ixgbevf: add wait for Rx queue disable

New function was added to wait for Rx queues to be disabled before
disabling NAPI. This function also allows us to  modify
ixgbevf_rx_desc_queue_enable() to better match ixgbe.  I also cleaned up
some msleep calls to usleep_range while I was in this code anyway.
Signed-off-by: NAlexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: NDon Skidmore <donald.c.skidmore@intel.com>
Tested-by: NStephen Ko <stephen.s.ko@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c

@@ -1302,27 +1302,51 @@ static void ixgbevf_configure(struct ixgbevf_adapter *adapter)
 	}
 }
 
-#define IXGBE_MAX_RX_DESC_POLL 10
-static inline void ixgbevf_rx_desc_queue_enable(struct ixgbevf_adapter *adapter,
-						int rxr)
+#define IXGBEVF_MAX_RX_DESC_POLL 10
+static void ixgbevf_rx_desc_queue_enable(struct ixgbevf_adapter *adapter,
+					 int rxr)
 {
 	struct ixgbe_hw *hw = &adapter->hw;
+	int wait_loop = IXGBEVF_MAX_RX_DESC_POLL;
+	u32 rxdctl;
 	int j = adapter->rx_ring[rxr].reg_idx;
-	int k;
 
-	for (k = 0; k < IXGBE_MAX_RX_DESC_POLL; k++) {
-		if (IXGBE_READ_REG(hw, IXGBE_VFRXDCTL(j)) & IXGBE_RXDCTL_ENABLE)
-			break;
-		else
-			msleep(1);
-	}
-	if (k >= IXGBE_MAX_RX_DESC_POLL) {
-		hw_dbg(hw, "RXDCTL.ENABLE on Rx queue %d "
-		       "not set within the polling period\n", rxr);
-	}
+	do {
+		usleep_range(1000, 2000);
+		rxdctl = IXGBE_READ_REG(hw, IXGBE_VFRXDCTL(j));
+	} while (--wait_loop && !(rxdctl & IXGBE_RXDCTL_ENABLE));
+
+	if (!wait_loop)
+		hw_dbg(hw, "RXDCTL.ENABLE queue %d not set while polling\n",
+		       rxr);
+
+	ixgbevf_release_rx_desc(&adapter->hw, &adapter->rx_ring[rxr],
+				(adapter->rx_ring[rxr].count - 1));
+}
 
-	ixgbevf_release_rx_desc(hw, &adapter->rx_ring[rxr],
-				adapter->rx_ring[rxr].count - 1);
+static void ixgbevf_disable_rx_queue(struct ixgbevf_adapter *adapter,
+				     struct ixgbevf_ring *ring)
+{
+	struct ixgbe_hw *hw = &adapter->hw;
+	int wait_loop = IXGBEVF_MAX_RX_DESC_POLL;
+	u32 rxdctl;
+	u8 reg_idx = ring->reg_idx;
+
+	rxdctl = IXGBE_READ_REG(hw, IXGBE_VFRXDCTL(reg_idx));
+	rxdctl &= ~IXGBE_RXDCTL_ENABLE;
+
+	/* write value back with RXDCTL.ENABLE bit cleared */
+	IXGBE_WRITE_REG(hw, IXGBE_VFRXDCTL(reg_idx), rxdctl);
+
+	/* the hardware may take up to 100us to really disable the rx queue */
+	do {
+		udelay(10);
+		rxdctl = IXGBE_READ_REG(hw, IXGBE_VFRXDCTL(reg_idx));
+	} while (--wait_loop && (rxdctl & IXGBE_RXDCTL_ENABLE));
+
+	if (!wait_loop)
+		hw_dbg(hw, "RXDCTL.ENABLE queue %d not cleared while polling\n",
+		       reg_idx);
 }
 
 static void ixgbevf_save_reset_stats(struct ixgbevf_adapter *adapter)
@@ -1654,7 +1678,10 @@ void ixgbevf_down(struct ixgbevf_adapter *adapter)
 
 	/* signal that we are down to the interrupt handler */
 	set_bit(__IXGBEVF_DOWN, &adapter->state);
-	/* disable receives */
+
+	/* disable all enabled rx queues */
+	for (i = 0; i < adapter->num_rx_queues; i++)
+		ixgbevf_disable_rx_queue(adapter, &adapter->rx_ring[i]);
 
 	netif_tx_disable(netdev);