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Diffstat (limited to 'documentation/kernel-dev/kernel-dev-intro.xml')
-rw-r--r-- | documentation/kernel-dev/kernel-dev-intro.xml | 87 |
1 files changed, 56 insertions, 31 deletions
diff --git a/documentation/kernel-dev/kernel-dev-intro.xml b/documentation/kernel-dev/kernel-dev-intro.xml index 67d8d93f08..32a4040e4b 100644 --- a/documentation/kernel-dev/kernel-dev-intro.xml +++ b/documentation/kernel-dev/kernel-dev-intro.xml | |||
@@ -3,44 +3,69 @@ | |||
3 | [<!ENTITY % poky SYSTEM "../poky.ent"> %poky; ] > | 3 | [<!ENTITY % poky SYSTEM "../poky.ent"> %poky; ] > |
4 | 4 | ||
5 | <chapter id='kernel-dev-intro'> | 5 | <chapter id='kernel-dev-intro'> |
6 | |||
7 | <title>Introduction</title> | 6 | <title>Introduction</title> |
8 | 7 | ||
9 | <para> | 8 | <section id='kernel-dev-overview'> |
10 | Regardless of how you intend to make use of the Yocto Project, | 9 | <title>Overview</title> |
11 | chances are you are going to need to work with the Linux kernel. | ||
12 | The Yocto Project provides a powerful set of tools for managing | ||
13 | Linux kernel sources and configuration data. | ||
14 | You can use this tooling to help you make a single configuration change, | ||
15 | apply a couple of patches, or work with your own sources. | ||
16 | </para> | ||
17 | |||
18 | <para> | ||
19 | The Yocto Project Kernel Development Manual describes common tasks | ||
20 | you can perform using the kernel tooling as well as provides information | ||
21 | about the metadata needed to work with the kernel inside the | ||
22 | Yocto Project. | ||
23 | </para> | ||
24 | |||
25 | <section id='kernel-dev-background'> | ||
26 | <title>Background</title> | ||
27 | 10 | ||
28 | <para> | 11 | <para> |
29 | Each Yocto Project release introduces a new set of linux-yocto | 12 | Regardless of how you intend to make use of the Yocto Project, |
30 | kernel recipes that tracks the latest upstream developments and | 13 | chances are you will work with the Linux kernel. |
31 | introduces newly supported platforms. | 14 | This manual provides background information on the Yocto Linux kernel |
32 | In addition to the new kernel recipes, the previous recipes are | 15 | <ulink url='&YOCTO_DOCS_DEV_URL;#metadata'>Metadata</ulink>, |
33 | refreshed and supported for at least one additional release. | 16 | describes common tasks you can perform using the kernel tools, |
17 | and shows you how to use the Metadata needed to work with | ||
18 | the kernel inside the Yocto Project. | ||
19 | </para> | ||
20 | |||
21 | <para> | ||
22 | Each Yocto Project release has a set of linux-yocto recipes, whose | ||
23 | Git repositories you can view in the Yocto | ||
24 | <ulink url='&YOCTO_GIT_URL;'>Source Repositories</ulink> under | ||
25 | the "Yocto Linux Kernel" heading. | ||
26 | New recipes for the release track the latest upstream developments | ||
27 | and introduce newly supported platforms. | ||
28 | Previous recipes in the release are refreshed and supported for at | ||
29 | least one additional release. | ||
34 | As they align, these previous releases are updated to include the | 30 | As they align, these previous releases are updated to include the |
35 | latest from the Long Term Support Initiative (LTSI) project. | 31 | latest from the Long Term Support Initiative (LTSI) project. |
36 | Besides these recipes, a <filename>linux-yocto-dev.bb</filename> | 32 | Also included is a linux-yocto development recipe |
37 | recipe is available for working with the very latest in upstream | 33 | (<filename>linux-yocto-dev.bb</filename>) should you want to work |
38 | Linux kernel development as well as metadata development. | 34 | with the very latest in upstream Linux kernel development and |
35 | Metadata development. | ||
36 | </para> | ||
37 | |||
38 | <para> | ||
39 | The Yocto Project also provides a powerful set of kernel | ||
40 | tools for managing Linux kernel sources and configuration data. | ||
41 | You can use these tools to make a single configuration change, | ||
42 | apply multiple patches, or work with your own kernel sources. | ||
43 | </para> | ||
44 | |||
45 | <para> | ||
46 | In particular, the kernel tools allow you to generate configuration | ||
47 | fragments that specify only what you must, and nothing more. | ||
48 | Configuration fragments only need to contain the highest level | ||
49 | visible <filename>CONFIG</filename> options as presented by the Linux | ||
50 | kernel <filename>menuconfig</filename> system. | ||
51 | Contrast this against a complete Linux kernel | ||
52 | <filename>.config</filename>, which includes all the automatically | ||
53 | selected <filename>CONFIG</filename> options. | ||
54 | This efficiency reduces your maintenance effort and allows you | ||
55 | to further separate your configuration in ways that make sense for | ||
56 | your project. | ||
57 | A common split separates policy and hardware. | ||
58 | For example, all your kernels might support | ||
59 | the <filename>proc</filename> and <filename>sys</filename> filesystems, | ||
60 | but only specific boards require sound, USB, or specific drivers. | ||
61 | Specifying these configurations individually allows you to aggregate | ||
62 | them together as needed, but maintains them in only one place. | ||
63 | Similar logic applies to separating source changes. | ||
39 | </para> | 64 | </para> |
40 | 65 | ||
41 | <para> | 66 | <para> |
42 | If you do not maintain your own kernel sources and need to make | 67 | If you do not maintain your own kernel sources and need to make |
43 | only minimal changes to the sources, these recipes provide a | 68 | only minimal changes to the sources, the released recipes provide a |
44 | vetted base upon which to layer your changes. | 69 | vetted base upon which to layer your changes. |
45 | Doing so allows you to benefit from the continual kernel | 70 | Doing so allows you to benefit from the continual kernel |
46 | integration and testing performed during development of the | 71 | integration and testing performed during development of the |
@@ -50,8 +75,8 @@ | |||
50 | <para> | 75 | <para> |
51 | If, instead, you have a very specific Linux kernel source tree | 76 | If, instead, you have a very specific Linux kernel source tree |
52 | and are unable to align with one of the many official linux-yocto | 77 | and are unable to align with one of the many official linux-yocto |
53 | releases, an alternative exists by which you can use the Yocto | 78 | recipes, an alternative exists by which you can use the Yocto |
54 | Project Linux kernel tools with your own sources. | 79 | Project Linux kernel tools with your own kernel sources. |
55 | </para> | 80 | </para> |
56 | </section> | 81 | </section> |
57 | 82 | ||
@@ -61,7 +86,7 @@ | |||
61 | <para> | 86 | <para> |
62 | The sections that follow provide instructions for completing | 87 | The sections that follow provide instructions for completing |
63 | specific Linux kernel development tasks. | 88 | specific Linux kernel development tasks. |
64 | These instructions assume you are familiar with working with | 89 | These instructions assume you are comfortable working with |
65 | <ulink url='http://developer.berlios.de/projects/bitbake/'>BitBake</ulink> | 90 | <ulink url='http://developer.berlios.de/projects/bitbake/'>BitBake</ulink> |
66 | recipes and basic open-source development tools. | 91 | recipes and basic open-source development tools. |
67 | Understanding these concepts will facilitate the process of working | 92 | Understanding these concepts will facilitate the process of working |