[PATCH net-next 09/10] eth: fbnic: support ring channel get and set while down

[Jakub Kicinski <kuba@kernel.org>]

Trivial implementation of ethtool channel get and set. Set is only
supported when device is closed, next patch will add code for
live reconfig.

Asymmetric configurations are supported (combined + extra Tx or Rx),
so are configurations with independent IRQs for Rx and Tx.
Having all 3 NAPI types (combined, Tx, Rx) is not supported.

We used to only call fbnic_reset_indir_tbl() during init.
Now that we call it after device had been register must
be careful not to override user config.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 .../net/ethernet/meta/fbnic/fbnic_ethtool.c   | 64 +++++++++++++++++++
 drivers/net/ethernet/meta/fbnic/fbnic_rpc.c   |  3 +
 2 files changed, 67 insertions(+)

diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c b/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c
index d1be8fc30404..d2fe97ae6a71 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c
@@ -304,6 +304,68 @@ fbnic_set_rxfh(struct net_device *netdev, struct ethtool_rxfh_param *rxfh,
 	return 0;
 }
 
+static void fbnic_get_channels(struct net_device *netdev,
+			       struct ethtool_channels *ch)
+{
+	struct fbnic_net *fbn = netdev_priv(netdev);
+	struct fbnic_dev *fbd = fbn->fbd;
+
+	ch->max_rx = fbd->max_num_queues;
+	ch->max_tx = fbd->max_num_queues;
+	ch->max_combined = min(ch->max_rx, ch->max_tx);
+	ch->max_other =	FBNIC_NON_NAPI_VECTORS;
+
+	if (fbn->num_rx_queues > fbn->num_napi ||
+	    fbn->num_tx_queues > fbn->num_napi)
+		ch->combined_count = min(fbn->num_rx_queues,
+					 fbn->num_tx_queues);
+	else
+		ch->combined_count =
+			fbn->num_rx_queues + fbn->num_tx_queues - fbn->num_napi;
+	ch->rx_count = fbn->num_rx_queues - ch->combined_count;
+	ch->tx_count = fbn->num_tx_queues - ch->combined_count;
+	ch->other_count = FBNIC_NON_NAPI_VECTORS;
+}
+
+static void fbnic_set_queues(struct fbnic_net *fbn, struct ethtool_channels *ch,
+			     unsigned int max_napis)
+{
+	fbn->num_rx_queues = ch->rx_count + ch->combined_count;
+	fbn->num_tx_queues = ch->tx_count + ch->combined_count;
+	fbn->num_napi = min(ch->rx_count + ch->tx_count + ch->combined_count,
+			    max_napis);
+}
+
+static int fbnic_set_channels(struct net_device *netdev,
+			      struct ethtool_channels *ch)
+{
+	struct fbnic_net *fbn = netdev_priv(netdev);
+	unsigned int max_napis, standalone;
+	struct fbnic_dev *fbd = fbn->fbd;
+
+	max_napis = fbd->num_irqs - FBNIC_NON_NAPI_VECTORS;
+	standalone = ch->rx_count + ch->tx_count;
+
+	/* Limits for standalone queues:
+	 *  - each queue has it's own NAPI (num_napi >= rx + tx + combined)
+	 *  - combining queues (combined not 0, rx or tx must be 0)
+	 */
+	if ((ch->rx_count && ch->tx_count && ch->combined_count) ||
+	    (standalone && standalone + ch->combined_count > max_napis) ||
+	    ch->rx_count + ch->combined_count > fbd->max_num_queues ||
+	    ch->tx_count + ch->combined_count > fbd->max_num_queues ||
+	    ch->other_count != FBNIC_NON_NAPI_VECTORS)
+		return -EINVAL;
+
+	if (!netif_running(netdev)) {
+		fbnic_set_queues(fbn, ch, max_napis);
+		fbnic_reset_indir_tbl(fbn);
+		return 0;
+	}
+
+	return -EBUSY;
+}
+
 static int
 fbnic_get_ts_info(struct net_device *netdev,
 		  struct kernel_ethtool_ts_info *tsinfo)
@@ -417,6 +479,8 @@ static const struct ethtool_ops fbnic_ethtool_ops = {
 	.get_rxfh_indir_size	= fbnic_get_rxfh_indir_size,
 	.get_rxfh		= fbnic_get_rxfh,
 	.set_rxfh		= fbnic_set_rxfh,
+	.get_channels		= fbnic_get_channels,
+	.set_channels		= fbnic_set_channels,
 	.get_ts_info		= fbnic_get_ts_info,
 	.get_ts_stats		= fbnic_get_ts_stats,
 	.get_eth_mac_stats	= fbnic_get_eth_mac_stats,
diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_rpc.c b/drivers/net/ethernet/meta/fbnic/fbnic_rpc.c
index b99c890ac43f..c25bd300b902 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_rpc.c
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_rpc.c
@@ -13,6 +13,9 @@ void fbnic_reset_indir_tbl(struct fbnic_net *fbn)
 	unsigned int num_rx = fbn->num_rx_queues;
 	unsigned int i;
 
+	if (netif_is_rxfh_configured(fbn->netdev))
+		return;
+
 	for (i = 0; i < FBNIC_RPC_RSS_TBL_SIZE; i++)
 		fbn->indir_tbl[0][i] = ethtool_rxfh_indir_default(i, num_rx);
 }
-- 
2.47.1