NTB: Enable link up and down event notification

Link-Up and Link-Down events can occur irrespective
of whether a data transfer is in progress or not.
So we need to enable the interrupt delivery for
these events early during driver load.
Signed-off-by: Arindam Nath <arindam.nath@amd.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>

drivers/ntb/hw/amd/ntb_hw_amd.c

@@ -994,6 +994,7 @@ static enum ntb_topo amd_get_topo(struct amd_ntb_dev *ndev)
 
 static int amd_init_dev(struct amd_ntb_dev *ndev)
 {
+	void __iomem *mmio = ndev->self_mmio;
 	struct pci_dev *pdev;
 	int rc = 0;
 
@@ -1015,6 +1016,10 @@ static int amd_init_dev(struct amd_ntb_dev *ndev)
 
 	ndev->db_valid_mask = BIT_ULL(ndev->db_count) - 1;
 
+	/* Enable Link-Up and Link-Down event interrupts */
+	ndev->int_mask &= ~(AMD_LINK_UP_EVENT | AMD_LINK_DOWN_EVENT);
+	writel(ndev->int_mask, mmio + AMD_INTMASK_OFFSET);
+
 	return 0;
 }