[PATCH net v2] net: stmmac: propagate PTP init failures in __stmmac_open() and stmmac_resume()
From: Lorenzo Bianconi <hidden>
Date: 2026-09-07 11:51:33
stmmac_setup_ptp() returns void and swallows both PTP setup errors:
the PTP reference clock enable and stmmac_init_timestamping()
failures are logged but never propagated. When they fail, the MAC
system time counter is left in its post-reset, non-running state,
while the driver keeps operating as if timestamping were up.
This matters for TAPRIO/EST qdisc offloading, which derives the EST
base time from the hardware timestamp counter: arming the gate list
against a non-advancing time base would leave the schedule permanently
stuck.
Make stmmac_setup_ptp() return an error code and propagate the
failure in __stmmac_open() and stmmac_resume(), stopping the DMA
engines when PTP setup fails.
Extend the same error propagation to the timestamping counter
initialisation: stmmac_update_subsecond_increment() and
stmmac_init_tstamp_counter() now return the addend and system time
programming errors instead of discarding them, so a counter that
cannot be configured is reported as a failure rather than silently
left non-running.
While at it, factor the timestamping availability check into a
stmmac_check_timestamp_cap() helper that requires both the hardware
timestamping capability and a valid PTP reference clock rate. This
keeps the interface operational on platforms with PTP-capable
silicon but an unconfigured PTP clock, where timestamping cannot be
enabled: those are treated as PTP-less rather than failing to open
or resume. Apply the same helper to the hwtstamp get/set paths so
they consistently report -EOPNOTSUPP when timestamping is not usable.
Fixes: 92ba6888510c ("stmmac: add the support for PTP hw clock driver")
Fixes: 0ad2be79f254 ("net: stmmac: Balance PTP reference clock enable/disable")
Signed-off-by: Lorenzo Bianconi <redacted>
---
Changes in v2:
- Check clk_ptp_rate value in stmmac_check_timestamp_cap().
- Return error code in stmmac_update_subsecond_increment() and
stmmac_init_tstamp_counter().
- Rely on stmmac_check_timestamp_cap() in stmmac_hwtstamp_set() and
stmmac_hwtstamp_get().
- Link to v1: https://lore.kernel.org/r/20260904-stmmac-ptp-error-propagate-v1-1-80f01b03dafa@oss.qualcomm.com
---
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 96 +++++++++++++++--------
1 file changed, 64 insertions(+), 32 deletions(-)
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 07a6fab6460e..99d4fbccc300 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c@@ -601,7 +601,7 @@ static void stmmac_get_rx_hwtstamp(struct stmmac_priv *priv, struct dma_desc *p, } } -static void stmmac_update_subsecond_increment(struct stmmac_priv *priv) +static int stmmac_update_subsecond_increment(struct stmmac_priv *priv) { bool xmac = dwmac_is_xmac(priv->plat->core_type); u32 sec_inc = 0;
@@ -625,7 +625,18 @@ static void stmmac_update_subsecond_increment(struct stmmac_priv *priv) */ temp = (u64)(temp << 32); priv->default_addend = div_u64(temp, priv->plat->clk_ptp_rate); - stmmac_config_addend(priv, priv->ptpaddr, priv->default_addend); + return stmmac_config_addend(priv, priv->ptpaddr, priv->default_addend); +} + +static bool stmmac_check_timestamp_cap(struct stmmac_priv *priv) +{ + if (!priv->dma_cap.time_stamp && !priv->dma_cap.atime_stamp) + return false; + + if (!priv->plat->clk_ptp_rate) + return false; + + return true; } /**
@@ -653,7 +664,7 @@ static int stmmac_hwtstamp_set(struct net_device *dev, u32 ts_master_en = 0; u32 ts_event_en = 0; - if (!(priv->dma_cap.time_stamp || priv->adv_ts)) { + if (!stmmac_check_timestamp_cap(priv)) { NL_SET_ERR_MSG_MOD(extack, "No support for HW time stamping"); priv->hwts_tx_en = 0; priv->hwts_rx_en = 0;
@@ -843,7 +854,7 @@ static int stmmac_hwtstamp_get(struct net_device *dev, { struct stmmac_priv *priv = netdev_priv(dev); - if (!(priv->dma_cap.time_stamp || priv->dma_cap.atime_stamp)) + if (!stmmac_check_timestamp_cap(priv)) return -EOPNOTSUPP; *config = priv->tstamp_config;
@@ -865,24 +876,21 @@ static int stmmac_init_tstamp_counter(struct stmmac_priv *priv, u32 systime_flags) { struct timespec64 now; - - if (!priv->plat->clk_ptp_rate) { - netdev_err(priv->dev, "Invalid PTP clock rate"); - return -EINVAL; - } + int ret; stmmac_config_hw_tstamping(priv, priv->ptpaddr, systime_flags); priv->systime_flags = systime_flags; - stmmac_update_subsecond_increment(priv); + ret = stmmac_update_subsecond_increment(priv); + if (ret) + return ret; /* initialize system time */ ktime_get_real_ts64(&now); /* lower 32 bits of tv_sec are safe until y2106 */ - stmmac_init_systime(priv, priv->ptpaddr, (u32)now.tv_sec, now.tv_nsec); - - return 0; + return stmmac_init_systime(priv, priv->ptpaddr, (u32)now.tv_sec, + now.tv_nsec); } /**
@@ -900,11 +908,6 @@ static int stmmac_init_timestamping(struct stmmac_priv *priv) if (priv->plat->ptp_clk_freq_config) priv->plat->ptp_clk_freq_config(priv); - if (!(priv->dma_cap.time_stamp || priv->dma_cap.atime_stamp)) { - netdev_info(priv->dev, "PTP not supported by HW\n"); - return -EOPNOTSUPP; - } - ret = stmmac_init_tstamp_counter(priv, STMMAC_HWTS_ACTIVE | PTP_TCR_TSCFUPDT); if (ret) {
@@ -937,22 +940,39 @@ static int stmmac_init_timestamping(struct stmmac_priv *priv) return 0; } -static void stmmac_setup_ptp(struct stmmac_priv *priv) +static int stmmac_setup_ptp(struct stmmac_priv *priv) { int ret; + if (!stmmac_check_timestamp_cap(priv)) { + netdev_info(priv->dev, "PTP not supported\n"); + return 0; + } + ret = clk_prepare_enable(priv->plat->clk_ptp_ref); - if (ret < 0) + if (ret < 0) { netdev_warn(priv->dev, "failed to enable PTP reference clock: %pe\n", ERR_PTR(ret)); + return ret; + } - if (stmmac_init_timestamping(priv) == 0) - stmmac_ptp_register(priv); + ret = stmmac_init_timestamping(priv); + if (ret) { + clk_disable_unprepare(priv->plat->clk_ptp_ref); + return ret; + } + + stmmac_ptp_register(priv); + + return 0; } static void stmmac_release_ptp(struct stmmac_priv *priv) { + if (!stmmac_check_timestamp_cap(priv)) + return; + stmmac_ptp_unregister(priv); clk_disable_unprepare(priv->plat->clk_ptp_ref); }
@@ -4161,10 +4181,12 @@ static int __stmmac_open(struct net_device *dev, ret = stmmac_hw_setup(dev); if (ret < 0) { netdev_err(priv->dev, "%s: Hw setup failed\n", __func__); - goto init_error; + return ret; } - stmmac_setup_ptp(priv); + ret = stmmac_setup_ptp(priv); + if (ret) + goto ptp_error; stmmac_init_coalesce(priv);
@@ -4185,13 +4207,13 @@ static int __stmmac_open(struct net_device *dev, irq_error: phylink_stop(priv->phylink); - stmmac_stop_all_dma(priv); - for (chan = 0; chan < priv->plat->tx_queues_to_use; chan++) hrtimer_cancel(&priv->dma_conf.tx_queue[chan].txtimer); stmmac_release_ptp(priv); -init_error: +ptp_error: + stmmac_stop_all_dma(priv); + return ret; }
@@ -8350,13 +8372,14 @@ int stmmac_resume(struct device *dev) ret = stmmac_hw_setup(ndev); if (ret < 0) { netdev_err(priv->dev, "%s: Hw setup failed\n", __func__); - stmmac_legacy_serdes_power_down(priv); - mutex_unlock(&priv->lock); - rtnl_unlock(); - return ret; + goto error_unlock; } - stmmac_init_timestamping(priv); + if (stmmac_check_timestamp_cap(priv)) { + ret = stmmac_init_timestamping(priv); + if (ret) + goto error_stop_dma; + } stmmac_init_coalesce(priv); phylink_rx_clk_stop_block(priv->phylink);
@@ -8380,6 +8403,15 @@ int stmmac_resume(struct device *dev) netif_device_attach(ndev); return 0; + +error_stop_dma: + stmmac_stop_all_dma(priv); +error_unlock: + stmmac_legacy_serdes_power_down(priv); + mutex_unlock(&priv->lock); + rtnl_unlock(); + + return ret; } EXPORT_SYMBOL_GPL(stmmac_resume);
--- base-commit: 7a036b5f83726ad5ea310fafae6cb7bb4c92072e change-id: 20260904-stmmac-ptp-error-propagate-6c0147b4ce29 Best regards, -- Lorenzo Bianconi [off-list ref]