X-Git-Url: http://git.droids-corp.org/?a=blobdiff_plain;f=drivers%2Fnet%2Fenetc%2Fenetc_rxtx.c;h=262ed8a0fdbcd823fca4a18e9348c271dd14a743;hb=11a6dc423bc626e28343b1df7a1570a64ca8ebc8;hp=81b0ef3b148cfac60a116c1931b265f2134d227c;hpb=e091c6915e3ed468d4f5299e409afa4a89436735;p=dpdk.git

diff --git a/drivers/net/enetc/enetc_rxtx.c b/drivers/net/enetc/enetc_rxtx.c
index 81b0ef3b14..262ed8a0fd 100644
--- a/drivers/net/enetc/enetc_rxtx.c
+++ b/drivers/net/enetc/enetc_rxtx.c
@@ -1,5 +1,5 @@
 /* SPDX-License-Identifier: BSD-3-Clause
- * Copyright 2018-2019 NXP
+ * Copyright 2018-2020 NXP
  */
 
 #include <stdbool.h>
@@ -14,19 +14,32 @@
 #include "enetc.h"
 #include "enetc_logs.h"
 
-#define ENETC_RXBD_BUNDLE 8 /* Number of BDs to update at once */
-
 static int
 enetc_clean_tx_ring(struct enetc_bdr *tx_ring)
 {
 	int tx_frm_cnt = 0;
 	struct enetc_swbd *tx_swbd;
-	int i;
+	int i, hwci;
+
+	/* we don't need barriers here, we just want a relatively current value
+	 * from HW.
+	 */
+	hwci = (int)(rte_read32_relaxed(tx_ring->tcisr) &
+		     ENETC_TBCISR_IDX_MASK);
 
 	i = tx_ring->next_to_clean;
 	tx_swbd = &tx_ring->q_swbd[i];
-	while ((int)(enetc_rd_reg(tx_ring->tcisr) &
-	       ENETC_TBCISR_IDX_MASK) != i) {
+
+	/* we're only reading the CI index once here, which means HW may update
+	 * it while we're doing clean-up.  We could read the register in a loop
+	 * but for now I assume it's OK to leave a few Tx frames for next call.
+	 * The issue with reading the register in a loop is that we're stalling
+	 * here trying to catch up with HW which keeps sending traffic as long
+	 * as it has traffic to send, so in effect we could be waiting here for
+	 * the Tx ring to be drained by HW, instead of us doing Rx in that
+	 * meantime.
+	 */
+	while (i != hwci) {
 		rte_pktmbuf_free(tx_swbd->buffer_addr);
 		tx_swbd->buffer_addr = NULL;
 		tx_swbd++;
@@ -61,7 +74,6 @@ enetc_xmit_pkts(void *tx_queue,
 
 	start = 0;
 	while (nb_pkts--) {
-		enetc_clean_tx_ring(tx_ring);
 		tx_ring->q_swbd[i].buffer_addr = tx_pkts[start];
 		txbd = ENETC_TXBD(*tx_ring, i);
 		tx_swbd = &tx_ring->q_swbd[i];
@@ -77,6 +89,14 @@ enetc_xmit_pkts(void *tx_queue,
 			i = 0;
 	}
 
+	/* we're only cleaning up the Tx ring here, on the assumption that
+	 * software is slower than hardware and hardware completed sending
+	 * older frames out by now.
+	 * We're also cleaning up the ring before kicking off Tx for the new
+	 * batch to minimize chances of contention on the Tx ring
+	 */
+	enetc_clean_tx_ring(tx_ring);
+
 	tx_ring->next_to_use = i;
 	enetc_wr_reg(tx_ring->tcir, i);
 	return start;
@@ -283,12 +303,6 @@ enetc_clean_rx_ring(struct enetc_bdr *rx_ring,
 		union enetc_rx_bd *rxbd;
 		uint32_t bd_status;
 
-		if (cleaned_cnt >= ENETC_RXBD_BUNDLE) {
-			int count = enetc_refill_rx_ring(rx_ring, cleaned_cnt);
-
-			cleaned_cnt -= count;
-		}
-
 		rxbd = ENETC_RXBD(*rx_ring, i);
 		bd_status = rte_le_to_cpu_32(rxbd->r.lstatus);
 		if (!bd_status)
@@ -315,6 +329,8 @@ enetc_clean_rx_ring(struct enetc_bdr *rx_ring,
 		rx_frm_cnt++;
 	}
 
+	enetc_refill_rx_ring(rx_ring, cleaned_cnt);
+
 	return rx_frm_cnt;
 }