i40e/i40evf: unhide and enable to one prefena field

The PREFENA field in the receive host memory cache (RX-HMC)
must be visible in order to be set to 1 at driver init for
best performance.

Change-ID: I16b0bcd84cf56f4b6c938201ff5e954bee5a1992
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Acked-by: Shannon Nelson <shannon.nelson@intel.com>
Tested-by: Kavindya Deegala <kavindya.s.deegala@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/i40e/i40e_lan_hmc.c

@@ -747,6 +747,7 @@ static struct i40e_context_ele i40e_hmc_rxq_ce_info[] = {
 	{ I40E_HMC_STORE(i40e_hmc_obj_rxq, tphdata_ena),  1,	195 },
 	{ I40E_HMC_STORE(i40e_hmc_obj_rxq, tphhead_ena),  1,	196 },
 	{ I40E_HMC_STORE(i40e_hmc_obj_rxq, lrxqthresh),   3,	198 },
+	{ I40E_HMC_STORE(i40e_hmc_obj_rxq, prefena),      1,	201 },
 	{ 0 }
 };
 

drivers/net/ethernet/intel/i40e/i40e_lan_hmc.h

@@ -56,6 +56,7 @@ struct i40e_hmc_obj_rxq {
 	u8  tphdata_ena;
 	u8  tphhead_ena;
 	u8  lrxqthresh;
+	u8  prefena;	/* NOTE: normally must be set to 1 at init */
 };
 
 /* Tx queue context data */

drivers/net/ethernet/intel/i40e/i40e_main.c

@@ -3140,6 +3140,8 @@ static void i40e_netpoll(struct net_device *netdev)
 	pf->flags &= ~I40E_FLAG_IN_NETPOLL;
 }
 #endif
+	/* set the prefena field to 1 because the manual says to */
+	rx_ctx.prefena = 1;
 
 /**
  * i40e_vsi_control_tx - Start or stop a VSI's rings

drivers/net/ethernet/intel/i40evf/i40e_lan_hmc.h

@@ -53,6 +53,7 @@ struct i40e_hmc_obj_rxq {
 	u8  tphdata_ena;
 	u8  tphhead_ena;
 	u8  lrxqthresh;
+	u8  prefena;	/* NOTE: normally must be set to 1 at init */
 };
 
 /* Tx queue context data */