netxen: add receive side scaling (rss) support

This patch enables the load balancing capability of firmware
and hardware to spray traffic into different cpus through
separate rx msix interrupts.

The feature is being enabled for NX3031, NX2031 (old) will be
enabled later. This depends on msi-x and compatibility with
msi and legacy is maintained by enabling single rx ring.

Signed-off-by: Dhananjay Phadke <dhananjay@netxen.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/netxen/netxen_nic_hw.c

@@ -670,6 +670,53 @@ int netxen_config_intr_coalesce(struct netxen_adapter *adapter)
 	return rv;
 }
 
+#define RSS_HASHTYPE_IP_TCP	0x3
+
+int netxen_config_rss(struct netxen_adapter *adapter, int enable)
+{
+	nx_nic_req_t req;
+	u64 word;
+	int i, rv;
+
+	u64 key[] = { 0xbeac01fa6a42b73bULL, 0x8030f20c77cb2da3ULL,
+			0xae7b30b4d0ca2bcbULL, 0x43a38fb04167253dULL,
+			0x255b0ec26d5a56daULL };
+
+
+	memset(&req, 0, sizeof(nx_nic_req_t));
+	req.qhdr = cpu_to_le64(NX_HOST_REQUEST << 23);
+
+	word = NX_NIC_H2C_OPCODE_CONFIG_RSS | ((u64)adapter->portnum << 16);
+	req.req_hdr = cpu_to_le64(word);
+
+	/*
+	 * RSS request:
+	 * bits 3-0: hash_method
+	 *      5-4: hash_type_ipv4
+	 *	7-6: hash_type_ipv6
+	 *	  8: enable
+	 *        9: use indirection table
+	 *    47-10: reserved
+	 *    63-48: indirection table mask
+	 */
+	word =  ((u64)(RSS_HASHTYPE_IP_TCP & 0x3) << 4) |
+		((u64)(RSS_HASHTYPE_IP_TCP & 0x3) << 6) |
+		((u64)(enable & 0x1) << 8) |
+		((0x7ULL) << 48);
+	req.words[0] = cpu_to_le64(word);
+	for (i = 0; i < 5; i++)
+		req.words[i+1] = cpu_to_le64(key[i]);
+
+
+	rv = netxen_send_cmd_descs(adapter, (struct cmd_desc_type0 *)&req, 1);
+	if (rv != 0) {
+		printk(KERN_ERR "%s: could not configure RSS\n",
+				adapter->netdev->name);
+	}
+
+	return rv;
+}
+
 /*
  * netxen_nic_change_mtu - Change the Maximum Transfer Unit
  * @returns 0 on success, negative on failure