kernel: porting: Light rewording, mention the ARM 64-bit arch

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

slides/kernel-porting-content/kernel-porting-content.tex

@@ -14,7 +14,7 @@
     \item For example, some architectures use the Device Tree, some do
       not.
     \end{itemize}
-  \item This presentation is focused on the \code{arm} (32 bit) architecture only
+  \item This presentation is mainly focused on the ARM (32-bit) architecture
   \end{itemize}
 \end{frame}
 
@@ -23,9 +23,10 @@
   \begin{itemize}
   \item In the source tree, each architecture has its own directory
     \begin{itemize}
-    \item \kdir{arch/arm} for the ARM architecture
+    \item \kdir{arch/arm} for the ARM 32-bit architecture
+    \item \kdir{arch/arm64} for the ARM 64-bit architecture
     \end{itemize}
-  \item This directory contains generic ARM code
+  \item The \kdir{arch/arm} directory contains generic ARM code
     \begin{itemize}
     \item \kreldir{arch/arm}{boot}, \kreldir{arch/arm}{common},
       \kreldir{arch/arm}{configs}, \kreldir{arch/arm}{kernel},
@@ -35,20 +36,18 @@
     \end{itemize}
   \item And many directories for different SoC families
     \begin{itemize}
-    \item \code{mach-*} directories: \kreldir{arch/arm}{mach-pxa} for PXA CPUs,
-      \kreldir{arch/arm}{mach-imx} for Freescale iMX CPUs, etc.
+    \item \code{mach-*} directories: \kreldir{arch/arm}{mach-pxa} for PXA SoCs,
+      \kreldir{arch/arm}{mach-imx} for Freescale iMX SoCs, etc. They
+      essentially contain:
       \begin{itemize}
-      \item Before the ARM cleanup, these directories contained
-        support for the SoC family (GPIO, clocks, pinmux, power
-        management, interrupt controller, etc.) and for the various
-        boards.
-      \item Nowadays, they contain a lot less code, essentially a
-        small SoC description file, power management and SMP code.
+      \item a small SoC description file
+      \item power management code
+      \item SMP code
       \end{itemize}
     \end{itemize}
-  \item Some CPU types share some code, in directories named
+  \item Some SoC families share some code, in directories named
     \code{plat-*}
-  \item Device Tree source files in \kdir{arch/arm/boot/dts}.
+  \item Device Tree source files are in \kdir{arch/arm/boot/dts}
   \end{itemize}
 \end{frame}
 
@@ -108,6 +107,8 @@
     \end{itemize}
   \item Modify \kfile{arch/arm/boot/dts/Makefile} to make sure your
     Device Tree gets built as a {\em DTB} during the kernel build.
+  \item Tweak an existing configuration that matches your SoC and save
+    it as \code{<board-name>_defconfig} in \kdir{arch/arm/configs}
   \item If needed, develop the missing device drivers for the devices
     that are on your board outside the SoC.
   \end{enumerate}

slides/kernel-porting-title/kernel-porting-title.tex

@@ -1 +1 @@
-\section{Porting the Linux Kernel to an ARM Board}
+\section{Porting the Linux kernel to an ARM board}