Bluetooth: controller: df: fix handling of max count of IQ reports

There was an error in handling of max number of IQ reports
generated by controller. Accordin to BT Core Spec 5.1 the host
may request a number of CTEs to be sampled and reported by
controller while enable IQ sampling. The max_cte_count value
set to zero means sample all CTEs in a periodic advertising chain.

The commit fixes wrong handling of the max_cte_count provided
value to generate expected number of IQ reports.
Signed-off-by: Piotr Pryga <piotr.pryga@nordicsemi.no>

subsys/bluetooth/controller/ll_sw/nordic/lll/lll_sync.c

@@ -58,6 +58,7 @@ static void isr_done(void *param);
 #if defined(CONFIG_BT_CTLR_DF_SCAN_CTE_RX)
 static int create_iq_report(struct lll_sync *lll, uint8_t rssi_ready,
 			    uint8_t packet_status);
+static bool is_max_cte_reached(uint8_t max_cte_count, uint8_t cte_count);
 #endif /* CONFIG_BT_CTLR_DF_SCAN_CTE_RX */
 static uint8_t data_channel_calc(struct lll_sync *lll);
 static enum sync_status sync_filtrate_by_cte_type(uint8_t cte_type_mask, uint8_t filter_policy);
@@ -547,10 +548,9 @@ static void isr_aux_setup(void *param)
 
 	cfg = lll_df_sync_cfg_latest_get(&lll->df_cfg, NULL);
 
-	if (cfg->is_enabled) {
-		lll_df_conf_cte_rx_enable(cfg->slot_durations, cfg->ant_sw_len,
-					  cfg->ant_ids, aux_ptr->chan_idx);
-		cfg->cte_count = 0;
+	if (cfg->is_enabled && is_max_cte_reached(cfg->max_cte_count, cfg->cte_count)) {
+		lll_df_conf_cte_rx_enable(cfg->slot_durations, cfg->ant_sw_len, cfg->ant_ids,
+					  aux_ptr->chan_idx);
 
 		radio_switch_complete_and_phy_end_disable();
 	} else
@@ -930,8 +930,7 @@ static inline int create_iq_report(struct lll_sync *lll, uint8_t rssi_ready,
 	cfg = lll_df_sync_cfg_curr_get(&lll->df_cfg);
 
 	if (cfg->is_enabled) {
-
-		if (cfg->cte_count < cfg->max_cte_count) {
+		if (is_max_cte_reached(cfg->max_cte_count, cfg->cte_count)) {
 			sample_cnt = radio_df_iq_samples_amount_get();
 
 			/* If there are no samples available, the CTEInfo was
@@ -954,6 +953,8 @@ static inline int create_iq_report(struct lll_sync *lll, uint8_t rssi_ready,
 				ftr->rssi = ((rssi_ready) ? radio_rssi_get() :
 					     BT_HCI_LE_RSSI_NOT_AVAILABLE);
 
+				cfg->cte_count += 1U;
+
 				ull_rx_put(iq_report->hdr.link, iq_report);
 			} else {
 				return -ENODATA;
@@ -963,6 +964,11 @@ static inline int create_iq_report(struct lll_sync *lll, uint8_t rssi_ready,
 
 	return 0;
 }
+
+static bool is_max_cte_reached(uint8_t max_cte_count, uint8_t cte_count)
+{
+	return max_cte_count == BT_HCI_LE_SAMPLE_CTE_ALL || cte_count < max_cte_count;
+}
 #endif /* CONFIG_BT_CTLR_DF_SCAN_CTE_RX */
 
 static uint8_t data_channel_calc(struct lll_sync *lll)