EBC Exercise 08 Installing Development Tools 4.4

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thumb‎ Embedded Linux Class by Mark A. Yoder

Early in the class most of the exercises we will do will all run on the BeagleBoard. You'll be able to edit (cloud9), compile (gcc) and run all on the Beagle. Later, when we start compiling the kernel or the boot loader, (U-boot) you will need to cross compile on a Linux machine and copy the results to the Beagle.

The purpose of this exercise is to install all the tools needed for compiling on your host so they will be ready when you need them.

Tip: Run this exercise using a wired connection if you can. The Ubuntu wireless driver can be finicky, and if it stops working you'll have to restart some of this.

The 5.x Kernel

Getting the 5.x Kernel

These notes taken from Beaglebone: Adding USB Wi-Fi & Building a Linux Kernel starting around 4 minutes and ending around 21 minutes. Uses kernel from Robert C. Nelson's BeagleBone Black page.

host$ git clone git@github.com:RobertCNelson/ti-linux-kernel-dev.git  (42M)
host$ cd ti-linux-kernel-dev
host$ git tag | wc
   1731    1731   30033

The last command lists all the versions of the kernel that are available and counts them. There are over 1700 versions! Let's narrow it a bit.

host$ git tag | grep 5.10.145

Pick one and check it out. I usually pick the one with the highest version number not equal to the version I'm running.

host$ git checkout 5.10.145-ti-r55 -b 5.10.145-ti-r55
Switched to a new branch '5.10.145-ti-r55'

Now at this point you have a choice, you can run ./build_kernel.sh and build the kernel, or run ./build_deb.sh which will also build the kernel, but it will combine all the output files in one .deb install file. I suggest running ./build_deb.sh,

host$ ./build_deb.sh
+ Detected build host [Ubuntu 22.04.1 LTS]
+ host: [x86_64]
+ git HEAD commit: [238026ea90fe508acc39a3e8a2be938cb6e66e88]
cpio: cpio (GNU cpio) 2.13
You're missing command lzop
Please install missing commands

You may need to install some additional files. Run the suggested commands.

host$ sudo apt-get update
host$ sudo apt install lzop
host$ ./build_deb.sh
+ Detected build host [Ubuntu 20.04.1 LTS]
+ host: [x86_64]
+ git HEAD commit: [a7ff6610037f33b2a8c19d7f111cf9e43aa3c4ef]
cpio: cpio (GNU cpio) 2.13
lzop: lzop 1.04
Debian/Ubuntu/Mint: missing dependencies, please install:
sudo apt-get update
sudo apt-get install build-essential fakeroot lzma gettext bison flex pkg-config libmpc-dev u-boot-tools libncurses5-dev:amd64
* Failed dependency check

host$ sudo apt-get install build-essential fakeroot lzma gettext bison flex pkg-config libmpc-dev u-boot-tools libncurses5-dev:amd64 libssl-dev:amd64 libssl-dev:amd64

Then run again.

host$ ./build_deb.sh
+ Detected build host [Ubuntu 20.04.1 LTS]
+ host: [x86_64]
+ git HEAD commit: [a7ff6610037f33b2a8c19d7f111cf9e43aa3c4ef]
cpio: cpio (GNU cpio) 2.13
lzop: lzop 1.04
'/home/mark_a_yoder/BeagleBoard/bb-kernel/system.sh.sample' -> '/home/mark_a_yoder/BeagleBoard/bb-kernel/system.sh'
Installing Toolchain: gcc_arm_gnueabihf_9

At this point the scripts are downloading the cross compiler, the kernel sources and anything else you need to compile the kernel for the bone.

Building the 5.x Kernel

At some point you will see


Hit the right arrow to select Exit and then hit ENTER. The compilation will continue.

Installing the Kernel on Your Bone

The following are three ways you can use to install a new kernel on your Bone. The first method works if you ran build_deb.sh.

The other two methods are used if you ran build_kernel.sh

You only need to use one method. If you ran build_kernel.sh I suggest you use the second one since you don't have to remove the SD card from the bone.

Installing the kernel package - build_deb.sh

The ./build_deb.sh script creates a single .deb file that contains all the files needed for the new kernel. You find it here:

host$ cd ti-linux-kernel-dev/deploy
host$ ls -sh
total 40M
7.3M linux-headers-5.8.11-bone17_1xross_armhf.deb  8.0K linux-upstream_1xross_armhf.buildinfo
 31M linux-image-5.8.11-bone17_1xross_armhf.deb    4.0K linux-upstream_1xross_armhf.changes
1.1M linux-libc-dev_1xross_armhf.deb

The linux-image- file is the one we want. It contains nearly 3000 files.

host$ dpkg -c linux-image-5.8.11-bone17_1xross_armhf.deb  | wc
   2981   17886  342664

The dpkg command lists all the files in the .deb file and the wc counts all the lines in the output. You can see those files with:

bone$ dpkg -c linux-image-5.8.11-bone17_1xross_armhf.deb  | less
drwxr-xr-x root/root         0 2020-09-29 14:16 ./
drwxr-xr-x root/root         0 2020-09-29 14:16 ./boot/
-rw-r--r-- root/root   4285674 2020-09-29 14:16 ./boot/System.map-5.8.11-bone17
-rw-r--r-- root/root    182474 2020-09-29 14:16 ./boot/config-5.8.11-bone17
drwxr-xr-x root/root         0 2020-09-29 14:16 ./boot/dtbs/
drwxr-xr-x root/root         0 2020-09-29 14:16 ./boot/dtbs/5.8.11-bone17/
-rwxr-xr-x root/root     87267 2020-09-29 14:16 ./boot/dtbs/5.8.11-bone17/am335x-abbbi.dtb
-rwxr-xr-x root/root     86826 2020-09-29 14:16 ./boot/dtbs/5.8.11-bone17/am335x-baltos-ir2110.dtb
-rwxr-xr-x root/root     87544 2020-09-29 14:16 ./boot/dtbs/5.8.11-bone17/am335x-baltos-ir3220.dtb

You can see it's putting things in the /boot directory.

Note: You can also look into the other two .deb files and see what they install.

Move the linux-image- file to your Bone.

host$ scp linux-image-5.8.11-bone17_1xross_armhf.deb bone:.

Hint: You might have to add -P<port> if you changed your port number. You might have to use debian@ for bone if you haven't set everything up.

Now ssh to the bone.

host$ ssh bone
bone$ ls -sh
bin  exercises linux-image-5.8.11-bone17_1xross_armhf.deb

Now install it.

bone$ sudo dpkg --install linux-image-5.8.11-bone17_1xross_armhf.deb

Wait a while. Once done check /boot.

bone$ ls -sh /boot
total 40M
160K config-4.19.94-ti-r50      4.0K SOC.sh                     4.0K uEnv.txt.orig
180K config-5.8.11-bone17       3.5M System.map-4.19.94-ti-r50  9.7M vmlinuz-4.19.94-ti-r50
4.0K dtbs                       4.1M System.map-5.8.11-bone17   8.6M vmlinuz-5.8.11-bone17
6.4M initrd.img-4.19.94-ti-r50  4.0K uboot
6.8M initrd.img-5.8.11-bone17   4.0K uEnv.txt

You see the new kernel files. Check uEnv.txt.

bone$ head /boot/uEnv.txt
#Docs: http://elinux.org/Beagleboard:U-boot_partitioning_layout_2.0
# uname_r=4.19.94-ti-r50

I added the commented out uname_r line to make it easy to switch between versions of the kernel.

Reboot and test out the new kernel.

bone$ sudo reboot

Copying to SD card on a running Bone - build_kernel.sh

You can stop here if you've just finished the build_deb.sh method of installing the kernel.

The Bone can have multiple versions of the kernel installed on it. It's possible to update the kernel on the Bone while it's running. After compiling on the host you need to install sshfs (you only need to do this once).

host$ sudo apt install sshfs 

Then copy may_install_kernel.sh to the bb-kernel directory.

host$ cd ~/BeagleBoard/bb-kernel
host$ cp ~/BeagleBoard/exercises/linux/kernel/may_install_kernel.sh tools

Now you can install the files using the following. Note, you must run may_install_kernel.sh from the directory above as shown.

host$ tools/may_install_kernel.sh
Mounting sshfs
sshfs mounted
Installing 4.4.15-bone11 to sshfs
‘/home/yoder/BeagleBoard/bb-kernel/deploy/4.4.15-bone11.zImage’ -> ‘/home/yoder/BeagleBoard/bb-kernel/deploy/disk/zImage’
Installing 4.4.15-bone11-dtbs.tar.gz to sshfs
Installing 4.4.15-bone11 to sshfs
‘/home/yoder/BeagleBoard/bb-kernel/deploy/4.4.15-bone11.zImage’ -> ‘/home/yoder/BeagleBoard/bb-kernel/deploy/disk/boot/vmlinuz-4.4.15-bone11’
Installing 4.4.15-bone11-dtbs.tar.gz to sshfs
info: /boot/uEnv.txt: uname_r=4.4.15-bone11
Installing 4.4.15-bone11-modules.tar.gz to sshfs
tar: ./lib/modules/4.4.15-bone11/build: Cannot utime: No such file or directory
tar: ./lib/modules/4.4.15-bone11/source: Cannot utime: No such file or directory
tar: Exiting with failure status due to previous errors
‘/home/yoder/BeagleBoard/bb-kernel/deploy/config-4.4.15-bone11’ -> ‘/home/yoder/BeagleBoard/bb-kernel/deploy/disk/boot/config-4.4.15-bone11’
info: [4.4.15-bone11] now installed...

You may see about couple of error messages about build and source, but it seems to work anyway. If you look in /boot/uEvt.txt, you'll see it's ready to boot your new kernel.

bone$ head -3 /boot/uEnv.txt
#Docs: http://elinux.org/Beagleboard:U-boot_partitioning_layout_2.0


If you change your mind about which kernel to boot, just edit the uname line.

Copying to the SD Card on Host - build_kernel.sh

You can also install the kernel on an SD card that is mounted on your host computer. Plug it into your host and machine and run:

host$ tools/install_kernel.sh

This works like the may_install_kernel.sh, but it copies it to local host. Once copied, eject the SD card and plug it into your Bone and boot.

Updating to a new version of the kernel

When you build your kernel the uImage file has some version information in the name. For example vmlinuz-4.4.21-ti-r47. The 4.4.21 is the version of the kernel and the -ti-r47 is the version of the patches applied to the kernel for the BeagleBone. Over time new patches will be posted. These instructions show how to get the latest version.

How do you know if you have the latest version? Run

bone$ uname -a
Linux yoder-debian-bone 4.4.21-ti-r47 #1 SMP Fri Sep 23 22:23:02 UTC 2016 armv7l GNU/Linux

This post to the Google Group lists the steps as "You need to recheckout master, delete your old branch and re-pull". Here's how you do it.

host$ cd linux-dev
host$ git checkout master
error: Your local changes to the following files would be overwritten by checkout:
Please, commit your changes or stash them before you can switch branches.

Hmm.... something has changed. See what it is.

host$ git diff patches/defconfig
diff --git a/patches/defconfig b/patches/defconfig
index d903776..3268287 100644
--- a/patches/defconfig
+++ b/patches/defconfig
@@ -2041,6 +2041,7 @@ CONFIG_JHD629_I2C=y
 # CONFIG_N_GSM is not set
 # CONFIG_TRACE_SINK is not set

It looks like some configuration setting have changed. Since we are getting a new version of the kernel, let's revert back to the previous file and try again.

host$ git checkout patches/defconfig
host$ git checkout master
Switched to branch 'master'

Success, now step 2.

host$ git branch -d am33x-v3.8
warning: deleting branch 'am33x-v3.8' that has been merged to
         'refs/remotes/origin/am33x-v3.8', but not yet merged to HEAD.
Deleted branch am33x-v3.8 (was 3fc8a73).

Now repull

host$ git pull

Then start over again

host$ git checkout origin/am33x-v3.8 -b am33x-v3.8
Branch am33x-v3.8 set up to track remote branch am33x-v3.8 from origin.
Switched to a new branch 'am33x-v3.8'

Your system.sh file should be unchanged, so start building

host$ ./build_kernel.sh

Mine took some 26 minutes on an 8 core machine.


If your Beagle fails to boot, follow the EBC_Exercise_22_Recovering instructions to recover.

thumb‎ Embedded Linux Class by Mark A. Yoder