IB/hfi1: Convert PortXmitWait/PortVLXmitWait counters to flit times

HFI's counters SendWaitCnt and SendWaitVlCnt are in units
of TXE cycle time (at 805MHz). OPA counters PortXmitWait and
PortVLXmtWait are in units of flit times.
Convert the counter values to flit units using following
conversion formula:

PortXmitWait =
	SendWaitCnt * 2 * (4 /link_width) * (25 Gbps /link_speed)
PortVLXmitWait =
	SendWaitVLCnt * 2 * (4 /link_width) * (25 Gbps /link_speed)

At link up or downgrade events, the link width can change. To ensure
accurate counter calculations, sample the counters after the events,
during counter requests, and then aggregate the OPA counters.

Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: Kamenee Arumugam <kamenee.arumugam@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

1 files changed, 46 insertions, 1 deletions

diff --git a/drivers/infiniband/hw/hfi1/mad.h b/drivers/infiniband/hw/hfi1/mad.h
index c4938f3d97c8..2f48e6953629 100644
--- a/drivers/infiniband/hw/hfi1/mad.h
+++ b/drivers/infiniband/hw/hfi1/mad.h
@@ -180,6 +180,15 @@ struct opa_mad_notice_attr {
 #define OPA_VLARB_PREEMPT_MATRIX     3
 
 #define IB_PMA_PORT_COUNTERS_CONG       cpu_to_be16(0xFF00)
+#define LINK_SPEED_25G		1
+#define LINK_SPEED_12_5G	2
+#define LINK_WIDTH_DEFAULT	4
+#define DECIMAL_FACTORING	1000
+/*
+ * The default link width is multiplied by 1000
+ * to get accurate value after division.
+ */
+#define FACTOR_LINK_WIDTH	(LINK_WIDTH_DEFAULT * DECIMAL_FACTORING)
 
 struct ib_pma_portcounters_cong {
 	u8 reserved;
@@ -429,5 +438,41 @@ struct sc2vlnt {
 
 void hfi1_event_pkey_change(struct hfi1_devdata *dd, u8 port);
 void hfi1_handle_trap_timer(struct timer_list *t);
-
+u16 tx_link_width(u16 link_width);
+u64 get_xmit_wait_counters(struct hfi1_pportdata *ppd, u16 link_width,
+			   u16 link_speed, int vl);
+/**
+ * get_link_speed - determine whether 12.5G or 25G speed
+ * @link_speed: the speed of active link
+ * @return: Return 2 if link speed identified as 12.5G
+ * or return 1 if link speed is 25G.
+ *
+ * The function indirectly calculate required link speed
+ * value for convert_xmit_counter function. If the link
+ * speed is 25G, the function return as 1 as it is required
+ * by xmit counter conversion formula :-( 25G / link_speed).
+ * This conversion will provide value 1 if current
+ * link speed is 25G or 2 if 12.5G.This is done to avoid
+ * 12.5 float number conversion.
+ */
+static inline u16 get_link_speed(u16 link_speed)
+{
+	return (link_speed == 1) ?
+		 LINK_SPEED_12_5G : LINK_SPEED_25G;
+}
+
+/**
+ * convert_xmit_counter - calculate flit times for given xmit counter
+ * value
+ * @xmit_wait_val: current xmit counter value
+ * @link_width: width of active link
+ * @link_speed: speed of active link
+ * @return: return xmit counter value in flit times.
+ */
+static inline u64 convert_xmit_counter(u64 xmit_wait_val, u16 link_width,
+				       u16 link_speed)
+{
+	return (xmit_wait_val * 2 * (FACTOR_LINK_WIDTH / link_width)
+		 * link_speed) / DECIMAL_FACTORING;
+}
 #endif				/* _HFI1_MAD_H */