el7_std: Added Application development chapter

Signed-off-by: Dragos Motrea <Dragos.Motrea@enea.com>

1 files changed, 263 insertions, 3 deletions

diff --git a/doc/book-enea-linux-user-guide/doc/application_development.xml b/doc/book-enea-linux-user-guide/doc/application_development.xml
index 40bb4d8..c8ee28c 100644
--- a/doc/book-enea-linux-user-guide/doc/application_development.xml
+++ b/doc/book-enea-linux-user-guide/doc/application_development.xml
@@ -5,18 +5,278 @@
   <section id="cross_comp_apps">
     <title>Cross-Compiling Applications</title>
 
-    <para></para>
+    <para>Running <command>make</command> cross-compiles your applications
+    according to the environment settings. By installing a Cross-Compilation
+    Toolchain for your target, the environment variables are set up for
+    cross-compilation. For more details, see <xref
+    linkend="install_el_sdk" />.</para>
+
+    <para>Once the cross-compilation environment is set up, you can make your
+    applications as usual and get them compiled for your target. Below you see
+    how to cross-compile from the command line. If Eclipse is installed, you
+    can also cross-compile your code from the Eclipse IDE. For more details,
+    see <xref linkend="enea-linux-eclipse-cross-compile" />.</para>
+
+    <orderedlist>
+      <listitem>
+        <para>Create a Makefile for your application. Example of a simple
+        Makefile and application:</para>
+
+        <programlisting>helloworld:helloworld.o
+        $(CC) -o helloworld helloworld.o
+
+clean:
+        rm -f *.o helloworld</programlisting>
+
+        <programlisting>#include &lt;stdio.h&gt;
+
+int main(void) {
+    printf("Hello World\n");
+    return 0;
+}</programlisting>
+      </listitem>
+
+      <listitem>
+        <para>Run <command>make</command> to cross-compile your application
+        according to the environment set up:</para>
+
+        <programlisting>$ make</programlisting>
+
+        <tip>
+          <para>If the build fails, check if the GNU Make workaround solves
+          your problem.</para>
+        </tip>
+      </listitem>
+
+      <listitem>
+        <para>Copy the <filename>helloworld</filename> program to your target
+        and run it:</para>
+
+        <programlisting># ./helloworld
+Hello World</programlisting>
+      </listitem>
+    </orderedlist>
   </section>
 
   <section id="cross_comp_kern_mod">
     <title>Cross-Compiling Kernel modules</title>
 
-    <para></para>
+    <para>Running <command>make</command> cross-compiles your kernel modules
+    according to the environment settings. By installing a Cross-Compilation
+    Toolchain for your target, the environment variables are set up for
+    cross-compilation. For more details, see <xref
+    linkend="install_el_sdk" />.</para>
+
+    <para>Before cross-compiling kernel modules, you need to make sure the
+    installed toolchain includes the kernel source tree, which should be
+    available at:
+    <literal>&lt;sdkdir&gt;/sysroots/&lt;targetarch&gt;-enea-linux/usr/src/kernel</literal>.
+    If the kernel source tree is not included in the toolchain, you need to
+    add the kernel-dev package into the image recipe enea-image-&lt;name&gt;
+    and build the toolchain again.</para>
+
+    <para>Once the cross-compilation environment is set up, you can make your
+    kernel modules as usual and get them compiled for your target. Below you
+    see how to cross-compile a kernel module.</para>
+
+    <orderedlist>
+      <listitem>
+        <para>Create a Makefile for the kernel module. Example of a simple
+        Makefile and kernel module:</para>
+
+        <programlisting>obj-m := hello.o
+PWD := $(shell pwd)
+
+KERNEL_SRC := &lt;full path to kernel source tree&gt;
+
+all: scripts
+    $(MAKE) -C $(KERNEL_SRC) M=$(PWD) LDFLAGS="" modules
+scripts:
+    $(MAKE) -C $(KERNEL_SRC) scripts
+clean:
+    $(MAKE) -C $(KERNEL_SRC) M=$(PWD) LDFLAGS="" clean</programlisting>
+
+        <programlisting>#include &lt;linux/module.h&gt;       /* Needed by all modules */
+#include &lt;linux/kernel.h&gt;       /* Needed for KERN_INFO */
+#include &lt;linux/init.h&gt;         /* Needed for the macros */
+
+static int __init hello_start(void)
+{
+    printk(KERN_INFO "Loading hello module...\n");
+    printk(KERN_INFO "Hello, world\n");
+    return 0;
+}
+
+static void __exit hello_end(void)
+{
+    printk(KERN_INFO "Goodbye, world\n");
+}
+
+module_init(hello_start);
+module_exit(hello_end);
+
+MODULE_LICENSE("GPL");</programlisting>
+      </listitem>
+
+      <listitem>
+        <para>Run <command>make</command> to cross-compile your kernel module
+        according to the environment set up:</para>
+
+        <programlisting>$ make</programlisting>
+      </listitem>
+
+      <listitem>
+        <para>Copy the kernel module <filename>hello.ko</filename> to your
+        target and install/remove it:</para>
+
+        <programlisting># insmod hello.ko
+# rmmod hello.ko
+# dmesg
+[...] Loading hello module...
+[...] Hello, world
+[...] Goodbye, world</programlisting>
+      </listitem>
+    </orderedlist>
   </section>
 
   <section id="use_devtool">
     <title>Add an Application using devtool</title>
 
-    <para></para>
+    <para>As a prerequisite, you need to install the SDK and set up the
+    environment. For this, see <xref linkend="install_el_sdk" />.</para>
+
+    <para>The following section, <ulink
+    url="http://www.yoctoproject.org/docs/2.3/sdk-manual/sdk-manual.html#sdk-use-devtool-to-add-an-application">Use
+    devtool add to Add an Application</ulink>, in Yocto Project Software
+    Development Kit (SDK) Developer's Guide, explains how to use devtool to
+    generate recipes from existing application code, edit and build recipes,
+    and deploy the output on target. If needed, replace the Yocto version in
+    the link.</para>
+
+    <para>This example will show how to generate a recipe from the existing
+    application code and Makefile, edit the recipe in order to provide an
+    installation path for the application, build the recipe, and deploy the
+    output on a target, or create a DEB package from the recipe and install
+    the package.</para>
+
+    <orderedlist>
+      <listitem>
+        <para>Create a simple application and Makefile in
+        <literal>&lt;workspace_dir&gt;/my_app</literal>:</para>
+
+        <para><literal>&lt;workspace_dir&gt;/my_app/my_hello_app.c</literal></para>
+
+        <programlisting>#include &lt;stdio.h&gt;
+
+int main(void)
+{
+    printf("Hello world!\n");
+    return 0;
+}</programlisting>
+
+        <para><literal>&lt;workspace_dir&gt;/my_app/Makefile</literal></para>
+
+        <programlisting>my_hello_app:</programlisting>
+      </listitem>
+
+      <listitem>
+        <para>Generate a recipe (my-hello-recipe) using the source tree of the
+        application (<literal>&lt;workspace_dir&gt;/my_app</literal>):</para>
+
+        <programlisting>$ devtool add my-hello-recipe &lt;workspace_dir&gt;/my_app
+NOTE: Using source tree as build directory since that would be the default for this
+recipe
+NOTE: Recipe &lt;SDK_dir&gt;/workspace/recipes/my-hello-recipe/my-hello-recipe.bb has been
+automatically created; further editing may be required to make it fully functional</programlisting>
+
+        <programlisting>$ cat &lt;SDK_dir&gt;/workspace/recipes/my-hello-recipe/my-hello-recipe.bb
+# Recipe created by recipetool
+# This is the basis of a recipe and may need further editing in order to be fully
+# functional.
+# (Feel free to remove these comments when editing.)
+#
+# Unable to find any files that looked like license statements. Check the
+# accompanying documentation and source headers and set LICENSE and
+# LIC_FILES_CHKSUM accordingly.
+#
+# NOTE: LICENSE is being set to "CLOSED" to allow you to at least start building - if
+# this is not accurate with respect to the licensing of the software being built (it
+# will not be in most cases) you must specify the correct value before using this
+# recipe for anything other than initial testing/development!
+LICENSE = "CLOSED"
+LIC_FILES_CHKSUM = ""
+
+# No information for SRC_URI yet (only an external source tree was specified)
+SRC_URI = ""
+
+
+# NOTE: this is a Makefile-only piece of software, so we cannot generate much of the
+# recipe automatically - you will need to examine the Makefile yourself and ensure
+# that the appropriate arguments are passed in.
+
+do_configure () {
+    # Specify any needed configure commands here
+    :
+}
+
+do_compile () {
+    # You will almost certainly need to add additional arguments here
+    oe_runmake
+}
+
+do_install () {
+    # NOTE: unable to determine what to put here - there is a Makefile but no
+    # target named "install", so you will need to define this yourself
+    :
+}</programlisting>
+      </listitem>
+
+      <listitem>
+        <para>Edit the recipe to provide an installation path for the
+        application:</para>
+
+        <programlisting>$ devtool edit-recipe my-hello-recipe</programlisting>
+
+        <programlisting>$ cat &lt;SDK_dir&gt;/workspace/recipes/my-hello-recipe/my-hello-recipe.bb
+...
+do_install () {
+    # NOTE: unable to determine what to put here - there is a Makefile but no
+    # target named "install", so you will need to define this yourself
+    install -d ${D}${bindir}
+    install -m 0777 ${S}/my_hello_app ${D}${bindir}
+}
+...</programlisting>
+      </listitem>
+
+      <listitem>
+        <para>Build the recipe:</para>
+
+        <programlisting>$ devtool build my-hello-recipe</programlisting>
+
+        <para>The recipe build results can be seen here:
+        <literal>&lt;SDK_dir&gt;/tmp/work/&lt;arch&gt;-enea-linux/my-hello-recipe/1.0-r0/</literal></para>
+      </listitem>
+
+      <listitem>
+        <para>Deploy the output (in this case, the application) on
+        target:</para>
+
+        <programlisting>$ devtool deploy-target my-hello-recipe root@&lt;target_ip_address&gt;
+Parsing recipes..done.
+NOTE: Successfully deployed
+&lt;SDK_dir&gt;/tmp/work/&lt;arch&gt;-enea-linux/my-hello-recipe/1.0-r0/image</programlisting>
+
+        <para>As an alternative you can create a DEB package:</para>
+
+        <programlisting>$ devtool package my-hello-recipe
+...
+NOTE: Your packages are in &lt;SDK_dir&gt;/tmp/deploy/deb</programlisting>
+
+        <para>Then copy the DEB package on the target and install it using
+        dpkg:</para>
+
+        <programlisting># dpkg -i my-hello-recipe-1.0-r0.1.&lt;arch&gt;.deb</programlisting>
+      </listitem>
+    </orderedlist>
   </section>
 </chapter>
\ No newline at end of file