ixgbe: Add ability to double reset on failure to clear master enable

Double resets are required for recovery from certain error conditions.
Between resets, it is necessary to stall to allow time for any pending HW
events to complete. We use 1usec since that is what is needed for
ixgbe_disable_pcie_master(). The second reset then clears out any effects
of those events.

Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Stephen Ko <stephen.s.ko@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

1 files changed, 41 insertions, 6 deletions

diff --git a/drivers/net/ixgbe/ixgbe_common.c b/drivers/net/ixgbe/ixgbe_common.c
index 345c32eab4a5..6d87c7491d10 100644
--- a/drivers/net/ixgbe/ixgbe_common.c
+++ b/drivers/net/ixgbe/ixgbe_common.c
@@ -454,8 +454,7 @@ s32 ixgbe_stop_adapter_generic(struct ixgbe_hw *hw)
 	 * Prevent the PCI-E bus from from hanging by disabling PCI-E master
 	 * access and verify no pending requests
 	 */
-	if (ixgbe_disable_pcie_master(hw) != 0)
-		hw_dbg(hw, "PCI-E Master disable polling has failed.\n");
+	ixgbe_disable_pcie_master(hw);
 
 	return 0;
 }
@@ -2161,10 +2160,16 @@ out:
  **/
 s32 ixgbe_disable_pcie_master(struct ixgbe_hw *hw)
 {
+	struct ixgbe_adapter *adapter = hw->back;
 	u32 i;
 	u32 reg_val;
 	u32 number_of_queues;
-	s32 status = IXGBE_ERR_MASTER_REQUESTS_PENDING;
+	s32 status = 0;
+	u16 dev_status = 0;
+
+	/* Just jump out if bus mastering is already disabled */
+	if (!(IXGBE_READ_REG(hw, IXGBE_STATUS) & IXGBE_STATUS_GIO))
+		goto out;
 
 	/* Disable the receive unit by stopping each queue */
 	number_of_queues = hw->mac.max_rx_queues;
@@ -2181,13 +2186,43 @@ s32 ixgbe_disable_pcie_master(struct ixgbe_hw *hw)
 	IXGBE_WRITE_REG(hw, IXGBE_CTRL, reg_val);
 
 	for (i = 0; i < IXGBE_PCI_MASTER_DISABLE_TIMEOUT; i++) {
-		if (!(IXGBE_READ_REG(hw, IXGBE_STATUS) & IXGBE_STATUS_GIO)) {
-			status = 0;
+		if (!(IXGBE_READ_REG(hw, IXGBE_STATUS) & IXGBE_STATUS_GIO))
+			goto check_device_status;
+		udelay(100);
+	}
+
+	hw_dbg(hw, "GIO Master Disable bit didn't clear - requesting resets\n");
+	status = IXGBE_ERR_MASTER_REQUESTS_PENDING;
+
+	/*
+	 * Before proceeding, make sure that the PCIe block does not have
+	 * transactions pending.
+	 */
+check_device_status:
+	for (i = 0; i < IXGBE_PCI_MASTER_DISABLE_TIMEOUT; i++) {
+		pci_read_config_word(adapter->pdev, IXGBE_PCI_DEVICE_STATUS,
+							 &dev_status);
+		if (!(dev_status & IXGBE_PCI_DEVICE_STATUS_TRANSACTION_PENDING))
 			break;
-		}
 		udelay(100);
 	}
 
+	if (i == IXGBE_PCI_MASTER_DISABLE_TIMEOUT)
+		hw_dbg(hw, "PCIe transaction pending bit also did not clear.\n");
+	else
+		goto out;
+
+	/*
+	 * Two consecutive resets are required via CTRL.RST per datasheet
+	 * 5.2.5.3.2 Master Disable.  We set a flag to inform the reset routine
+	 * of this need.  The first reset prevents new master requests from
+	 * being issued by our device.  We then must wait 1usec for any
+	 * remaining completions from the PCIe bus to trickle in, and then reset
+	 * again to clear out any effects they may have had on our device.
+	 */
+	 hw->mac.flags |= IXGBE_FLAGS_DOUBLE_RESET_REQUIRED;
+
+out:
 	return status;
 }