sky2: override for PCI legacy power management

Some BIOS's don't setup power management correctly (what else is
new) and don't allow use of PCI Express power control. Add a special
exception module parameter to allow working around this issue.
Based on slightly different patch by Knut Petersen.
Reported-by: Arkadiusz Miskiewicz <arekm@maven.pl>
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/sky2.c

@@ -95,6 +95,10 @@ static int disable_msi = 0;
 module_param(disable_msi, int, 0);
 MODULE_PARM_DESC(disable_msi, "Disable Message Signaled Interrupt (MSI)");
 
+static int legacy_pme = 0;
+module_param(legacy_pme, int, 0);
+MODULE_PARM_DESC(legacy_pme, "Legacy power management");
+
 static DEFINE_PCI_DEVICE_TABLE(sky2_id_table) = {
 	{ PCI_DEVICE(PCI_VENDOR_ID_SYSKONNECT, 0x9000) }, /* SK-9Sxx */
 	{ PCI_DEVICE(PCI_VENDOR_ID_SYSKONNECT, 0x9E00) }, /* SK-9Exx */
@@ -867,6 +871,13 @@ static void sky2_wol_init(struct sky2_port *sky2)
 	/* Disable PiG firmware */
 	sky2_write16(hw, B0_CTST, Y2_HW_WOL_OFF);
 
+	/* Needed by some broken BIOSes, use PCI rather than PCI-e for WOL */
+	if (legacy_pme) {
+		u32 reg1 = sky2_pci_read32(hw, PCI_DEV_REG1);
+		reg1 |= PCI_Y2_PME_LEGACY;
+		sky2_pci_write32(hw, PCI_DEV_REG1, reg1);
+	}
+
 	/* block receiver */
 	sky2_write8(hw, SK_REG(port, RX_GMF_CTRL_T), GMF_RST_SET);
 	sky2_read32(hw, B0_CTST);