tests/netstat_l2: workaround for esp32 boards

[gschorcht]

Contribution description

Since ESP32 boards only have network interfaces if the esp_wifi, esp_now and esp_eth modules are explicitly enabled, they are removed from the list of boards that provide network interfaces.

Instead, the variable BOARD_PROVIDES_NETIF is made adjustable in the environment. Thus the test can be used for ESP32 with and without network interfaces.

Fixes the test tests/netstat_l2 for ESP32.

This PR belongs to the series of PRs, each with very small changes that fix automatic tests on ESP32 boards.

Testing procedure

Make, flash and test with

BOARD_PROVIDES_NETIF=esp32-wroom-32 USEMODULE=esp_wifi make BOARD=esp32-wroom-32 -C tests/netstats_l2 flash test

and without network interfaces.

make BOARD=esp32-wroom-32 -C tests/netstats_l2

Issues/PRs references

Requires #12752

[benpicco]

I was always wondering why you don't just do

ifneq (,$(filter gnrc_netdev_default netdev_default,$(USEMODULE)))
  USEMODULE += esp_wifi
endif

for esp32/esp8266 since WiFi is pretty much the defining feature of this MCU.

[gschorcht]

I was always wondering why you don't just do

ifneq (,$(filter gnrc_netdev_default netdev_default,$(USEMODULE)))
  USEMODULE += esp_wifi
endif

for esp32/esp8266 since WiFi is pretty much the defining feature of this MCU.

Because you have different options to use the WiFi interface, esp_wifi and esp_now. ESP32 also provides an Ethernet interface. Which one should be the default? So I decided to let the user define it.

[benpicco]

You could do ESP_NETDEV_DEFAULT ?= esp_wifi (or esp_now, afaik that doesn't need any additional config), then you could do

ifneq (,$(filter gnrc_netdev_default netdev_default,$(USEMODULE)))
  USEMODULE += $(ESP_NETDEV_DEFAULT)
endif

[miri64]

What to do if #11676 is merged then?

[aabadie]

Maybe use the following:

Suggested change

	BOARD_PROVIDES_NETIF ?= airfy-beacon fox iotlab-m3 mulle native nrf51dk nrf51dongle \
	BOARD_PROVIDES_NETIF += airfy-beacon fox iotlab-m3 mulle native nrf51dk nrf51dongle \

Not sure if it's useful or not (if not you can ignore).

[gschorcht]

It should not make any difference if you specify this variable explicitly for its use with a single board. BTW, netstat_l2 could be used with ESP8266 boards in same way.

[aabadie]

What to do if #11676 is merged then?

That won't happen in its current state. I think an adaption of @cladmi's approach in #12427 would be better (this is in my plans).

[gschorcht]

You could do ESP_NETDEV_DEFAULT ?= esp_wifi (or esp_now, afaik that doesn't need any additional config), then you could do

ifneq (,$(filter gnrc_netdev_default netdev_default,$(USEMODULE)))
  USEMODULE += $(ESP_NETDEV_DEFAULT)
endif

Should be possible in that way. But I wouldn't do that with this PR if you don't insist on this change because it changes the documented way on how to enable and select the network interface for ESPs.

[gschorcht]

@benpicco How do we continue with this PR?

[benpicco]

I mean if you were to make a PR to add a default netdev for esp*, this PR would be obsolete.
IMHO this would be the better solution, also from a user perspective.

[gschorcht]

Ok, I can try to find a usefull configuration. esp_now might be better as default since it doesn't require additional setting. But it might become a problem to activate esp_wifi which is probably used more often. I have to test.

[benpicco]

esp_netdev_default could be a pseudomodule that depends on esp_now if no other esp_wifi|esp_now|esp_ethernet module is used.

[gschorcht]

Hm, sounds good. I will try. BTW, esp_wifi and esp_now can also be used together, e.g., to realize a border router.

[benpicco]

esp_wifi and esp_now can also be used together, e.g., to realize a border router.

Wow, I didn't know - this is neat!

[gschorcht]

Closed in favor of PR #12787.