bnxt_en: Fix PCI AER error recovery flow

[ Upstream commit df3875ec ]

When a PCI error is detected the PCI state could be corrupt, save
the PCI state after initialization and restore it after the slot
reset.

Fixes: 6316ea6d ("bnxt_en: Enable AER support.")
Signed-off-by: Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -7085,6 +7085,7 @@ static int bnxt_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	bnxt_parse_log_pcie_link(bp);
 
+	pci_save_state(pdev);
 	return 0;
 
 init_err:
@@ -7158,6 +7159,8 @@ static pci_ers_result_t bnxt_io_slot_reset(struct pci_dev *pdev)
 			"Cannot re-enable PCI device after reset.\n");
 	} else {
 		pci_set_master(pdev);
+		pci_restore_state(pdev);
+		pci_save_state(pdev);
 
 		if (netif_running(netdev))
 			err = bnxt_open(netdev);