r8169: improve WoL handling

WoL handling for the RTL8168 family is a little bit tricky because of
different types of broken BIOS and/or chip quirks.

Two known issues:
1. Network properly resumes from suspend only if WoL is enabled in the chip.
2. Some notebooks wake up immediately if system is suspended and network
   device is wakeup-enabled.

Few patches tried to deal with this:
7edf6d31 ("r8169: disable WOL per default")
18041b52 ("r8169: restore previous behavior to accept BIOS WoL
settings")

Currently we have the situation that the chip WoL settings as set by
the BIOS are respected (to prevent issue 1), but the device doesn't get
wakeup-enabled (to prevent issue 2).

This leads to another issue:
If systemd is told to set WoL it first checks whether the requested
settings are active already (and does nothing if yes). Due to the chip
WoL flags being set properly systemd assumes that WoL is configured
properly in our case. Result is that device doesn't get wakeup-enabled
and WoL doesn't work (until it's set e.g. by ethtool).

This patch now:
- leaves the chip WoL settings as is (to prevent issue 1)
- keeps the behavior to not wakeup-enable the device initially
  (to prevent issue 2)
- In addition we report WoL as being disabled in get_wol, matching
  that device isn't wakeup-enabled. If systemd is told to enable WoL,
  it will therefore detect that it has to do something and will
  call set_wol.

Of course the user still has the option to override this with
e.g. ethtool.

v2:
- Don't just exclude __rtl8169_get_wol() from compiling, remove it.
v3:
- adjust commit message
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/realtek/r8169.c

@@ -1371,41 +1371,6 @@ static void rtl_link_chg_patch(struct rtl8169_private *tp)
 
 #define WAKE_ANY (WAKE_PHY | WAKE_MAGIC | WAKE_UCAST | WAKE_BCAST | WAKE_MCAST)
 
-static u32 __rtl8169_get_wol(struct rtl8169_private *tp)
-{
-	u8 options;
-	u32 wolopts = 0;
-
-	options = RTL_R8(tp, Config1);
-	if (!(options & PMEnable))
-		return 0;
-
-	options = RTL_R8(tp, Config3);
-	if (options & LinkUp)
-		wolopts |= WAKE_PHY;
-	switch (tp->mac_version) {
-	case RTL_GIGA_MAC_VER_34 ... RTL_GIGA_MAC_VER_38:
-	case RTL_GIGA_MAC_VER_40 ... RTL_GIGA_MAC_VER_51:
-		if (rtl_eri_read(tp, 0xdc, ERIAR_EXGMAC) & MagicPacket_v2)
-			wolopts |= WAKE_MAGIC;
-		break;
-	default:
-		if (options & MagicPacket)
-			wolopts |= WAKE_MAGIC;
-		break;
-	}
-
-	options = RTL_R8(tp, Config5);
-	if (options & UWF)
-		wolopts |= WAKE_UCAST;
-	if (options & BWF)
-		wolopts |= WAKE_BCAST;
-	if (options & MWF)
-		wolopts |= WAKE_MCAST;
-
-	return wolopts;
-}
-
 static void rtl8169_get_wol(struct net_device *dev, struct ethtool_wolinfo *wol)
 {
 	struct rtl8169_private *tp = netdev_priv(dev);
@@ -4284,7 +4249,7 @@ static void rtl_wol_suspend_quirk(struct rtl8169_private *tp)
 
 static bool rtl_wol_pll_power_down(struct rtl8169_private *tp)
 {
-	if (!__rtl8169_get_wol(tp))
+	if (!device_may_wakeup(tp_to_dev(tp)))
 		return false;
 
 	phy_speed_down(tp->phydev, false);
@@ -7441,8 +7406,6 @@ static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 		return rc;
 	}
 
-	tp->saved_wolopts = __rtl8169_get_wol(tp);
-
 	mutex_init(&tp->wk.mutex);
 	INIT_WORK(&tp->wk.work, rtl_task);
 	u64_stats_init(&tp->rx_stats.syncp);