[PATCH net v2] net: stmmac: propagate PTP init failures in __stmmac_open() and stmmac_resume()
From: Lorenzo Bianconi
Date: Mon Sep 07 2026 - 08:03:36 EST
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 <lorenzo.bianconi@xxxxxxxxxxxxxxxx>
---
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@xxxxxxxxxxxxxxxx
---
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 <lorenzo.bianconi@xxxxxxxxxxxxxxxx>