Merge branch 'net-stmmac-use-correct-pps-input-indexing'

Johannes Zink says:

====================
net: stmmac: use correct PPS input indexing

The stmmac can have 0 to 4 auxiliary snapshot in channels, which can be
used for capturing external triggers with respect to the eqos PTP timer.

Previously when enabling the auxiliary snapshot, an invalid request was
written to the hardware register, except for the Intel variant of this
driver, where the only snapshot available was hardcoded.

Patch 1 of this series cleans up the debug netdev_dbg message indicating
the auxiliary snapshot being {en,dis}abled. No functional changes here

Patch 2 of this series writes the correct PPS input indexing to the
hardware registers instead of a previously used fixed value

Patch 3 of this series removes a field member from plat_stmmacnet_data
that is no longer needed

Patch 4 of this series prepares Patch 5 by protecting the snapshot
enabled flag by the aux_ts_lock mutex

Patch 5 of this series adds a temporary workaround, since at the moment
the driver can handle only one single auxiliary snapshot at a time.
Previously the driver silently dropped the previous configuration and
enabled the new one. Now, if a snapshot is already enabled and userspace
tries to enable another without previously disabling the snapshot currently
enabled: issue a netdev_err and return an errorcode indicating the device is
busy.

This series is a "never worked, doesn't hurt anyone" touchup to the PPS
capture for non-intel variants of the dwmac driver.
====================

Link: https://lore.kernel.org/r/20231010-stmmac_fix_auxiliary_event_capture-v2-0-51d5f56542d7@pengutronix.de
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

4 files changed, 21 insertions, 15 deletions

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c
index a3a249c63598..60283543ffc8 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c
@@ -605,7 +605,6 @@ static int intel_mgbe_common_data(struct pci_dev *pdev,
 	plat->mdio_bus_data->phy_mask |= 1 << INTEL_MGBE_XPCS_ADDR;
 
 	plat->int_snapshot_num = AUX_SNAPSHOT1;
-	plat->ext_snapshot_num = AUX_SNAPSHOT0;
 
 	plat->crosststamp = intel_crosststamp;
 	plat->flags &= ~STMMAC_FLAG_INT_SNAPSHOT_EN;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
index 1be06b96c35f..bffa5c017032 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
@@ -191,26 +191,33 @@ static int stmmac_enable(struct ptp_clock_info *ptp,
 					     priv->systime_flags);
 		write_unlock_irqrestore(&priv->ptp_lock, flags);
 		break;
-	case PTP_CLK_REQ_EXTTS:
-		if (on)
-			priv->plat->flags |= STMMAC_FLAG_EXT_SNAPSHOT_EN;
-		else
-			priv->plat->flags &= ~STMMAC_FLAG_EXT_SNAPSHOT_EN;
+	case PTP_CLK_REQ_EXTTS: {
+		u8 channel;
+
 		mutex_lock(&priv->aux_ts_lock);
 		acr_value = readl(ptpaddr + PTP_ACR);
+		channel = ilog2(FIELD_GET(PTP_ACR_MASK, acr_value));
 		acr_value &= ~PTP_ACR_MASK;
+
 		if (on) {
+			if (FIELD_GET(PTP_ACR_MASK, acr_value)) {
+				netdev_err(priv->dev,
+					   "Cannot enable auxiliary snapshot %d as auxiliary snapshot %d is already enabled",
+					rq->extts.index, channel);
+				mutex_unlock(&priv->aux_ts_lock);
+				return -EBUSY;
+			}
+
+			priv->plat->flags |= STMMAC_FLAG_EXT_SNAPSHOT_EN;
+
 			/* Enable External snapshot trigger */
-			acr_value |= priv->plat->ext_snapshot_num;
+			acr_value |= PTP_ACR_ATSEN(rq->extts.index);
 			acr_value |= PTP_ACR_ATSFC;
-			netdev_dbg(priv->dev, "Auxiliary Snapshot %d enabled.\n",
-				   priv->plat->ext_snapshot_num >>
-				   PTP_ACR_ATSEN_SHIFT);
 		} else {
-			netdev_dbg(priv->dev, "Auxiliary Snapshot %d disabled.\n",
-				   priv->plat->ext_snapshot_num >>
-				   PTP_ACR_ATSEN_SHIFT);
+			priv->plat->flags &= ~STMMAC_FLAG_EXT_SNAPSHOT_EN;
 		}
+		netdev_dbg(priv->dev, "Auxiliary Snapshot %d %s.\n",
+			   rq->extts.index, on ? "enabled" : "disabled");
 		writel(acr_value, ptpaddr + PTP_ACR);
 		mutex_unlock(&priv->aux_ts_lock);
 		/* wait for auxts fifo clear to finish */
@@ -218,6 +225,7 @@ static int stmmac_enable(struct ptp_clock_info *ptp,
 					 !(acr_value & PTP_ACR_ATSFC),
 					 10, 10000);
 		break;
+	}
 
 	default:
 		break;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.h b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.h
index d1fe4b46f162..fce3fba2ffd2 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.h
@@ -79,7 +79,7 @@
 #define	PTP_ACR_ATSEN1		BIT(5)	/* Auxiliary Snapshot 1 Enable */
 #define	PTP_ACR_ATSEN2		BIT(6)	/* Auxiliary Snapshot 2 Enable */
 #define	PTP_ACR_ATSEN3		BIT(7)	/* Auxiliary Snapshot 3 Enable */
-#define	PTP_ACR_ATSEN_SHIFT	5	/* Auxiliary Snapshot shift */
+#define	PTP_ACR_ATSEN(index)	(PTP_ACR_ATSEN0 << (index))
 #define	PTP_ACR_MASK		GENMASK(7, 4)	/* Aux Snapshot Mask */
 #define	PMC_ART_VALUE0		0x01	/* PMC_ART[15:0] timer value */
 #define	PMC_ART_VALUE1		0x02	/* PMC_ART[31:16] timer value */
diff --git a/include/linux/stmmac.h b/include/linux/stmmac.h
index c0079a7574ae..0b4658a7eceb 100644
--- a/include/linux/stmmac.h
+++ b/include/linux/stmmac.h
@@ -303,7 +303,6 @@ struct plat_stmmacenet_data {
 	unsigned int eee_usecs_rate;
 	struct pci_dev *pdev;
 	int int_snapshot_num;
-	int ext_snapshot_num;
 	int msi_mac_vec;
 	int msi_wol_vec;
 	int msi_lpi_vec;