samples: net: lwm2m_client: Use Ethernet in QEMU Cortex-M3

By default, qemu_coxtex_m3 target selected SLIP driver as
a network backend. This requires some unstandard tool (tunslip6),
which are error prone and might not necessary work.
Ethernet backend work equally well as in native_posix so
use the same for both.

Change the default emulation platform from X86 to Cortex-M3
because it supports Ethernet by default.

Signed-off-by: Seppo Takalo <seppo.takalo@nordicsemi.no>

samples/net/lwm2m_client/README.rst

@@ -24,7 +24,7 @@ The source code for this sample application can be found at:
 Requirements
 ************
 
-- :ref:`networking_with_qemu`
+- :ref:`networking_with_eth_qemu`, :ref:`networking_with_qemu` or :ref:`networking_with_native_posix`
 - Linux machine
 - Leshan Demo Server (https://eclipse.org/leshan/)
 
@@ -62,8 +62,8 @@ Build the lwm2m-client sample application like this:
    :compact:
 
 The easiest way to setup this sample application is to build and run it
-via QEMU using the default configuration :file:`prj.conf`.
+as native POSIX application or as a QEMU target using the default configuration :file:`prj.conf`.
-This requires a small amount of setup described in :ref:`networking_with_qemu`.
+This requires a small amount of setup described in :ref:`networking_with_eth_qemu`, :ref:`networking_with_qemu` and :ref:`networking_with_native_posix`.
 
 Download and run the latest build of the Leshan Demo Server:
 

samples/net/lwm2m_client/boards/qemu_cortex_m3.conf

@@ -0,0 +1,4 @@
+CONFIG_NET_L2_ETHERNET=y
+CONFIG_ETH_DRIVER=y
+CONFIG_ETH_STELLARIS=y
+CONFIG_NET_QEMU_ETHERNET=y

samples/net/lwm2m_client/sample.yaml

@@ -5,16 +5,20 @@ tests:
   sample.net.lwm2m_client:
     harness: net
     depends_on: netif
-    platform_allow: qemu_x86 frdm_k64f pinnacle_100_dvk mg100
+    platform_allow: qemu_cortex_m3 qemu_x86 native_posix frdm_k64f pinnacle_100_dvk mg100
     integration_platforms:
       - qemu_x86
+      - qemu_cortex_m3
+      - native_posix
     tags: net lwm2m
   sample.net.lwm2m_client.all_objects:
     harness: net
     depends_on: netif
-    platform_allow: qemu_x86
+    platform_allow: qemu_cortex_m3 qemu_x86 native_posix
     integration_platforms:
       - qemu_x86
+      - qemu_cortex_m3
+      - native_posix
     tags: net lwm2m
     extra_configs:
       - CONFIG_LWM2M_CONN_MON_OBJ_SUPPORT=y
@@ -30,9 +34,11 @@ tests:
     harness: net
     depends_on: netif
     extra_args: OVERLAY_CONFIG=overlay-dtls.conf
-    platform_allow: qemu_x86 frdm_k64f pinnacle_100_dvk mg100
+    platform_allow: qemu_cortex_m3 qemu_x86 native_posix frdm_k64f pinnacle_100_dvk mg100
     integration_platforms:
       - qemu_x86
+      - qemu_cortex_m3
+      - native_posix
     tags: net lwm2m
   sample.net.lwm2m_client.bt:
     harness: net
@@ -45,9 +51,11 @@ tests:
     harness: net
     depends_on: netif
     extra_args: OVERLAY_CONFIG=overlay-queue.conf
-    platform_allow: qemu_x86
+    platform_allow: qemu_cortex_m3 qemu_x86 native_posix
     integration_platforms:
       - qemu_x86
+      - qemu_cortex_m3
+      - native_posix
     tags: net lwm2m
   sample.net.lwm2m_client.wnc_m14a2a:
     harness: net