fm10k: check if PCIe link is restored

Sometimes, a VF driver will lose PCIe address access, such as due to
a PF FLR event. In fm10k_detach_subtask, poll and check whether the
PCIe register space is active again and restore the device when it has.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Krishneil Singh <Krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Orabug: 25394529
(cherry picked from commit 9d7dbf0604d37f8cae0c6d184a646037636a8b30)
Signed-off-by: Jack Vogel <jack.vogel@oracle.com>

diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_pci.c b/drivers/net/ethernet/intel/fm10k/fm10k_pci.c
index 5d23096cdb22ac11948a417fa983920140fdf847..4751e664ae84839b2029d7de45d4640e25e4c857 100644 (file)
--- a/drivers/net/ethernet/intel/fm10k/fm10k_pci.c
+++ b/drivers/net/ethernet/intel/fm10k/fm10k_pci.c
@@ -123,11 +123,24 @@ static void fm10k_service_timer(unsigned long data)
 static void fm10k_detach_subtask(struct fm10k_intfc *interface)
 {
        struct net_device *netdev = interface->netdev;
+       u32 __iomem *hw_addr;
+       u32 value;
 
        /* do nothing if device is still present or hw_addr is set */
        if (netif_device_present(netdev) || interface->hw.hw_addr)
                return;
 
+       /* check the real address space to see if we've recovered */
+       hw_addr = READ_ONCE(interface->uc_addr);
+       value = readl(hw_addr);
+       if ((~value)) {
+               interface->hw.hw_addr = interface->uc_addr;
+               netif_device_attach(netdev);
+               interface->flags |= FM10K_FLAG_RESET_REQUESTED;
+               netdev_warn(netdev, "PCIe link restored, device now attached\n");
+               return;
+       }
+
        rtnl_lock();
 
        if (netif_running(netdev))