forked from Archive/PX4-Autopilot
212 lines
8.2 KiB
Plaintext
212 lines
8.2 KiB
Plaintext
Application Folder
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==================
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Contents
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--------
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General
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Directory Location
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Named Applications
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Named Startup main() function
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NuttShell (NSH) Built-In Commands
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Synchronous Built-In Commands
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Application Configuration File
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Example Named Application
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Building NuttX with Board-Specific Pieces Outside the Source Tree
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General
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-------
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This folder provides various applications found in sub-directories. These
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applications are not inherently a part of NuttX but are provided you help
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you develop your own applications. The apps/ directory is a "break away"
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part of the configuration that you may chose to use or not.
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Directory Location
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------------------
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The default application directory used by the NuttX build should be named
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apps/ (or apps-x.y/ where x.y is the NuttX version number). This apps/
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directoy should appear in the directory tree at the same level as the
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NuttX directory. Like:
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.
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|- nuttx
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`- apps
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If all of the above conditions are TRUE, then NuttX will be able to
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find the application directory. If your application directory has a
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different name or is location at a different position, then you will
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have to inform the NuttX build system of that location. There are several
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ways to do that:
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1) You can define CONFIG_APPS_DIR to be the full path to your application
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directory in the NuttX configuration file.
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2) You can provide the path to the application directory on the command line
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like: make APPDIR=<path> or make CONFIG_APPS_DIR=<path>
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3) When you configure NuttX using tools/configure.sh, you can provide that
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path to the application directory on the configuration command line
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like: ./configure.sh -a <app-dir> <board-name>/<config-name>
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Named Applications
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------------------
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NuttX also supports applications that can be started using a name string.
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In this case, zpplication entry points with their requirements are gathered
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together in two files:
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- namedapp/namedapp_proto.h Entry points, prototype function
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- namedapp/namedapp_list.h Application specific information and requirements
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The build occurs in several phases as different build targets are executed:
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(1) context, (2) depend, and (3) default (all). Application information is
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collected during the make context build phase.
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To execute an application function:
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exec_namedapp() is defined in the nuttx/include/apps/apps.h
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NuttShell (NSH) Built-In Commands
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---------------------------------
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One use of named applications is to provide a way of invoking your custom
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application through the NuttShell (NSH) command line. NSH will support
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a seamless method invoking the applications, when the following option is
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enabled in the NuttX configuration file:
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CONFIG_NSH_BUILTIN_APPS=y
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Applications registered in the apps/namedapp/namedapp_list.h file will then
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be accessible from the NSH command line. If you type 'help' at the NSH
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prompt, you will see a list of the registered commands.
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Synchronous Built-In Commands
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-----------------------------
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By default, built-in commands started from the NSH command line will run
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asynchronously with NSH. If you want to force NSH to execute commands
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then wait for the command to execute, you can enable that feature by
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adding the following to the NuttX configuration file:
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CONFIG_SCHED_WAITPID=y
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The configuration option enables support for the waitpid() RTOS interface.
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When that interface is enabled, NSH will use it to wait, sleeping until
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the built-in command executes to completion.
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Of course, even with CONFIG_SCHED_WAITPID=y defined, specific commands
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can still be forced to run asynchronously by adding the ampersand (&)
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after the NSH command.
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Application Configuration File
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------------------------------
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A special configuration file is used to configure which applications
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are to be included in the build. The source for this file is
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configs/<board>/<configuration>/appconfig. The existence of the appconfig
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file in the board configuration directory is sufficient to enable building
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of applications.
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The appconfig file is copied into the apps/ directory as .config when
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NuttX is configured. .config is included in the toplevel apps/Makefile.
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As a minimum, this configuration file must define files to add to the
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CONFIGURED_APPS list like:
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CONFIGURED_APPS += vsn/hello vsn/poweroff vsn/jvm
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Named Start-Up main() function
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------------------------------
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A named application can even be used as the main, start-up entry point
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into your embedded software. When the user defines this option in
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the NuttX configuration file:
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CONFIG_BUILTIN_APP_START=<application name>
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that application shall be invoked immediately after system starts
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*instead* of the normal, default "user_start" entry point.
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Note that <application name> must be provided as: "hello",
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will call:
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int hello_main(int argc, char *argv[])
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Example Named Application
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-------------------------
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An example application skeleton can be found under the vsn/hello
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sub-directory. This example shows how a named application can be added
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to the project. One must define:
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1. create sub-directory as: appname
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2. provide entry point: appname_main()
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3. set the requirements in the file: Makefile, specially the lines:
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APPNAME = appname
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PRIORITY = SCHED_PRIORITY_DEFAULT
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STACKSIZE = 768
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ASRCS = asm source file list as a.asm b.asm ...
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CSRCS = C source file list as foo1.c foo2.c ..
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4. add application in the apps/.config
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Building NuttX with Board-Specific Pieces Outside the Source Tree
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-----------------------------------------------------------------
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Q: Has anyone come up with a tidy way to build NuttX with board-
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specific pieces outside the source tree?
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A: Here are four:
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1) There is a make target called 'make export'. It will build
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NuttX, then bundle all of the header files, libaries, startup
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objects, and other build components into a .zip file. You
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can can move that .zip file into any build environment you
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want. You even build NuttX under a DOS CMD window.
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This make target is documented in the top level nuttx/README.txt.
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2) You can replace the entire apps/ directory. If there is
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nothing in the apps/ directory that you need, you can define
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CONFIG_APPS_DIR in your .config file so that it points to a
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different, custom application directory.
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You can copy any pieces that you like from the old apps/directory
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to your custom apps directory as necessary.
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This is documented in NuttX/configs/README.txt and
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nuttx/Documentation/NuttxPortingGuide.html (Online at
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http://nuttx.sourceforge.net/NuttxPortingGuide.html#apndxconfigs
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under Build options). And in the apps/README.txt file.
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3) If you like the random collection of stuff in the apps/ directory
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but just want to expand the existing components with your own,
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external sub-directory then there is an easy way to that too:
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You just create the sympolic link at apps/external that
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redirects to your application sub-directory. The apps/Makefile
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will always automatically check for the existence of an
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apps/external directory and if it exists, it will automatically
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incorporate it into the build.
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This feature of the apps/Makefile is documented only here.
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You can, for example, create a script called install.sh that
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installs a custom application, configuration, and board specific
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directory:
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a) Copy 'MyBoard' directory to configs/MyBoard.
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b) At a symbolic link to MyApplication at apps/external
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c) Configure NuttX (usually by:
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tools/configure.sh MyBoard/MyConfiguration
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or simply by copying defconfig->nutt/.config,
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setenv.sh->nuttx/setenv.sh, Make.defs->nuttx/Make.defs,
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appconfig->apps/.config
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Using the 'external' link makes it especially easy to add a
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'built-in' application an existing configuration.
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4) Add any link to apps/
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a) Add symbolic links apps/ to as many other directories as you
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want.
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b) Then just add the (relative) paths to the links in your
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appconfig file (that becomes the apps/.config file).
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That is basically the same as my option #3 but doesn't use the
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magic 'external' link. The toplevel apps/Makefile will always
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to build whatever in finds in the apps/.config file (plus the
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external link if present).
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