Fix crosslink NTB requester ID issue

It was observed in a crosslink NT setup with two hosts having different
numbers of requester IDs that the traffic can go only in one direction.

In the setup, the switch of host A connects to CPU1, while the switch
of host B connects to CPU0. After loading the driver, the two hosts
have the following requester IDs. And the traffic only goes from B to A.

Host A  -  Host B
0:0.0      0:0.0
80:3.0

When a TLP gose from host A to host B, it first goes from host A CPU to
the local crosslink partition (there are a pair of virtual partitions in
between the two switches in the crosslink NTB setup), with the original
requester ID be replaced with a proxy ID, then be routed to the peer
crosslink partition. If the new requester ID (prxoy ID of the local
crosslink partition) hit one entry in the requester ID table of the peer
crosslink partition, it will finally be routed to Host B. Otherwise, it
will be dropped.

The reason for the above phenomenon is that the driver wrongly registers
the requester IDs to the local crosslink partition, instead of to its
peer. So when the traffic from host A with requester ID reaches the
crosslink partition of host B and hits no entry, it goes nowhere.

This patch fixes this by registering the proper requester IDs to the
peer crosslink partition. Another internal LUT window is allocated for
routing the configuration traffic to the GAS region of the peer
crosslink partition.

Author: kelvin-cao

ntb_hw_switchtec.c

@@ -94,10 +94,12 @@ struct switchtec_ntb {
 	struct ntb_dbmsg_regs __iomem *mmio_dbmsg;
 	struct ntb_ctrl_regs __iomem *mmio_self_ctrl;
 	struct ntb_ctrl_regs __iomem *mmio_peer_ctrl;
+	struct ntb_ctrl_regs __iomem *mmio_xlink_peer_ctrl;
 	struct ntb_dbmsg_regs __iomem *mmio_self_dbmsg;
 	struct ntb_dbmsg_regs __iomem *mmio_peer_dbmsg;
 
 	void __iomem *mmio_xlink_dbmsg_win;
+	void __iomem *mmio_xlink_ctrl_win;
 
 	struct shared_mw *self_shared;
 	struct shared_mw __iomem *peer_shared;
@@ -616,6 +618,9 @@ 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)
@@ -627,6 +632,9 @@ 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;
@@ -1154,7 +1162,9 @@ static int clr_req_ids(struct switchtec_ntb *sndev,
 	return 0;
 }
 
-static int crosslink_setup_mws(struct switchtec_ntb *sndev, int dbmsg_lut_idx,
+static int crosslink_setup_mws(struct switchtec_ntb *sndev,
+			       int ntb_dbmsg_lut_idx,
+			       int ntb_req_id_lut_idx,
 			       u64 *mw_addrs, int mw_count)
 {
 	int rc, i;
@@ -1171,7 +1181,7 @@ static int crosslink_setup_mws(struct switchtec_ntb *sndev, int dbmsg_lut_idx,
 		return rc;
 
 	for (i = 0; i < sndev->nr_lut_mw; i++) {
-		if (i == dbmsg_lut_idx)
+		if (i == ntb_dbmsg_lut_idx || i == ntb_req_id_lut_idx)
 			continue;
 
 		addr = mw_addrs[0] + LUT_SIZE * i;
@@ -1290,6 +1300,7 @@ static int switchtec_ntb_init_crosslink(struct switchtec_ntb *sndev)
 	int rc;
 	int bar = sndev->direct_mw_to_bar[0];
 	const int dbmsg_lut_idx = 1;
+	const int req_id_lut_idx = 2;
 	u64 bar_addrs[6];
 	u64 addr;
 	int offset;
@@ -1320,34 +1331,60 @@ static int switchtec_ntb_init_crosslink(struct switchtec_ntb *sndev)
 	if (rc)
 		return rc;
 
-	rc = crosslink_setup_mws(sndev, dbmsg_lut_idx, &bar_addrs[1],
-				 bar_cnt - 1);
-	if (rc)
+	sndev->mmio_xlink_dbmsg_win = pci_iomap_range(sndev->stdev->pdev, bar,
+						      dbmsg_lut_idx * LUT_SIZE,
+						      LUT_SIZE);
+	if (!sndev->mmio_xlink_dbmsg_win) {
+		rc = -ENOMEM;
 		return rc;
+	}
+
+	sndev->mmio_peer_dbmsg = sndev->mmio_xlink_dbmsg_win + offset;
+	sndev->nr_rsvd_luts++;
+
+	addr = (bar_addrs[0] + SWITCHTEC_GAS_NTB_OFFSET +
+		SWITCHTEC_NTB_REG_CTRL_OFFSET +
+		sizeof(struct ntb_ctrl_regs) * sndev->peer_partition);
+
+	offset = addr & (LUT_SIZE - 1);
+	addr -= offset;
 
-	rc = crosslink_setup_req_ids(sndev, sndev->mmio_peer_ctrl);
+	rc = config_rsvd_lut_win(sndev, sndev->mmio_self_ctrl,
+				 req_id_lut_idx,
+				 sndev->peer_partition, addr);
 	if (rc)
 		return rc;
 
-	sndev->mmio_xlink_dbmsg_win = pci_iomap_range(sndev->stdev->pdev, bar,
-						      LUT_SIZE, LUT_SIZE);
-	if (!sndev->mmio_xlink_dbmsg_win) {
+	sndev->mmio_xlink_ctrl_win = pci_iomap_range(sndev->stdev->pdev, bar,
+						     req_id_lut_idx * LUT_SIZE,
+						     LUT_SIZE);
+	if (!sndev->mmio_xlink_ctrl_win) {
 		rc = -ENOMEM;
 		return rc;
 	}
 
-	sndev->mmio_peer_dbmsg = sndev->mmio_xlink_dbmsg_win + offset;
+	sndev->mmio_xlink_peer_ctrl = sndev->mmio_xlink_ctrl_win + offset;
 	sndev->nr_rsvd_luts++;
 
+	rc = crosslink_setup_mws(sndev, dbmsg_lut_idx, req_id_lut_idx,
+				 &bar_addrs[1], bar_cnt - 1);
+	if (rc)
+		return rc;
+
 	crosslink_init_dbmsgs(sndev);
 
+	crosslink_setup_req_ids(sndev, sndev->mmio_xlink_peer_ctrl);
+
 	return 0;
 }
 
 static void switchtec_ntb_deinit_crosslink(struct switchtec_ntb *sndev)
 {
 	if (sndev->mmio_xlink_dbmsg_win)
 		pci_iounmap(sndev->stdev->pdev, sndev->mmio_xlink_dbmsg_win);
+
+	if (sndev->mmio_xlink_ctrl_win)
+		pci_iounmap(sndev->stdev->pdev, sndev->mmio_xlink_ctrl_win);
 }
 
 static int map_bars(int *map, struct ntb_ctrl_regs __iomem *ctrl)
@@ -1659,7 +1696,8 @@ static ssize_t add_requester_id_store(struct device *dev,
 		return rc;
 
 	if (crosslink_is_enabled(sndev)) {
-		rc = crosslink_setup_req_ids(sndev, sndev->mmio_peer_ctrl);
+		rc = crosslink_setup_req_ids(sndev,
+					     sndev->mmio_xlink_peer_ctrl);
 		if (rc)
 			return rc;
 	}
@@ -1687,7 +1725,8 @@ static ssize_t del_requester_id_store(struct device *dev,
 		return rc;
 
 	if (crosslink_is_enabled(sndev)) {
-		rc = crosslink_setup_req_ids(sndev, sndev->mmio_peer_ctrl);
+		rc = crosslink_setup_req_ids(sndev,
+					     sndev->mmio_xlink_peer_ctrl);
 		if (rc)
 			return rc;
 	}