NTB: Alter Scratchpads API to support multi-ports devices

Even though there is no any real NTB hardware, which would have both more
than two ports and Scratchpad registers, it is logically correct to have
Scratchpad API accepting a peer port index as well. Intel/AMD drivers utilize
Primary and Secondary topology to split Scratchpad between connected root
devices. Since port-index API introduced, Intel/AMD NTB hardware drivers can
use device port to determine which Scratchpad registers actually belong to
local and peer devices. The same approach can be used if some potential
hardware in future will be multi-port and have some set of Scratchpads.
Here are the brief of changes in the API:
 ntb_spad_count() - return number of Scratchpads per each port
 ntb_peer_spad_addr(pidx, sidx) - address of Scratchpad register of the
peer device with pidx-index
 ntb_peer_spad_read(pidx, sidx) - read specified Scratchpad register of the
peer with pidx-index
 ntb_peer_spad_write(pidx, sidx) - write data to Scratchpad register of the
peer with pidx-index

Since there is hardware which doesn't support Scratchpad registers, the
corresponding API methods are now made optional.

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
Acked-by: Allen Hubbe <Allen.Hubbe@dell.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>

1 files changed, 7 insertions, 8 deletions

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index 771b469cebf0..9a03c5871efe 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -862,17 +862,17 @@ static void ntb_transport_link_work(struct work_struct *work)
 			size = max_mw_size;
 
 		spad = MW0_SZ_HIGH + (i * 2);
-		ntb_peer_spad_write(ndev, spad, upper_32_bits(size));
+		ntb_peer_spad_write(ndev, PIDX, spad, upper_32_bits(size));
 
 		spad = MW0_SZ_LOW + (i * 2);
-		ntb_peer_spad_write(ndev, spad, lower_32_bits(size));
+		ntb_peer_spad_write(ndev, PIDX, spad, lower_32_bits(size));
 	}
 
-	ntb_peer_spad_write(ndev, NUM_MWS, nt->mw_count);
+	ntb_peer_spad_write(ndev, PIDX, NUM_MWS, nt->mw_count);
 
-	ntb_peer_spad_write(ndev, NUM_QPS, nt->qp_count);
+	ntb_peer_spad_write(ndev, PIDX, NUM_QPS, nt->qp_count);
 
-	ntb_peer_spad_write(ndev, VERSION, NTB_TRANSPORT_VERSION);
+	ntb_peer_spad_write(ndev, PIDX, VERSION, NTB_TRANSPORT_VERSION);
 
 	/* Query the remote side for its info */
 	val = ntb_spad_read(ndev, VERSION);
@@ -948,7 +948,7 @@ static void ntb_qp_link_work(struct work_struct *work)
 
 	val = ntb_spad_read(nt->ndev, QP_LINKS);
 
-	ntb_peer_spad_write(nt->ndev, QP_LINKS, val | BIT(qp->qp_num));
+	ntb_peer_spad_write(nt->ndev, PIDX, QP_LINKS, val | BIT(qp->qp_num));
 
 	/* query remote spad for qp ready bits */
 	dev_dbg_ratelimited(&pdev->dev, "Remote QP link status = %x\n", val);
@@ -2108,8 +2108,7 @@ void ntb_transport_link_down(struct ntb_transport_qp *qp)
 
 	val = ntb_spad_read(qp->ndev, QP_LINKS);
 
-	ntb_peer_spad_write(qp->ndev, QP_LINKS,
-			    val & ~BIT(qp->qp_num));
+	ntb_peer_spad_write(qp->ndev, PIDX, QP_LINKS, val & ~BIT(qp->qp_num));
 
 	if (qp->link_is_up)
 		ntb_send_link_down(qp);