tools/edbg: Use openocd to reset instead of edbg.

[jcarrano]

Contribution description

A few commits ago edbg changed its behaviour and now it resets the board twice. This makes some tests fail, as the start on the first reset, but shortly after the board is reset again.

I already reported upstream (ataradov/edbg#77) but in the meanwhile we need a workaround.

This comments out RESET and RESET_FLAGS in the edbg tool setting. Reset will now be done via OpenOCD, which is available and used anyways because it is needed for make debug.

Testing procedure

Before trying this out, verify that edbg is on the latest version:

$ cd <RIOT REPO>
$ rm -rf dist/tools/edbg/edbg dist/tools/edbg/bin
$ make -C examples/hello-world $(pwd)/dist/tools/edbg/edbg

Compile and flash hello-world in any atmel board:

BOARD=saml21-xpro make -C examples/hello-world  all flash term

Open another terminal and reset the board:

BOARD=saml21-xpro make -C examples/hello-world  reset

Without this change: two resets

Welcome to pyterm!
Type '/exit' to exit.
2019-03-07 12:56:34,816 - INFO # main(): This is RIOT! (Version: 2019.04-devel-365-gda2f47-HEAD)
2019-03-07 12:56:34,817 - INFO # Hello World!
2019-03-07 12:56:34,822 - INFO # You are running RIOT on a(n) saml21-xpro board.
2019-03-07 12:56:34,838 - INFO # main(): This is RIOT! (Version: 2019.04-devel-365-gda2f47-HEAD)
2019-03-07 12:56:34,839 - INFO # Hello World!
2019-03-07 12:56:34,843 - INFO # You are running RIOT on a(n) saml21-xpro board.
2019-03-07 12:56:34,847 - INFO # This board features a(n) saml21 MCU.

With this change: only one reset (there's no point on pasting the output.)

Issues/PRs references

Issue in edbg: ataradov/edbg#77

[kaspar030]

A few commits ago edbg changed its behaviour and now it resets the board twice.

This sucks. Does it affect the in-tree edbg version? If not, let's wait whether they fix it.

As is this PR will probably break the CI samr21-xpro workers, as they don't have openocd installer.

[jcarrano]

Does it affect the in-tree edbg version?

Yes, but you may or may not have that version: because of the way "pkg.mk" works it will not update the repo after it is downloaded, even if PKG_VERSION changes. I have two git worktrees in my machine, and one had an old EDBG version and the other the "correct" one.

I'm trying to fix pkg.mk.

[dylad]

If not, let's wait whether they fix it.

Usually, edbg's author is quick to react so this PR may not be needed since you reported it upstream.
I also need an edbg version bump for RIOT (need MCU port) this comes at the perfect time :)

[jcarrano]

@dylad Yes, he's fast: fixed it on Friday. Are you going to do the bump PR or shall I do it?

[dylad]

@jcarrano as you want. I'm a bit busy today and tommorow but I can do it on wednesday