sky2: jumbo packet changes

Change how FIFO is programmed in jumbo mode (to match vendor driver).
Mostly cosmetic, the only register change is that the bits 22,23
are not programemd used.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/sky2.c

@@ -798,29 +798,15 @@ static void sky2_set_tx_stfwd(struct sky2_hw *hw, unsigned port)
 	      hw->chip_rev != CHIP_REV_YU_EX_A0) ||
 	     hw->chip_id >= CHIP_ID_YUKON_FE_P) {
 		/* Yukon-Extreme B0 and further Extreme devices */
-		/* enable Store & Forward mode for TX */
+		sky2_write32(hw, SK_REG(port, TX_GMF_CTRL_T), TX_STFW_ENA);
+	} else if (dev->mtu > ETH_DATA_LEN) {
+		/* set Tx GMAC FIFO Almost Empty Threshold */
+		sky2_write32(hw, SK_REG(port, TX_GMF_AE_THR),
+			     (ECU_JUMBO_WM << 16) | ECU_AE_THR);
 
-		if (dev->mtu <= ETH_DATA_LEN)
-			sky2_write32(hw, SK_REG(port, TX_GMF_CTRL_T),
-				     TX_JUMBO_DIS | TX_STFW_ENA);
-
-		else
-			sky2_write32(hw, SK_REG(port, TX_GMF_CTRL_T),
-				     TX_JUMBO_ENA| TX_STFW_ENA);
-	} else {
-		if (dev->mtu <= ETH_DATA_LEN)
-			sky2_write32(hw, SK_REG(port, TX_GMF_CTRL_T), TX_STFW_ENA);
-		else {
-			/* set Tx GMAC FIFO Almost Empty Threshold */
-			sky2_write32(hw, SK_REG(port, TX_GMF_AE_THR),
-				     (ECU_JUMBO_WM << 16) | ECU_AE_THR);
-
-			sky2_write32(hw, SK_REG(port, TX_GMF_CTRL_T), TX_STFW_DIS);
-
-			/* Can't do offload because of lack of store/forward */
-			dev->features &= ~(NETIF_F_TSO | NETIF_F_SG | NETIF_F_ALL_CSUM);
-		}
-	}
+		sky2_write32(hw, SK_REG(port, TX_GMF_CTRL_T), TX_STFW_DIS);
+	} else
+		sky2_write32(hw, SK_REG(port, TX_GMF_CTRL_T), TX_STFW_ENA);
 }
 
 static void sky2_mac_init(struct sky2_hw *hw, unsigned port)
@@ -2206,14 +2192,20 @@ static int sky2_change_mtu(struct net_device *dev, int new_mtu)
 	u16 ctl, mode;
 	u32 imask;
 
+	/* MTU size outside the spec */
 	if (new_mtu < ETH_ZLEN || new_mtu > ETH_JUMBO_MTU)
 		return -EINVAL;
 
+	/* MTU > 1500 on yukon FE and FE+ not allowed */
 	if (new_mtu > ETH_DATA_LEN &&
 	    (hw->chip_id == CHIP_ID_YUKON_FE ||
 	     hw->chip_id == CHIP_ID_YUKON_FE_P))
 		return -EINVAL;
 
+	/* TSO, etc on Yukon Ultra and MTU > 1500 not supported */
+	if (new_mtu > ETH_DATA_LEN && hw->chip_id == CHIP_ID_YUKON_EC_U)
+		dev->features &= ~(NETIF_F_TSO|NETIF_F_SG|NETIF_F_ALL_CSUM);
+
 	if (!netif_running(dev)) {
 		dev->mtu = new_mtu;
 		return 0;

drivers/net/sky2.h

@@ -1895,14 +1895,14 @@ enum {
 
 /*	TX_GMF_CTRL_T	32 bit	Tx GMAC FIFO Control/Test */
 enum {
-	TX_STFW_DIS	= 1<<31,/* Disable Store & Forward (Yukon-EC Ultra) */
-	TX_STFW_ENA	= 1<<30,/* Enable  Store & Forward (Yukon-EC Ultra) */
+	TX_STFW_DIS	= 1<<31,/* Disable Store & Forward */
+	TX_STFW_ENA	= 1<<30,/* Enable  Store & Forward */
 
 	TX_VLAN_TAG_ON	= 1<<25,/* enable  VLAN tagging */
 	TX_VLAN_TAG_OFF	= 1<<24,/* disable VLAN tagging */
 
-	TX_JUMBO_ENA	= 1<<23,/* PCI Jumbo Mode enable (Yukon-EC Ultra) */
-	TX_JUMBO_DIS	= 1<<22,/* PCI Jumbo Mode enable (Yukon-EC Ultra) */
+	TX_PCI_JUM_ENA  = 1<<23,/* PCI Jumbo Mode enable */
+	TX_PCI_JUM_DIS  = 1<<22,/* PCI Jumbo Mode enable */
 
 	GMF_WSP_TST_ON	= 1<<18,/* Write Shadow Pointer Test On */
 	GMF_WSP_TST_OFF	= 1<<17,/* Write Shadow Pointer Test Off */