Fprime on FreeRTOS

[donwalkarsoham]

I wanted to know whether fprime is compatible with FreeRTOS operating system.
If so, is there any tutorial or reference guide on how to integrate and use fprime with FreeRTOS ?

[timcanham]

@donwalkarsoham We haven't done a port yet to FreeRTOS. I think it would be great for more deeply embedded applications. It is in our plans to write a porting guide, but we haven't gotten there yet. If you want to fork the devel branch of the repo, I could help you walk through the process. It essentially consists of providing implementations for the classes defined in the Os directory. It would be for tasks, threads, mutexes, etc.

[donwalkarsoham]

Sure, I have forked the repo to "donwalkarsoham / fprime". It would be really helpful if you could walk us through the process of porting fprime on FreeRTOS.
Thanks

[timcanham]

Can you give me a little background as to how you would like to use F'?

[timcanham]

Note that F` requires running its own build system to generate the code, so you won't be able to build through Code Composer. We have done that here at JPL with another TI MCU.

[donwalkarsoham]

This is the "Cube Rover" project for which we had an SDR presentation on 3rd August and you were a part of the reviewing committee.
We are planning to use Fprime for its publish subscribe utility to manage the various tasks of the rover from sensor readings to motor control and telemetry operation.
Also, we want the software to be modular so that any added components in the future like extra cameras or sensors can be used easily interfaced with the existing system.

Thanks for the suggestion about building Fprime. Can you please put some more light on it and help us in taking it forward ?

[timcanham]

There are a set of configuration files to navigate through. The can be a bit complicated, but they were set up that way to try and reuse settings across targets. It's actually helpful to see how the other ones in the repo were done to catch the pattern.

1. Run a build in Code Composer with a dummy hello world file so you can see what the compiler command line so we can update the compiler configuration for the build system.

2. Add a build target to:

mk/configs/builds/builds.mk

Add a name to the BUILDS that is indicative of the target name. (Maybe TIR4)

BUILDS := \
	DARWIN \
	LINUX \
	CYGWIN \
	RASPIAN \
	RASPIAN-CROSS \
        TIR4

3. Create a file in the mk/configs/builds directory that matches the target name and add the .mk extension.

TIR4.mk

4. Inside that build target configuration file, define the two variables:

COMPILER := compiler-name
TARGET := target-name

These variables are used to define variables for the compiler and target respectively.
The compiler name is used to include a file from the compiler configuration directory:

mk/configs/compiler/$(COMPILER).mk

The target variable is used to include a file from the target configuration directory:

mk/configs/target/$(TARGET).mk

5. The compiler configuration file mk/configs/compiler/$(COMPILER).mk needs to define the following variables:

CC - C compiler
CXX - C++ compiler
CFLAGS - C Compiler flags
CXXFLAGS - C++ compiler flags
COMPILE_ONLY - Generate object code, don't link (like -c on gcc)
COMPILE_TO - The destination object file (like -o on gcc)
INCLUDE_PATH - Not the include path itself, but the compiler argument to set it (like -I on gcc)
LINK_LIB - Tool to create libraries ( like ar)
LINK_LIB_FLAGS - arguments to library linker
LIBRARY_TO - argument specifying the file to create the argument (this is empty for ar)
POST_LINK_LIB - any post library linking needed (not needed for ar). If not needed, set it to: $(BUILD_ROOT)/mk/bin/empty.py
LINK_BIN - Link to an executable binary
LINK_BIN_FLAGS - Flags for binary linker
LINK_BIN_TO - flag to indicate binary output file
LIBS_START - argument to start a list of libraries, if needed
LIBS_END - argument to end a list of libraries, if needed
POST_LINK_BIN - tool that runs on binary, if necessary
POST_LINK_PRE_ARGS - arguments for post linker tool that go before binary file in tool command
POST_LINK_POST_ARGS - arguments for post linker tool that go after binary
SIZE - tool to dump file size

6. The target configuration file (mk/configs/target/$(TARGET).mk) has the following variables:

OUTPUT_DIR - output directory to put object/binary code
OBJ_PREFIX - any prefix needed for object files
OBJ_SUFFIX - any suffix needed for object files (ex. .o)

LIB_PREFIX - prefix needed for library files (ex. lib)
LIB_SUFFIX - suffix needed for library files (ex. .a)

BIN_PREFIX - prefix needed for binary files
BIN_SUFFIX - suffix needed for binary

We're working on a project using the TMS570 MCU, which is very similar to the R4. It takes a bit to tease out the Code Composer link rules. I can fork your repo and give you them, but you will have to modify them for the R4.

[timcanham]

The next step is to write implementation classes for the OS classes in the Os directory.

Specifically:

Task.hpp
Queue.hpp
Mutex.hpp
IntervalTimer.hpp
InterruptLock.hpp

The new files can be added to the OS/mod.mk file by adding the following variable:

SRC_<Target> = ....

For the name I suggested above, it would be:

SRC_TIR4 = ... ...

[lchomas]

Hi Tim. I work with Soham at CMU on this. Would be able to give us the setup you have for the TMS570? We'd like to have an example of what we need to put together. Thank you so much for all your help on this!

[timcanham]

@ichomas: If you can identify a fork I can do a pull request from, I can check it in.

[lchomas]

Soham's (@donwalkarsoham ) fork would be great. https://github.com/donwalkarsoham/fprime

[timcanham]

Why don't you make a branch for my PR?

[lchomas]

I've forked this again and made a branch for the TMS57 https://github.com/PlanetaryRobotics/fprime/tree/TMS57

[timcanham]

PR is created. Note that there are references inside to HalCoGen created files. If you haven't used HalCoGen yet, I highly recommend it.

[timcanham]

I created a new branch, feature/freertos to bring the FreeRtos port into Fprime.

[nasigoren]

Is it proceed developing to bring the FreeRTOS port into Fprime?
I'd like to use Fprime on FreeRTOS.