dpaa2-eth: Add pause frame support

Starting with firmware version MC10.18.0, we have support for
L2 flow control. Asymmetrical configuration (Rx or Tx only) is
supported, but not pause frame autonegotioation.

Pause frame configuration is done via ethtool. By default, we start
with flow control enabled on both Rx and Tx. Changes are propagated
to hardware through firmware commands, using two flags (PAUSE,
ASYM_PAUSE) to specify Rx and Tx pause configuration, as follows:

PAUSE | ASYM_PAUSE | Rx pause | Tx pause
----------------------------------------
  0   |     0      | disabled | disabled
  0   |     1      | disabled | enabled
  1   |     0      | enabled  | enabled
  1   |     1      | enabled  | disabled

The hardware can automatically send pause frames when the number
of buffers in the pool goes below a predefined threshold. Due to
this, flow control is incompatible with Rx frame queue taildrop
(both mechanisms target the case when processing of ingress
frames can't keep up with the Rx rate; for large frames, the number
of buffers in the pool may never get low enough to trigger pause
frames as long as taildrop is enabled). So we set pause frame
generation and Rx FQ taildrop as mutually exclusive.

Signed-off-by: Ioana Radulescu <ruxandra.radulescu@nxp.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 55 insertions, 0 deletions

diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-ethtool.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-ethtool.c
index fb170425e9ce..93076fe01b45 100644
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-ethtool.c
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-ethtool.c
@@ -88,6 +88,59 @@ dpaa2_eth_get_link_ksettings(struct net_device *net_dev,
 	return 0;
 }
 
+static void dpaa2_eth_get_pauseparam(struct net_device *net_dev,
+				     struct ethtool_pauseparam *pause)
+{
+	struct dpaa2_eth_priv *priv = netdev_priv(net_dev);
+	u64 link_options = priv->link_state.options;
+
+	pause->rx_pause = !!(link_options & DPNI_LINK_OPT_PAUSE);
+	pause->tx_pause = pause->rx_pause ^
+			  !!(link_options & DPNI_LINK_OPT_ASYM_PAUSE);
+	pause->autoneg = AUTONEG_DISABLE;
+}
+
+static int dpaa2_eth_set_pauseparam(struct net_device *net_dev,
+				    struct ethtool_pauseparam *pause)
+{
+	struct dpaa2_eth_priv *priv = netdev_priv(net_dev);
+	struct dpni_link_cfg cfg = {0};
+	int err;
+
+	if (!dpaa2_eth_has_pause_support(priv)) {
+		netdev_info(net_dev, "No pause frame support for DPNI version < %d.%d\n",
+			    DPNI_PAUSE_VER_MAJOR, DPNI_PAUSE_VER_MINOR);
+		return -EOPNOTSUPP;
+	}
+
+	if (pause->autoneg)
+		return -EOPNOTSUPP;
+
+	cfg.rate = priv->link_state.rate;
+	cfg.options = priv->link_state.options;
+	if (pause->rx_pause)
+		cfg.options |= DPNI_LINK_OPT_PAUSE;
+	else
+		cfg.options &= ~DPNI_LINK_OPT_PAUSE;
+	if (!!pause->rx_pause ^ !!pause->tx_pause)
+		cfg.options |= DPNI_LINK_OPT_ASYM_PAUSE;
+	else
+		cfg.options &= ~DPNI_LINK_OPT_ASYM_PAUSE;
+
+	if (cfg.options == priv->link_state.options)
+		return 0;
+
+	err = dpni_set_link_cfg(priv->mc_io, 0, priv->mc_token, &cfg);
+	if (err) {
+		netdev_err(net_dev, "dpni_set_link_state failed\n");
+		return err;
+	}
+
+	priv->link_state.options = cfg.options;
+
+	return 0;
+}
+
 static void dpaa2_eth_get_strings(struct net_device *netdev, u32 stringset,
 				  u8 *data)
 {
@@ -664,6 +717,8 @@ const struct ethtool_ops dpaa2_ethtool_ops = {
 	.get_drvinfo = dpaa2_eth_get_drvinfo,
 	.get_link = ethtool_op_get_link,
 	.get_link_ksettings = dpaa2_eth_get_link_ksettings,
+	.get_pauseparam = dpaa2_eth_get_pauseparam,
+	.set_pauseparam = dpaa2_eth_set_pauseparam,
 	.get_sset_count = dpaa2_eth_get_sset_count,
 	.get_ethtool_stats = dpaa2_eth_get_ethtool_stats,
 	.get_strings = dpaa2_eth_get_strings,