Support for CMake builds. Added Linux stub port for now to allow cross compilation

[phelter]

Adding CMake support with a separate build.

• Supports inclusion via CMake FetchContent.
• Support for selection of enabling/disabling device support -see ffconfigDEV_SUPPORT
• Support selection of port to use as well as support for a custom port if defined in the main project that includes the fat.
  • FREERTOS_PLUS_FAT_PORT=A_CUSTOM_PORT

Note only tested compiling with Linux so far.

To integrate into your overall project can now use:

FetchContent_Declare( freertos_kernel
  GIT_REPOSITORY git@github.com:phelter/FreeRTOS-Kernel.git
  GIT_TAG        feature/cmake-updates
)

FetchContent_Declare( freertos_plus_fat
  GIT_REPOSITORY https://github.com/phelter/Lab-Project-FreeRTOS-FAT.git
  GIT_TAG        feature/cmake-support # typically a hash or a version tag.
  GIT_SUBMODULES "" # Don't grab any submodules since not latest
)

# -----------------------------------------------------------------------------
add_library(freertos_config INTERFACE)

target_sources(freertos_config
  INTERFACE
    inc/FreeRTOSConfig.h
    inc/FreeRTOSFATConfig.h
)

target_include_directories(freertos_config SYSTEM
INTERFACE
    inc
)

target_compile_definitions(freertos_config
  INTERFACE
    projCOVERAGE_TEST=0
)

# -----------------------------------------------------------------------------
set( FREERTOS_HEAP "4" CACHE STRING "" FORCE)
set( FREERTOS_PORT "GCC_POSIX" CACHE STRING "" FORCE)
if (CMAKE_CROSSCOMPILING)
  set(FREERTOS_PORT "GCC_ARM_CA9" CACHE STRING "" FORCE)
endif()

# Note using modified cmake files off of 10.5.0 to allow FREERTOS_PORT = A_CUSTOM_PORT
FetchContent_MakeAvailable(freertos_kernel)

# -----------------------------------------------------------------------------
set( FREERTOS_PLUS_FAT_DEV_SUPPORT OFF CACHE BOOL "" FORCE)
set( FREERTOS_PLUS_FAT_PORT "POSIX" CACHE STRING "" FORCE)
if (CMAKE_CROSSCOMPILING)
  set(FREERTOS_PLUS_FAT_PORT "ZYNQ_2019_3" CACHE STRING "" FORCE)
endif()
FetchContent_MakeAvailable(freertos_plus_fat)

[archigup]

Hey, this seems not to be formatted; Could you format the c files with with uncrustify and the config in tools/uncrustify.cfg?
If you would like, I could add the formatting for you.

[phelter]

Hey, this seems not to be formatted; Could you format the c files with with uncrustify and the config in tools/uncrustify.cfg? If you would like, I could add the formatting for you.

Please go ahead and add the formatting. I typically use clang-format for my formatting and do not have uncrustify installed on my machine. The other option would be to provide a docker image where the appropriate toolchain and dev tools are pre-installed for developers to use and consume. Thanks.

[htibosch]

In stead of casting to unsigned long, the +FAT library normally uses unsigned in combination with %u:

-    FF_PRINTF( "TotalSectors   %8lu\n", (unsigned long) pxIOManager->xPartition.ulTotalSectors );
+    FF_PRINTF( "TotalSectors   %8u\n", (unsigned) pxIOManager->xPartition.ulTotalSectors );

It also removes the warning and it works well on 64-bit platforms as well.
Thank you

[htibosch]

Until now, I didn't comment on this PR ( except about FF_PRINTF() ) because I am totally inexperienced with cmake ( I only use GNU make ).

I checked out your branch and typed "cmake", which doesn't work obviously.
Would you mind to give a short description of how I can compile the project for dummies?

Also, if you open this PR, you will see that "This branch is out-of-date with the base branch", with a button "Update branch". Could you update it with the master branch?

I will talk to the team and see who can further review this PR. Sorry for the long delay.

[phelter]

@htibosch -

• Short description on how to compile the project:

I've added a build check in ci/cd environment similar to the FreeRTOS-Plus-TCP repo (the .github directory is a copy and modify from that).

I've also updated the main README.md as to how to integrate with CMake in a higher level project.

• Branch is now up-to-date with master in FreeRTOS repo.
• As for the FF_PRINTF - all but one of the ff_ramdisk.c files are using %8lu rather than what you requested:
  See: https://github.com/FreeRTOS/Lab-Project-FreeRTOS-FAT/search?q=%22TotalSectors%22
  Leaving as defined since it matches others.

[htibosch]

As for the FF_PRINTF - all but one of the ff_ramdisk.c files are using %8lu rather than what you requested

That is possibly true, but we would like to get rid of all %ld and %lu formats, both in FreeRTOS+TCP and in FreeRTOS+TCP.

[phelter]

@htibosch - My goal was to add the necessary code to have a linux port build similar to other FreeRTOS git repos (Kernel and Plus-TCP) and follow the same coding style and usage of the existing ports inside this Plus-FAT repo. Changing some code to reflect an arbitrary request to get rid of a particular format in this and other repos is out of scope (from my perspective) of this particular PR.

Since this is an unrelated issue to any of the CMake build support (a different feature/clean-up task), I'll add it to a follow on PR associated with fixing compile warnings of this repo instead (and I'll change all of the various portable code instead of just this new Linux port).

See similar ones for:

• FreeRTOS-Kernel: Fixing clang and gnu compiler warnings. phelter/FreeRTOS-Kernel#1
  • waiting on: Adding in ability to support a library for freertos_config and a custom port FreeRTOS-Kernel#571
• FreeRTOS-Plus-TCP: phelter/FreeRTOS-Plus-TCP@feature/cmake-support...feature/fixing-clang-gnu-compiler-warnings
  • waiting on: #556 Initial Cmake Module definition. FreeRTOS-Plus-TCP#557
• FreeRTOS-Plus-FAT: - will do once have this PR completed.

I intend to update the above ones and provide them, but have been blocked in continuing with this effort due to the outstanding pull requests.