e1000e: add Receive Packet Steering (RPS) support

Enable RPS by default.  Disallow jumbo frames when both receive checksum
and receive hashing are enabled because the hardware cannot do both IP
payload checksum (enabled when receive checksum is enabled when using
packet split which is used for jumbo frames) and provide RSS hash at the
same time.

v2: added ethtool command to query flow hashing behavior per Ben Hutchings
    and changed the type of rsskey to cleanup the setting of the register
    array and avoid unnecessary casts (as pointed out by Joe Perches).
    The long error messages are not changed since there is nothing in
    the kernel ./Documentation that suggests the preferred method for
    dealing with long messages other than to never break strings; leaving
    them as-is for now.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/ethernet/intel/e1000e/defines.h b/drivers/net/ethernet/intel/e1000e/defines.h
index c516a74..c73795f 100644
--- a/drivers/net/ethernet/intel/e1000e/defines.h
+++ b/drivers/net/ethernet/intel/e1000e/defines.h
@@ -126,6 +126,13 @@
     E1000_RXDEXT_STATERR_CXE |            \
     E1000_RXDEXT_STATERR_RXE)
 
+#define E1000_MRQC_RSS_FIELD_MASK              0xFFFF0000
+#define E1000_MRQC_RSS_FIELD_IPV4_TCP          0x00010000
+#define E1000_MRQC_RSS_FIELD_IPV4              0x00020000
+#define E1000_MRQC_RSS_FIELD_IPV6_TCP_EX       0x00040000
+#define E1000_MRQC_RSS_FIELD_IPV6              0x00100000
+#define E1000_MRQC_RSS_FIELD_IPV6_TCP          0x00200000
+
 #define E1000_RXDPS_HDRSTAT_HDRSP              0x00008000
 
 /* Management Control */
@@ -326,6 +333,7 @@
 /* Receive Checksum Control */
 #define E1000_RXCSUM_TUOFL     0x00000200   /* TCP / UDP checksum offload */
 #define E1000_RXCSUM_IPPCSE    0x00001000   /* IP payload checksum enable */
+#define E1000_RXCSUM_PCSD      0x00002000   /* packet checksum disabled */
 
 /* Header split receive */
 #define E1000_RFCTL_NFSW_DIS            0x00000040