From: Alexander Kochetkov <al.kochet@gmail.com>
Date: Tue, 9 Feb 2016 15:20:39 +0000 (+0300)
Subject: UPSTREAM: net: arc_emac: reset txbd_curr and txbd_dirty pointers to zero
X-Git-Tag: firefly_0821_release~2567
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=a1f14d6216762bc9ba14eff88d6709544d96aaeb;p=firefly-linux-kernel-4.4.55.git

UPSTREAM: net: arc_emac: reset txbd_curr and txbd_dirty pointers to zero

EMAC reset internal tx ring pointer to zero at statup.
txbd_curr and txbd_dirty can be different from zero.
That cause ethernet transfer hang (no packets transmitted).

In order to reproduce, run on device:
    ifconfig eth0 down
    ifconfig eth0 up

Change-Id: Ie37cbd4761f8df216b2ddc5d07c0d6f036ac7092
Signed-off-by: Alexander Kochetkov <al.kochet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Caesar Wang <wxt@rock-chips.com>
(cherry picked from git.kernel.org next/linux-next.git master
 commit 99f93a156a2aa9ac1e44f7cb1a197425e6d9879a)
---

diff --git a/drivers/net/ethernet/arc/emac_main.c b/drivers/net/ethernet/arc/emac_main.c
index 63a63e31d59d..4f6e5be184df 100644
--- a/drivers/net/ethernet/arc/emac_main.c
+++ b/drivers/net/ethernet/arc/emac_main.c
@@ -447,6 +447,9 @@ static int arc_emac_open(struct net_device *ndev)
 		*last_rx_bd = (*last_rx_bd + 1) % RX_BD_NUM;
 	}
 
+	priv->txbd_curr = 0;
+	priv->txbd_dirty = 0;
+
 	/* Clean Tx BD's */
 	memset(priv->txbd, 0, TX_RING_SZ);