lib: lte_link_control: Send NEIGHBOR_CELL_MEAS event in case of error

Earlier, no LTE_LC_EVT_NEIGHBOR_CELL_MEAS event was sent in case an
error occurred during parsing of the %NCELLMEAS notification. Because
of this, the user of the library did not have any way to determine
when the operation had been completed. The implementation has been
changed so, that an LTE_LC_EVT_NEIGHBOR_CELL_MEAS event is always
sent, if lte_lc_neighbor_cell_measurement() has returned 0. In case
of an error, an empty LTE_LC_EVT_NEIGHBOR_CELL_MEAS (current_cell
set to LTE_LC_CELL_EUTRAN_ID_INVALID) is sent.

Signed-off-by: Tommi Kangas <[email protected]>

Author: tokangas

doc/nrf/releases_and_maturity/releases/release-notes-changelog.rst

@@ -495,6 +495,7 @@ Modem libraries
 * :ref:`lte_lc_readme` library:
 
   * Fixed handling of ``%NCELLMEAS`` notification with status 2 (measurement interrupted) and no cells.
+  * Added sending of ``LTE_LC_EVT_NEIGHBOR_CELL_MEAS`` event with ``current_cell`` set to ``LTE_LC_CELL_EUTRAN_ID_INVALID`` in case an error occurs while parsing the ``%NCELLMEAS`` notification.
 
 * :ref:`modem_key_mgmt` library:
 

include/modem/lte_lc.h

@@ -283,7 +283,10 @@ enum lte_lc_evt_type {
 	 * Neighbor cell measurement results.
 	 *
 	 * The associated payload is the @c lte_lc_evt.cells_info member of type
-	 * @ref lte_lc_cells_info in the event.
+	 * @ref lte_lc_cells_info in the event. In case of an error or if no cells were found,
+	 * the @c lte_lc_cells_info.current_cell member is set to
+	 * @ref LTE_LC_CELL_EUTRAN_ID_INVALID, and @c lte_lc_cells_info.ncells_count and
+	 * @c lte_lc_cells_info.gci_cells_count members are set to zero.
 	 */
 	LTE_LC_EVT_NEIGHBOR_CELL_MEAS		= 7,
 #endif /* CONFIG_LTE_LC_NEIGHBOR_CELL_MEAS_MODULE */
@@ -1688,7 +1691,8 @@ int lte_lc_lte_mode_get(enum lte_lc_lte_mode *mode);
  * @ref LTE_LC_EVT_NEIGHBOR_CELL_MEAS, meaning that an event handler must be registered to receive
  * the information. Depending on the network conditions, LTE connection state and requested search
  * type, it may take a while before the measurement result is ready and reported back. After the
- * event is received, the neighbor cell measurements are automatically stopped.
+ * event is received, the neighbor cell measurements are automatically stopped. If the
+ * function returns successfully, the @ref LTE_LC_EVT_NEIGHBOR_CELL_MEAS event is always reported.
  *
  * @note This feature is only supported by modem firmware versions >= 1.3.0.
  *

lib/lte_link_control/modules/ncellmeas.c

@@ -610,6 +610,17 @@ static int parse_ncellmeas(const char *at_response, struct lte_lc_cells_info *ce
 	return err;
 }
 
+static void ncellmeas_empty_event_dispatch(void)
+{
+	struct lte_lc_evt evt = {0};
+
+	LOG_DBG("Dispatching empty LTE_LC_EVT_NEIGHBOR_CELL_MEAS event");
+
+	evt.type = LTE_LC_EVT_NEIGHBOR_CELL_MEAS;
+	evt.cells_info.current_cell.id = LTE_LC_CELL_EUTRAN_ID_INVALID;
+	event_handler_list_dispatch(&evt);
+}
+
 static void at_handler_ncellmeas_gci(const char *response)
 {
 	int err;
@@ -625,6 +636,7 @@ static void at_handler_ncellmeas_gci(const char *response)
 	cells = k_calloc(ncellmeas_params.gci_count, sizeof(struct lte_lc_cell));
 	if (cells == NULL) {
 		LOG_ERR("Failed to allocate memory for the GCI cells");
+		ncellmeas_empty_event_dispatch();
 		return;
 	}
 
@@ -646,6 +658,7 @@ static void at_handler_ncellmeas_gci(const char *response)
 		break;
 	default:
 		LOG_ERR("Parsing of neighbor cells failed, err: %d", err);
+		ncellmeas_empty_event_dispatch();
 		break;
 	}
 
@@ -655,14 +668,9 @@ static void at_handler_ncellmeas_gci(const char *response)
 
 static void ncellmeas_cancel_timeout_work_fn(struct k_work *work)
 {
-	struct lte_lc_evt evt = {0};
-
-	LOG_DBG("No %%NCELLMEAS notification received after AT%%NCELLMEASSTOP, "
-		"sending empty results");
+	LOG_DBG("No %%NCELLMEAS notification received after AT%%NCELLMEASSTOP");
 
-	evt.type = LTE_LC_EVT_NEIGHBOR_CELL_MEAS;
-	evt.cells_info.current_cell.id = LTE_LC_CELL_EUTRAN_ID_INVALID;
-	event_handler_list_dispatch(&evt);
+	ncellmeas_empty_event_dispatch();
 
 	k_sem_give(&ncellmeas_idle_sem);
 }
@@ -709,6 +717,7 @@ static void at_handler_ncellmeas(const char *response)
 		neighbor_cells = k_calloc(ncell_count, sizeof(struct lte_lc_ncell));
 		if (neighbor_cells == NULL) {
 			LOG_ERR("Failed to allocate memory for neighbor cells");
+			ncellmeas_empty_event_dispatch();
 			goto exit;
 		}
 	}
@@ -730,6 +739,7 @@ static void at_handler_ncellmeas(const char *response)
 		break;
 	default:
 		LOG_ERR("Parsing of neighbor cells failed, err: %d", err);
+		ncellmeas_empty_event_dispatch();
 		break;
 	}
 

tests/lib/lte_lc_api/src/lte_lc_api_test.c

@@ -16,7 +16,7 @@
 #include "cmock_nrf_modem_at.h"
 #include "cmock_nrf_modem.h"
 
-#define TEST_EVENT_MAX_COUNT 10
+#define TEST_EVENT_MAX_COUNT 20
 
 static struct lte_lc_evt test_event_data[TEST_EVENT_MAX_COUNT];
 static struct lte_lc_ncell test_neighbor_cells[CONFIG_LTE_NEIGHBOR_CELLS_MAX];
@@ -2746,6 +2746,14 @@ void test_lte_lc_neighbor_cell_measurement_cell_id_missing_fail(void)
 	       "%NCELLMEAS:0,,\"98712\",\"0AB9\",4800,7,63,31,456,4800,"
 	       "8,60,29,4,3500,9,99,18,5,5300,11\r\n");
 
+	lte_lc_callback_count_expected = 1;
+
+	/* In case of an error, we're expected to receive an empty event. */
+	test_event_data[0].type = LTE_LC_EVT_NEIGHBOR_CELL_MEAS;
+	test_event_data[0].cells_info.current_cell.id = LTE_LC_CELL_EUTRAN_ID_INVALID;
+	test_event_data[0].cells_info.ncells_count = 0;
+	test_event_data[0].cells_info.gci_cells_count = 0;
+
 	__mock_nrf_modem_at_printf_ExpectAndReturn("AT%NCELLMEAS", EXIT_SUCCESS);
 
 	ret = lte_lc_neighbor_cell_measurement(NULL);
@@ -2762,6 +2770,14 @@ void test_lte_lc_neighbor_cell_measurement_cell_id_too_big_fail(void)
 	       "%NCELLMEAS:0,\"FFFFFFFF\",\"98712\",\"0AB9\",4800,7,63,31,456,4800,"
 	       "8,60,29,4,3500,9,99,18,5,5300,11\r\n");
 
+	lte_lc_callback_count_expected = 1;
+
+	/* In case of an error, we're expected to receive an empty event. */
+	test_event_data[0].type = LTE_LC_EVT_NEIGHBOR_CELL_MEAS;
+	test_event_data[0].cells_info.current_cell.id = LTE_LC_CELL_EUTRAN_ID_INVALID;
+	test_event_data[0].cells_info.ncells_count = 0;
+	test_event_data[0].cells_info.gci_cells_count = 0;
+
 	__mock_nrf_modem_at_printf_ExpectAndReturn("AT%NCELLMEAS", EXIT_SUCCESS);
 
 	ret = lte_lc_neighbor_cell_measurement(NULL);
@@ -2778,6 +2794,14 @@ void test_lte_lc_neighbor_cell_measurement_malformed_fail(void)
 	       "%NCELLMEAS:0,\"00112233\",\"98712\",\"0AB9\",4800,7,63,31,456,4800,"
 	       "8,60,29,4,35 00,9,99,18,5,5300,11\r\n");
 
+	lte_lc_callback_count_expected = 1;
+
+	/* In case of an error, we're expected to receive an empty event. */
+	test_event_data[0].type = LTE_LC_EVT_NEIGHBOR_CELL_MEAS;
+	test_event_data[0].cells_info.current_cell.id = LTE_LC_CELL_EUTRAN_ID_INVALID;
+	test_event_data[0].cells_info.ncells_count = 0;
+	test_event_data[0].cells_info.gci_cells_count = 0;
+
 	__mock_nrf_modem_at_printf_ExpectAndReturn("AT%NCELLMEAS", EXIT_SUCCESS);
 
 	ret = lte_lc_neighbor_cell_measurement(NULL);
@@ -3506,6 +3530,16 @@ void test_lte_lc_neighbor_cell_measurement_normal_invalid_field_format_fail(void
 		.gci_count = 0,
 	};
 
+	lte_lc_callback_count_expected = 16;
+
+	/* In case of an error, we're expected to receive an empty event. */
+	for (int i = 0; i < lte_lc_callback_count_expected; i++) {
+		test_event_data[i].type = LTE_LC_EVT_NEIGHBOR_CELL_MEAS;
+		test_event_data[i].cells_info.current_cell.id = LTE_LC_CELL_EUTRAN_ID_INVALID;
+		test_event_data[i].cells_info.ncells_count = 0;
+		test_event_data[i].cells_info.gci_cells_count = 0;
+	}
+
 	/* Syntax:
 	 * %NCELLMEAS: status
 	 * [,<cell_id>,<plmn>,<tac>,<ta>,<earfcn>,<phys_cell_id>,<rsrp>,<rsrq>,<meas_time>
@@ -3671,6 +3705,16 @@ void test_lte_lc_neighbor_cell_measurement_gci_invalid_field_format_fail(void)
 		.gci_count = 10,
 	};
 
+	lte_lc_callback_count_expected = 18;
+
+	/* In case of an error, we're expected to receive an empty event. */
+	for (int i = 0; i < lte_lc_callback_count_expected; i++) {
+		test_event_data[i].type = LTE_LC_EVT_NEIGHBOR_CELL_MEAS;
+		test_event_data[i].cells_info.current_cell.id = LTE_LC_CELL_EUTRAN_ID_INVALID;
+		test_event_data[i].cells_info.ncells_count = 0;
+		test_event_data[i].cells_info.gci_cells_count = 0;
+	}
+
 	/* Syntax for GCI search types:
 	 * High level:
 	 * status[,
@@ -3881,6 +3925,16 @@ void test_lte_lc_neighbor_cell_measurement_normal_invalid_mccmnc_fail(void)
 {
 	int ret;
 
+	lte_lc_callback_count_expected = 2;
+
+	/* In case of an error, we're expected to receive an empty event. */
+	for (int i = 0; i < lte_lc_callback_count_expected; i++) {
+		test_event_data[i].type = LTE_LC_EVT_NEIGHBOR_CELL_MEAS;
+		test_event_data[i].cells_info.current_cell.id = LTE_LC_CELL_EUTRAN_ID_INVALID;
+		test_event_data[i].cells_info.ncells_count = 0;
+		test_event_data[i].cells_info.gci_cells_count = 0;
+	}
+
 	/* Invalid MCC */
 	__mock_nrf_modem_at_printf_ExpectAndReturn("AT%NCELLMEAS", EXIT_SUCCESS);
 	ret = lte_lc_neighbor_cell_measurement(NULL);
@@ -3908,6 +3962,16 @@ void test_lte_lc_neighbor_cell_measurement_gci_invalid_mccmnc_fail(void)
 		.gci_count = 2,
 	};
 
+	lte_lc_callback_count_expected = 2;
+
+	/* In case of an error, we're expected to receive an empty event. */
+	for (int i = 0; i < lte_lc_callback_count_expected; i++) {
+		test_event_data[i].type = LTE_LC_EVT_NEIGHBOR_CELL_MEAS;
+		test_event_data[i].cells_info.current_cell.id = LTE_LC_CELL_EUTRAN_ID_INVALID;
+		test_event_data[i].cells_info.ncells_count = 0;
+		test_event_data[i].cells_info.gci_cells_count = 0;
+	}
+
 	/* Invalid MCC */
 	__mock_nrf_modem_at_printf_ExpectAndReturn("AT%NCELLMEAS=5,2", EXIT_SUCCESS);
 	ret = lte_lc_neighbor_cell_measurement(&params);