[bootlin/training-materials updates] master: yocto: slides: clarify FILESPATH (6a61648c)

[Luca Ceresoli]

Repository : https://github.com/bootlin/training-materials
On branch  : master
Link       : https://github.com/bootlin/training-materials/commit/6a61648c78fa521d4e60f00c0def84453a12b4d8

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

commit 6a61648c78fa521d4e60f00c0def84453a12b4d8
Author: Luca Ceresoli <luca.ceresoli at bootlin.com>
Date:   Tue May 9 16:15:34 2023 +0200

    yocto: slides: clarify FILESPATH
    
    Remove details about how it is implemented and explain the idea, step by
    step. Also mention the possibility to use a different file per-MACHINE with
    an example.
    
    Signed-off-by: Luca Ceresoli <luca.ceresoli at bootlin.com>


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

6a61648c78fa521d4e60f00c0def84453a12b4d8
 slides/yocto-recipe-basics/file-overrides.dia      | Bin 0 -> 877 bytes
 slides/yocto-recipe-basics/yocto-recipe-basics.tex |  93 +++++++++++++++++----
 2 files changed, 75 insertions(+), 18 deletions(-)

diff --git a/slides/yocto-recipe-basics/file-overrides.dia b/slides/yocto-recipe-basics/file-overrides.dia
new file mode 100644
index 00000000..a229fad1
Binary files /dev/null and b/slides/yocto-recipe-basics/file-overrides.dia differ
diff --git a/slides/yocto-recipe-basics/yocto-recipe-basics.tex b/slides/yocto-recipe-basics/yocto-recipe-basics.tex
index be4e6735..dd54087b 100644
--- a/slides/yocto-recipe-basics/yocto-recipe-basics.tex
+++ b/slides/yocto-recipe-basics/yocto-recipe-basics.tex
@@ -178,31 +178,88 @@ SRC_URI[patch.md5sum]   = "b184acf9eb39df794ffd..."
   \end{block}
 \end{frame}
 
-\begin{frame}[fragile]
+\begin{frame}
   \frametitle{The source locations: local files}
   \begin{itemize}
-    \item All local files found in \code{SRC_URI} are copied into the
-      recipe's working directory, in \code{$BUILDDIR/tmp/work/}.
+    \item \code{SRC_URI} items using the \code{file://} scheme are {\em
+      local files}
+    \item They are not downloaded, but rather copied from the layer to the
+      work directory
     \item The searched paths are defined in the \code{FILESPATH}
-      variable.
+      variable
+    \item \code{FILESPATH} is a colon-separated list of paths to look for
+      files
+    \item The order matters: when a file is found in a paths, the search
+      ends
   \end{itemize}
-  \begin{block}{}
-  \begin{minted}{sh}
-FILESPATH = "${@base_set_filespath(["${FILE_DIRNAME}/${BP}",
-                "${FILE_DIRNAME}/${BPN}","${FILE_DIRNAME}/files"], d)}
+\end{frame}
 
-FILESOVERRIDES = "${TRANSLATED_TARGET_ARCH}:
-                  ${MACHINEOVERRIDES}:${DISTROOVERRIDES}"
-  \end{minted}
-  \end{block}
+\begin{frame}
+  \frametitle{\code{FILESPATH} 1/3}
+  \begin{itemize}
+    \item \code{FILESPATH} is generated with all combinations of:
+    \item Base paths
+      \begin{itemize}
+        \item \code{${FILE_DIRNAME}/${BP}}  (e.g. \code{BP} = \code{dropbear-2020.81})
+        \item \code{${FILE_DIRNAME}/${BPN}} (e.g. \code{BPN} = \code{dropbear})
+        \item \code{${FILE_DIRNAME}/files}
+        \item Items in \code{FILESEXTRAPATHS} (none by default)
+        \item \code{${FILE_DIRNAME}} is the directory containing the \code{.bb} file
+      \end{itemize}
+    \item The overrides in \code{FILESOVERRIDES}
+      \begin{itemize}
+        \item Set as \code{${TRANSLATED_TARGET_ARCH}:${MACHINEOVERRIDES}:${DISTROOVERRIDES}}
+        \item E.g. \code{arm:armv7a:ti-soc:ti33x:beaglebone:poky}
+        \item Applied right to left
+      \end{itemize}
+  \end{itemize}
+\end{frame}
+
+\begin{frame}
+  \frametitle{\code{FILESPATH} 2/3}
+  \begin{itemize}
+    \item This results in a long list, including:
+      \begin{itemize}
+      {\scriptsize
+        \item \code{/.../meta/recipes-core/dropbear/dropbear-2020.81/poky}
+        \item \code{/.../meta/recipes-core/dropbear/dropbear/poky}
+        \item \code{/.../meta/recipes-core/dropbear/files/poky}
+        \item \code{/.../meta/recipes-core/dropbear/dropbear-2020.81/beaglebone}
+        \item \code{/.../meta/recipes-core/dropbear/dropbear/beaglebone}
+        \item \code{/.../meta/recipes-core/dropbear/files/beaglebone}
+        \item \code{/.../meta/recipes-core/dropbear/dropbear-2020.81/ti33x}
+        \item \code{/.../meta/recipes-core/dropbear/dropbear/ti33x}
+        \item \code{/.../meta/recipes-core/dropbear/files/ti33x}
+        \item\dots
+        \item \code{/.../meta/recipes-core/dropbear/dropbear-2020.81/armv7a}
+        \item \code{/.../meta/recipes-core/dropbear/dropbear/armv7a}
+        \item \code{/.../meta/recipes-core/dropbear/files/armv7a}
+        \item\dots
+        \item \code{/.../meta/recipes-core/dropbear/dropbear-2020.81/}
+        \item \code{/.../meta/recipes-core/dropbear/dropbear/}
+        \item \code{/.../meta/recipes-core/dropbear/files/}
+      }
+      \end{itemize}
+  \end{itemize}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{\code{FILESPATH} 3/3}
   \begin{itemize}
-    \item The \code{base_set_filespath(path)} function uses its
-      \code{path} parameter,  \code{FILESEXTRAPATHS} and
-      \code{FILESOVERRIDES} to fill the \code{FILESPATH} variable.
-    \item Custom paths and files can be added using
-      \code{FILESEXTRAPATHS} and \code{FILESOVERRIDES}.
-    \item Prepend the paths, as the order matters.
+    \item This complex logic allows to use different files without
+      conditional code
+    \item Example: with a single item in \code{SRC_URI}:
+      \begin{block}{}
+        \begin{minted}{sh}
+SRC_URI += "file://defconfig"
+        \end{minted}
+      \end{block}
+    a different \code{defconfig} can be used for different MACHINE
+      values:
   \end{itemize}
+  \begin{center}
+    \includegraphics[width=0.7\textwidth]{slides/yocto-recipe-basics/file-overrides.pdf}
+  \end{center}
 \end{frame}
 
 \begin{frame}