Setup crosslink requester IDs when updating link status

When accessing the peer status for link status update, we need to setup
the crosslink requester IDs first to ensure we have access to the peer
status.

Earlier crosslink requester IDs setup during device initialization or
link enabling can fail because the peer switch may not in a good state
or the link to the peer switch may not be well connected at the moment.

Therefore, we add the requester IDs setup during link status update
which could be triggered by a peer link up event at which the peer
switch and the connection to the peer switch must be in a good state.

For more background about the requester IDs setup, please refer to
commit fd0edee.

Author: kelvin-cao

ntb_hw_switchtec.c

@@ -588,14 +588,21 @@ enum switchtec_msg {
 
 static int switchtec_ntb_reinit_peer(struct switchtec_ntb *sndev);
 
+static int crosslink_setup_req_ids(struct switchtec_ntb *sndev,
+		struct ntb_ctrl_regs __iomem *mmio_ctrl);
+
 static void switchtec_ntb_link_status_update(struct switchtec_ntb *sndev)
 {
 	int link_sta;
 	int old = sndev->link_is_up;
+	u64 peer;
 
 	link_sta = sndev->self_shared->link_sta;
 	if (link_sta) {
-		u64 peer = ioread64(&sndev->peer_shared->magic);
+		if (!sndev->link_is_up && crosslink_is_enabled(sndev))
+			crosslink_setup_req_ids(sndev, sndev->mmio_xlink_peer_ctrl);
+
+		peer = ioread64(&sndev->peer_shared->magic);
 
 		if ((peer & 0xFFFFFFFF) == SWITCHTEC_NTB_MAGIC)
 			link_sta = peer >> 32;
@@ -670,9 +677,6 @@ static u64 switchtec_ntb_link_is_up(struct ntb_dev *ntb,
 	return sndev->link_is_up;
 }
 
-static int crosslink_setup_req_ids(struct switchtec_ntb *sndev,
-	struct ntb_ctrl_regs __iomem *mmio_ctrl);
-
 static int switchtec_ntb_link_enable(struct ntb_dev *ntb,
 				     enum ntb_speed max_speed,
 				     enum ntb_width max_width)
@@ -684,9 +688,6 @@ static int switchtec_ntb_link_enable(struct ntb_dev *ntb,
 	sndev->self_shared->link_sta = 1;
 	switchtec_ntb_send_msg(sndev, LINK_MESSAGE, MSG_LINK_UP);
 
-	if (crosslink_is_enabled(sndev))
-		crosslink_setup_req_ids(sndev, sndev->mmio_xlink_peer_ctrl);
-
 	switchtec_ntb_link_status_update(sndev);
 
 	return 0;