[bootlin/training-materials updates] master: Embedded Linux: misc minor improvements (6fe9b5f6)
Michael Opdenacker
michael.opdenacker at bootlin.com
Thu Mar 18 12:36:00 CET 2021
Repository : https://github.com/bootlin/training-materials
On branch : master
Link : https://github.com/bootlin/training-materials/commit/6fe9b5f6f6876e72645d48f048c74efa62dbba72
>---------------------------------------------------------------
commit 6fe9b5f6f6876e72645d48f048c74efa62dbba72
Author: Michael Opdenacker <michael.opdenacker at bootlin.com>
Date: Thu Mar 18 12:36:00 2021 +0100
Embedded Linux: misc minor improvements
Signed-off-by: Michael Opdenacker <michael.opdenacker at bootlin.com>
>---------------------------------------------------------------
6fe9b5f6f6876e72645d48f048c74efa62dbba72
labs/sysdev-flash-filesystems/sysdev-flash-filesystems.tex | 3 +++
.../sysdev-block-filesystems/sysdev-block-filesystems.tex | 3 ++-
slides/sysdev-embedded-linux/sysdev-embedded-linux.tex | 6 +++---
.../sysdev-flash-filesystems/sysdev-flash-filesystems.tex | 13 ++++++++-----
4 files changed, 16 insertions(+), 9 deletions(-)
diff --git a/labs/sysdev-flash-filesystems/sysdev-flash-filesystems.tex b/labs/sysdev-flash-filesystems/sysdev-flash-filesystems.tex
index 91ea1f93..cf05ad14 100644
--- a/labs/sysdev-flash-filesystems/sysdev-flash-filesystems.tex
+++ b/labs/sysdev-flash-filesystems/sysdev-flash-filesystems.tex
@@ -190,6 +190,9 @@ command \code{nand write}\footnote{The command \code{nand write.trimffs} skips
not recommended writing more than one time on a page and its OOB
even if the page is blank.}.
+With the \code{ubi part UBI} command, make sure that U-Boot could process
+the UBI image that you've just flashed.
+
\section{Loading kernel and DTB images from UBI and booting it}
From U-Boot, retrieve the kernel and DTB images from their respective
diff --git a/slides/sysdev-block-filesystems/sysdev-block-filesystems.tex b/slides/sysdev-block-filesystems/sysdev-block-filesystems.tex
index 3b361456..62259fdf 100644
--- a/slides/sysdev-block-filesystems/sysdev-block-filesystems.tex
+++ b/slides/sysdev-block-filesystems/sysdev-block-filesystems.tex
@@ -269,7 +269,8 @@ major minor #blocks name
\item More space-efficient than ramdisks: files are directly in the
file cache, grows and shrinks to accommodate stored files
\item How to use: choose a name to distinguish the various tmpfs
- instances you could have. Examples:\\
+ instances you have (unlike in most other filesystems, each
+ tmpfs instance is different). Examples:\\
\code{mount -t tmpfs run /var/run}\\
\code{mount -t tmpfs shm /dev/shm}
\item See \kerneldochtml{filesystems/tmpfs} in kernel sources.
diff --git a/slides/sysdev-embedded-linux/sysdev-embedded-linux.tex b/slides/sysdev-embedded-linux/sysdev-embedded-linux.tex
index 9b71ae0b..4c42f915 100644
--- a/slides/sysdev-embedded-linux/sysdev-embedded-linux.tex
+++ b/slides/sysdev-embedded-linux/sysdev-embedded-linux.tex
@@ -522,8 +522,8 @@ met:
\item Supports hardware encoders and decoders through plugins,
proprietary/specific plugins are often provided by SoC vendors.
\end{itemize}
- \item {\bf alsa-lib}, the user space tools associated to the ALSA sound
- kernel subsystem
+ \item {\bf alsa-lib}, the user space tools associated to the ALSA
+ kernel sound subsystem
\item Directly using encoding and decoding libraries, if you decide
not to use GStreamer:
\begin{itemize}
@@ -915,7 +915,7 @@ met:
\item The {\em build} space, which will contain a lot more files
than the {\em target} space, since it is used to keep everything
needed to {\bf compile} libraries and applications. So we must
- keep the headers, documentation, and other configuration files
+ keep at least the headers, binaries and configuration files.
\end{itemize}
\end{itemize}
\includegraphics[width=\textwidth]{slides/sysdev-embedded-linux/source-build-target-spaces.pdf}
diff --git a/slides/sysdev-flash-filesystems/sysdev-flash-filesystems.tex b/slides/sysdev-flash-filesystems/sysdev-flash-filesystems.tex
index d7426cea..04714a93 100644
--- a/slides/sysdev-flash-filesystems/sysdev-flash-filesystems.tex
+++ b/slides/sysdev-flash-filesystems/sysdev-flash-filesystems.tex
@@ -30,7 +30,7 @@
\item Encode bits with voltage levels
\begin{itemize}
\item SLC: {\em Single Level Cell} - 1 bit per memory cell
- \item MLC: {\em Multi Level Cell} - Multiple bits per cell)
+ \item MLC: {\em Multi Level Cell} - Multiple bits per cell
\end{itemize}
\item Start with all bits set to 1
\item Writing implies changing some bits from 1 to 0
@@ -522,7 +522,7 @@ Device 0 bad blocks:
\item These file systems are relying on the MTD layer to access
flash chips
\item There are several legacy flash filesystems which might be
- useful for specific usage: JFFS2, YAFFS2.
+ useful for specific uses: JFFS2, YAFFS2.
\item Nowadays, UBI/UBIFS is the de facto standard for medium to
large capacity NANDs
\end{itemize}
@@ -532,6 +532,7 @@ Device 0 bad blocks:
\frametitle{Legacy flash filesystems: JFFS2}
\begin{columns}
\column{0.7\textwidth}
+ {\em Journaling Flash File System version 2}
\begin{itemize}
\item Supports on the fly compression
\item Wear leveling, power failure resistant
@@ -551,6 +552,7 @@ Device 0 bad blocks:
\frametitle{Legacy flash filesystems: YAFFS2}
\begin{columns}
\column{0.7\textwidth}
+ {\em Yet Another Flash File System version 2}
\begin{itemize}
\item Mainly supports NAND flash
\item No compression
@@ -568,9 +570,10 @@ Device 0 bad blocks:
\begin{frame}
- \frametitle{UBI/UBIFS}
+ \frametitle{UBI / UBIFS}
\begin{columns}
\column{0.7\textwidth}
+ {\em Unsorted Block Images}
\begin{itemize}
\item Aimed at replacing JFFS2 by addressing its limitations
\item Design choices:
@@ -648,7 +651,7 @@ Device 0 bad blocks:
bootloaders.
\item U-Boot now even supports storing its environment in a UBI volume!
\item If you do need extra MTD partitions, try to group them at the end
- or the beginning of the flash device
+ or the beginning of the flash device (often more reliable areas).
\end{itemize}
\end{frame}
@@ -851,7 +854,7 @@ Device 0 bad blocks:
\begin{itemize}
\item \code{-m 4096}, minimal I/O size\\
(see \code{/sys/class/mtd/mtdx/writesize}).
- \item \code{-e 258048}, logical erase block size (smaller than
+ \item \code{-e 258048}, {\bf logical} erase block size (smaller than
PEB size, can be found in the kernel log after running
\code{ubiattach})
\item \code{-c 1000}, maximum size of the UBI volume the image
More information about the training-materials-updates
mailing list