Blame - import-layers/yocto-poky/documentation/dev-manual/dev-manual-start.xml - openbmc/openbmc

$ oe-run-native bmaptool copy ./tmp/deploy/images/qemux86-64/core-image-minimal-<replaceable>machine</replaceable>.wic /dev/sd<replaceable>X</replaceable>

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</literallayout>

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</para></listitem>

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If you do not have write access to

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the media, use the following

commands:

$ sudo bash

$ PATH=tmp/sysroots/x86_64-linux/usr/bin/ bmaptool copy ./tmp/deploy/images/qemux86-64/core-image-minimal-<replaceable>machine</replaceable>.wic /dev/sd<replaceable>X</replaceable>

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</literallayout>

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<note>

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If you are using Ubuntu or Debian distributions,

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you can install the

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<filename>bmap-tools</filename> package using the

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following command and then use the tool

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without specifying

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<filename>PATH</filename> even from the

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root account:

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$ sudo apt-get install bmap-tools

</literallayout>

</note>

</para></listitem>

</itemizedlist>

</para></listitem>

</orderedlist>

</para>

<para>

For help on the <filename>bmaptool</filename> command, use either of

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the following commands:

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$ bmaptool --help

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$ oe-run-native bmaptool --help

</literallayout>

</para>

</section>

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<title>Using Pre-Built Binaries and QEMU</title>

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<para>

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Another option you have to get started is to use pre-built binaries.

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The Yocto Project provides many types of binaries with each release.

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See the "<ulink url='&YOCTO_DOCS_REF_URL;#ref-images'>Images</ulink>"

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chapter in the Yocto Project Reference Manual

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for descriptions of the types of binaries that ship with a Yocto Project

release.

</para>

<para>

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Using a pre-built binary is ideal for developing software

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applications to run on your target hardware.

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To do this, you need to be able to access the appropriate

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cross-toolchain tarball for the architecture on which you are

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developing.

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If you are using an SDK type image, the image ships with the complete

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toolchain native to the architecture (i.e. a toolchain designed to

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run on the

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<ulink url='&YOCTO_DOCS_REF_URL;#var-SDKMACHINE'><filename>SDKMACHINE</filename></ulink>).

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If you are not using an SDK type image, you need to separately download

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and install the stand-alone Yocto Project cross-toolchain tarball.

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See the

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"<ulink url='&YOCTO_DOCS_SDK_URL;#sdk-appendix-obtain'>Obtaining the SDK</ulink>"

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appendix in the Yocto Project Software Development Kit (SDK)

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Developer's Guide for more information on locating and installing

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cross-toolchains.

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</para>

<para>

Regardless of the type of image you are using, you need to download the pre-built kernel

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that you will boot in the QEMU emulator and then download and extract the target root

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filesystem for your target machine’s architecture.

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You can get architecture-specific binaries and file systems from

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<ulink url='&YOCTO_MACHINES_DL_URL;'>machines</ulink>.

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You can get installation scripts for stand-alone toolchains from

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<ulink url='&YOCTO_TOOLCHAIN_DL_URL;'>toolchains</ulink>.

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Once you have all your files, you set up the environment to emulate the hardware

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by sourcing an environment setup script.

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Finally, you start the QEMU emulator.

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You can find details on all these steps in the

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<ulink url='&YOCTO_DOCS_SDK_URL;#sdk-manual'>Yocto Project Software Development Kit (SDK) Developer's Guide</ulink>.

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You can learn more about using QEMU with the Yocto Project in the

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"<link linkend='dev-manual-qemu'>Using the Quick EMUlator (QEMU)</link>"

section.

</para>

<para>

Using QEMU to emulate your hardware can result in speed issues

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depending on the target and host architecture mix.

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For example, using the <filename>qemux86</filename> image in the emulator

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on an Intel-based 32-bit (x86) host machine is fast because the target and

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host architectures match.

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On the other hand, using the <filename>qemuarm</filename> image on the same Intel-based

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host can be slower.

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But, you still achieve faithful emulation of ARM-specific issues.

</para>

<para>

To speed things up, the QEMU images support using <filename>distcc</filename>

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to call a cross-compiler outside the emulated system.

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If you used <filename>runqemu</filename> to start QEMU, and the

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<filename>distccd</filename> application is present on the host system, any

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BitBake cross-compiling toolchain available from the build system is automatically

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used from within QEMU simply by calling <filename>distcc</filename>.

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You can accomplish this by defining the cross-compiler variable

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(e.g. <filename>export CC="distcc"</filename>).

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Alternatively, if you are using a suitable SDK image or the appropriate

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stand-alone toolchain is present,

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the toolchain is also automatically used.

</para>

<note>

Several mechanisms exist that let you connect to the system running on the

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QEMU emulator:

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<listitem><para>QEMU provides a framebuffer interface that makes standard

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consoles available.</para></listitem>

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<listitem><para>Generally, headless embedded devices have a serial port.

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If so, you can configure the operating system of the running image

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to use that port to run a console.

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The connection uses standard IP networking.</para></listitem>

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SSH servers exist in some QEMU images.

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The <filename>core-image-sato</filename> QEMU image has a

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Dropbear secure shell (SSH) server that runs with the root

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password disabled.

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The <filename>core-image-full-cmdline</filename> and

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<filename>core-image-lsb</filename> QEMU images

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have OpenSSH instead of Dropbear.

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Including these SSH servers allow you to use standard

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<filename>ssh</filename> and <filename>scp</filename> commands.

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The <filename>core-image-minimal</filename> QEMU image,

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however, contains no SSH server.

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</para></listitem>

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<listitem><para>You can use a provided, user-space NFS server to boot the QEMU session

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using a local copy of the root filesystem on the host.

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In order to make this connection, you must extract a root filesystem tarball by using the

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<filename>runqemu-extract-sdk</filename> command.

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After running the command, you must then point the <filename>runqemu</filename>

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script to the extracted directory instead of a root filesystem image file.</para></listitem>

</itemizedlist>

</note>

</section>

</chapter>

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