From 60afdd43a9ac0fbf947bd492f5219c90d03d23ec Mon Sep 17 00:00:00 2001
From: Jose Abreu <Jose.Abreu@synopsys.com>
Date: Wed, 6 Nov 2019 16:03:05 +0100
Subject: [PATCH 11/13] net: stmmac: Fix the TX IOC in xmit path
Git-commit: 7df4a3a76d34fe1f550e82c6ef368c7c40f0aaa4
Patch-mainline: v5.4-rc7
References: git-fixes

IOC bit must be only set in the last descriptor. Move the logic up a
little bit to make sure it's set in the correct descriptor.

Signed-off-by: Jose Abreu <Jose.Abreu@synopsys.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Denis Kirjanov <denis.kirjanov@suse.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 34 +++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index c6078ed37b03..9c4fa9639b42 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -2936,6 +2936,19 @@ static netdev_tx_t stmmac_tso_xmit(struct sk_buff *skb, struct net_device *dev)
 	/* Only the last descriptor gets to point to the skb. */
 	tx_q->tx_skbuff[tx_q->cur_tx] = skb;
 
+	/* Manage tx mitigation */
+	tx_q->tx_count_frames += nfrags + 1;
+	if (likely(priv->tx_coal_frames > tx_q->tx_count_frames) &&
+	    !((skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) &&
+	      priv->hwts_tx_en)) {
+		stmmac_tx_timer_arm(priv, queue);
+	} else {
+		desc = &tx_q->dma_tx[tx_q->cur_tx];
+		tx_q->tx_count_frames = 0;
+		stmmac_set_tx_ic(priv, desc);
+		priv->xstats.tx_set_ic_bit++;
+	}
+
 	/* We've used all descriptors we need for this skb, however,
 	 * advance cur_tx so that it references a fresh descriptor.
 	 * ndo_start_xmit will fill this descriptor the next time it's
@@ -3127,6 +3140,27 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
 	/* Only the last descriptor gets to point to the skb. */
 	tx_q->tx_skbuff[entry] = skb;
 
+	/* According to the coalesce parameter the IC bit for the latest
+	 * segment is reset and the timer re-started to clean the tx status.
+	 * This approach takes care about the fragments: desc is the first
+	 * element in case of no SG.
+	 */
+	tx_q->tx_count_frames += nfrags + 1;
+	if (likely(priv->tx_coal_frames > tx_q->tx_count_frames) &&
+	    !((skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) &&
+	      priv->hwts_tx_en)) {
+		stmmac_tx_timer_arm(priv, queue);
+	} else {
+		if (likely(priv->extend_desc))
+			desc = &tx_q->dma_etx[entry].basic;
+		else
+			desc = &tx_q->dma_tx[entry];
+
+		tx_q->tx_count_frames = 0;
+		stmmac_set_tx_ic(priv, desc);
+		priv->xstats.tx_set_ic_bit++;
+	}
+
 	/* We've used all descriptors we need for this skb, however,
 	 * advance cur_tx so that it references a fresh descriptor.
 	 * ndo_start_xmit will fill this descriptor the next time it's
-- 
2.16.4