qcacmn: Add support to drop monitor destination ring entries

Currently, in case of station+monitor mode on KIWI target,
we are not attempting to drop the entries received in the
monitor destination ring, when no channel has been
configured for the monitor interface. This leads to the
monitor destination ring full condition and an eventual
backpressure on the ring.

Fix this issue, by dropping the entries in the monitor
destination ring, which have been received before the
monitor channel has been configured.

Change-Id: Ic9c432b438d0a5dce2d2bb38053c31ce508c27f5
CRs-Fixed: 3332327

dp/wifi3.0/monitor/1.0/dp_rx_mon_dest_1.0.c

@@ -97,6 +97,8 @@ dp_tx_capture_get_user_id(struct dp_pdev *dp_pdev, void *rx_desc_tlv)
  *
  * @dp_pdev: core txrx pdev context
  * @buf_addr_info: void pointer to monitor link descriptor buf addr info
+ * @mac_id: mac_id for which the link desc is released.
+ *
  * Return: QDF_STATUS
  */
 QDF_STATUS
@@ -608,7 +610,7 @@ dp_rx_mon_check_n_drop_mpdu(struct dp_pdev *pdev, uint32_t mac_id,
 	QDF_STATUS status;
 
 	if (mon_pdev->mon_chan_band == REG_BAND_UNKNOWN)
-		return QDF_STATUS_E_INVAL;
+		goto drop_mpdu;
 
 	lmac_id = pdev->ch_band_lmac_id_mapping[mon_pdev->mon_chan_band];
 
@@ -621,6 +623,7 @@ dp_rx_mon_check_n_drop_mpdu(struct dp_pdev *pdev, uint32_t mac_id,
 	if (src_link_id == lmac_id)
 		return QDF_STATUS_E_INVAL;
 
+drop_mpdu:
 	*rx_bufs_dropped = dp_rx_mon_drop_one_mpdu(pdev, mac_id,
 						   rxdma_dst_ring_desc,
 						   head, tail);
@@ -957,7 +960,9 @@ dp_mon_dest_srng_drop_for_mac(struct dp_pdev *pdev, uint32_t mac_id)
 	uint32_t rx_bufs_used = 0;
 	struct rx_desc_pool *rx_desc_pool;
 	uint32_t reap_cnt = 0;
+	uint32_t rx_bufs_dropped;
 	struct dp_mon_pdev *mon_pdev;
+	bool is_rxdma_dst_ring_common;
 
 	if (qdf_unlikely(!soc || !soc->hal_soc))
 		return reap_cnt;
@@ -978,14 +983,33 @@ dp_mon_dest_srng_drop_for_mac(struct dp_pdev *pdev, uint32_t mac_id)
 	}
 
 	rx_desc_pool = dp_rx_get_mon_desc_pool(soc, mac_id, pdev->pdev_id);
+	is_rxdma_dst_ring_common = dp_is_rxdma_dst_ring_common(pdev);
 
 	while ((rxdma_dst_ring_desc =
 		hal_srng_dst_peek(hal_soc, mon_dst_srng)) &&
 		reap_cnt < MON_DROP_REAP_LIMIT) {
-
-		rx_bufs_used += dp_rx_mon_drop_one_mpdu(pdev, mac_id,
+		if (is_rxdma_dst_ring_common) {
+			if (QDF_STATUS_SUCCESS ==
+			    dp_rx_mon_check_n_drop_mpdu(pdev, mac_id,
 							rxdma_dst_ring_desc,
-							&head, &tail);
+							&head, &tail,
+							&rx_bufs_dropped)) {
+				/* Increment stats */
+				rx_bufs_used += rx_bufs_dropped;
+			} else {
+				/*
+				 * If the mpdu was not dropped, we need to
+				 * wait for the entry to be processed, along
+				 * with the status ring entry for the other
+				 * mac. Hence we bail out here.
+				 */
+				break;
+			}
+		} else {
+			rx_bufs_used += dp_rx_mon_drop_one_mpdu(pdev, mac_id,
+								rxdma_dst_ring_desc,
+								&head, &tail);
+		}
 		reap_cnt++;
 		rxdma_dst_ring_desc = hal_srng_dst_get_next(hal_soc,
 							    mon_dst_srng);

dp/wifi3.0/monitor/1.0/dp_rx_mon_status_1.0.c

@@ -1296,8 +1296,7 @@ uint32_t dp_mon_drop_packets_for_mac(struct dp_pdev *pdev, uint32_t mac_id,
 	uint32_t work_done;
 
 	work_done = dp_mon_status_srng_drop_for_mac(pdev, mac_id, quota);
-	if (!dp_is_rxdma_dst_ring_common(pdev))
-		dp_mon_dest_srng_drop_for_mac(pdev, mac_id);
+	dp_mon_dest_srng_drop_for_mac(pdev, mac_id);
 
 	return work_done;
 }