE PART BELOW HAS NOT BEEN FINISHED YET

Edit Filesystem

The initial Fileystem is generated when YOCTO is compiled. You can do some changes there. Here are some examples.

TODO: This part is under testing, here are just some of my notes


//changing to debian, adding support for apt-get
//edit ~/fsl-community-bsp/build-openrex/conf/local.conf
MACHINE ??= 'imx6q-openrex'
DISTRO ?= 'poky'
PACKAGE_CLASSES ?= "package_deb"
IMAGE_FEATURES += "package-management"
IMAGE_INSTALL_append += "dpkg"
CORE_IMAGE_EXTRA_INSTALL += "apt"
EXTRA_IMAGE_FEATURES = "debug-tweaks"
USER_CLASSES ?= "buildstats image-mklibs"
PATCHRESOLVE = "noop"
BB_DISKMON_DIRS = "\
    STOPTASKS,${TMPDIR},1G,100K \
    STOPTASKS,${DL_DIR},1G,100K \
    STOPTASKS,${SSTATE_DIR},1G,100K \
    STOPTASKS,/tmp,100M,100K \
    ABORT,${TMPDIR},100M,1K \
    ABORT,${DL_DIR},100M,1K \
    ABORT,${SSTATE_DIR},100M,1K \
    ABORT,/tmp,10M,1K"
PACKAGECONFIG_append_pn-qemu-native = " sdl"
PACKAGECONFIG_append_pn-nativesdk-qemu = " sdl"
ASSUME_PROVIDED += "libsdl-native"
CONF_VERSION = "1"

DL_DIR ?= "${BSPDIR}/downloads/"
ACCEPT_FSL_EULA = "1"

!!!! TODO !!!! //TODO uBoot problem - fatwrite doesn't work for the image generated by YOCOTO I guess, it has something with: WARNING: Not enough clusters for .... (FAT32/16). Uboot detects it as FAT12 and getting error: writing zImage Error: Invalid FAT entry: 0x00000fff error: overflow occurs Error: writing contents ** Unable to write "zImage" from mmc 0:1 ** OpenRex U-Boot> You can go around it by formating Partition 1 with this command: sudo mkfs.vfat -F16 -s 2 /dev/sdb1 SD card formated this way will work. vi /etc/apt/sources.list Press i: deb http://ftp.us.debian.org/debian wheezy main deb-src http://ftp.us.debian.org/debian wheezy main deb http://security.debian.org/ wheezy/updates main contrib non-free deb-src http://security.debian.org/ wheezy/updates main contrib non-free //this will download and istall everything, problem is, it doesnt work deb http://ftp.de.debian.org/debian jessie main deb http://ftp.de.debian.org/debian wheezy main root@imx6q-openrex:~# alsamixer -sh: /usr/bin/alsamixer: No such file or directory root@imx6q-openrex:~# Press ESC:wq apt-get update Test if your apt-get works oki, we can for example install nano: apt-get install nano //armhf vs armel ... default we use armel (?) DPKG_ARCH = "armhf" ... didnt work dpkg --print-architecture dpkg --add-architecture armhf apt-get update apt-get -f install apt-get update apt-get upgrade https://community.freescale.com/docs/DOC-95044 apt-get install binfmt-support qemu-user-static debootstrap

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How to edit, customize and test the uBoot, Kernel source codes and YOCTO meta layer

Content

See also

Prepare a host machine

Edit uBoot

Get the source code

Install & select cross compiler

Edit files

Compile uBoot

Reflash uBoot

Upload the new uBoot to Github

Edit Linux Kernel

Get the source code

Install & select cross compiler

Edit files

Compile Kernel

Test the Kernel

Upload the new Kernel to Github

Edit YOCTO meta layer

If you have updated uBoot

If you have updated Kernel

Upload the new Meta Layer to Github

Compile YOCTO, Create SD card and Test it

Compile

Create SD Card

Test the new SD card

THE PART BELOW HAS NOT BEEN FINISHED YET

Edit Filesystem