i40e: tweaking icr0 handling for legacy irq

Fix the overactive irq issue seen in testing and allow use of
the legacy interrupt.

Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@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.h

@@ -545,6 +545,7 @@ static inline void i40e_dbg_init(void) {}
 static inline void i40e_dbg_exit(void) {}
 #endif /* CONFIG_DEBUG_FS*/
 void i40e_irq_dynamic_enable(struct i40e_vsi *vsi, int vector);
+void i40e_irq_dynamic_enable_icr0(struct i40e_pf *pf);
 int i40e_ioctl(struct net_device *netdev, struct ifreq *ifr, int cmd);
 void i40e_vlan_stripping_disable(struct i40e_vsi *vsi);
 int i40e_vsi_add_vlan(struct i40e_vsi *vsi, s16 vid);

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

@@ -2532,7 +2532,7 @@ static void i40e_configure_msi_and_legacy(struct i40e_vsi *vsi)
  * i40e_irq_dynamic_enable_icr0 - Enable default interrupt generation for icr0
  * @pf: board private structure
  **/
-static void i40e_irq_dynamic_enable_icr0(struct i40e_pf *pf)
+void i40e_irq_dynamic_enable_icr0(struct i40e_pf *pf)
 {
 	struct i40e_hw *hw = &pf->hw;
 	u32 val;
@@ -2742,14 +2742,14 @@ static irqreturn_t i40e_intr(int irq, void *data)
 
 	icr0 = rd32(hw, I40E_PFINT_ICR0);
 
-	/* if sharing a legacy IRQ, we might get called w/o an intr pending */
-	if ((icr0 & I40E_PFINT_ICR0_INTEVENT_MASK) == 0)
-		return IRQ_NONE;
-
 	val = rd32(hw, I40E_PFINT_DYN_CTL0);
 	val = val | I40E_PFINT_DYN_CTL0_CLEARPBA_MASK;
 	wr32(hw, I40E_PFINT_DYN_CTL0, val);
 
+	/* if sharing a legacy IRQ, we might get called w/o an intr pending */
+	if ((icr0 & I40E_PFINT_ICR0_INTEVENT_MASK) == 0)
+		return IRQ_NONE;
+
 	ena_mask = rd32(hw, I40E_PFINT_ICR0_ENA);
 
 	/* only q0 is used in MSI/Legacy mode, and none are used in MSIX */
@@ -2763,7 +2763,6 @@ static irqreturn_t i40e_intr(int irq, void *data)
 		qval = rd32(hw, I40E_QINT_TQCTL(0));
 		qval &= ~I40E_QINT_TQCTL_CAUSE_ENA_MASK;
 		wr32(hw, I40E_QINT_TQCTL(0), qval);
-		i40e_flush(hw);
 
 		if (!test_bit(__I40E_DOWN, &pf->state))
 			napi_schedule(&pf->vsi[pf->lan_vsi]->q_vectors[0]->napi);
@@ -2825,7 +2824,6 @@ static irqreturn_t i40e_intr(int irq, void *data)
 
 	/* re-enable interrupt causes */
 	wr32(hw, I40E_PFINT_ICR0_ENA, ena_mask);
-	i40e_flush(hw);
 	if (!test_bit(__I40E_DOWN, &pf->state)) {
 		i40e_service_event_schedule(pf);
 		i40e_irq_dynamic_enable_icr0(pf);

drivers/net/ethernet/intel/i40e/i40e_txrx.c

@@ -1142,7 +1142,8 @@ int i40e_napi_poll(struct napi_struct *napi, int budget)
 			qval = rd32(hw, I40E_QINT_TQCTL(0));
 			qval |= I40E_QINT_TQCTL_CAUSE_ENA_MASK;
 			wr32(hw, I40E_QINT_TQCTL(0), qval);
-			i40e_flush(hw);
+
+			i40e_irq_dynamic_enable_icr0(vsi->back);
 		}
 	}