Zephyr: Initial Zephyr integration setup

[mrdeep1]

zephyr/ Initial files added

Tested with

west build -p always -b native_posix samples/net/eth_native_posix -- -DCONF_FILE=prj.conf -DEXTRA_ZEPHYR_MODULES=//<libcoap path>/libcoap -DEXTRA_CONF_FILE=/<libcoap path>/libcoap/zephyr/libcoap.conf -DCONFIG_LIBCOAP=y

with samples/net/eth_native_posix/src/main.c updated to run a simple libcoap CoAP client.

[jeffwelder-ellenbytech]

@mrdeep1 This is awesome work!

My colleague tried to use this PR, but this heavily depends on native_posix and associated functions. Therefore you cannot use it for real hardware quite yet.

Might be worth checking out the work the team at Golioth did:
https://github.com/golioth/golioth-firmware-sdk/tree/main/port/zephyr

[mrdeep1]

@jeffwelder-ellenbytech Thanks for the feedback.

I will look at what the Goliath port does to see how reliance on Posix can be reduced / removed.

[mrdeep1]

Reduction on reliance on Posix support will be another PR, but this PR gets all the Zephyr build requirements in place.

[chrsag]

Hello @mrdeep1 , could you please provide your zephyr prj.conf? I am having issues building libcoap with zephyr, I guess due to missing configuration.

[mrdeep1]

I was using zephyr 3.5.0 as native_posix samples/net/eth_native_posix has been removed in later versions.

prj.conf.txt

With this change to main.c

main.c.diff.txt