IB: simplify static rate encoding

Push translation of static rate to HCA format into low-level drivers,
where it belongs.  For static rate encoding, use encoding of rate
field from IB standard PathRecord, with addition of value 0, for
backwards compatibility with current usage.  The changes are:

 - Add enum ib_rate to midlayer includes.
 - Get rid of static rate translation in IPoIB; just use static rate
   directly from Path and MulticastGroup records.
 - Update mthca driver to translate absolute static rate into the
   format used by hardware.  This also fixes mthca's static rate
   handling for HCAs that are capable of 4X DDR.

Signed-off-by: Jack Morgenstein <jackm@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 99 insertions, 1 deletions

diff --git a/drivers/infiniband/hw/mthca/mthca_av.c b/drivers/infiniband/hw/mthca/mthca_av.c
index bc5bdcbe51b..b12aa03be25 100644
--- a/drivers/infiniband/hw/mthca/mthca_av.c
+++ b/drivers/infiniband/hw/mthca/mthca_av.c
@@ -42,6 +42,20 @@
 
 #include "mthca_dev.h"
 
+enum {
+      MTHCA_RATE_TAVOR_FULL   = 0,
+      MTHCA_RATE_TAVOR_1X     = 1,
+      MTHCA_RATE_TAVOR_4X     = 2,
+      MTHCA_RATE_TAVOR_1X_DDR = 3
+};
+
+enum {
+      MTHCA_RATE_MEMFREE_FULL    = 0,
+      MTHCA_RATE_MEMFREE_QUARTER = 1,
+      MTHCA_RATE_MEMFREE_EIGHTH  = 2,
+      MTHCA_RATE_MEMFREE_HALF    = 3
+};
+
 struct mthca_av {
 	__be32 port_pd;
 	u8     reserved1;
@@ -55,6 +69,90 @@ struct mthca_av {
 	__be32 dgid[4];
 };
 
+static enum ib_rate memfree_rate_to_ib(u8 mthca_rate, u8 port_rate)
+{
+	switch (mthca_rate) {
+	case MTHCA_RATE_MEMFREE_EIGHTH:
+		return mult_to_ib_rate(port_rate >> 3);
+	case MTHCA_RATE_MEMFREE_QUARTER:
+		return mult_to_ib_rate(port_rate >> 2);
+	case MTHCA_RATE_MEMFREE_HALF:
+		return mult_to_ib_rate(port_rate >> 1);
+	case MTHCA_RATE_MEMFREE_FULL:
+	default:
+		return mult_to_ib_rate(port_rate);
+	}
+}
+
+static enum ib_rate tavor_rate_to_ib(u8 mthca_rate, u8 port_rate)
+{
+	switch (mthca_rate) {
+	case MTHCA_RATE_TAVOR_1X:     return IB_RATE_2_5_GBPS;
+	case MTHCA_RATE_TAVOR_1X_DDR: return IB_RATE_5_GBPS;
+	case MTHCA_RATE_TAVOR_4X:     return IB_RATE_10_GBPS;
+	default:		      return port_rate;
+	}
+}
+
+enum ib_rate mthca_rate_to_ib(struct mthca_dev *dev, u8 mthca_rate, u8 port)
+{
+	if (mthca_is_memfree(dev)) {
+		/* Handle old Arbel FW */
+		if (dev->limits.stat_rate_support == 0x3 && mthca_rate)
+			return IB_RATE_2_5_GBPS;
+
+		return memfree_rate_to_ib(mthca_rate, dev->rate[port - 1]);
+	} else
+		return tavor_rate_to_ib(mthca_rate, dev->rate[port - 1]);
+}
+
+static u8 ib_rate_to_memfree(u8 req_rate, u8 cur_rate)
+{
+	if (cur_rate <= req_rate)
+		return 0;
+
+	/*
+	 * Inter-packet delay (IPD) to get from rate X down to a rate
+	 * no more than Y is (X - 1) / Y.
+	 */
+	switch ((cur_rate - 1) / req_rate) {
+	case 0:	 return MTHCA_RATE_MEMFREE_FULL;
+	case 1:	 return MTHCA_RATE_MEMFREE_HALF;
+	case 2:	 /* fall through */
+	case 3:	 return MTHCA_RATE_MEMFREE_QUARTER;
+	default: return MTHCA_RATE_MEMFREE_EIGHTH;
+	}
+}
+
+static u8 ib_rate_to_tavor(u8 static_rate)
+{
+	switch (static_rate) {
+	case IB_RATE_2_5_GBPS: return MTHCA_RATE_TAVOR_1X;
+	case IB_RATE_5_GBPS:   return MTHCA_RATE_TAVOR_1X_DDR;
+	case IB_RATE_10_GBPS:  return MTHCA_RATE_TAVOR_4X;
+	default:	       return MTHCA_RATE_TAVOR_FULL;
+	}
+}
+
+u8 mthca_get_rate(struct mthca_dev *dev, int static_rate, u8 port)
+{
+	u8 rate;
+
+	if (!static_rate || ib_rate_to_mult(static_rate) >= dev->rate[port - 1])
+		return 0;
+
+	if (mthca_is_memfree(dev))
+		rate = ib_rate_to_memfree(ib_rate_to_mult(static_rate),
+					  dev->rate[port - 1]);
+	else
+		rate = ib_rate_to_tavor(static_rate);
+
+	if (!(dev->limits.stat_rate_support & (1 << rate)))
+		rate = 1;
+
+	return rate;
+}
+
 int mthca_create_ah(struct mthca_dev *dev,
 		    struct mthca_pd *pd,
 		    struct ib_ah_attr *ah_attr,
@@ -107,7 +205,7 @@ on_hca_fail:
 	av->g_slid  = ah_attr->src_path_bits;
 	av->dlid    = cpu_to_be16(ah_attr->dlid);
 	av->msg_sr  = (3 << 4) | /* 2K message */
-		ah_attr->static_rate;
+		mthca_get_rate(dev, ah_attr->static_rate, ah_attr->port_num);
 	av->sl_tclass_flowlabel = cpu_to_be32(ah_attr->sl << 28);
 	if (ah_attr->ah_flags & IB_AH_GRH) {
 		av->g_slid |= 0x80;