[bootlin/training-materials updates] master: Embedded Linux: misc improvements (be282a17)

Michael Opdenacker michael.opdenacker at bootlin.com
Thu Oct 1 09:43:10 CEST 2020

Repository : https://github.com/bootlin/training-materials
On branch  : master
Link       : https://github.com/bootlin/training-materials/commit/be282a172b0cb49ffcc56f43a2632408c21b0c2e


commit be282a172b0cb49ffcc56f43a2632408c21b0c2e
Author: Michael Opdenacker <michael.opdenacker at bootlin.com>
Date:   Thu Oct 1 09:43:10 2020 +0200

    Embedded Linux: misc improvements
    Signed-off-by: Michael Opdenacker <michael.opdenacker at bootlin.com>


 .../sysdev-bootloaders-u-boot.tex                  | 26 +++++++++++++---------
 .../sysdev-linux-intro-features.tex                |  5 +++--
 2 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/slides/sysdev-bootloaders-u-boot/sysdev-bootloaders-u-boot.tex b/slides/sysdev-bootloaders-u-boot/sysdev-bootloaders-u-boot.tex
index 35b879da..25724459 100644
--- a/slides/sysdev-bootloaders-u-boot/sysdev-bootloaders-u-boot.tex
+++ b/slides/sysdev-bootloaders-u-boot/sysdev-bootloaders-u-boot.tex
@@ -28,11 +28,14 @@
   \frametitle{U-Boot configuration}
   \item Get the source code from the website or from git, and uncompress it
-  \item The \projdir{u-boot}{configs} directory contains one configuration file
-    for each supported board
+  \item The \projdir{u-boot}{configs} directory contains one or several
+        configuration file(s) for each supported board
     \item It defines the CPU type, the peripherals and their configuration, the
       memory mapping, the U-Boot features that should be compiled in, etc.
+     \item Examples:\\
+           \projfile{u-boot}{configs/stm32mp15_basic_defconfig}\\
+           \projfile{u-boot}{configs/stm32mp15_trusted_defconfig}
   \item Note: U-Boot is migrating from board configuration defined in
     C header files (\projdir{u-boot}{include/configs}) to {\em defconfig} like in
@@ -40,8 +43,9 @@
     \item Not all boards have been converted to the new configuration
-    \item Older U-Boot releases provided by hardware vendors may not
-      yet use this new configuration system.
+    \item Many boards still have {\em both} hardcoded configuration settings in
+          \code{.h} files, and configuration settings in \code{defconfig}
+          files that can be overriden with configuration interfaces.
@@ -110,7 +114,7 @@ CONFIG_USB_EHCI_HCD=y
   installation of U-Boot is done in a different way:
   \item The CPU provides some kind of specific boot monitor with
-    which you can communicate through serial port or USB using a
+    which you can communicate through the serial port or USB using a
     specific protocol
   \item The CPU boots first on removable media (MMC) before booting
     from fixed media (NAND). In this case, boot from MMC to reflash
@@ -348,7 +352,7 @@ u-boot # saveenv
   \item \code{netmask}, the network mask to contact the server
   \item \code{ethaddr}, the MAC address, can only be set once
   \item \code{autostart}, if set to \code{yes}, U-Boot automatically
-    starts an image after loading it in memory (\code{tftp},
+    tries to execute a binary after loading it in memory (\code{tftp},
   \item \code{filesize}, the size of the latest copy to memory
     (from \code{tftp}, \code{fatload}, \code{nand read}...)
@@ -388,9 +392,9 @@ u-boot # saveenv
   \item Files must be exchanged between the target and the development
     workstation. This is possible:
-    \item Through the network if the target has an Ethernet
-      connection, and U-Boot contains a driver for the Ethernet
-      chip. This is the fastest and most efficient solution.
+    \item Through the network (Ethernet if a network port is available,
+      Ethernet over USB device...), if U-Boot has drivers for such networking.
+      This is the fastest and most efficient solution.
     \item Through a USB key, if U-Boot supports the USB controller of
       your platform
     \item Through a SD or microSD card, if U-Boot supports the MMC
@@ -421,8 +425,8 @@ u-boot # saveenv
   \item A TFTP client is integrated into U-Boot
-    \item Configure the \code{ipaddr} and \code{serverip} environment
-      variables
+    \item Configure the \code{ipaddr}, \code{serverip}, and
+      \code{ethaddr} environment variables
     \item Use \code{tftp <address> <filename>} to load file contents to
       the specified RAM address
     \item Example: \code{tftp 0x21000000 zImage}
diff --git a/slides/sysdev-linux-intro-features/sysdev-linux-intro-features.tex b/slides/sysdev-linux-intro-features/sysdev-linux-intro-features.tex
index 2fe367b6..9ccee3bd 100644
--- a/slides/sysdev-linux-intro-features/sysdev-linux-intro-features.tex
+++ b/slides/sysdev-linux-intro-features/sysdev-linux-intro-features.tex
@@ -119,8 +119,9 @@
       Operating system related information (processes, memory
       management parameters...)
     \item \code{sysfs}, usually mounted on \code{/sys}: \\
-       Representation of the system as a set of
-       devices and buses. Information about these devices.
+       Representation of the system as a tree of
+       devices connected by buses. Information
+       gathered by the kernel frameworks managing these devices.

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