From ba6d39256bed87a0e8ee1770b5f7638bb3e0cfe4 Mon Sep 17 00:00:00 2001
From: Steve Wise <swise@opengridcomputing.com>
Date: Wed, 23 Jun 2010 15:46:49 +0000
Subject: RDMA/cxgb4: Add module option to tweak delayed ack

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

diff --git a/drivers/infiniband/hw/cxgb4/cm.c b/drivers/infiniband/hw/cxgb4/cm.c
index 4185c3b..e7b08dc 100644
--- a/drivers/infiniband/hw/cxgb4/cm.c
+++ b/drivers/infiniband/hw/cxgb4/cm.c
@@ -61,6 +61,10 @@ static char *states[] = {
 	NULL,
 };
 
+static int dack_mode;
+module_param(dack_mode, int, 0644);
+MODULE_PARM_DESC(dack_mode, "Delayed ack mode (default=0)");
+
 int c4iw_max_read_depth = 8;
 module_param(c4iw_max_read_depth, int, 0644);
 MODULE_PARM_DESC(c4iw_max_read_depth, "Per-connection max ORD/IRD (default=8)");
@@ -474,6 +478,7 @@ static int send_connect(struct c4iw_ep *ep)
 	cxgb4_best_mtu(ep->com.dev->rdev.lldi.mtus, ep->mtu, &mtu_idx);
 	wscale = compute_wscale(rcv_win);
 	opt0 = KEEP_ALIVE(1) |
+	       DELACK(1) |
 	       WND_SCALE(wscale) |
 	       MSS_IDX(mtu_idx) |
 	       L2T_IDX(ep->l2t->idx) |
@@ -845,7 +850,9 @@ static int update_rx_credits(struct c4iw_ep *ep, u32 credits)
 	INIT_TP_WR(req, ep->hwtid);
 	OPCODE_TID(req) = cpu_to_be32(MK_OPCODE_TID(CPL_RX_DATA_ACK,
 						    ep->hwtid));
-	req->credit_dack = cpu_to_be32(credits);
+	req->credit_dack = cpu_to_be32(credits | RX_FORCE_ACK(1) |
+				       F_RX_DACK_CHANGE |
+				       V_RX_DACK_MODE(dack_mode));
 	set_wr_txq(skb, CPL_PRIORITY_ACK, ep->txq_idx);
 	c4iw_ofld_send(&ep->com.dev->rdev, skb);
 	return credits;
@@ -1264,6 +1271,7 @@ static void accept_cr(struct c4iw_ep *ep, __be32 peer_ip, struct sk_buff *skb,
 	cxgb4_best_mtu(ep->com.dev->rdev.lldi.mtus, ep->mtu, &mtu_idx);
 	wscale = compute_wscale(rcv_win);
 	opt0 = KEEP_ALIVE(1) |
+	       DELACK(1) |
 	       WND_SCALE(wscale) |
 	       MSS_IDX(mtu_idx) |
 	       L2T_IDX(ep->l2t->idx) |
diff --git a/drivers/infiniband/hw/cxgb4/t4fw_ri_api.h b/drivers/infiniband/hw/cxgb4/t4fw_ri_api.h
index fc706bd..dc193c2 100644
--- a/drivers/infiniband/hw/cxgb4/t4fw_ri_api.h
+++ b/drivers/infiniband/hw/cxgb4/t4fw_ri_api.h
@@ -826,4 +826,14 @@ struct ulptx_idata {
 #define S_ULPTX_NSGE    0
 #define M_ULPTX_NSGE    0xFFFF
 #define V_ULPTX_NSGE(x) ((x) << S_ULPTX_NSGE)
+
+#define S_RX_DACK_MODE    29
+#define M_RX_DACK_MODE    0x3
+#define V_RX_DACK_MODE(x) ((x) << S_RX_DACK_MODE)
+#define G_RX_DACK_MODE(x) (((x) >> S_RX_DACK_MODE) & M_RX_DACK_MODE)
+
+#define S_RX_DACK_CHANGE    31
+#define V_RX_DACK_CHANGE(x) ((x) << S_RX_DACK_CHANGE)
+#define F_RX_DACK_CHANGE    V_RX_DACK_CHANGE(1U)
+
 #endif /* _T4FW_RI_API_H_ */
-- 
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