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| -rw-r--r-- | documentation/kernel-manual/kernel-how-to.xml | 66 |
1 files changed, 41 insertions, 25 deletions
diff --git a/documentation/kernel-manual/kernel-how-to.xml b/documentation/kernel-manual/kernel-how-to.xml index e21d1137dd..711291326b 100644 --- a/documentation/kernel-manual/kernel-how-to.xml +++ b/documentation/kernel-manual/kernel-how-to.xml @@ -1008,12 +1008,19 @@ That's it. Configure and build. <title>Creating a BSP Based on an Existing Similar BSP</title> <para> - This section provides an example for creating a BSP - that is based on an existing, and hopefully, similar - one. It assumes you will be using a local kernel - repository and will be pointing the kernel recipe at - that. Follow these steps and keep in mind your - particular situation and differences: + This section provides an example for creating a BSP that is based on an existing, and hopefully, + similar one. + The example assumes you will be using a local kernel repository and you will be pointing the + kernel recipes at that repository. + Follow the steps in this section and keep in mind your particular situation and differences. + </para> + + + <para> + If you are interested in a more detailed example with complete transcripts showing how to + create a BSP that is based on an existing similar BSP, see the information on the wiki + page at <ulink url='https://wiki.yoctoproject.org/wiki/BKM:_starting_a_new_BSP'></ulink>. + </para> <orderedlist> <listitem><para> @@ -1058,27 +1065,37 @@ That's it. Configure and build. <listitem><para>Copy the "emenlow" BSP layer to a new BSP layer named <filename>meta-mymachine</filename>. Now you have two identical BSP layers ‐ but with different names.</para></listitem> - <listitem><para>This example assumes you only need to change some machine - configurations and inform the Yocto Project build process of the new layer. - Consequently, modify the new layer's structure so that all it contains - is the <filename>linux-yocto_git.bbappend</filename> file in the - <filename>meta-mymachine/recipes-kernel/linux</filename> directory - and the <filename>emenlow.conf</filename> configuration file in the - <filename>meta-mymachine/conf/machine</filename> directory as well as the - <filename>layer.conf</filename> file in the parent <filename>conf</filename> directory. - </para></listitem>. + <listitem><para>This example assumes the hardware for your new BSP is very similar to + the hardware used for <filename>meta-emenlow</filename>. + And, you only need to change some machine configurations and inform the Yocto Project build + process of the new layer. + Consequently, you just need to modify some files in the the new layer so that the Yocto Project + build process uses the recipes and configurations in the new layer. + Since you are basing your new layer on a copied existing layer you need to be sure to rename + any directories named "emenlow" to "mymachine". + There is one in the <filename>recipes-bsp</filename> directory and one in the + <filename>recipes-graphics</filename> directory.</para></listitem>. + <listitem><para>In the <filename>recipes-graphics</filename> directory make sure you locate and + change all occurences of "emenlow" to "mymachine". + Several instances exist.</para></listitem> <listitem><para>Rename the <filename>emenlow.conf</filename> file to <filename>mymachine.conf</filename> and fix or remove any configurations. You need to be sure that "mymachine" replaces "emenlow". Note also that "linux-yocto" is the kernel specified in the configuration file.</para></listitem> <listitem><para>Make sure the Yocto Project build process knows about the new BSP - layer by adding the layer to the <filename>bblayers.conf</filename> configuration + layer by adding the pathname to the new layer to the <filename>bblayers.conf</filename> configuration file located in the Yocto Project build tree at <filename>build/conf/bblayers.conf</filename>. Adding the layer allows Bitbake to find the new layer. - </para></listitem> + + <note> + The above example creates a BSP layer named <filename>meta-mymachine</filename> that is + functionally identical to the BSP layer on which it was based - <filename>meta-emenlow</filename>. + In a real-world scenario you would need to differentiate features and configurations to enable + your "similar" BSP layer to work on your target hardware. + </note></para></listitem> </orderedlist> </para></listitem> - + <listitem><para> Create a machine branch for your machine in a the Yocto Project git repository. </para> @@ -1090,7 +1107,7 @@ That's it. Configure and build. Then, create a local clone of that bare clone. Here are the commands: <literallayout class='monospaced'> - $ git clone --bare git://git.yoctoproject.org/linux-yocto-2.6.37.git linux-yocto-2.6.37.git + $ git clone ‐‐bare git://git.yoctoproject.org/linux-yocto-2.6.37.git linux-yocto-2.6.37.git $ git clone linux-yocto-2.6.37.git linux-yocto-2.6.37 </literallayout> </para> @@ -1106,7 +1123,7 @@ That's it. Configure and build. <listitem><para> In your new layer you need to edit the <filename>linux-yocto_git.bbappend</filename> file so that the compatible machine is "mymachine". - It is also convenient point to a cloned Yocto Project git repository that is local + It is also convenient to point to a cloned Yocto Project git repository that is local to your system for development purposes. Thus, change the <filename>linux-yocto_git.bbappend</filename> file in your <filename>meta-mymachine</filename> layer to the following: @@ -1148,7 +1165,7 @@ That's it. Configure and build. <para> You should now be able to build and boot an image with the new kernel: <literallayout class='monospaced'> - $ bitbake core-image-sato-live + $ bitbake -k core-image-sato-live </literallayout> </para></listitem> @@ -1173,12 +1190,11 @@ That's it. Configure and build. <literallayout class='monospaced'> CONFIG_LOG_BUF_SHIFT=18 </literallayout> + </para> <para> These configuration fragments could then be picked up and applied to the kernel .config by appending them to the kernel SRC_URI: - </para> - <literallayout class='monospaced'> SRC_URI_append_mymachine = " file://some.cfg \ file://other.cfg \ @@ -1222,10 +1238,10 @@ That's it. Configure and build. For example, in this case, commit the patch to the "yocto/standard/mymachine" branch, and during the next build it is applied from there. </para></listitem> - </orderedlist> - </para> + </orderedlist> </section> + <section id='bsp-creating-bsp-without-a-local-kernel-repo'> <title>Creating a BSP Based on an Existing Similar BSP Without a Local Kernel Repository</title> |