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Message-ID: <20251112180427.2904990-1-mohsin.bashr@gmail.com>
Date: Wed, 12 Nov 2025 10:04:27 -0800
From: Mohsin Bashir <mohsin.bashr@...il.com>
To: netdev@...r.kernel.org
Cc: alexanderduyck@...com,
almasrymina@...gle.com,
andrew+netdev@...n.ch,
davem@...emloft.net,
edumazet@...gle.com,
horms@...nel.org,
kernel-team@...a.com,
kuba@...nel.org,
linux-kernel@...r.kernel.org,
linux@...linux.org.uk,
mohsin.bashr@...il.com,
pabeni@...hat.com,
rmk+kernel@...linux.org.uk
Subject: [PATCH net-next] eth: fbnic: Configure RDE settings for pause frame
fbnic supports pause frames. When pause frames are enabled presumably
user expects lossless operation from the NIC. Make sure we configure
RDE (Rx DMA Engine) to DROP_NEVER mode to avoid discards due to delays
in fetching Rx descriptors from the host.
While at it enable DROP_NEVER when NIC only has a single queue
configured. In this case the NIC acts as a FIFO so there's no risk
of head-of-line blocking other queues by making RDE wait. If pause
is disabled this just moves the packet loss from the DMA engine to
the Rx buffer.
Remove redundant call to fbnic_config_drop_mode_rcq(), introduced by
commit 0cb4c0a13723 ("eth: fbnic: Implement Rx queue
alloc/start/stop/free"). This call does not add value as
fbnic_enable_rcq(), which is called immediately afterward, already
handles this.
Signed-off-by: Mohsin Bashir <mohsin.bashr@...il.com>
Signed-off-by: Jakub Kicinski <kuba@...nel.org>
---
.../net/ethernet/meta/fbnic/fbnic_netdev.h | 2 ++
.../net/ethernet/meta/fbnic/fbnic_phylink.c | 8 +++++-
drivers/net/ethernet/meta/fbnic/fbnic_txrx.c | 26 ++++++++++++++++---
drivers/net/ethernet/meta/fbnic/fbnic_txrx.h | 1 +
4 files changed, 32 insertions(+), 5 deletions(-)
diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_netdev.h b/drivers/net/ethernet/meta/fbnic/fbnic_netdev.h
index b0a87c57910f..e6ca23a9957d 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_netdev.h
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_netdev.h
@@ -73,6 +73,8 @@ struct fbnic_net {
/* Time stamping filter config */
struct kernel_hwtstamp_config hwtstamp_config;
+
+ bool tx_pause;
};
int __fbnic_open(struct fbnic_net *fbn);
diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_phylink.c b/drivers/net/ethernet/meta/fbnic/fbnic_phylink.c
index 7ce3fdd25282..c9ed13e37d62 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_phylink.c
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_phylink.c
@@ -36,8 +36,13 @@ int fbnic_phylink_set_pauseparam(struct net_device *netdev,
struct ethtool_pauseparam *pause)
{
struct fbnic_net *fbn = netdev_priv(netdev);
+ int err;
+
+ err = phylink_ethtool_set_pauseparam(fbn->phylink, pause);
+ if (!err)
+ fbn->tx_pause = pause->tx_pause ? true : false;
- return phylink_ethtool_set_pauseparam(fbn->phylink, pause);
+ return err;
}
static void
@@ -208,6 +213,7 @@ fbnic_phylink_mac_link_up(struct phylink_config *config,
struct fbnic_net *fbn = netdev_priv(netdev);
struct fbnic_dev *fbd = fbn->fbd;
+ fbnic_config_drop_mode(fbn, tx_pause);
fbd->mac->link_up(fbd, tx_pause, rx_pause);
}
diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_txrx.c b/drivers/net/ethernet/meta/fbnic/fbnic_txrx.c
index 57e18a68f5d2..c2d7b67fec28 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_txrx.c
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_txrx.c
@@ -2574,11 +2574,15 @@ static void fbnic_enable_bdq(struct fbnic_ring *hpq, struct fbnic_ring *ppq)
}
static void fbnic_config_drop_mode_rcq(struct fbnic_napi_vector *nv,
- struct fbnic_ring *rcq)
+ struct fbnic_ring *rcq, bool tx_pause)
{
+ struct fbnic_net *fbn = netdev_priv(nv->napi.dev);
u32 drop_mode, rcq_ctl;
- drop_mode = FBNIC_QUEUE_RDE_CTL0_DROP_IMMEDIATE;
+ if (!tx_pause && fbn->num_rx_queues > 1)
+ drop_mode = FBNIC_QUEUE_RDE_CTL0_DROP_IMMEDIATE;
+ else
+ drop_mode = FBNIC_QUEUE_RDE_CTL0_DROP_NEVER;
/* Specify packet layout */
rcq_ctl = FIELD_PREP(FBNIC_QUEUE_RDE_CTL0_DROP_MODE_MASK, drop_mode) |
@@ -2588,6 +2592,21 @@ static void fbnic_config_drop_mode_rcq(struct fbnic_napi_vector *nv,
fbnic_ring_wr32(rcq, FBNIC_QUEUE_RDE_CTL0, rcq_ctl);
}
+void fbnic_config_drop_mode(struct fbnic_net *fbn, bool tx_pause)
+{
+ int i, t;
+
+ for (i = 0; i < fbn->num_napi; i++) {
+ struct fbnic_napi_vector *nv = fbn->napi[i];
+
+ for (t = 0; t < nv->rxt_count; t++) {
+ struct fbnic_q_triad *qt = &nv->qt[nv->txt_count + t];
+
+ fbnic_config_drop_mode_rcq(nv, &qt->cmpl, tx_pause);
+ }
+ }
+}
+
static void fbnic_config_rim_threshold(struct fbnic_ring *rcq, u16 nv_idx, u32 rx_desc)
{
u32 threshold;
@@ -2637,7 +2656,7 @@ static void fbnic_enable_rcq(struct fbnic_napi_vector *nv,
u32 hds_thresh = fbn->hds_thresh;
u32 rcq_ctl = 0;
- fbnic_config_drop_mode_rcq(nv, rcq);
+ fbnic_config_drop_mode_rcq(nv, rcq, fbn->tx_pause);
/* Force lower bound on MAX_HEADER_BYTES. Below this, all frames should
* be split at L4. It would also result in the frames being split at
@@ -2700,7 +2719,6 @@ static void __fbnic_nv_enable(struct fbnic_napi_vector *nv)
&nv->napi);
fbnic_enable_bdq(&qt->sub0, &qt->sub1);
- fbnic_config_drop_mode_rcq(nv, &qt->cmpl);
fbnic_enable_rcq(nv, &qt->cmpl);
}
}
diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_txrx.h b/drivers/net/ethernet/meta/fbnic/fbnic_txrx.h
index ca37da5a0b17..27776e844e29 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_txrx.h
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_txrx.h
@@ -184,6 +184,7 @@ void fbnic_reset_netif_queues(struct fbnic_net *fbn);
irqreturn_t fbnic_msix_clean_rings(int irq, void *data);
void fbnic_napi_enable(struct fbnic_net *fbn);
void fbnic_napi_disable(struct fbnic_net *fbn);
+void fbnic_config_drop_mode(struct fbnic_net *fbn, bool tx_pause);
void fbnic_enable(struct fbnic_net *fbn);
void fbnic_disable(struct fbnic_net *fbn);
void fbnic_flush(struct fbnic_net *fbn);
--
2.47.3
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