Merge pull request #11902 from AriParkkila/cell-bg96-epco

Cellular: Enable ePCO IE for BG96 driver

Author: 0xc0170

features/cellular/framework/targets/QUECTEL/BG96/QUECTEL_BG96_CellularNetwork.cpp

@@ -43,6 +43,12 @@ nsapi_error_t QUECTEL_BG96_CellularNetwork::set_access_technology_impl(RadioAcce
             _at.at_cmd_discard("+QCFG", "=\"nwscanseq\",030201");
             _at.at_cmd_discard("+QCFG", "=\"nwscanmode\",3,1");
             _at.at_cmd_discard("+QCFG", "=\"iotopmode\",1,1");
+#ifdef MBED_CONF_CELLULAR_OFFLOAD_DNS_QUERIES
+            // enable ePCO IE for DNS address
+            _at.cmd_start("AT+QNVFW=");
+            _at.write_string("/nv/item_files/modem/nas/nas_ciot_capability_config");
+            _at.write_string("0101", false);
+#endif
             break;
         case RAT_GSM:
         case RAT_GSM_COMPACT:

features/cellular/framework/targets/QUECTEL/BG96/QUECTEL_BG96_CellularStack.cpp

@@ -32,6 +32,9 @@ using namespace mbed;
 
 QUECTEL_BG96_CellularStack::QUECTEL_BG96_CellularStack(ATHandler &atHandler, int cid, nsapi_ip_stack_t stack_type) : AT_CellularStack(atHandler, cid, stack_type)
 #ifdef MBED_CONF_CELLULAR_OFFLOAD_DNS_QUERIES
+#if (MBED_CONF_CELLULAR_OFFLOAD_DNS_QUERIES != 1)
+#error Define cellular.offload-dns-queries to null or 1.
+#endif
     , _dns_callback(NULL), _dns_version(NSAPI_UNSPEC)
 #endif
     , _tls_sec_level(0)