r8169: add helper rtl_pci_commit

In few places we do a PCI commit by reading an arbitrary chip register.
It's not always obvious that the read is meant to be a PCI commit,
therefore add a helper for it.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/realtek/r8169_main.c

@@ -689,6 +689,12 @@ static void rtl_unlock_config_regs(struct rtl8169_private *tp)
 	RTL_W8(tp, Cfg9346, Cfg9346_Unlock);
 }
 
+static void rtl_pci_commit(struct rtl8169_private *tp)
+{
+	/* Read an arbitrary register to commit a preceding PCI write */
+	RTL_R8(tp, ChipCmd);
+}
+
 static bool rtl_is_8125(struct rtl8169_private *tp)
 {
 	return tp->mac_version >= RTL_GIGA_MAC_VER_60;
@@ -1319,8 +1325,7 @@ static void rtl8169_irq_mask_and_ack(struct rtl8169_private *tp)
 {
 	rtl_irq_disable(tp);
 	rtl_ack_events(tp, 0xffffffff);
-	/* PCI commit */
-	RTL_R8(tp, ChipCmd);
+	rtl_pci_commit(tp);
 }
 
 static void rtl_link_chg_patch(struct rtl8169_private *tp)
@@ -1532,7 +1537,7 @@ static int rtl8169_set_features(struct net_device *dev,
 	}
 
 	RTL_W16(tp, CPlusCmd, tp->cp_cmd);
-	RTL_R16(tp, CPlusCmd);
+	rtl_pci_commit(tp);
 
 	rtl_unlock_work(tp);
 
@@ -1618,7 +1623,7 @@ static bool rtl8169_do_counters(struct rtl8169_private *tp, u32 counter_cmd)
 	u32 cmd;
 
 	RTL_W32(tp, CounterAddrHigh, (u64)paddr >> 32);
-	RTL_R32(tp, CounterAddrHigh);
+	rtl_pci_commit(tp);
 	cmd = (u64)paddr & DMA_BIT_MASK(32);
 	RTL_W32(tp, CounterAddrLow, cmd);
 	RTL_W32(tp, CounterAddrLow, cmd | counter_cmd);
@@ -1942,7 +1947,7 @@ static int rtl_set_coalesce(struct net_device *dev, struct ethtool_coalesce *ec)
 
 	tp->cp_cmd = (tp->cp_cmd & ~INTT_MASK) | cp01;
 	RTL_W16(tp, CPlusCmd, tp->cp_cmd);
-	RTL_R16(tp, CPlusCmd);
+	rtl_pci_commit(tp);
 
 	rtl_unlock_work(tp);
 
@@ -2260,10 +2265,10 @@ static void rtl_rar_set(struct rtl8169_private *tp, u8 *addr)
 	rtl_unlock_config_regs(tp);
 
 	RTL_W32(tp, MAC4, addr[4] | addr[5] << 8);
-	RTL_R32(tp, MAC4);
+	rtl_pci_commit(tp);
 
 	RTL_W32(tp, MAC0, addr[0] | addr[1] << 8 | addr[2] << 16 | addr[3] << 24);
-	RTL_R32(tp, MAC0);
+	rtl_pci_commit(tp);
 
 	if (tp->mac_version == RTL_GIGA_MAC_VER_34)
 		rtl_rar_exgmac_set(tp, addr);
@@ -3873,7 +3878,8 @@ static void rtl_hw_start(struct  rtl8169_private *tp)
 	rtl_jumbo_config(tp, tp->dev->mtu);
 
 	/* Initially a 10 us delay. Turned it into a PCI commit. - FR */
-	RTL_R16(tp, CPlusCmd);
+	rtl_pci_commit(tp);
+
 	RTL_W8(tp, ChipCmd, CmdTxEnb | CmdRxEnb);
 	rtl_init_rxcfg(tp);
 	rtl_set_tx_config_registers(tp);
@@ -5091,8 +5097,7 @@ static void rtl_wol_shutdown_quirk(struct rtl8169_private *tp)
 		pci_clear_master(tp->pci_dev);
 
 		RTL_W8(tp, ChipCmd, CmdRxEnb);
-		/* PCI commit */
-		RTL_R8(tp, ChipCmd);
+		rtl_pci_commit(tp);
 		break;
 	default:
 		break;