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net: enetc: restore RX ring congestion mode after ring reconfiguration

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The RX ring congestion mode (CM) is only configured in the phylink
.mac_link_up() callback enetc_pl_mac_link_up(), which sets the
ENETC_RBMR_CM bit when tx_pause is enabled. This callback runs only when
the link status changes.

However, enetc_reconfigure() tears down and re-creates the RX BD rings at
runtime without any link status change, for example when attaching or
detaching an XDP program, or when enabling/disabling PTP RX hardware
timestamping. The rings are rebuilt from a cleared RBMR, so the CM bit is
lost. Since the link status does not change, enetc_pl_mac_link_up() is
not called again and the CM bit is never restored.

As a result, the ENETC MAC can no longer generate PAUSE frames on ingress
congestion, and flow control stops working after such a reconfiguration.

Track the desired CM state in a software flag ENETC_RXBDR_CM. Set or clear
this flag in enetc_pl_mac_link_up() according to tx_pause. When the RX BD
rings are (re)enabled, enetc_enable_rxbdr() consults this flag and restores
the ENETC_RBMR_CM bit accordingly, so flow control survives ring
reconfiguration even when the link status does not change.

RBMR is now written as a whole word from enetc_enable_rxbdr() rather than
by read-modify-write from several call sites. Serialize the remaining RBMR
read-modify-write paths, the congestion mode update and the RX VLAN offload
update, with the new si->gen_lock so they cannot race each other.

Fixes: 5093406c78 ("net: enetc: implement ring reconfiguration procedure for PTP RX timestamping")
Signed-off-by: Wei Fang <wei.fang@nxp.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260821064140.1315611-2-wei.fang@oss.nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Wei Fang 2026-08-21 14:41:39 +08:00 committed by Jakub Kicinski
parent 9edf8d4876
commit 9e94d8e14a
3 changed files with 68 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

72
drivers/net/ethernet/freescale/enetc/enetc.c
View File

@ -81,6 +81,33 @@ void enetc_reset_mac_addr_filter(struct enetc_mac_filter *filter)
}
EXPORT_SYMBOL_GPL(enetc_reset_mac_addr_filter);
void enetc_set_congestion_mode(struct enetc_ndev_priv *priv, bool enable)
{
struct enetc_si *si = priv->si;
struct enetc_hw *hw = &si->hw;
spin_lock(&si->gen_lock);
if (enable)
set_bit(ENETC_RXBDR_CM, &priv->flags);
else
clear_bit(ENETC_RXBDR_CM, &priv->flags);
for (int i = 0; i < priv->num_rx_rings; i++) {
u32 old_rbmr = enetc_rxbdr_rd(hw, i, ENETC_RBMR);
u32 rbmr;
rbmr = u32_replace_bits(old_rbmr, enable, ENETC_RBMR_CM);
if (rbmr == old_rbmr)
continue;
enetc_rxbdr_wr(hw, i, ENETC_RBMR, rbmr);
}
spin_unlock(&si->gen_lock);
}
EXPORT_SYMBOL_GPL(enetc_set_congestion_mode);
static int enetc_num_stack_tx_queues(struct enetc_ndev_priv *priv)
{
int num_tx_rings = priv->num_tx_rings;
@ -2632,7 +2659,6 @@ static void enetc_setup_rxbdr(struct enetc_hw *hw, struct enetc_bdr *rx_ring,
bool extended)
{
int idx = rx_ring->index;
u32 rbmr = 0;
enetc_rxbdr_wr(hw, idx, ENETC_RBBAR0,
lower_32_bits(rx_ring->bd_dma_base));
@ -2660,12 +2686,6 @@ static void enetc_setup_rxbdr(struct enetc_hw *hw, struct enetc_bdr *rx_ring,
enetc_rxbdr_wr(hw, idx, ENETC_RBICR0, ENETC_RBICR0_ICEN | 0x1);
rx_ring->ext_en = extended;
if (rx_ring->ext_en)
rbmr |= ENETC_RBMR_BDS;
if (rx_ring->ndev->features & NETIF_F_HW_VLAN_CTAG_RX)
rbmr |= ENETC_RBMR_VTE;
rx_ring->rcir = hw->reg + ENETC_BDR(RX, idx, ENETC_RBCIR);
rx_ring->idr = hw->reg + ENETC_SIRXIDR;
@ -2676,8 +2696,6 @@ static void enetc_setup_rxbdr(struct enetc_hw *hw, struct enetc_bdr *rx_ring,
enetc_lock_mdio();
enetc_refill_rx_ring(rx_ring, enetc_bd_unused(rx_ring));
enetc_unlock_mdio();
enetc_rxbdr_wr(hw, idx, ENETC_RBMR, rbmr);
}
static void enetc_setup_bdrs(struct enetc_ndev_priv *priv, bool extended)
@ -2704,21 +2722,34 @@ static void enetc_enable_txbdr(struct enetc_hw *hw, struct enetc_bdr *tx_ring)
static void enetc_enable_rxbdr(struct enetc_hw *hw, struct enetc_bdr *rx_ring)
{
struct enetc_ndev_priv *priv = netdev_priv(rx_ring->ndev);
int idx = rx_ring->index;
u32 rbmr;
u32 rbmr = ENETC_RBMR_EN;
if (rx_ring->ext_en)
rbmr |= ENETC_RBMR_BDS;
if (rx_ring->ndev->features & NETIF_F_HW_VLAN_CTAG_RX)
rbmr |= ENETC_RBMR_VTE;
if (test_bit(ENETC_RXBDR_CM, &priv->flags))
rbmr |= ENETC_RBMR_CM;
rbmr = enetc_rxbdr_rd(hw, idx, ENETC_RBMR);
rbmr |= ENETC_RBMR_EN;
enetc_rxbdr_wr(hw, idx, ENETC_RBMR, rbmr);
}
static void enetc_enable_rx_bdrs(struct enetc_ndev_priv *priv)
{
struct enetc_hw *hw = &priv->si->hw;
struct enetc_si *si = priv->si;
struct enetc_hw *hw = &si->hw;
int i;
spin_lock(&si->gen_lock);
for (i = 0; i < priv->num_rx_rings; i++)
enetc_enable_rxbdr(hw, priv->rx_ring[i]);
spin_unlock(&si->gen_lock);
}
static void enetc_enable_tx_bdrs(struct enetc_ndev_priv *priv)
@ -2748,11 +2779,16 @@ static void enetc_disable_txbdr(struct enetc_hw *hw, struct enetc_bdr *rx_ring)
static void enetc_disable_rx_bdrs(struct enetc_ndev_priv *priv)
{
struct enetc_hw *hw = &priv->si->hw;
struct enetc_si *si = priv->si;
struct enetc_hw *hw = &si->hw;
int i;
spin_lock(&si->gen_lock);
for (i = 0; i < priv->num_rx_rings; i++)
enetc_disable_rxbdr(hw, priv->rx_ring[i]);
spin_unlock(&si->gen_lock);
}
static void enetc_disable_tx_bdrs(struct enetc_ndev_priv *priv)
@ -3344,11 +3380,16 @@ EXPORT_SYMBOL_GPL(enetc_get_stats);
static void enetc_enable_rxvlan(struct net_device *ndev, bool en)
{
struct enetc_ndev_priv *priv = netdev_priv(ndev);
struct enetc_hw *hw = &priv->si->hw;
struct enetc_si *si = priv->si;
struct enetc_hw *hw = &si->hw;
int i;
spin_lock(&si->gen_lock);
for (i = 0; i < priv->num_rx_rings; i++)
enetc_bdr_enable_rxvlan(hw, i, en);
spin_unlock(&si->gen_lock);
}
static void enetc_enable_txvlan(struct net_device *ndev, bool en)
@ -3679,6 +3720,7 @@ int enetc_pci_probe(struct pci_dev *pdev, const char *name, int sizeof_priv)
si = PTR_ALIGN(p, ENETC_SI_ALIGN);
si->pad = (char *)si - (char *)p;
spin_lock_init(&si->gen_lock);
pci_set_drvdata(pdev, si);
si->pdev = pdev;

9
drivers/net/ethernet/freescale/enetc/enetc.h
View File

@ -309,6 +309,13 @@ struct enetc_si {
struct net_device *ndev; /* back ref. */
/* General-purpose lock serializing updates that must not race,
* e.g. read-modify-write of shared hardware registers and of
* selected priv->flags bits between the phylink link callbacks
* and the ring (re)configuration path.
*/
spinlock_t gen_lock;
union {
struct enetc_cbdr cbd_ring; /* Only ENETC 1.0 */
struct ntmp_user ntmp_user; /* ENETC 4.1 and later */
@ -417,6 +424,7 @@ enum enetc_active_offloads {
enum enetc_flags_bit {
ENETC_TX_ONESTEP_TSTAMP_IN_PROGRESS = 0,
ENETC_TX_DOWN,
ENETC_RXBDR_CM,
};
/* interrupt coalescing modes */
@ -505,6 +513,7 @@ int enetc_get_driver_data(struct enetc_si *si);
void enetc_add_mac_addr_ht_filter(struct enetc_mac_filter *filter,
const unsigned char *addr);
void enetc_reset_mac_addr_filter(struct enetc_mac_filter *filter);
void enetc_set_congestion_mode(struct enetc_ndev_priv *priv, bool enable);
int enetc_open(struct net_device *ndev);
int enetc_close(struct net_device *ndev);

14
drivers/net/ethernet/freescale/enetc/enetc_pf.c
View File

@ -556,8 +556,7 @@ static void enetc_pl_mac_link_up(struct phylink_config *config,
struct enetc_hw *hw = &pf->si->hw;
struct enetc_si *si = pf->si;
struct enetc_ndev_priv *priv;
u32 rbmr, cmd_cfg;
int idx;
u32 cmd_cfg;
priv = netdev_priv(pf->si->ndev);
@ -569,16 +568,7 @@ static void enetc_pl_mac_link_up(struct phylink_config *config,
enetc_force_rgmii_mac(si, speed, duplex);
/* Flow control */
for (idx = 0; idx < priv->num_rx_rings; idx++) {
rbmr = enetc_rxbdr_rd(hw, idx, ENETC_RBMR);
if (tx_pause)
rbmr |= ENETC_RBMR_CM;
else
rbmr &= ~ENETC_RBMR_CM;
enetc_rxbdr_wr(hw, idx, ENETC_RBMR, rbmr);
}
enetc_set_congestion_mode(priv, tx_pause);
if (tx_pause) {
/* When the port first enters congestion, send a PAUSE request