dpaa2-eth: Keep congestion group taildrop enabled when PFC on
Leave congestion group taildrop enabled for all traffic classes
when PFC is enabled. Notification threshold is low enough such
that it will be hit first and this also ensures that FQs on
traffic classes which are not PFC enabled won't drain the buffer
pool.
FQ taildrop threshold is kept disabled as long as any form of
flow control is on. Since FQ taildrop works with bytes, not number
of frames, we can't guarantee it will not interfere with the
congestion notification mechanism for all frame sizes.
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
index cde9d0e..8fb48de 100644
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
@@ -1287,18 +1287,22 @@ static void disable_ch_napi(struct dpaa2_eth_priv *priv)
}
}
-static void dpaa2_eth_set_rx_taildrop(struct dpaa2_eth_priv *priv,
- bool tx_pause)
+void dpaa2_eth_set_rx_taildrop(struct dpaa2_eth_priv *priv,
+ bool tx_pause, bool pfc)
{
struct dpni_taildrop td = {0};
struct dpaa2_eth_fq *fq;
int i, err;
+ /* FQ taildrop: threshold is in bytes, per frame queue. Enabled if
+ * flow control is disabled (as it might interfere with either the
+ * buffer pool depletion trigger for pause frames or with the group
+ * congestion trigger for PFC frames)
+ */
td.enable = !tx_pause;
- if (priv->rx_td_enabled == td.enable)
- return;
+ if (priv->rx_fqtd_enabled == td.enable)
+ goto set_cgtd;
- /* FQ taildrop: threshold is in bytes, per frame queue */
td.threshold = DPAA2_ETH_FQ_TAILDROP_THRESH;
td.units = DPNI_CONGESTION_UNIT_BYTES;
@@ -1316,9 +1320,20 @@ static void dpaa2_eth_set_rx_taildrop(struct dpaa2_eth_priv *priv,
}
}
+ priv->rx_fqtd_enabled = td.enable;
+
+set_cgtd:
/* Congestion group taildrop: threshold is in frames, per group
* of FQs belonging to the same traffic class
+ * Enabled if general Tx pause disabled or if PFCs are enabled
+ * (congestion group threhsold for PFC generation is lower than the
+ * CG taildrop threshold, so it won't interfere with it; we also
+ * want frames in non-PFC enabled traffic classes to be kept in check)
*/
+ td.enable = !tx_pause || (tx_pause && pfc);
+ if (priv->rx_cgtd_enabled == td.enable)
+ return;
+
td.threshold = DPAA2_ETH_CG_TAILDROP_THRESH(priv);
td.units = DPNI_CONGESTION_UNIT_FRAMES;
for (i = 0; i < dpaa2_eth_tc_count(priv); i++) {
@@ -1332,7 +1347,7 @@ static void dpaa2_eth_set_rx_taildrop(struct dpaa2_eth_priv *priv,
}
}
- priv->rx_td_enabled = td.enable;
+ priv->rx_cgtd_enabled = td.enable;
}
static int link_state_update(struct dpaa2_eth_priv *priv)
@@ -1353,7 +1368,7 @@ static int link_state_update(struct dpaa2_eth_priv *priv)
* only when pause frame generation is disabled.
*/
tx_pause = dpaa2_eth_tx_pause_enabled(state.options);
- dpaa2_eth_set_rx_taildrop(priv, tx_pause);
+ dpaa2_eth_set_rx_taildrop(priv, tx_pause, priv->pfc_enabled);
/* When we manage the MAC/PHY using phylink there is no need
* to manually update the netif_carrier.