[PATCH net-next v3 0/2] net: stmmac: dwxgmac2: timestamp interrupt + Agilex5 fix

[PATCH net-next v3 0/2] net: stmmac: dwxgmac2: timestamp interrupt + Agilex5 fix

[Zxyan Zhu]

This series adds auxiliary snapshot (EXTTS) interrupt support to
DWXGMAC2/DWXLGMAC2 and fixes a regression it would introduce on the
Agilex5 cross-timestamp path.

Patch 1 wires up a dedicated DWXGMAC2 timestamp interrupt handler.
Before this change the XGMAC hwif entries used the generic stmmac_ptp
ops, whose timestamp_interrupt callback read the dwmac4 offset
GMAC_TIMESTAMP_STATUS (0xb20) instead of the XGMAC register at 0xd20,
and XGMAC_TSIE was never enabled, so auxiliary snapshot events were
never reported on XGMAC platforms.

Patch 1 also unmasks XGMAC_TSIE in XGMAC_INT_DEFAULT_EN.  That makes the
new handler run from hardirq on every XGMAC timestamp event, which races
with the Agilex5 smtg_crosststamp() poll loop: the handler clears TSIS
by reading XGMAC_TIMESTAMP_STATUS before the poll loop in process
context can observe it, so getcrosststamp() times out.  Patch 2 fixes
this by masking XGMAC_TSIE for the duration of the cross-timestamp so
the handler cannot steal TSIS while smtg_crosststamp() owns the
snapshot FIFO.

Patch 2 has been verified on Agilex5 hardware: with both patches
applied, smtg_crosststamp() no times out (no "Wait for time sync
operation timeout" in dmesg) and the PTP clock registers and operates
normally.

v1: https://lore.kernel.org/netdev/20260806-dwxgmac2-timestamp-irq-v1-1-c051c79c9d90@gmail.com/
v2: https://lore.kernel.org/netdev/20260810100221.9166-1-zxyan0222@gmail.com/
v3:
- Add patch 2 to mask XGMAC_TSIE during the Agilex5 cross-timestamp, so
  enabling XGMAC_TSIE in patch 1 does not break getcrosststamp() on
  Agilex5 XGMAC (reported by the netdev sashiko review, fixed approach
  discussed with Maxime).
- Patch 2 verified on Agilex5 by Nazim Amirul (Tested-by tag carried on
  patch 2).

Zxyan Zhu (2):
  net: stmmac: dwxgmac2: add XGMAC timestamp interrupt support
  net: stmmac: dwmac-socfpga: mask XGMAC_TSIE during cross-timestamp

 .../ethernet/stmicro/stmmac/dwmac-socfpga.c   | 11 +++++
 .../net/ethernet/stmicro/stmmac/dwxgmac2.h    |  2 +-
 .../ethernet/stmicro/stmmac/dwxgmac2_core.c   | 43 +++++++++++++++++++
 drivers/net/ethernet/stmicro/stmmac/hwif.c    |  4 +-
 drivers/net/ethernet/stmicro/stmmac/hwif.h    |  1 +
 .../ethernet/stmicro/stmmac/stmmac_hwtstamp.c | 12 ++++++
 .../net/ethernet/stmicro/stmmac/stmmac_ptp.h  |  1 +
 7 files changed, 71 insertions(+), 3 deletions(-)

--
2.34.1

[PATCH net-next v3 1/2] net: stmmac: dwxgmac2: add XGMAC timestamp interrupt support

[Zxyan Zhu]

DWXGMAC2 uses XGMAC_TIMESTAMP_STATUS at offset 0xd20, while the
generic stmmac PTP handler reads the dwmac4 offset GMAC_TIMESTAMP_STATUS
(0xb20).  Before this change, the DWXGMAC2 and DWXLGMAC2 hwif entries
used &stmmac_ptp, whose timestamp_interrupt callback read the wrong
register and whose config_hw_tstamping callback never enabled the
XGMAC timestamp interrupt (XGMAC_TSIE was not in XGMAC_INT_DEFAULT_EN).
As a result, auxiliary snapshot events were never reported on XGMAC
platforms.

Add a dedicated DWXGMAC2 timestamp interrupt handler that:
- reads XGMAC_TIMESTAMP_STATUS before checking
  STMMAC_FLAG_EXT_SNAPSHOT_EN, so that the timestamp interrupt status is
  cleared even when auxiliary snapshots are disabled
- derives the pending auxiliary snapshot count from the persistent
  ATSNS field instead of the transient AUXTSTRIG status bit
- generates the corresponding PTP_CLOCK_EXTTS events

Also enable XGMAC_TSIE in XGMAC_INT_DEFAULT_EN and hook the new
handler into the DWXGMAC2 and DWXLGMAC2 hwif entries.

Signed-off-by: Zxyan Zhu <zxyan0222@gmail.com>
---
 .../net/ethernet/stmicro/stmmac/dwxgmac2.h    |  2 +-
 .../ethernet/stmicro/stmmac/dwxgmac2_core.c   | 43 +++++++++++++++++++
 drivers/net/ethernet/stmicro/stmmac/hwif.c    |  4 +-
 drivers/net/ethernet/stmicro/stmmac/hwif.h    |  1 +
 .../ethernet/stmicro/stmmac/stmmac_hwtstamp.c | 12 ++++++
 .../net/ethernet/stmicro/stmmac/stmmac_ptp.h  |  1 +
 6 files changed, 60 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h
index 61b6d45a02f5..76e2860a9517 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h
+++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h
@@ -87,7 +87,7 @@
 #define XGMAC_TSIE			BIT(12)
 #define XGMAC_LPIIE			BIT(5)
 #define XGMAC_PMTIE			BIT(4)
-#define XGMAC_INT_DEFAULT_EN		(XGMAC_LPIIE | XGMAC_PMTIE)
+#define XGMAC_INT_DEFAULT_EN		(XGMAC_LPIIE | XGMAC_PMTIE | XGMAC_TSIE)
 #define XGMAC_Qx_TX_FLOW_CTRL(x)	(0x00000070 + (x) * 4)
 #define XGMAC_PT			GENMASK(31, 16)
 #define XGMAC_TFE			BIT(1)
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
index f02b434bbd50..b849cebf9b29 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
@@ -1154,6 +1154,49 @@ static int dwxgmac2_get_mac_tx_timestamp(struct mac_device_info *hw, u64 *ts)
 	return 0;
 }
 
+void dwxgmac2_timestamp_interrupt(struct stmmac_priv *priv)
+{
+	u32 ts_status, pending_snapshots, acr_value, channel;
+	struct ptp_clock_event event;
+	unsigned long flags;
+	u64 ptp_time;
+	int i;
+
+	/* Read XGMAC_TIMESTAMP_STATUS to get the AUX snapshot
+	 * count.  This read also clears the TSIS bit in
+	 * XGMAC_INT_STATUS.
+	 * TX timestamp polling may have already cleared TSIS
+	 * and AUXTSTRIG, so rely on ATSNS instead.
+	 * TXTSC is cleared by XGMAC_TXTIMESTAMP_SEC, not by
+	 * this register, so there is no conflict.
+	 */
+	ts_status = readl(priv->ioaddr + XGMAC_TIMESTAMP_STATUS);
+
+	if (!(priv->plat->flags & STMMAC_FLAG_EXT_SNAPSHOT_EN))
+		return;
+
+	pending_snapshots = FIELD_GET(XGMAC_TIMESTAMP_ATSNS_MASK, ts_status);
+	if (!pending_snapshots)
+		return;
+
+	acr_value = readl(priv->ptpaddr + PTP_ACR);
+	channel = FIELD_GET(PTP_ACR_MASK, acr_value);
+	if (!channel)
+		return;
+	channel = ilog2(channel);
+
+	for (i = 0; i < pending_snapshots; i++) {
+		read_lock_irqsave(&priv->ptp_lock, flags);
+		stmmac_get_ptptime(priv, priv->ptpaddr, &ptp_time);
+		read_unlock_irqrestore(&priv->ptp_lock, flags);
+
+		event.type = PTP_CLOCK_EXTTS;
+		event.index = channel;
+		event.timestamp = ptp_time;
+		ptp_clock_event(priv->ptp_clock, &event);
+	}
+}
+
 static int dwxgmac2_flex_pps_config(void __iomem *ioaddr, int index,
 				    struct stmmac_pps_cfg *cfg, bool enable,
 				    u32 sub_second_inc, u32 systime_flags)
diff --git a/drivers/net/ethernet/stmicro/stmmac/hwif.c b/drivers/net/ethernet/stmicro/stmmac/hwif.c
index 511b0fd5e834..9718582b8480 100644
--- a/drivers/net/ethernet/stmicro/stmmac/hwif.c
+++ b/drivers/net/ethernet/stmicro/stmmac/hwif.c
@@ -258,7 +258,7 @@ static const struct stmmac_hwif_entry {
 		.dma = &dwxgmac210_dma_ops,
 		.mac = &dwxgmac210_ops,
 		.vlan = &dwxgmac210_vlan_ops,
-		.hwtimestamp = &stmmac_ptp,
+		.hwtimestamp = &dwxgmac2_ptp,
 		.ptp = &stmmac_ptp_clock_ops,
 		.mode = NULL,
 		.tc = &dwmac510_tc_ops,
@@ -280,7 +280,7 @@ static const struct stmmac_hwif_entry {
 		.dma = &dwxgmac210_dma_ops,
 		.mac = &dwxlgmac2_ops,
 		.vlan = &dwxlgmac2_vlan_ops,
-		.hwtimestamp = &stmmac_ptp,
+		.hwtimestamp = &dwxgmac2_ptp,
 		.ptp = &stmmac_ptp_clock_ops,
 		.mode = NULL,
 		.tc = &dwmac510_tc_ops,
diff --git a/drivers/net/ethernet/stmicro/stmmac/hwif.h b/drivers/net/ethernet/stmicro/stmmac/hwif.h
index e6317b94fff7..818ab3daa91c 100644
--- a/drivers/net/ethernet/stmicro/stmmac/hwif.h
+++ b/drivers/net/ethernet/stmicro/stmmac/hwif.h
@@ -671,6 +671,7 @@ extern const struct stmmac_desc_ops ndesc_ops;
 
 extern const struct stmmac_hwtimestamp stmmac_ptp;
 extern const struct stmmac_hwtimestamp dwmac1000_ptp;
+extern const struct stmmac_hwtimestamp dwxgmac2_ptp;
 
 extern const struct stmmac_mode_ops ring_mode_ops;
 extern const struct stmmac_mode_ops chain_mode_ops;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c
index b9a985fa772c..9d7d24259abd 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c
@@ -277,3 +277,15 @@ const struct stmmac_hwtimestamp dwmac1000_ptp = {
 	.get_ptptime = dwmac1000_get_ptptime,
 	.timestamp_interrupt = dwmac1000_timestamp_interrupt,
 };
+
+const struct stmmac_hwtimestamp dwxgmac2_ptp = {
+	.config_hw_tstamping = config_hw_tstamping,
+	.init_systime = init_systime,
+	.config_sub_second_increment = config_sub_second_increment,
+	.config_addend = config_addend,
+	.adjust_systime = adjust_systime,
+	.get_systime = get_systime,
+	.get_ptptime = get_ptptime,
+	.timestamp_interrupt = dwxgmac2_timestamp_interrupt,
+	.hwtstamp_correct_latency = hwtstamp_correct_latency,
+};
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.h b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.h
index 3fe0e3a80e80..dade09614163 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.h
@@ -103,6 +103,7 @@ int dwmac1000_ptp_enable(struct ptp_clock_info *ptp,
 
 void dwmac1000_get_ptptime(void __iomem *ptpaddr, u64 *ptp_time);
 void dwmac1000_timestamp_interrupt(struct stmmac_priv *priv);
+void dwxgmac2_timestamp_interrupt(struct stmmac_priv *priv);
 
 extern const struct ptp_clock_info stmmac_ptp_clock_ops;
 extern const struct ptp_clock_info dwmac1000_ptp_clock_ops;
-- 
2.34.1

[PATCH net-next v3 2/2] net: stmmac: dwmac-socfpga: mask XGMAC_TSIE during cross-timestamp

[Zxyan Zhu]

The Agilex5 smtg_crosststamp() handler arms an internal auxiliary
snapshot, toggles GPO0 and then polls XGMAC_INT_STATUS for TSIS in
process context to learn that the snapshot is ready.

Once XGMAC_TSIE is unmasked (done by a companion change that enables it
in XGMAC_INT_DEFAULT_EN), the DWXGMAC2 timestamp interrupt handler runs
from hardirq on every timestamp event and clears TSIS by reading
XGMAC_TIMESTAMP_STATUS.  That read can win the race against the poll
loop, which then times out and makes PTP_SYS_OFFSET_PRECISE fail with
"Wait for time sync operation timeout".

Mask XGMAC_TSIE around the snapshot trigger and FIFO read so the hardirq
handler cannot clear TSIS while smtg_crosststamp() owns it, and restore
it on every return path.

Tested-by: Nazim Amirul <muhammad.nazim.amirul.nazle.asmade@altera.com>
Signed-off-by: Zxyan Zhu <zxyan0222@gmail.com>
---
 drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c
index 1d7f0a57d288..a4d00bf81423 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c
@@ -310,6 +310,13 @@ static int smtg_crosststamp(ktime_t *device, struct system_counterval_t *system,
 	if (priv->plat->flags & STMMAC_FLAG_EXT_SNAPSHOT_EN)
 		return -EBUSY;
 
+	/* The XGMAC timestamp interrupt handler clears TSIS by reading
+	 * XGMAC_TIMESTAMP_STATUS, which would race with the TSIS poll
+	 * below.  Mask XGMAC_TSIE for the duration of the cross-timestamp
+	 * so the handler does not run while we own the snapshot FIFO.
+	 */
+	stmmac_mac_irq_modify(priv, XGMAC_TSIE, 0);
+
 	mutex_lock(&priv->aux_ts_lock);
 	/* Enable Internal snapshot trigger */
 	acr_value = readl(ptpaddr + PTP_ACR);
@@ -329,6 +336,7 @@ static int smtg_crosststamp(ktime_t *device, struct system_counterval_t *system,
 		break;
 	default:
 		mutex_unlock(&priv->aux_ts_lock);
+		stmmac_mac_irq_modify(priv, 0, XGMAC_TSIE);
 		return -EINVAL;
 	}
 	writel(acr_value, ptpaddr + PTP_ACR);
@@ -353,6 +361,7 @@ static int smtg_crosststamp(ktime_t *device, struct system_counterval_t *system,
 	ret = readl_poll_timeout(priv->ioaddr + XGMAC_INT_STATUS, v,
 				 (v & XGMAC_INT_TSIS), 100, 10000);
 	if (ret) {
+		stmmac_mac_irq_modify(priv, 0, XGMAC_TSIE);
 		netdev_err(priv->dev, "%s: Wait for time sync operation timeout\n",
 			   __func__);
 		return ret;
@@ -375,6 +384,8 @@ static int smtg_crosststamp(ktime_t *device, struct system_counterval_t *system,
 		read_unlock_irqrestore(&priv->ptp_lock, flags);
 	}
 
+	stmmac_mac_irq_modify(priv, 0, XGMAC_TSIE);
+
 	get_smtgtime(priv->mii, SMTG_MDIO_ADDR, &smtg_time);
 	system->cycles = smtg_time;
 
-- 
2.34.1

Re: [PATCH net-next v3 2/2] net: stmmac: dwmac-socfpga: mask XGMAC_TSIE during cross-timestamp

[Andrew Lunn]

On Tue, Aug 18, 2026 at 09:27:22PM +0800, Zxyan Zhu wrote:
> The Agilex5 smtg_crosststamp() handler arms an internal auxiliary
> snapshot, toggles GPO0 and then polls XGMAC_INT_STATUS for TSIS in
> process context to learn that the snapshot is ready.
> 
> Once XGMAC_TSIE is unmasked (done by a companion change that enables it
> in XGMAC_INT_DEFAULT_EN), the DWXGMAC2 timestamp interrupt handler runs
> from hardirq on every timestamp event and clears TSIS by reading
> XGMAC_TIMESTAMP_STATUS.  That read can win the race against the poll
> loop, which then times out and makes PTP_SYS_OFFSET_PRECISE fail with
> "Wait for time sync operation timeout".
> 
> Mask XGMAC_TSIE around the snapshot trigger and FIFO read so the hardirq
> handler cannot clear TSIS while smtg_crosststamp() owns it, and restore
> it on every return path.

Did you look at the other system which implement crosststamp?
dwmac-intel.c? Does it need similar changes?

	Andrew

Re: [PATCH net-next v3 0/2] net: stmmac: dwxgmac2: timestamp interrupt + Agilex5 fix

[Jakub Kicinski]

On Tue, 18 Aug 2026 21:27:20 +0800 Zxyan Zhu wrote:
> This series adds auxiliary snapshot (EXTTS) interrupt support to
> DWXGMAC2/DWXLGMAC2 and fixes a regression it would introduce on the
> Agilex5 cross-timestamp path.

## Form letter - net-next-closed

The merge window for v7.3 has started, and therefore net-next is closed
for new drivers, features, code refactoring and optimizations.
We will only consider applying net-next patches which were posted
before the announcement:

https://lore.kernel.org/20260816155953.072d73da@kernel.org

Fixes are obviously welcome at any time. net-next patches may be sent
for review and discussion only with an RFC tag.

Please repost when net-next reopens.

See: https://www.kernel.org/doc/html/next/process/maintainer-netdev.html#development-cycle
-- 
pw-bot: defer
pv-bot: closed