net: stmmac: Add support for external trigger timestamping

The Synopsis MAC controller supports auxiliary snapshot feature that
allows user to store a snapshot of the system time based on an external
event.

This patch add supports to the above mentioned feature. Users will be
able to triggered capturing the time snapshot from user-space using
application such as testptp or any other applications that uses the
PTP_EXTTS_REQUEST ioctl request.

Cc: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Tan Tee Min <tee.min.tan@intel.com>
Co-developed-by: Wong Vee Khee <vee.khee.wong@linux.intel.com>
Signed-off-by: Wong Vee Khee <vee.khee.wong@linux.intel.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c

@@ -296,6 +296,13 @@ static int intel_crosststamp(ktime_t *device,
 
 	intel_priv = priv->plat->bsp_priv;
 
+	/* Both internal crosstimestamping and external triggered event
+	 * timestamping cannot be run concurrently.
+	 */
+	if (priv->plat->ext_snapshot_en)
+		return -EBUSY;
+
+	mutex_lock(&priv->aux_ts_lock);
 	/* Enable Internal snapshot trigger */
 	acr_value = readl(ptpaddr + PTP_ACR);
 	acr_value &= ~PTP_ACR_MASK;
@@ -321,6 +328,8 @@ static int intel_crosststamp(ktime_t *device,
 	acr_value = readl(ptpaddr + PTP_ACR);
 	acr_value |= PTP_ACR_ATSFC;
 	writel(acr_value, ptpaddr + PTP_ACR);
+	/* Release the mutex */
+	mutex_unlock(&priv->aux_ts_lock);
 
 	/* Trigger Internal snapshot signal
 	 * Create a rising edge by just toggle the GPO1 to low
@@ -520,6 +529,7 @@ 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->has_crossts = true;
 	plat->crosststamp = intel_crosststamp;

drivers/net/ethernet/stmicro/stmmac/hwif.h

@@ -504,6 +504,8 @@ struct stmmac_ops {
 #define stmmac_fpe_irq_status(__priv, __args...) \
 	stmmac_do_callback(__priv, mac, fpe_irq_status, __args)
 
+struct stmmac_priv;
+
 /* PTP and HW Timer helpers */
 struct stmmac_hwtimestamp {
 	void (*config_hw_tstamping) (void __iomem *ioaddr, u32 data);
@@ -515,6 +517,7 @@ struct stmmac_hwtimestamp {
 			       int add_sub, int gmac4);
 	void (*get_systime) (void __iomem *ioaddr, u64 *systime);
 	void (*get_ptptime)(void __iomem *ioaddr, u64 *ptp_time);
+	void (*timestamp_interrupt)(struct stmmac_priv *priv);
 };
 
 #define stmmac_config_hw_tstamping(__priv, __args...) \
@@ -531,6 +534,8 @@ struct stmmac_hwtimestamp {
 	stmmac_do_void_callback(__priv, ptp, get_systime, __args)
 #define stmmac_get_ptptime(__priv, __args...) \
 	stmmac_do_void_callback(__priv, ptp, get_ptptime, __args)
+#define stmmac_timestamp_interrupt(__priv, __args...) \
+	stmmac_do_void_callback(__priv, ptp, timestamp_interrupt, __args)
 
 /* Helpers to manage the descriptors for chain and ring modes */
 struct stmmac_mode_ops {

drivers/net/ethernet/stmicro/stmmac/stmmac.h

@@ -250,6 +250,9 @@ struct stmmac_priv {
 	int use_riwt;
 	int irq_wake;
 	spinlock_t ptp_lock;
+	/* Protects auxiliary snapshot registers from concurrent access. */
+	struct mutex aux_ts_lock;
+
 	void __iomem *mmcaddr;
 	void __iomem *ptpaddr;
 	unsigned long active_vlans[BITS_TO_LONGS(VLAN_N_VID)];

drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c

@@ -12,8 +12,11 @@
 #include <linux/io.h>
 #include <linux/iopoll.h>
 #include <linux/delay.h>
+#include <linux/ptp_clock_kernel.h>
 #include "common.h"
 #include "stmmac_ptp.h"
+#include "dwmac4.h"
+#include "stmmac.h"
 
 static void config_hw_tstamping(void __iomem *ioaddr, u32 data)
 {
@@ -163,6 +166,41 @@ static void get_ptptime(void __iomem *ptpaddr, u64 *ptp_time)
 	*ptp_time = ns;
 }
 
+static void timestamp_interrupt(struct stmmac_priv *priv)
+{
+	u32 num_snapshot, ts_status, tsync_int;
+	struct ptp_clock_event event;
+	unsigned long flags;
+	u64 ptp_time;
+	int i;
+
+	tsync_int = readl(priv->ioaddr + GMAC_INT_STATUS) & GMAC_INT_TSIE;
+
+	if (!tsync_int)
+		return;
+
+	/* Read timestamp status to clear interrupt from either external
+	 * timestamp or start/end of PPS.
+	 */
+	ts_status = readl(priv->ioaddr + GMAC_TIMESTAMP_STATUS);
+
+	if (!priv->plat->ext_snapshot_en)
+		return;
+
+	num_snapshot = (ts_status & GMAC_TIMESTAMP_ATSNS_MASK) >>
+		       GMAC_TIMESTAMP_ATSNS_SHIFT;
+
+	for (i = 0; i < num_snapshot; i++) {
+		spin_lock_irqsave(&priv->ptp_lock, flags);
+		get_ptptime(priv->ptpaddr, &ptp_time);
+		spin_unlock_irqrestore(&priv->ptp_lock, flags);
+		event.type = PTP_CLOCK_EXTTS;
+		event.index = 0;
+		event.timestamp = ptp_time;
+		ptp_clock_event(priv->ptp_clock, &event);
+	}
+}
+
 const struct stmmac_hwtimestamp stmmac_ptp = {
 	.config_hw_tstamping = config_hw_tstamping,
 	.init_systime = init_systime,
@@ -171,4 +209,5 @@ const struct stmmac_hwtimestamp stmmac_ptp = {
 	.adjust_systime = adjust_systime,
 	.get_systime = get_systime,
 	.get_ptptime = get_ptptime,
+	.timestamp_interrupt = timestamp_interrupt,
 };

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -5687,6 +5687,8 @@ static void stmmac_common_interrupt(struct stmmac_priv *priv)
 			else
 				netif_carrier_off(priv->dev);
 		}
+
+		stmmac_timestamp_interrupt(priv, priv);
 	}
 }
 

drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c

@@ -135,7 +135,10 @@ static int stmmac_enable(struct ptp_clock_info *ptp,
 {
 	struct stmmac_priv *priv =
 	    container_of(ptp, struct stmmac_priv, ptp_clock_ops);
+	void __iomem *ptpaddr = priv->ptpaddr;
+	void __iomem *ioaddr = priv->hw->pcsr;
 	struct stmmac_pps_cfg *cfg;
+	u32 intr_value, acr_value;
 	int ret = -EOPNOTSUPP;
 	unsigned long flags;
 
@@ -159,6 +162,37 @@ static int stmmac_enable(struct ptp_clock_info *ptp,
 					     priv->systime_flags);
 		spin_unlock_irqrestore(&priv->ptp_lock, flags);
 		break;
+	case PTP_CLK_REQ_EXTTS:
+		priv->plat->ext_snapshot_en = on;
+		mutex_lock(&priv->aux_ts_lock);
+		acr_value = readl(ptpaddr + PTP_ACR);
+		acr_value &= ~PTP_ACR_MASK;
+		if (on) {
+			/* Enable External snapshot trigger */
+			acr_value |= priv->plat->ext_snapshot_num;
+			acr_value |= PTP_ACR_ATSFC;
+			netdev_dbg(priv->dev, "Auxiliary Snapshot %d enabled.\n",
+				   priv->plat->ext_snapshot_num >>
+				   PTP_ACR_ATSEN_SHIFT);
+			/* Enable Timestamp Interrupt */
+			intr_value = readl(ioaddr + GMAC_INT_EN);
+			intr_value |= GMAC_INT_TSIE;
+			writel(intr_value, ioaddr + GMAC_INT_EN);
+
+		} else {
+			netdev_dbg(priv->dev, "Auxiliary Snapshot %d disabled.\n",
+				   priv->plat->ext_snapshot_num >>
+				   PTP_ACR_ATSEN_SHIFT);
+			/* Disable Timestamp Interrupt */
+			intr_value = readl(ioaddr + GMAC_INT_EN);
+			intr_value &= ~GMAC_INT_TSIE;
+			writel(intr_value, ioaddr + GMAC_INT_EN);
+		}
+		writel(acr_value, ptpaddr + PTP_ACR);
+		mutex_unlock(&priv->aux_ts_lock);
+		ret = 0;
+		break;
+
 	default:
 		break;
 	}
@@ -202,7 +236,7 @@ static struct ptp_clock_info stmmac_ptp_clock_ops = {
 	.name = "stmmac ptp",
 	.max_adj = 62500000,
 	.n_alarm = 0,
-	.n_ext_ts = 0,
+	.n_ext_ts = 0, /* will be overwritten in stmmac_ptp_register */
 	.n_per_out = 0, /* will be overwritten in stmmac_ptp_register */
 	.n_pins = 0,
 	.pps = 0,
@@ -237,8 +271,10 @@ void stmmac_ptp_register(struct stmmac_priv *priv)
 		stmmac_ptp_clock_ops.max_adj = priv->plat->ptp_max_adj;
 
 	stmmac_ptp_clock_ops.n_per_out = priv->dma_cap.pps_out_num;
+	stmmac_ptp_clock_ops.n_ext_ts = priv->dma_cap.aux_snapshot_n;
 
 	spin_lock_init(&priv->ptp_lock);
+	mutex_init(&priv->aux_ts_lock);
 	priv->ptp_clock_ops = stmmac_ptp_clock_ops;
 
 	priv->ptp_clock = ptp_clock_register(&priv->ptp_clock_ops,
@@ -264,4 +300,6 @@ void stmmac_ptp_unregister(struct stmmac_priv *priv)
 		pr_debug("Removed PTP HW clock successfully on %s\n",
 			 priv->dev->name);
 	}
+
+	mutex_destroy(&priv->aux_ts_lock);
 }

drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.h

@@ -73,6 +73,7 @@
 #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_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 */

include/linux/stmmac.h

@@ -238,6 +238,8 @@ struct plat_stmmacenet_data {
 	struct pci_dev *pdev;
 	bool has_crossts;
 	int int_snapshot_num;
+	int ext_snapshot_num;
+	bool ext_snapshot_en;
 	bool multi_msi_en;
 	int msi_mac_vec;
 	int msi_wol_vec;