[v2, PATCH 4/4] net: stmmac: dwmac4: fix flow control issue

[Biao Huang <biao.huang@mediatek.com>]

Current dwmac4_flow_ctrl will not clear
GMAC_RX_FLOW_CTRL_RFE/GMAC_RX_FLOW_CTRL_RFE bits,
so MAC hw will keep flow control on although expecting
flow control off by ethtool. Add codes to fix it.

Fixes: 477286b53f55 ("stmmac: add GMAC4 core support")
Signed-off-by: Biao Huang <biao.huang@mediatek.com>
---
 drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
index 2544cff..9322b71 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
@@ -488,8 +488,9 @@ static void dwmac4_flow_ctrl(struct mac_device_info *hw, unsigned int duplex,
 	if (fc & FLOW_RX) {
 		pr_debug("\tReceive Flow-Control ON\n");
 		flow |= GMAC_RX_FLOW_CTRL_RFE;
-		writel(flow, ioaddr + GMAC_RX_FLOW_CTRL);
 	}
+	writel(flow, ioaddr + GMAC_RX_FLOW_CTRL);
+
 	if (fc & FLOW_TX) {
 		pr_debug("\tTransmit Flow-Control ON\n");
 
@@ -497,7 +498,7 @@ static void dwmac4_flow_ctrl(struct mac_device_info *hw, unsigned int duplex,
 			pr_debug("\tduplex mode: PAUSE %d\n", pause_time);
 
 		for (queue = 0; queue < tx_cnt; queue++) {
-			flow |= GMAC_TX_FLOW_CTRL_TFE;
+			flow = GMAC_TX_FLOW_CTRL_TFE;
 
 			if (duplex)
 				flow |=
@@ -505,6 +506,9 @@ static void dwmac4_flow_ctrl(struct mac_device_info *hw, unsigned int duplex,
 
 			writel(flow, ioaddr + GMAC_QX_TX_FLOW_CTRL(queue));
 		}
+	} else {
+		for (queue = 0; queue < tx_cnt; queue++)
+			writel(0, ioaddr + GMAC_QX_TX_FLOW_CTRL(queue));
 	}
 }
 
-- 
1.7.9.5