sky2: add support for receive hashing

Sky2 hardware supports hardware receive hash calculation.
Now that Receive Packet Steering is available, add support
to enable it.

This version does not depend on CONFIG_RPS. Also set_flags rejects
all values except RXHASH, so driver won't have to change next time
somebody adds a new one.

Signed-off-by: Stephen Hemminger <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/sky2.c

···
 		     ? BMU_ENA_RX_CHKSUM : BMU_DIS_RX_CHKSUM);
 }
 
+/* Enable/disable receive hash calculation (RSS) */
+static void rx_set_rss(struct net_device *dev)
+{
+	struct sky2_port *sky2 = netdev_priv(dev);
+	struct sky2_hw *hw = sky2->hw;
+	int i, nkeys = 4;
+
+	/* Supports IPv6 and other modes */
+	if (hw->flags & SKY2_HW_NEW_LE) {
+		nkeys = 10;
+		sky2_write32(hw, SK_REG(sky2->port, RSS_CFG), HASH_ALL);
+	}
+
+	/* Program RSS initial values */
+	if (dev->features & NETIF_F_RXHASH) {
+		u32 key[nkeys];
+
+		get_random_bytes(key, nkeys * sizeof(u32));
+		for (i = 0; i < nkeys; i++)
+			sky2_write32(hw, SK_REG(sky2->port, RSS_KEY + i * 4),
+				     key[i]);
+
+		/* Need to turn on (undocumented) flag to make hashing work  */
+		sky2_write32(hw, SK_REG(sky2->port, RX_GMF_CTRL_T),
+			     RX_STFW_ENA);
+
+		sky2_write32(hw, Q_ADDR(rxqaddr[sky2->port], Q_CSR),
+			     BMU_ENA_RX_RSS_HASH);
+	} else
+		sky2_write32(hw, Q_ADDR(rxqaddr[sky2->port], Q_CSR),
+			     BMU_DIS_RX_RSS_HASH);
+}
+
 /*
  * The RX Stop command will not work for Yukon-2 if the BMU does not
  * reach the end of packet and since we can't make sure that we have
···
 
 	if (!(hw->flags & SKY2_HW_NEW_LE))
 		rx_set_checksum(sky2);
+
+	if (!(hw->flags & SKY2_HW_RSS_BROKEN))
+		rx_set_rss(sky2->netdev);
 
 	/* submit Rx ring */
 	for (i = 0; i < sky2->rx_pending; i++) {
···
 	}
 }
 
+static void sky2_rx_hash(struct sky2_port *sky2, u32 status)
+{
+	struct sk_buff *skb;
+
+	skb = sky2->rx_ring[sky2->rx_next].skb;
+	skb->rxhash = le32_to_cpu(status);
+}
+
 /* Process status response ring */
 static int sky2_status_intr(struct sky2_hw *hw, int to_do, u16 idx)
 {
···
 		case OP_RXCHKS:
 			if (likely(sky2->flags & SKY2_FLAG_RX_CHECKSUM))
 				sky2_rx_checksum(sky2, status);
+			break;
+
+		case OP_RSS_HASH:
+			sky2_rx_hash(sky2, status);
 			break;
 
 		case OP_TXINDEXLE:
···
 	switch(hw->chip_id) {
 	case CHIP_ID_YUKON_XL:
 		hw->flags = SKY2_HW_GIGABIT | SKY2_HW_NEWER_PHY;
+		if (hw->chip_rev < CHIP_REV_YU_XL_A2)
+			hw->flags |= SKY2_HW_RSS_BROKEN;
 		break;
 
 	case CHIP_ID_YUKON_EC_U:
···
 			dev_err(&hw->pdev->dev, "unsupported revision Yukon-EC rev A1\n");
 			return -EOPNOTSUPP;
 		}
-		hw->flags = SKY2_HW_GIGABIT;
+		hw->flags = SKY2_HW_GIGABIT | SKY2_HW_RSS_BROKEN;
 		break;
 
 	case CHIP_ID_YUKON_FE:
+		hw->flags = SKY2_HW_RSS_BROKEN;
 		break;
 
 	case CHIP_ID_YUKON_FE_P:
···
 	return sky2_vpd_write(sky2->hw, cap, data, eeprom->offset, eeprom->len);
 }
 
+static int sky2_set_flags(struct net_device *dev, u32 data)
+{
+	struct sky2_port *sky2 = netdev_priv(dev);
+
+	if (data & ~ETH_FLAG_RXHASH)
+		return -EOPNOTSUPP;
+
+	if (data & ETH_FLAG_RXHASH) {
+		if (sky2->hw->flags & SKY2_HW_RSS_BROKEN)
+			return -EINVAL;
+
+		dev->features |= NETIF_F_RXHASH;
+	} else
+		dev->features &= ~NETIF_F_RXHASH;
+
+	rx_set_rss(dev);
+
+	return 0;
+}
 
 static const struct ethtool_ops sky2_ethtool_ops = {
 	.get_settings	= sky2_get_settings,
···
 	.phys_id	= sky2_phys_id,
 	.get_sset_count = sky2_get_sset_count,
 	.get_ethtool_stats = sky2_get_ethtool_stats,
+	.set_flags	= sky2_set_flags,
 };
 
 #ifdef CONFIG_SKY2_DEBUG
···
 	if (highmem)
 		dev->features |= NETIF_F_HIGHDMA;
 
+	/* Enable receive hashing unless hardware is known broken */
+	if (!(hw->flags & SKY2_HW_RSS_BROKEN))
+		dev->features |= NETIF_F_RXHASH;
+
 #ifdef SKY2_VLAN_TAG_USED
 	/* The workaround for FE+ status conflicts with VLAN tag detection. */
 	if (!(sky2->hw->chip_id == CHIP_ID_YUKON_FE_P &&
···
 		goto err_out_iounmap;
 
 	/* ring for status responses */
-	hw->st_size = hw->ports * roundup_pow_of_two(2*RX_MAX_PENDING + TX_MAX_PENDING);
+	hw->st_size = hw->ports * roundup_pow_of_two(3*RX_MAX_PENDING + TX_MAX_PENDING);
 	hw->st_le = pci_alloc_consistent(pdev, hw->st_size * sizeof(struct sky2_status_le),
 					 &hw->st_dma);
 	if (!hw->st_le)

drivers/net/sky2.h

···
 	TXA_CTRL	= 0x0210,/*  8 bit	Tx Arbiter Control Register */
 	TXA_TEST	= 0x0211,/*  8 bit	Tx Arbiter Test Register */
 	TXA_STAT	= 0x0212,/*  8 bit	Tx Arbiter Status Register */
+
+	RSS_KEY		= 0x0220, /* RSS Key setup */
+	RSS_CFG		= 0x0248, /* RSS Configuration */
 };
 
+enum {
+	HASH_TCP_IPV6_EX_CTRL	= 1<<5,
+	HASH_IPV6_EX_CTRL	= 1<<4,
+	HASH_TCP_IPV6_CTRL	= 1<<3,
+	HASH_IPV6_CTRL		= 1<<2,
+	HASH_TCP_IPV4_CTRL	= 1<<1,
+	HASH_IPV4_CTRL		= 1<<0,
+
+	HASH_ALL		= 0x3f,
+};
 
 enum {
 	B6_EXT_REG	= 0x0300,/* External registers (GENESIS only) */
···
 #define SKY2_HW_NEW_LE		0x00000020	/* new LSOv2 format */
 #define SKY2_HW_AUTO_TX_SUM	0x00000040	/* new IP decode for Tx */
 #define SKY2_HW_ADV_POWER_CTL	0x00000080	/* additional PHY power regs */
+#define SKY2_HW_RSS_BROKEN	0x00000100
 
 	u8	     	     chip_id;
 	u8		     chip_rev;