r8169: improve driver unload and system shutdown behavior on DASH-enabled systems

There's a number of systems supporting DASH remote management.
Driver unload and system shutdown can result in the PHY suspending,
thus making DASH unusable. Improve this by handling DASH being enabled
very similar to WoL being enabled.
Tested-by: NYanko Kaneti <yaneti@declera.com>
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Link: https://lore.kernel.org/r/1de3b176-c09c-1654-6f00-9785f7a4f954@gmail.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/realtek/r8169_main.c

@@ -1397,8 +1397,11 @@ static void __rtl8169_set_wol(struct rtl8169_private *tp, u32 wolopts)
 	rtl_lock_config_regs(tp);
 
 	device_set_wakeup_enable(tp_to_dev(tp), wolopts);
-	rtl_set_d3_pll_down(tp, !wolopts);
-	tp->dev->wol_enabled = wolopts ? 1 : 0;
+
+	if (tp->dash_type == RTL_DASH_NONE) {
+		rtl_set_d3_pll_down(tp, !wolopts);
+		tp->dev->wol_enabled = wolopts ? 1 : 0;
+	}
 }
 
 static int rtl8169_set_wol(struct net_device *dev, struct ethtool_wolinfo *wol)
@@ -4938,6 +4941,9 @@ static int rtl8169_runtime_idle(struct device *device)
 {
 	struct rtl8169_private *tp = dev_get_drvdata(device);
 
+	if (tp->dash_type != RTL_DASH_NONE)
+		return -EBUSY;
+
 	if (!netif_running(tp->dev) || !netif_carrier_ok(tp->dev))
 		pm_schedule_suspend(device, 10000);
 
@@ -4978,7 +4984,8 @@ static void rtl_shutdown(struct pci_dev *pdev)
 	/* Restore original MAC address */
 	rtl_rar_set(tp, tp->dev->perm_addr);
 
-	if (system_state == SYSTEM_POWER_OFF) {
+	if (system_state == SYSTEM_POWER_OFF &&
+	    tp->dash_type == RTL_DASH_NONE) {
 		if (tp->saved_wolopts)
 			rtl_wol_shutdown_quirk(tp);
 
@@ -5449,7 +5456,12 @@ static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 	/* configure chip for default features */
 	rtl8169_set_features(dev, dev->features);
 
-	rtl_set_d3_pll_down(tp, true);
+	if (tp->dash_type == RTL_DASH_NONE) {
+		rtl_set_d3_pll_down(tp, true);
+	} else {
+		rtl_set_d3_pll_down(tp, false);
+		dev->wol_enabled = 1;
+	}
 
 	jumbo_max = rtl_jumbo_max(tp);
 	if (jumbo_max)