[bootlin/training-materials updates] master: labs/buildroot-basic: update lab to Buildroot 2021.02 + newer U-Boot (29d5055e)

[Thomas Petazzoni]

Repository : https://github.com/bootlin/training-materials
On branch  : master
Link       : https://github.com/bootlin/training-materials/commit/29d5055e6c337e5b114b93d8b797b796cde803af

>---------------------------------------------------------------

commit 29d5055e6c337e5b114b93d8b797b796cde803af
Author: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
Date:   Fri May 21 09:16:33 2021 +0200

    labs/buildroot-basic: update lab to Buildroot 2021.02 + newer U-Boot
    
    Keep Linux at 5.4.x as newer versions seem to have a USB Gadget issue.
    
    Signed-off-by: Thomas Petazzoni <thomas.petazzoni at bootlin.com>


>---------------------------------------------------------------

29d5055e6c337e5b114b93d8b797b796cde803af
 labs/buildroot-basic/buildroot-basic.tex | 40 ++++++++++++++++++--------------
 1 file changed, 22 insertions(+), 18 deletions(-)

diff --git a/labs/buildroot-basic/buildroot-basic.tex b/labs/buildroot-basic/buildroot-basic.tex
index 98a7c0d9..6ea3ced4 100644
--- a/labs/buildroot-basic/buildroot-basic.tex
+++ b/labs/buildroot-basic/buildroot-basic.tex
@@ -42,18 +42,18 @@ git clone https://git.buildroot.net/git/buildroot.git
 \end{verbatim}
 
 In the worst case, if neither work, you can download the Buildroot
-tarball \code{buildroot-2020.02.tar.bz2} from
+tarball \code{buildroot-2021.02.tar.bz2} from
 \code{https://buildroot.org/downloads/} and extract it. However in this
 case, you won't be able to use {\em Git} to visualize your changes and
 keep track of them.
 
 Go into the newly created \code{buildroot} directory.
 
-We're going to start a branch from the {\em 2020.02} Buildroot
+We're going to start a branch from the {\em 2021.02} Buildroot
 release, with which this training has been tested.
 
 \begin{verbatim}
-git checkout -b felabs 2020.02
+git checkout -b felabs 2021.02
 \end{verbatim}
 
 \section{Configuring Buildroot}
@@ -122,7 +122,7 @@ Now, let's do the configuration:
     hesitate however to look at the available options when you select
     \code{Buildroot toolchain} as the \code{Toolchain type}.
 
-  \item Select \code{Arm ARM 2019.12} as the
+  \item Select \code{Arm ARM 2020.11} as the
     \code{Toolchain}. Buildroot can either use pre-defined toolchains
     such as the ones provided by ARM, or custom toolchains (either
     downloaded from a given location, or pre-installed on your
@@ -151,16 +151,18 @@ Now, let's do the configuration:
 
   \item By default, the most recent Linux kernel version available at
     the time of the Buildroot release is used. In our case, we want to
-    use a specific version: \code{5.4.30}. So select \code{Custom
-      version} as the \code{Kernel version}, and enter \code{5.4.30} in
-    the \code{Kernel version} text field that appears.
+    use a specific version: \code{5.10.27}\footnote{Later versions in
+      the 5.10.x stable branch have a regression on Ethernet over USB
+      support}. So select \code{Custom version} as the \code{Kernel
+      version}, and enter \code{5.10.27} in the \code{Kernel version}
+    text field that appears.
 
   \item Now, we need to define which kernel configuration to
     use. We'll start by using a default configuration provided within
     the kernel sources themselves, called a {\em defconfig}. To
     identify which {\em defconfig} to use, you can look in the kernel
     sources directly, at
-    \url{https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/arm/configs/?id=v5.4}. In
+    \url{https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/arm/configs/?id=v5.10}. In
     practice, for this platform, it is not trivial to find which one
     to use: the AM335x processor is supported in the Linux kernel as
     part of the support for many other Texas Instruments processors:
@@ -180,27 +182,29 @@ Now, let's do the configuration:
 
   \item On ARM, all modern platforms now use the {\em Device Tree} to
     describe the hardware. The BeagleBone Black Wireless is in this
-    situation, so you'll have to enable the \code{Build a Device Tree
-      Blob} option. At
-    \url{https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/?id=v5.4},
+    situation, so you'll have to enable the
+    \code{Build a Device Tree Blob} option. At
+    \url{https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/?id=v5.10},
     you can see the list of all Device Tree files available in the
-    5.4 Linux kernel (note: the Device Tree files for boards use the
+    5.10 Linux kernel (note: the Device Tree files for boards use the
     \code{.dts} extension). The one for the BeagleBone Black Wireless
     is \code{am335x-boneblack-wireless.dts}. Even if talking about
     Device Tree is beyond the scope of this training, feel free to
     have a look at this file to see what it contains. Back in
-    Buildroot, type \code{am335x-boneblack-wireless} as the
-    \code{In-tree Device Tree Source file names}.
+    Buildroot, enable \code{Build a Device Tree Blob (DTB)} and type
+    \code{am335x-boneblack-wireless} as the \code{In-tree Device Tree
+      Source file names}.
 
   \item The kernel configuration for this platform requires having
     OpenSSL available on the host machine. To avoid depending on the
-    OpenSSL installed on the host machine, Buildroot can build its own
-    version: just enable the \code{Needs host OpenSSL} option.
+    OpenSSL development files installed by your host machine Linux
+    distribution, Buildroot can build its own version: just enable the
+    \code{Needs host OpenSSL} option.
 
   \end{itemize}
 
 \item \code{Target packages} menu. This is probably the most important
-  menu, as this is the one where you can select amongst the 2500+
+  menu, as this is the one where you can select amongst the 2800+
   available Buildroot packages which ones should be built and
   installed in your system. For our basic system, enabling
   \code{Busybox} is sufficient and is already enabled by default, but
@@ -225,7 +229,7 @@ Now, let's do the configuration:
     recent enough U-Boot version, we are going to use the latter,
     called {\em Kconfig}.
 
-  \item Use the custom version of U-Boot \code{2020.01}.
+  \item Use the custom version of U-Boot \code{2021.04}.
 
   \item Look at
     \url{https://gitlab.denx.de/u-boot/u-boot/-/tree/master/configs} to