RTEMS Development Environment Guide (6.17c582f).#
The authors have used their best efforts in preparing this material. These efforts include the development, research, and testing of the theories and programs to determine their effectiveness. No warranty of any kind, expressed or implied, with regard to the software or the material contained in this document is provided. No liability arising out of the application or use of any product described in this document is assumed. The authors reserve the right to revise this material and to make changes from time to time in the content hereof without obligation to notify anyone of such revision or changes.
The RTEMS Project is hosted at https://www.rtems.org. Any inquiries concerning RTEMS, its related support components, or its documentation should be directed to the RTEMS Project community.
1. Introduction#
This document describes the RTEMS development environment. Discussions are provided for the following topics:
the directory structure used by RTEMS,
usage of the GNU Make utility within the RTEMS development environment,
sample applications, and
the RTEMS specific utilities.
RTEMS was designed as a reusable software component. Highly reusable software such as RTEMS is typically distributed in the form of source code without providing any support tools. RTEMS is the foundation for a complex family of facilities including board support packages, device drivers, and support libraries. The RTEMS Development Environment is not a CASE tool. It is a collection of tools designed to reduce the complexity of using and enhancing the RTEMS family. Tools are provided which aid in the management of the development, maintenance, and usage of RTEMS, its run-time support facilities, and applications which utilize the executive.
A key component of the RTEMS development environment is the GNU family of free tools. This is robust set of development and POSIX compatible tools for which source code is freely available. The primary compilers, assemblers, linkers, and make utility used by the RTEMS development team are the GNU tools. They are highly portable supporting a wide variety of host computers and, in the case of the development tools, a wide variety of target processors.
It is recommended that the RTEMS developer become familiar with the RTEMS Development Environment before proceeding with any modifications to the executive source tree. The source code for the executive is very modular and source code is divided amongst directories based upon functionality as well as dependencies on CPU and target board. This organization is aimed at isolating and minimizing non-portable code. This has the immediate result that adding support for a new CPU or target board requires very little “wandering” around the source tree.
2. Directory Structure#
The RTEMS directory structure is designed to meet the following requirements:
encourage development of modular components.
isolate processor and target dependent code, while allowing as much common source code as possible to be shared across multiple processors and target boards.
allow multiple RTEMS users to perform simultaneous compilation of RTEMS and its support facilities for different processors and targets.
The resulting directory structure has processor and board dependent source files isolated from generic files. When RTEMS is configured and built, object directories and an install point will be automatically created based upon the target CPU family and BSP selected.
The placement of object files based upon the selected BSP name ensures that object files are not mixed across CPUs or targets. This in combination with the makefiles allows the specific compilation options to be tailored for a particular target board. For example, the efficiency of the memory subsystem for a particular target board may be sensitive to the alignment of data structures, while on another target board with the same processor memory may be very limited. For the first target, the options could specify very strict alignment requirements, while on the second the data structures could be packed to conserve memory. It is impossible to achieve this degree of flexibility without providing source code.
The RTEMS source tree is organized based on the following variables:
functionality,
target processor family,
target processor model,
peripherals, and
target board.
Each of the following sections will describe the contents of the directories in the RTEMS source tree. The top of the tree will be referenced as ${RTEMS_ROOT} in this discussion.
rtems-VERSION
|
+----+----+----+--+-----+---+-------+--------+
| | | | | | | |
c contrib cpukit doc make testsuites tools
${RTEMS_ROOT}/c/Historically, this directory was the root of the portions of the RTEMS source tree which must be built tailored for a particular CPU model or BSP. In the current source, only the build support files for the autoconf/automake based build system remain in this subdirectory.
${RTEMS_ROOT}/cpukit/This directory is the root for all of the “multilib’able” portions of RTEMS. This is a GNU way of saying the contents of this directory can be compiled like the C Library (
libc.a) and the functionality is neither CPU model nor BSP specific. The source code for most RTEMS services reside under this directory. The contents of this directory will be discussed in the CPU Kit Directory section.${RTEMS_ROOT}/bspsThis directory is the root for all of the BSP specific source in RTEMS. The contents of this directory are discussed in the BSPs Directory section.
${RTEMS_ROOT}/make/This directory contains files which support RTEMS Makefile’s. From a user’s perspective, the most important part is the BSP specific information found in the
configsubdirectory of each BSP. Each “.cfg” file is associated with a specific BSP and describes the CPU model, and compiler flags used to produce an executable for the target board. These files are described in detail in the RTEMS BSP and Driver Guide and will not be discussed further in this document.${RTEMS_ROOT}/testsuites/This directory contains the test suites for the various RTEMS APIs and support libraries. The contents of this directory are discussed in the testsuites/ Test Suites section.
2.1. BSPs Directory#
The “bsps” directory contains a directory for each CPU family supported by RTEMS. Beneath each CPU directory is a directory for each BSP for that processor family.
The “bsps” directory provides all the BSPs provided with this release of RTEMS. The subdirectories are divided, as discussed previously, based on specific processor family, then further broken down into specific target board environments. The “no_cpu” subdirectory provides a starting point template BSP which can be used to develop a specific BSP for an unsupported target board. The files in this subdirectory may aid in preliminary testing of the RTEMS development environment that has been built for no particular target in mind.
Below each CPU dependent directory is a directory for each target BSP supported in this release.
Each BSP provides the modules which comprise an RTEMS BSP. The modules are separated into various subdirectories such as “clock”, “console”, “include”, “shmsupp”, “startup”, and “timer” as shown in the following figure:
Each BSP
|
+-----------+----------+-----+-----+----------+----------+
| | | | | |
clock console include shmsupp startup timer
2.1.1. CPU Kit Directory#
The @code{cpukit/} directory contains many subdirectories with the most important ones being shown in the structure below:
cpukit
|
+-----------+----------+-----------+
| | | |
posix rtems sapi score
The cpukit/ directory contains a set of subdirectories which contains the source files comprising the executive portion of the RTEMS development environment as well as portable support libraries such as support for the C Library and filesystems. The API specific and “SuperCore” (e.g. score/ directory) source code files are separated into distinct directory trees.
The following is a description of each of the subdirectories under cpukit/:
${RTEMS_ROOT}/cpukit/ftpd/This directory contains the RTEMS ftpd server.
${RTEMS_ROOT}/cpukit/mhttpd/This directory contains the port of the Mongoose web server to RTEMS.
${RTEMS_ROOT}/cpukit/include/This directory contains header files which are private to RTEMS and not considered to be owned by any other component in the CPU Kit.
${RTEMS_ROOT}/cpukit/libblock/This directory contains support code for using Block Devices such as hard drives, floppies, and CD-ROMs. It includes the generic IO primitives for block device drivers, disk caching support, and a RAM disk block device driver.
${RTEMS_ROOT}/cpukit/libcsupport/This directory contains the RTEMS specific support routines for the Newlib C Library. This includes what are referred to as system calls and found in section 2 of the traditional UNIX manual. In addition, it contains a thread-safe implementation of the Malloc family of routines as well as BSD and POSIX services not found in Newlib.
${RTEMS_ROOT}/cpukit/libfs/This directory contains the various non-networked filesystem implementations for RTEMS. It includes the In-Memory FileSystem (IMFS), the mini-IMFS, and FAT filesystems.
${RTEMS_ROOT}/cpukit/libi2c/This directory contains the RTEMS I2C framework.
${RTEMS_ROOT}/cpukit/libmd/This directory contains a port of the standard MD5 checksum code.
${RTEMS_ROOT}/cpukit/libmisc/This directory contains support facilities which are RTEMS specific but otherwise unclassified. In general, they do not adhere to a standard API. Among the support facilities in this directory are a
/dev/nulldevice driver, the Stack Overflow Checker, a mini-shell, the CPU and rate monotonic period usage monitoring libraries, and a utility to “dump a buffer” in a nicely formatted way similar to many ROM monitors.${RTEMS_ROOT}/cpukit/libnetworking/This directory contains the port of the FreeBSD TCP/IP stack to RTEMS.
${RTEMS_ROOT}/cpukit/librpc/This directory contains the port of the FreeBSD RPC/XDR source to RTEMS.
${RTEMS_ROOT}/cpukit/libpci/This directory contains RTEMS PCI Library.
${RTEMS_ROOT}/cpukit/posix/This directory contains the RTEMS implementation of the threading portions of the POSIX API.
${RTEMS_ROOT}/cpukit/pppd/This directory contains a port of the free implementation of the PPPD network protocol.
${RTEMS_ROOT}/cpukit/rtems/This directory contains the implementation of the Classic API.
${RTEMS_ROOT}/cpukit/sapi/This directory contains the implementation of RTEMS services which are required but beyond the realm of any standardization efforts. It includes initialization, shutdown, and IO services.
${RTEMS_ROOT}/cpukit/score/This directory contains the “SuperCore” of RTEMS. All APIs are implemented in terms of SuperCore services. For example, Classic API tasks and POSIX threads are all implemented in terms of SuperCore threads. This provides a common infrastructure and a high degree of interoperability between the APIs. For example, services from all APIs may be used by any task/thread independent of the API used to create it. Within the
score/directory the CPU dependent modules are found. Thescore/cpu/subdirectory contains a subdirectory for each target CPU supported by this release of the RTEMS executive. Each processor directory contains the CPU dependent code necessary to host RTEMS. Theno_cpudirectory provides a starting point for developing a new port to an unsupported processor. The files contained within theno_cpudirectory may also be used as a reference for the other ports to specific processors.${RTEMS_ROOT}/cpukit/telnetd/This directory contains the RTEMS telnetd server.
${RTEMS_ROOT}/cpukit/wrapup/This directory is responsible for taking the individual libraries and objects built in each of the components in the RTEMS CPU Kit source tree and bundling them together to form the single RTEMS library
librtemscpu.a. This library contains all BSP and CPU model specific software.${RTEMS_ROOT}/cpukit/zlib/This directory contains a port of the GNU Zlib compression library to RTEMS.
2.1.2. testsuites/ Test Suites#
This directory provides all of the RTEMS Test Suite except those for the Classic API Ada95 binding This includes the single processor tests, multiprocessor tests, timing tests, library tests, and sample tests. Additionally, subdirectories for support functions and test related header files are provided. The following table lists the test suites currently included with the RTEMS and the directory in which they may be located:
${RTEMS_ROOT}/testsuites/libtests/This directory contains the test suite for the various RTEMS support components.
${RTEMS_ROOT}/testsuites/mptests/This directory contains the test suite for the multiprocessor support in the Classic API. The tests provided address two node configurations and provide coverage for the multiprocessor code found in RTEMS.
${RTEMS_ROOT}/testsuites/psxtests/This directory contains the test suite for the RTEMS POSIX API.
${RTEMS_ROOT}/testsuites/samples/This directory provides sample application tests which aid in the testing a newly built RTEMS environment, a new BSP, or as starting points for the development of an application using the RTEMS executive. They are discussed in ::ref::Sample Applications.
${RTEMS_ROOT}/testsuites/sptests/This directory contains the test suite for the RTEMS Classic API when executing on a single processor. The tests were originally designed to provide near complete test coverage for the entire executive code. With the addition of multiple APIs, this is no longer the case as some SuperCore functionality is not available through the Classic API. Thus some functionality in the SuperCore is only covered by tests in the POSIX API Test Suites.
${RTEMS_ROOT}/testsuites/support/This directory contains support software and header files for the various test suites.
${RTEMS_ROOT}/testsuites/tmtests/This directory contains the timing test suite for the RTEMS Classic API. This include tests that benchmark each directive in the Classic API as well as a set of critical SuperCore functions. These tests are important for helping to verify that RTEMS performs as expected on your target hardware. It is not uncommon to discover mistakes in board initialization such as caching being disabled as a side-effect of analyzing the results of these tests.
${RTEMS_ROOT}/testsuites/tools/This directory contains tools which execute on the development host and aid in executing and evaluating the results of the test suite. The tools
difftestcompares the output of one or more tests with the expected output. If you place the output of all thetmtests/in a single file, then the utilitysorttimeswill be able to produce a report organizing the execution times by manager.
3. Sample Applications#
3.1. Introduction#
The RTEMS source distribution includes a set of sample applications that are located in the ${RTEMS_ROOT}/testsuites/samples/ directory. These applications are intended to illustrate the basic format of RTEMS single and multiple processor applications and the use of some features. In addition, these relatively simple applications can be used to test locally developed board support packages and device drivers as they exercise a critical subset of RTEMS functionality that is often broken in new BSPs.
Some of the following sample applications will be covered in more detail in subsequent sections:
- Hello World
The RTEMS Hello World test is provided in the subdirectory
${RTEMS_ROOT}/testsuites/samples/hello/. This test is helpful when testing new RTEMS development environment.- Clock Tick
The
${RTEMS_ROOT}/testsuites/samples/ticker/subdirectory provides a test for verification of clock chip device drivers of BSPs.- Base Single Processor
A simple single processor test similar to those in the single processor test suite is provided in
${RTEMS_ROOT}/testsuites/samples/base_sp/.- Base Multiple Processor
A simple two node multiprocessor test capable of testing an newly developed MPCI layer is provided in
${RTEMS_ROOT}/testsuites/samples/base_mp/.- Capture
The RTEMS Capture test is provided in the subdirectory
${RTEMS_ROOT}/testsuites/samples/capture/. This is an interactive test which demonstrates the capabilities of the RTEMS Capture Engine. It includes a few test threads which generate interesting execution patterns. Look at the file${RTEMS_ROOT}/testsuites/samples/capture/capture.scnfor a sample session.- Constructor/Destructor C++ Test
The
${RTEMS_ROOT}/testsuites/samples/cdtest/subdirectory provides a simple C++ application using constructors and destructors. It is only built when C++ is enabled and its primary purpose is to demonstrate that global constructors and destructors work. Since this requires that the linker script for your BSP be correct, this is an important test.- File IO
The RTEMS File IO test is provided in the subdirectory
${RTEMS_ROOT}/testsuites/samples/fileio/. This is an interactive test which allows the user to interact with an ATA/IDE device. It will read the partition table and allow the user to dynamically mount one of the FAT32 partitions it finds. Commands are also provided to write and read files on the disk.- IO Stream
The RTEMS IO Stream test is provided in the subdirectory
${RTEMS_ROOT}/testsuites/samples/iostream/. This test is a simple C++ application which demonstrates that C++ iostreams are functional. This requires that the RTEMS C++ run-time support is functioning properly. This test is only build when C++ is enabled.- Network Loopback Test
The
${RTEMS_ROOT}/testsuites/samples/loopback/directory contains a sample test that demonstrates the use of sockets and the loopback network device. It does not require the presence of network hardware in order to run. It is only built if RTEMS was configured with networking enabled.- Minimum Size Test
The directory
${RTEMS_ROOT}/testsuites/samples/minimum/contains a simple RTEMS program that results in a non-functional executable. It is intended to show the size of a minimum footprint application based upon the current RTEMS configuration.- Nanoseconds
The RTEMS Nanoseconds test is provided in the subdirectory
${RTEMS_ROOT}/testsuites/samples/nsecs/. This test demonstrates that the BSP has support for nanosecond timestamp granularity. It prints the time of day and uptime multiple times as quickly as possible. It should be possible from the output to determine if your BSP has nanosecond accurate clock support and it is functional.- Paranoia Floating Point Test
The directory
${RTEMS_ROOT}/testsuites/samples/paranoia/contains the public domain floating point and math library test.- Point-to-Point Protocol Daemon
The RTEMS Point-to-Point Protocol Daemon test is provided in the subdirectory
${RTEMS_ROOT}/testsuites/samples/pppd/. This test primarily serves as the baseline for a user application using the PPP protocol.- Unlimited Object Allocation
The
${RTEMS_ROOT}/testsuites/samples/unlimited/directory contains a sample test that demonstrates the use of the*unlimited* object allocation configuration option to RTEMS.
The sample tests are written using the Classic API so the reader should be familiar with the terms used and material presented in the RTEMS Applications Users Guide.
3.2. Hello World#
This sample application is in the following directory:
${RTEMS_ROOT}/testsuites/samples/hello/
It provides a rudimentary test of the BSP start up code and the console output routine. The C version of this sample application uses the printf function from the RTEMS Standard C Library to output messages. The Ada version of this sample uses the TEXT_IO package to output the hello messages. The following messages are printed:
*** HELLO WORLD TEST ***
Hello World
*** END OF HELLO WORLD TEST ***
These messages are printed from the application’s single initialization task. If the above messages are not printed correctly, then either the BSP start up code or the console output routine is not operating properly.
3.3. Clock Tick#
This sample application is in the following directory:
${RTEMS_ROOT}/testsuites/samples/ticker/
This application is designed as a simple test of the clock tick device driver. In addition, this application also tests the printf function from the RTEMS Standard C Library by using it to output the following messages:
*** CLOCK TICK TEST ***
TA1 - tm_get - 09:00:00 12/31/1988
TA2 - tm_get - 09:00:00 12/31/1988
TA3 - tm_get - 09:00:00 12/31/1988
TA1 - tm_get - 09:00:05 12/31/1988
TA1 - tm_get - 09:00:10 12/31/1988
TA2 - tm_get - 09:00:10 12/31/1988
TA1 - tm_get - 09:00:15 12/31/1988
TA3 - tm_get - 09:00:15 12/31/1988
TA1 - tm_get - 09:00:20 12/31/1988
TA2 - tm_get - 09:00:20 12/31/1988
TA1 - tm_get - 09:00:25 12/31/1988
TA1 - tm_get - 09:00:30 12/31/1988
TA2 - tm_get - 09:00:30 12/31/1988
TA3 - tm_get - 09:00:30 12/31/1988
*** END OF CLOCK TICK TEST ***
The clock tick sample application utilizes a single initialization task and three copies of the single application task. The initialization task prints the test herald, sets the time and date, and creates and starts the three application tasks before deleting itself. The three application tasks generate the rest of the output. Every five seconds, one or more of the tasks will print the current time obtained via the tm_get directive. The first task, TA1, executes every five seconds, the second task, TA2, every ten seconds, and the third task, TA3, every fifteen seconds. If the time printed does not match the above output, then the clock device driver is not operating properly.
3.4. Base Single Processor Application#
This sample application is in the following directory:
${RTEMS_ROOT}/testsuites/samples/base_sp/
It provides a framework from which a single processor RTEMS application can be developed. The use of the task argument is illustrated. This sample application uses the printf function from the RTEMS Standard C Library or TEXT_IO functions when using the Ada version to output the following messages:
*** SAMPLE SINGLE PROCESSOR APPLICATION ***
Creating and starting an application task
Application task was invoked with argument (0) and has id of 0x10002
*** END OF SAMPLE SINGLE PROCESSOR APPLICATION ***
The first two messages are printed from the application’s single initialization task. The final messages are printed from the single application task.
3.5. Base Multiple Processor Application#
This sample application is in the following directory:
${RTEMS_ROOT}/testsuites/samples/base_mp/
It provides a framework from which a multiprocessor RTEMS application can be developed. This directory has a subdirectory for each node in the multiprocessor system. The task argument is used to distinguish the node on which the application task is executed. The first node will print the following messages:
*** SAMPLE MULTIPROCESSOR APPLICATION ***
Creating and starting an application task
This task was invoked with the node argument (1)
This task has the id of 0x10002
*** END OF SAMPLE MULTIPROCESSOR APPLICATION ***
The second node will print the following messages:
*** SAMPLE MULTIPROCESSOR APPLICATION ***
Creating and starting an application task
This task was invoked with the node argument (2)
This task has the id of 0x20002
*** END OF SAMPLE MULTIPROCESSOR APPLICATION ***
The herald is printed from the application’s single initialization task on each node. The final messages are printed from the single application task on each node.
In this sample application, all source code is shared between the nodes except for the node dependent configuration files. These files contains the definition of the node number used in the initialization of the RTEMS Multiprocessor Configuration Table. This file is not shared because the node number field in the RTEMS Multiprocessor Configuration Table must be unique on each node.
3.6. Constructor/Destructor C++ Application#
This sample application is in the following directory:
${RTEMS_ROOT}/testsuites/samples/cdtest/
This sample application demonstrates that RTEMS is compatible with C++ applications. It uses constructors, destructor, and I/O stream output in testing these various capabilities. The board support package responsible for this application must support a C++ environment.
This sample application uses the printf function from the RTEMS Standard C Library to output the following messages:
Hey I'M in base class constructor number 1 for 0x400010cc.
Hey I'M in base class constructor number 2 for 0x400010d4.
Hey I'M in derived class constructor number 3 for 0x400010d4.
*** CONSTRUCTOR/DESTRUCTOR TEST ***
Hey I'M in base class constructor number 4 for 0x4009ee08.
Hey I'M in base class constructor number 5 for 0x4009ee10.
Hey I'M in base class constructor number 6 for 0x4009ee18.
Hey I'M in base class constructor number 7 for 0x4009ee20.
Hey I'M in derived class constructor number 8 for 0x4009ee20.
Testing a C++ I/O stream
Hey I'M in derived class constructor number 8 for 0x4009ee20.
Derived class - Instantiation order 8
Hey I'M in base class constructor number 7 for 0x4009ee20.
Instantiation order 8
Hey I'M in base class constructor number 6 for 0x4009ee18.
Instantiation order 6
Hey I'M in base class constructor number 5 for 0x4009ee10.
Instantiation order 5
Hey I'M in base class constructor number 4 for 0x4009ee08.
Instantiation order 5
*** END OF CONSTRUCTOR/DESTRUCTOR TEST ***
Hey I'M in base class constructor number 3 for 0x400010d4.
Hey I'M in base class constructor number 2 for 0x400010d4.
Hey I'M in base class constructor number 1 for 0x400010cc.
3.7. Minimum Size Test#
This sample application is in the following directory:
${RTEMS_ROOT}/testsuites/samples/minimum/
This sample application is designed to produce the minimum code space required for any RTEMS application based upon the current RTEMS configuration and BSP. In many situations, the bulk of this executable consists of hardware and RTEMS initialization, basic infrastructure such as malloc(), and RTEMS and hardware shutdown support.
3.8. Nanosecond Granularity Application#
This sample application is in the following directory:
${RTEMS_ROOT}/testsuites/samples/nsecs/
This sample application exercises the Clock Driver for this BSP and demonstrates its ability to generate accurate timestamps. This application does this by exercising the time subsystem in three ways:
Obtain Time of Day Twice Back to Back
Obtain System Up Time Twice Back to Back
Use System Up Time to Measure Loops
The following is an example of what the output of this test may appear like:
*** NANOSECOND CLOCK TEST ***
10 iterations of getting TOD
Start: Sat Mar 24 11:15:00 2007:540000
Stop : Sat Mar 24 11:15:00 2007:549000 --> 0:9000
Start: Sat Mar 24 11:15:00 2007:3974000
Stop : Sat Mar 24 11:15:00 2007:3983000 --> 0:9000
Start: Sat Mar 24 11:15:00 2007:7510000
Stop : Sat Mar 24 11:15:00 2007:7519000 --> 0:9000
Start: Sat Mar 24 11:15:00 2007:11054000
Stop : Sat Mar 24 11:15:00 2007:11063000 --> 0:9000
Start: Sat Mar 24 11:15:00 2007:14638000
Stop : Sat Mar 24 11:15:00 2007:14647000 --> 0:9000
Start: Sat Mar 24 11:15:00 2007:18301000
Stop : Sat Mar 24 11:15:00 2007:18310000 --> 0:9000
Start: Sat Mar 24 11:15:00 2007:21901000
Stop : Sat Mar 24 11:15:00 2007:21910000 --> 0:9000
Start: Sat Mar 24 11:15:00 2007:25526000
Stop : Sat Mar 24 11:15:00 2007:25535000 --> 0:9000
Start: Sat Mar 24 11:15:00 2007:29196000
Stop : Sat Mar 24 11:15:00 2007:29206000 --> 0:10000
Start: Sat Mar 24 11:15:00 2007:32826000
Stop : Sat Mar 24 11:15:00 2007:32835000 --> 0:9000
10 iterations of getting Uptime
0:38977000 0:38986000 --> 0:9000
0:40324000 0:40332000 --> 0:8000
0:41636000 0:41645000 --> 0:9000
0:42949000 0:42958000 --> 0:9000
0:44295000 0:44304000