be2net: fix spurious interrupt handling in intx mode

Occasionally we may see an interrupt without an event in the eq.
In intx, we currently see the event queue and return IRQ_NONE causing
a the irq to be disabled ("no one cared".) Instead, read the CEV_ISR
reg to check the existence of the interrupt.

Signed-off-by: Sathya Perla <sathyap@serverengines.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 13 insertions, 7 deletions

diff --git a/drivers/net/benet/be_hw.h b/drivers/net/benet/be_hw.h
index b02e805c1db3..29c33c709c6d 100644
--- a/drivers/net/benet/be_hw.h
+++ b/drivers/net/benet/be_hw.h
@@ -55,6 +55,10 @@
 #define MEMBAR_CTRL_INT_CTRL_PFUNC_MASK         0x7     /* bits 26 - 28 */
 #define MEMBAR_CTRL_INT_CTRL_PFUNC_SHIFT        26
 
+/********* ISR0 Register offset **********/
+#define CEV_ISR0_OFFSET                         0xC18
+#define CEV_ISR_SIZE                            4
+
 /********* Event Q door bell *************/
 #define DB_EQ_OFFSET                    DB_CQ_OFFSET
 #define DB_EQ_RING_ID_MASK              0x1FF   /* bits 0 - 8 */
diff --git a/drivers/net/benet/be_main.c b/drivers/net/benet/be_main.c
index 308eb09ca56b..c43f6a119295 100644
--- a/drivers/net/benet/be_main.c
+++ b/drivers/net/benet/be_main.c
@@ -1274,15 +1274,17 @@ static irqreturn_t be_intx(int irq, void *dev)
 {
         struct be_adapter *adapter = dev;
         struct be_ctrl_info *ctrl = &adapter->ctrl;
-        int rx, tx;
+        int isr;
 
-        tx = event_handle(ctrl, &adapter->tx_eq);
-        rx = event_handle(ctrl, &adapter->rx_eq);
+        isr = ioread32(ctrl->csr + CEV_ISR0_OFFSET +
+                      ctrl->pci_func * CEV_ISR_SIZE);
+        if (!isr)
+                return IRQ_NONE;
 
-        if (rx || tx)
-                return IRQ_HANDLED;
-        else
-                return IRQ_NONE;
+        event_handle(ctrl, &adapter->tx_eq);
+        event_handle(ctrl, &adapter->rx_eq);
+
+        return IRQ_HANDLED;
 }
 
 static irqreturn_t be_msix_rx(int irq, void *dev)