1page.title=Building Kernels 2@jd:body 3 4<!-- 5 Copyright 2010 The Android Open Source Project 6 7 Licensed under the Apache License, Version 2.0 (the "License"); 8 you may not use this file except in compliance with the License. 9 You may obtain a copy of the License at 10 11 http://www.apache.org/licenses/LICENSE-2.0 12 13 Unless required by applicable law or agreed to in writing, software 14 distributed under the License is distributed on an "AS IS" BASIS, 15 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 16 See the License for the specific language governing permissions and 17 limitations under the License. 18--> 19<div id="qv-wrapper"> 20 <div id="qv"> 21 <h2>In this document</h2> 22 <ol id="auto-toc"> 23 </ol> 24 </div> 25</div> 26 27<p>If you are only interested in the kernel, you may use this guide 28to download and build the appropriate kernel.</p> 29<p>The following instructions assume that you have not downloaded all 30of AOSP. If you have downloaded all of AOSP, you may skip the git 31clone steps other than the step to download the actual kernel sources.</p> 32<p>We will use the Pandaboard kernel in all the following examples.</p> 33<h2 id="figuring-out-which-kernel-to-build">Figuring out which kernel to build</h2> 34<p>This table lists the name and locations of the kernel sources and binaries: 35<table> 36 <tr> 37 <th>Device</th> 38 <th>Binary location</th> 39 <th>Source location</th> 40 <th>Build configuration</th> 41 </tr> 42 <tr> 43 <td>flo</td> 44 <td>device/asus/flo-kernel/kernel</td> 45 <td>kernel/msm</td> 46 <td>flo_defconfig</td> 47 </tr> 48 <tr> 49 <td>deb</td> 50 <td>device/asus/flo-kernel/kernel</td> 51 <td>kernel/msm</td> 52 <td>flo_defconfig</td> 53 </tr> 54 <tr> 55 <td>manta</td> 56 <td>device/samsung/manta/kernel</td> 57 <td>kernel/exynos</td> 58 <td>manta_defconfig</td> 59 </tr> 60 <tr> 61 <td>mako</td> 62 <td>device/lge/mako-kernel/kernel</td> 63 <td>kernel/msm</td> 64 <td>mako_defconfig</td> 65 </tr> 66 <tr> 67 <td>grouper</td> 68 <td>device/asus/grouper/kernel</td> 69 <td>kernel/tegra</td> 70 <td>tegra3_android_defconfig</td> 71 </tr> 72 <tr> 73 <td>tilapia</td> 74 <td>device/asus/grouper/kernel</td> 75 <td>kernel/tegra</td> 76 <td>tegra3_android_defconfig</td> 77 </tr> 78 <tr> 79 <td>maguro</td> 80 <td>device/samsung/tuna/kernel</td> 81 <td>kernel/omap</td> 82 <td>tuna_defconfig</td> 83 </tr> 84 <tr> 85 <td>toro</td> 86 <td>device/samsung/tuna/kernel</td> 87 <td>kernel/omap</td> 88 <td>tuna_defconfig</td> 89 </tr> 90 <tr> 91 <td>panda</td> 92 <td>device/ti/panda/kernel</td> 93 <td>kernel/omap</td> 94 <td>panda_defconfig</td> 95 </tr> 96 <tr> 97 <td>stingray</td> 98 <td>device/moto/wingray/kernel</td> 99 <td>kernel/tegra</td> 100 <td>stingray_defconfig</td> 101 </tr> 102 <tr> 103 <td>wingray</td> 104 <td>device/moto/wingray/kernel </td> 105 <td>kernel/tegra</td> 106 <td>stingray_defconfig</td> 107 </tr> 108 <tr> 109 <td>crespo</td> 110 <td>device/samsung/crespo/kernel</td> 111 <td>kernel/samsung</td> 112 <td>herring_defconfig</td> 113 </tr> 114 <tr> 115 <td>crespo4g</td> 116 <td>device/samsung/crespo/kernel</td> 117 <td>kernel/samsung</td> 118 <td>herring_defconfig</td> 119 </tr> 120</table> 121 122<p>You will want to look at the git log for the kernel binary in the device 123project that you are interested in.</p> 124 125 126 127Device projects are of the form device/<vendor>/<name>.</p> 128<pre><code>$ git clone https://android.googlesource.com/device/ti/panda 129$ cd panda 130$ git log --max-count=1 kernel 131</code></pre> 132 133<p>The commit message for the kernel binary contains a partial git log 134of the kernel sources that were used to build the binary in question. 135The first entry in the log is the most recent, i.e. the one used to 136build that kernel. You will need it at a later step.</p> 137 138<h2 id="downloading-sources">Downloading sources</h2> 139<p>Depending on which kernel you want,</p> 140<pre><code>$ git clone https://android.googlesource.com/kernel/common.git 141$ git clone https://android.googlesource.com/kernel/exynos.git 142$ git clone https://android.googlesource.com/kernel/goldfish.git 143$ git clone https://android.googlesource.com/kernel/msm.git 144$ git clone https://android.googlesource.com/kernel/omap.git 145$ git clone https://android.googlesource.com/kernel/samsung.git 146$ git clone https://android.googlesource.com/kernel/tegra.git 147</code></pre> 148<ul> 149<li>The <code>goldfish</code> project contains the kernel sources for the emulated 150platforms.</li> 151<li>The <code>msm</code> project has the sources for ADP1, ADP2, Nexus One, Nexus 4, 152and can be used as a starting point for work on Qualcomm MSM chipsets.</li> 153<li>The <code>omap</code> project is used for PandaBoard and Galaxy Nexus, 154and can be used as a starting point for work on TI OMAP chipsets.</li> 155<li>The <code>samsung</code> project is used for Nexus S, 156and can be used as a starting point for work on Samsung Hummingbird chipsets.</li> 157<li>The <code>tegra</code> project is for Xoom and Nexus 7, 158and can be used as a starting point for work on NVIDIA Tegra chipsets.</li> 159<li>The <code>exynos</code> project has the kernel sources for Nexus 10, 160and can be used as a starting point for work on Samsung Exynos chipsets.</li> 161</ul> 162<h2 id="downloading-a-prebuilt-gcc">Downloading a prebuilt gcc</h2> 163<p>Ensure that the prebuilt toolchain is in your path.</p> 164<pre>$ export PATH=$(pwd)/prebuilts/gcc/linux-x86/arm/arm-eabi-4.6/bin:$PATH</pre> 165 166or 167<pre>$ export PATH=$(pwd)/prebuilts/gcc/darwin-x86/arm/arm-eabi-4.6/bin:$PATH</pre> 168 169<p>On a linux host, if you don't have an Android source tree, you can download 170the prebuilt toolchain from: 171<pre>$ git clone https://android.googlesource.com/platform/prebuilts/gcc/linux-x86/arm/arm-eabi-4.6</pre> 172 173<h2 id="building">Building</h2> 174<p>As an example, we would build the panda kernel using the following commands:</p> 175<pre><code>$ export ARCH=arm 176$ export SUBARCH=arm 177$ export CROSS_COMPILE=arm-eabi- 178$ cd omap 179$ git checkout <commit_from_first_step> 180$ make panda_defconfig 181$ make 182</code></pre> 183<p>To build the tuna kernel, you may run the previous commands replacing all 184instances of "panda" with "tuna".</p> 185<p> 186The kernel binary is output as `arch/arm/boot/zImage`, and needs to be copied 187into the Android source tree in order to build the matching boot image. 188</p> 189