be2net: set interrupt moderation for Skyhawk-R using EQ-DB

Currently adaptive interrupt moderation is set by calculating
and configuring an EQ-delay every second. This is done via
a FW-cmd. But, on Skyhawk-R a "re-arm to interrupt" delay
can be set while ringing the EQ-DB. This patch uses this
facility to calculate and set the interrupt delay every 1ms.
This helps moderating interrupts better when the traffic
is bursty.

Signed-off-by: Padmanabh Ratnakar <padmanabh.ratnakar@avagotech.com>
Signed-off-by: Sathya Perla <sathya.perla@avagotech.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/emulex/benet/be.h

@@ -805,6 +805,7 @@ bool be_pause_supported(struct be_adapter *adapter);
 u32 be_get_fw_log_level(struct be_adapter *adapter);
 int be_update_queues(struct be_adapter *adapter);
 int be_poll(struct napi_struct *napi, int budget);
+void be_eqd_update(struct be_adapter *adapter, bool force_update);
 
 /*
  * internal function to initialize-cleanup roce device.

drivers/net/ethernet/emulex/benet/be_ethtool.c

@@ -368,6 +368,14 @@ static int be_set_coalesce(struct net_device *netdev,
 		aic++;
 	}
 
+	/* For Skyhawk, the EQD setting happens via EQ_DB when AIC is enabled.
+	 * When AIC is disabled, persistently force set EQD value via the
+	 * FW cmd, so that we don't have to calculate the delay multiplier
+	 * encode value each time EQ_DB is rung
+	 */
+	if (!et->use_adaptive_rx_coalesce && skyhawk_chip(adapter))
+		be_eqd_update(adapter, true);
+
 	return 0;
 }
 

drivers/net/ethernet/emulex/benet/be_hw.h

@@ -132,6 +132,18 @@
 #define DB_EQ_NUM_POPPED_SHIFT		(16)	/* bits 16 - 28 */
 /* Rearm bit */
 #define DB_EQ_REARM_SHIFT		(29)	/* bit 29 */
+/* Rearm to interrupt delay encoding */
+#define DB_EQ_R2I_DLY_SHIFT		(30)    /* bits 30 - 31 */
+
+/* Rearm to interrupt (R2I) delay multiplier encoding represents 3 different
+ * values configured in CEV_REARM2IRPT_DLY_MULT_CSR register. This value is
+ * programmed by host driver while ringing an EQ doorbell(EQ_DB) if a delay
+ * between rearming the EQ and next interrupt on this EQ is desired.
+ */
+#define	R2I_DLY_ENC_0			0	/* No delay */
+#define	R2I_DLY_ENC_1			1	/* maps to 160us EQ delay */
+#define	R2I_DLY_ENC_2			2	/* maps to 96us EQ delay */
+#define	R2I_DLY_ENC_3			3	/* maps to 48us EQ delay */
 
 /********* Compl Q door bell *************/
 #define DB_CQ_OFFSET 			0x120

drivers/net/ethernet/emulex/benet/be_main.c

@@ -211,7 +211,8 @@ static void be_txq_notify(struct be_adapter *adapter, struct be_tx_obj *txo,
 }
 
 static void be_eq_notify(struct be_adapter *adapter, u16 qid,
-			 bool arm, bool clear_int, u16 num_popped)
+			 bool arm, bool clear_int, u16 num_popped,
+			 u32 eq_delay_mult_enc)
 {
 	u32 val = 0;
 
@@ -227,6 +228,7 @@ static void be_eq_notify(struct be_adapter *adapter, u16 qid,
 		val |= 1 << DB_EQ_CLR_SHIFT;
 	val |= 1 << DB_EQ_EVNT_SHIFT;
 	val |= num_popped << DB_EQ_NUM_POPPED_SHIFT;
+	val |= eq_delay_mult_enc << DB_EQ_R2I_DLY_SHIFT;
 	iowrite32(val, adapter->db + DB_EQ_OFFSET);
 }
 
@@ -1686,61 +1688,110 @@ static void be_aic_update(struct be_aic_obj *aic, u64 rx_pkts, u64 tx_pkts,
 	aic->jiffies = now;
 }
 
-static void be_eqd_update(struct be_adapter *adapter)
+static int be_get_new_eqd(struct be_eq_obj *eqo)
 {
-	struct be_set_eqd set_eqd[MAX_EVT_QS];
+	struct be_adapter *adapter = eqo->adapter;
-	int eqd, i, num = 0, start;
+	int eqd, start;
 	struct be_aic_obj *aic;
-	struct be_eq_obj *eqo;
 	struct be_rx_obj *rxo;
 	struct be_tx_obj *txo;
-	u64 rx_pkts, tx_pkts;
+	u64 rx_pkts = 0, tx_pkts = 0;
 	ulong now;
 	u32 pps, delta;
+	int i;
+
+	aic = &adapter->aic_obj[eqo->idx];
+	if (!aic->enable) {
+		if (aic->jiffies)
+			aic->jiffies = 0;
+		eqd = aic->et_eqd;
+		return eqd;
+	}
+
+	for_all_rx_queues_on_eq(adapter, eqo, rxo, i) {
+		do {
+			start = u64_stats_fetch_begin_irq(&rxo->stats.sync);
+			rx_pkts += rxo->stats.rx_pkts;
+		} while (u64_stats_fetch_retry_irq(&rxo->stats.sync, start));
+	}
+
+	for_all_tx_queues_on_eq(adapter, eqo, txo, i) {
+		do {
+			start = u64_stats_fetch_begin_irq(&txo->stats.sync);
+			tx_pkts += txo->stats.tx_reqs;
+		} while (u64_stats_fetch_retry_irq(&txo->stats.sync, start));
+	}
+
+	/* Skip, if wrapped around or first calculation */
+	now = jiffies;
+	if (!aic->jiffies || time_before(now, aic->jiffies) ||
+	    rx_pkts < aic->rx_pkts_prev ||
+	    tx_pkts < aic->tx_reqs_prev) {
+		be_aic_update(aic, rx_pkts, tx_pkts, now);
+		return aic->prev_eqd;
+	}
+
+	delta = jiffies_to_msecs(now - aic->jiffies);
+	if (delta == 0)
+		return aic->prev_eqd;
+
+	pps = (((u32)(rx_pkts - aic->rx_pkts_prev) * 1000) / delta) +
+		(((u32)(tx_pkts - aic->tx_reqs_prev) * 1000) / delta);
+	eqd = (pps / 15000) << 2;
+
+	if (eqd < 8)
+		eqd = 0;
+	eqd = min_t(u32, eqd, aic->max_eqd);
+	eqd = max_t(u32, eqd, aic->min_eqd);
+
+	be_aic_update(aic, rx_pkts, tx_pkts, now);
+
+	return eqd;
+}
+
+/* For Skyhawk-R only */
+static u32 be_get_eq_delay_mult_enc(struct be_eq_obj *eqo)
+{
+	struct be_adapter *adapter = eqo->adapter;
+	struct be_aic_obj *aic = &adapter->aic_obj[eqo->idx];
+	ulong now = jiffies;
+	int eqd;
+	u32 mult_enc;
+
+	if (!aic->enable)
+		return 0;
+
+	if (time_before_eq(now, aic->jiffies) ||
+	    jiffies_to_msecs(now - aic->jiffies) < 1)
+		eqd = aic->prev_eqd;
+	else
+		eqd = be_get_new_eqd(eqo);
+
+	if (eqd > 100)
+		mult_enc = R2I_DLY_ENC_1;
+	else if (eqd > 60)
+		mult_enc = R2I_DLY_ENC_2;
+	else if (eqd > 20)
+		mult_enc = R2I_DLY_ENC_3;
+	else
+		mult_enc = R2I_DLY_ENC_0;
+
+	aic->prev_eqd = eqd;
+
+	return mult_enc;
+}
+
+void be_eqd_update(struct be_adapter *adapter, bool force_update)
+{
+	struct be_set_eqd set_eqd[MAX_EVT_QS];
+	struct be_aic_obj *aic;
+	struct be_eq_obj *eqo;
+	int i, num = 0, eqd;
 
 	for_all_evt_queues(adapter, eqo, i) {
 		aic = &adapter->aic_obj[eqo->idx];
-		if (!aic->enable) {
+		eqd = be_get_new_eqd(eqo);
-			if (aic->jiffies)
+		if (force_update || eqd != aic->prev_eqd) {
-				aic->jiffies = 0;
-			eqd = aic->et_eqd;
-			goto modify_eqd;
-		}
-
-		rxo = &adapter->rx_obj[eqo->idx];
-		do {
-			start = u64_stats_fetch_begin_irq(&rxo->stats.sync);
-			rx_pkts = rxo->stats.rx_pkts;
-		} while (u64_stats_fetch_retry_irq(&rxo->stats.sync, start));
-
-		txo = &adapter->tx_obj[eqo->idx];
-		do {
-			start = u64_stats_fetch_begin_irq(&txo->stats.sync);
-			tx_pkts = txo->stats.tx_reqs;
-		} while (u64_stats_fetch_retry_irq(&txo->stats.sync, start));
-
-		/* Skip, if wrapped around or first calculation */
-		now = jiffies;
-		if (!aic->jiffies || time_before(now, aic->jiffies) ||
-		    rx_pkts < aic->rx_pkts_prev ||
-		    tx_pkts < aic->tx_reqs_prev) {
-			be_aic_update(aic, rx_pkts, tx_pkts, now);
-			continue;
-		}
-
-		delta = jiffies_to_msecs(now - aic->jiffies);
-		pps = (((u32)(rx_pkts - aic->rx_pkts_prev) * 1000) / delta) +
-			(((u32)(tx_pkts - aic->tx_reqs_prev) * 1000) / delta);
-		eqd = (pps / 15000) << 2;
-
-		if (eqd < 8)
-			eqd = 0;
-		eqd = min_t(u32, eqd, aic->max_eqd);
-		eqd = max_t(u32, eqd, aic->min_eqd);
-
-		be_aic_update(aic, rx_pkts, tx_pkts, now);
-modify_eqd:
-		if (eqd != aic->prev_eqd) {
 			set_eqd[num].delay_multiplier = (eqd * 65)/100;
 			set_eqd[num].eq_id = eqo->q.id;
 			aic->prev_eqd = eqd;
@@ -2248,7 +2299,7 @@ static void be_eq_clean(struct be_eq_obj *eqo)
 {
 	int num = events_get(eqo);
 
-	be_eq_notify(eqo->adapter, eqo->q.id, false, true, num);
+	be_eq_notify(eqo->adapter, eqo->q.id, false, true, num, 0);
 }
 
 static void be_rx_cq_clean(struct be_rx_obj *rxo)
@@ -2609,7 +2660,7 @@ static irqreturn_t be_intx(int irq, void *dev)
 		if (num_evts)
 			eqo->spurious_intr = 0;
 	}
-	be_eq_notify(adapter, eqo->q.id, false, true, num_evts);
+	be_eq_notify(adapter, eqo->q.id, false, true, num_evts, 0);
 
 	/* Return IRQ_HANDLED only for the the first spurious intr
 	 * after a valid intr to stop the kernel from branding
@@ -2625,7 +2676,7 @@ static irqreturn_t be_msix(int irq, void *dev)
 {
 	struct be_eq_obj *eqo = dev;
 
-	be_eq_notify(eqo->adapter, eqo->q.id, false, true, 0);
+	be_eq_notify(eqo->adapter, eqo->q.id, false, true, 0, 0);
 	napi_schedule(&eqo->napi);
 	return IRQ_HANDLED;
 }
@@ -2874,6 +2925,7 @@ int be_poll(struct napi_struct *napi, int budget)
 	int max_work = 0, work, i, num_evts;
 	struct be_rx_obj *rxo;
 	struct be_tx_obj *txo;
+	u32 mult_enc = 0;
 
 	num_evts = events_get(eqo);
 
@@ -2899,10 +2951,18 @@ int be_poll(struct napi_struct *napi, int budget)
 
 	if (max_work < budget) {
 		napi_complete(napi);
-		be_eq_notify(adapter, eqo->q.id, true, false, num_evts);
+
+		/* Skyhawk EQ_DB has a provision to set the rearm to interrupt
+		 * delay via a delay multiplier encoding value
+		 */
+		if (skyhawk_chip(adapter))
+			mult_enc = be_get_eq_delay_mult_enc(eqo);
+
+		be_eq_notify(adapter, eqo->q.id, true, false, num_evts,
+			     mult_enc);
 	} else {
 		/* As we'll continue in polling mode, count and clear events */
-		be_eq_notify(adapter, eqo->q.id, false, false, num_evts);
+		be_eq_notify(adapter, eqo->q.id, false, false, num_evts, 0);
 	}
 	return max_work;
 }
@@ -3299,7 +3359,7 @@ static int be_open(struct net_device *netdev)
 	for_all_evt_queues(adapter, eqo, i) {
 		napi_enable(&eqo->napi);
 		be_enable_busy_poll(eqo);
-		be_eq_notify(adapter, eqo->q.id, true, true, 0);
+		be_eq_notify(adapter, eqo->q.id, true, true, 0, 0);
 	}
 	adapter->flags |= BE_FLAGS_NAPI_ENABLED;
 
@@ -4225,7 +4285,7 @@ static void be_netpoll(struct net_device *netdev)
 	int i;
 
 	for_all_evt_queues(adapter, eqo, i) {
-		be_eq_notify(eqo->adapter, eqo->q.id, false, true, 0);
+		be_eq_notify(eqo->adapter, eqo->q.id, false, true, 0, 0);
 		napi_schedule(&eqo->napi);
 	}
 }
@@ -5227,7 +5287,9 @@ static void be_worker(struct work_struct *work)
 			be_post_rx_frags(rxo, GFP_KERNEL, MAX_RX_POST);
 	}
 
-	be_eqd_update(adapter);
+	/* EQ-delay update for Skyhawk is done while notifying EQ */
+	if (!skyhawk_chip(adapter))
+		be_eqd_update(adapter, false);
 
 	if (adapter->flags & BE_FLAGS_EVT_INCOMPATIBLE_SFP)
 		be_log_sfp_info(adapter);