Fix a crosslink target partition configuration issue

The remote crosslink partition needs to have its outbound message mapped
to the remote host partition which connects to the remote NT host, so
that when a message from the local switch hits the remote crosslink
partition, it can be forwarded to the remote host. Program the remote
host partition ID into the corresponding message registers of the remote
crosslink partition.

Author: kelvin-cao

ntb_hw_switchtec.c

@@ -566,23 +566,59 @@ static int crosslink_is_enabled(struct switchtec_ntb *sndev)
 	return ioread8(&inf->ntp_info[sndev->peer_partition].xlink_enabled);
 }
 
-static void crosslink_init_dbmsgs(struct switchtec_ntb *sndev)
+static int crosslink_init_dbmsgs(struct switchtec_ntb *sndev)
 {
 	int i;
+	u64 tpart_vec;
+	u64 part_map;
+	struct ntb_info_regs *xlink_ntb = sndev->mmio_xlink_peer_ntb;
+	int xlink_self, xlink_peer;
 	u32 msg_map = 0;
 
 	if (!crosslink_is_enabled(sndev))
-		return;
+		return 0;
+
+	xlink_peer = ioread8(&xlink_ntb->partition_id);
+	if (xlink_peer == 0xFF)
+		return -EIO;
+
+	tpart_vec = ioread32(&xlink_ntb->ntp_info[xlink_peer].target_part_high);
+	tpart_vec <<= 32;
+	tpart_vec |= ioread32(&xlink_ntb->ntp_info[xlink_peer].target_part_low);
+	part_map = ioread32(&xlink_ntb->ep_map_high);
+	part_map <<= 32;
+	part_map |= ioread32(&xlink_ntb->ep_map_low);
+	part_map &= ~(1 << xlink_peer);
+	tpart_vec &= part_map;
+
+	if (!tpart_vec) {
+		dev_err(&sndev->stdev->dev,
+			"Remote crosslink partition has no NT target defined\n");
+		return -ENODEV;
+	}
+
+	if (__ffs64(tpart_vec) != (fls64(tpart_vec) - 1)) {
+		dev_err(&sndev->stdev->dev,
+			"Remote crosslink partition has more than 1 NT target\n");
+		return -ENODEV;
+	}
+
+	xlink_self = __ffs64(tpart_vec);
+
+	dev_dbg(&sndev->stdev->dev,
+		"Remote self %d, peer %d\n", xlink_self, xlink_peer);
 
 	for (i = 0; i < ARRAY_SIZE(sndev->mmio_peer_dbmsg->imsg); i++) {
-		int m = i | sndev->self_partition << 2;
+		int m = i | xlink_self << 2;
 
 		msg_map |= m << i * 8;
 	}
 
 	iowrite32(msg_map, &sndev->mmio_peer_dbmsg->msg_map);
 	iowrite64(sndev->db_valid_mask << sndev->db_peer_shift,
 		  &sndev->mmio_peer_dbmsg->odb_mask);
+
+	return 0;
 }
 
 enum switchtec_msg {