ionic: separate interrupt for Tx and Rx

Add the capability to split the Tx queues onto their own
interrupts with their own napi contexts.  This gives the
opportunity for more direct control of Tx interrupt
handling, such as CPU affinity and interrupt coalescing,
useful for some traffic loads.

v2: use ethtool -L, not a vendor specific priv-flag
v3: simplify logging, drop unnecessary "no-change" tests

Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 76 insertions, 20 deletions

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_ethtool.c b/drivers/net/ethernet/pensando/ionic/ionic_ethtool.c
index 095561924bdc..3c57c331729f 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_ethtool.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_ethtool.c
@@ -403,8 +403,7 @@ static int ionic_get_coalesce(struct net_device *netdev,
 {
 	struct ionic_lif *lif = netdev_priv(netdev);
 
-	/* Tx uses Rx interrupt */
-	coalesce->tx_coalesce_usecs = lif->rx_coalesce_usecs;
+	coalesce->tx_coalesce_usecs = lif->tx_coalesce_usecs;
 	coalesce->rx_coalesce_usecs = lif->rx_coalesce_usecs;
 
 	return 0;
@@ -417,7 +416,8 @@ static int ionic_set_coalesce(struct net_device *netdev,
 	struct ionic_identity *ident;
 	struct ionic_qcq *qcq;
 	unsigned int i;
-	u32 coal;
+	u32 rx_coal;
+	u32 tx_coal;
 
 	ident = &lif->ionic->ident;
 	if (ident->dev.intr_coal_div == 0) {
@@ -426,26 +426,31 @@ static int ionic_set_coalesce(struct net_device *netdev,
 		return -EIO;
 	}
 
-	/* Tx uses Rx interrupt, so only change Rx */
-	if (coalesce->tx_coalesce_usecs != lif->rx_coalesce_usecs) {
+	/* Tx normally shares Rx interrupt, so only change Rx */
+	if (!test_bit(IONIC_LIF_F_SPLIT_INTR, lif->state) &&
+	    coalesce->tx_coalesce_usecs != lif->rx_coalesce_usecs) {
 		netdev_warn(netdev, "only the rx-usecs can be changed\n");
 		return -EINVAL;
 	}
 
-	/* Convert the usec request to a HW useable value.  If they asked
+	/* Convert the usec request to a HW usable value.  If they asked
 	 * for non-zero and it resolved to zero, bump it up
 	 */
-	coal = ionic_coal_usec_to_hw(lif->ionic, coalesce->rx_coalesce_usecs);
-	if (!coal && coalesce->rx_coalesce_usecs)
-		coal = 1;
-
-	if (coal > IONIC_INTR_CTRL_COAL_MAX)
+	rx_coal = ionic_coal_usec_to_hw(lif->ionic, coalesce->rx_coalesce_usecs);
+	if (!rx_coal && coalesce->rx_coalesce_usecs)
+		rx_coal = 1;
+	tx_coal = ionic_coal_usec_to_hw(lif->ionic, coalesce->tx_coalesce_usecs);
+	if (!tx_coal && coalesce->tx_coalesce_usecs)
+		tx_coal = 1;
+
+	if (rx_coal > IONIC_INTR_CTRL_COAL_MAX ||
+	    tx_coal > IONIC_INTR_CTRL_COAL_MAX)
 		return -ERANGE;
 
-	/* Save the new value */
+	/* Save the new values */
 	lif->rx_coalesce_usecs = coalesce->rx_coalesce_usecs;
-	if (coal != lif->rx_coalesce_hw) {
-		lif->rx_coalesce_hw = coal;
+	if (rx_coal != lif->rx_coalesce_hw) {
+		lif->rx_coalesce_hw = rx_coal;
 
 		if (test_bit(IONIC_LIF_F_UP, lif->state)) {
 			for (i = 0; i < lif->nxqs; i++) {
@@ -457,6 +462,23 @@ static int ionic_set_coalesce(struct net_device *netdev,
 		}
 	}
 
+	if (test_bit(IONIC_LIF_F_SPLIT_INTR, lif->state))
+		lif->tx_coalesce_usecs = coalesce->tx_coalesce_usecs;
+	else
+		lif->tx_coalesce_usecs = coalesce->rx_coalesce_usecs;
+	if (tx_coal != lif->tx_coalesce_hw) {
+		lif->tx_coalesce_hw = tx_coal;
+
+		if (test_bit(IONIC_LIF_F_UP, lif->state)) {
+			for (i = 0; i < lif->nxqs; i++) {
+				qcq = lif->txqcqs[i].qcq;
+				ionic_intr_coal_init(lif->ionic->idev.intr_ctrl,
+						     qcq->intr.index,
+						     lif->tx_coalesce_hw);
+			}
+		}
+	}
+
 	return 0;
 }
 
@@ -510,29 +532,63 @@ static void ionic_get_channels(struct net_device *netdev,
 
 	/* report maximum channels */
 	ch->max_combined = lif->ionic->ntxqs_per_lif;
+	ch->max_rx = lif->ionic->ntxqs_per_lif / 2;
+	ch->max_tx = lif->ionic->ntxqs_per_lif / 2;
 
 	/* report current channels */
-	ch->combined_count = lif->nxqs;
+	if (test_bit(IONIC_LIF_F_SPLIT_INTR, lif->state)) {
+		ch->rx_count = lif->nxqs;
+		ch->tx_count = lif->nxqs;
+	} else {
+		ch->combined_count = lif->nxqs;
+	}
 }
 
 static void ionic_set_queuecount(struct ionic_lif *lif, void *arg)
 {
 	struct ethtool_channels *ch = arg;
 
-	lif->nxqs = ch->combined_count;
+	if (ch->combined_count) {
+		lif->nxqs = ch->combined_count;
+		if (test_bit(IONIC_LIF_F_SPLIT_INTR, lif->state)) {
+			clear_bit(IONIC_LIF_F_SPLIT_INTR, lif->state);
+			lif->tx_coalesce_usecs = lif->rx_coalesce_usecs;
+			lif->tx_coalesce_hw = lif->rx_coalesce_hw;
+			netdev_info(lif->netdev, "Sharing queue interrupts\n");
+		}
+	} else {
+		lif->nxqs = ch->rx_count;
+		if (!test_bit(IONIC_LIF_F_SPLIT_INTR, lif->state)) {
+			set_bit(IONIC_LIF_F_SPLIT_INTR, lif->state);
+			netdev_info(lif->netdev, "Splitting queue interrupts\n");
+		}
+	}
 }
 
 static int ionic_set_channels(struct net_device *netdev,
 			      struct ethtool_channels *ch)
 {
 	struct ionic_lif *lif = netdev_priv(netdev);
+	int new_cnt;
 
-	if (!ch->combined_count || ch->other_count ||
-	    ch->rx_count || ch->tx_count)
+	if (ch->rx_count != ch->tx_count) {
+		netdev_info(netdev, "The rx and tx count must be equal\n");
 		return -EINVAL;
+	}
 
-	if (ch->combined_count == lif->nxqs)
-		return 0;
+	if (ch->combined_count && ch->rx_count) {
+		netdev_info(netdev, "Use either combined_count or rx/tx_count, not both\n");
+		return -EINVAL;
+	}
+
+	if (ch->combined_count)
+		new_cnt = ch->combined_count;
+	else
+		new_cnt = ch->rx_count;
+
+	if (lif->nxqs != new_cnt)
+		netdev_info(netdev, "Changing queue count from %d to %d\n",
+			    lif->nxqs, new_cnt);
 
 	return ionic_reset_queues(lif, ionic_set_queuecount, ch);
 }