Unable to compile for ESP32-S2 and ESP IDF v4.2

[MS71]

Hi,
i am trying to build the int32_publisher example for the ESP32-S2.

My steps:

1.)
Install IDF as defined in:
https://docs.espressif.com/projects/esp-idf/en/release-v4.2/esp32/get-started/index.html
git clone -b release/v4.2 --recursive https://github.com/espressif/esp-idf.git

2.)
checkout micro_ros_espidf_component

3.)
idf.py set-target esp32s2
idf.py build

Problem A:
This build is not working because the cmake IDF_TARGET variable is not used.
IDF_TARGET contains "esp32" or "esp32s2".

If I modify the include path in esp32_toolchain.cmake.in, then i am able to compile
the example. I think esp32_toolchain.cmake.in should use the IDF_TARGET variable
for building the include path.

esp32s2.patch.txt

Unfortunately, it is still not linking. I get this error:

[ 99%] Linking CXX executable int32_publisher.elf
.espressif/tools/xtensa-esp32s2-elf/esp-2020r3-8.4.0/xtensa-esp32s2-elf/bin/../lib/gcc/xtensa-esp32s2-elf/8.4.0/../../../../xtensa-esp32s2-elf/bin/ld: esp-idf/xtensa/libxtensa.a(stdatomic.c.obj): in function `__atomic_fetch_add_8':
esp-idf-v4.2/components/xtensa/stdatomic.c:116: multiple definition of `__atomic_fetch_add_8'; micro_ros_espidf_component/libmicroros.a(librcutils-atomic_64bits.c.obj):atomic_64bits.c:(.text.__atomic_fetch_add_8+0x0): first defined here
collect2: error: ld returned 1 exit status
make[2]: *** [CMakeFiles/int32_publisher.elf.dir/build.make:396: int32_publisher.elf] Error 1
make[1]: *** [CMakeFiles/Makefile2:2245: CMakeFiles/int32_publisher.elf.dir/all] Error 2
make: *** [Makefile:130: all] Error 2
make failed with exit code 2

Do you have got any hint?

I would be great, if this component could support esp32-s2 too.

[pablogs9]

Hello @MS71, thanks for the ideas. I'm creating a PR for integrating this ESP32-S2 support: #19

Regarding the atomics: we have a problem here, micro-ROS provides a minimal implementation of 64-bits atomics that of course can be enabled and disabled with the flag RCUTILS_NO_64_ATOMIC in the colcon.meta.

This optional extension provides implementations if the platform does not have support for:

• __atomic_load_8
• __atomic_store_8
• __atomic_exchange_8
• __atomic_fetch_add_8

The point is that ESP-IDF for ESP32-S2 is providing just some of them:

• __atomic_fetch_add_8

This way, if you disable the micro-ROS 64-bit atomic extension it complains about missing load and store, but if you enable it it complains about having fetch_add twice.

Do you have any suggestion?

[pablogs9]

Cool, we are going to merge the PR: https://github.com/micro-ROS/micro_ros_espidf_component/pull/19/checks?check_run_id=1472900469.

Reopen this if you have any problem or question.

BTW: I don't have here an ESP32-S2 for testing this. If you could give us some feedback, it would be super nice.