[NET-NEXT PATCH 01/14] e1000e: disable correctable errors for quad ports while going to D3

[Jeff Kirsher <jeffrey.t.kirsher@intel.com>]

From: Alexander Duyck <alexander.h.duyck@intel.com>

There has been an issue seen with the pci-e quad port adapters that will
cause them to generate a pci-e correctable error on some system while
transitioning to D3.

Since no action is needed on this correctable error the simplest solution
is to mask off the reporting of correctable errors.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
---

 drivers/net/e1000e/netdev.c |   22 +++++++++++++++++++++-
 1 files changed, 21 insertions(+), 1 deletions(-)

diff --git a/drivers/net/e1000e/netdev.c b/drivers/net/e1000e/netdev.c
index cc0502b..ebbb9f0 100644
--- a/drivers/net/e1000e/netdev.c
+++ b/drivers/net/e1000e/netdev.c
@@ -4462,7 +4462,27 @@ static int e1000_suspend(struct pci_dev *pdev, pm_message_t state)
 
 	pci_disable_device(pdev);
 
-	pci_set_power_state(pdev, pci_choose_state(pdev, state));
+	/*
+	 * The pci-e switch on some quad port adapters will report a
+	 * correctable error when the MAC transitions from D0 to D3.  To
+	 * prevent this we need to mask off the correctable errors on the
+	 * downstream port of the pci-e switch.
+	 */
+	if (adapter->flags & FLAG_IS_QUAD_PORT) {
+		struct pci_dev *us_dev = pdev->bus->self;
+		int pos = pci_find_capability(us_dev, PCI_CAP_ID_EXP);
+		u16 devctl;
+
+		pci_read_config_word(us_dev, pos + PCI_EXP_DEVCTL, &devctl);
+		pci_write_config_word(us_dev, pos + PCI_EXP_DEVCTL,
+		                      (devctl & ~PCI_EXP_DEVCTL_CERE));
+
+		pci_set_power_state(pdev, pci_choose_state(pdev, state));
+
+		pci_write_config_word(us_dev, pos + PCI_EXP_DEVCTL, devctl);
+	} else {
+		pci_set_power_state(pdev, pci_choose_state(pdev, state));
+	}
 
 	return 0;
 }