net: mscc: PTP Hardware Clock (PHC) support

This patch adds support for PTP Hardware Clock (PHC) to the Ocelot
switch for both PTP 1-step and 2-step modes.
Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mscc/ocelot.h

@@ -11,9 +11,11 @@
 #include <linux/bitops.h>
 #include <linux/etherdevice.h>
 #include <linux/if_vlan.h>
+#include <linux/net_tstamp.h>
 #include <linux/phy.h>
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
+#include <linux/ptp_clock_kernel.h>
 #include <linux/regmap.h>
 
 #include "ocelot_ana.h"
@@ -39,6 +41,8 @@
 
 #define OCELOT_STATS_CHECK_DELAY (2 * HZ)
 
+#define OCELOT_PTP_QUEUE_SZ	128
+
 #define IFH_LEN 4
 
 struct frame_info {
@@ -46,6 +50,8 @@ struct frame_info {
 	u16 port;
 	u16 vid;
 	u8 tag_type;
+	u16 rew_op;
+	u32 timestamp;	/* rew_val */
 };
 
 #define IFH_INJ_BYPASS	BIT(31)
@@ -54,6 +60,12 @@ struct frame_info {
 #define IFH_TAG_TYPE_C 0
 #define IFH_TAG_TYPE_S 1
 
+#define IFH_REW_OP_NOOP			0x0
+#define IFH_REW_OP_DSCP			0x1
+#define IFH_REW_OP_ONE_STEP_PTP		0x2
+#define IFH_REW_OP_TWO_STEP_PTP		0x3
+#define IFH_REW_OP_ORIGIN_PTP		0x5
+
 #define OCELOT_SPEED_2500 0
 #define OCELOT_SPEED_1000 1
 #define OCELOT_SPEED_100  2
@@ -401,6 +413,13 @@ enum ocelot_regfield {
 	REGFIELD_MAX
 };
 
+enum ocelot_clk_pins {
+	ALT_PPS_PIN	= 1,
+	EXT_CLK_PIN,
+	ALT_LDST_PIN,
+	TOD_ACC_PIN
+};
+
 struct ocelot_multicast {
 	struct list_head list;
 	unsigned char addr[ETH_ALEN];
@@ -450,6 +469,13 @@ struct ocelot {
 	u64 *stats;
 	struct delayed_work stats_work;
 	struct workqueue_struct *stats_queue;
+
+	u8 ptp:1;
+	struct ptp_clock *ptp_clock;
+	struct ptp_clock_info ptp_info;
+	struct hwtstamp_config hwtstamp_config;
+	struct mutex ptp_lock; /* Protects the PTP interface state */
+	spinlock_t ptp_clock_lock; /* Protects the PTP clock */
 };
 
 struct ocelot_port {
@@ -473,6 +499,16 @@ struct ocelot_port {
 	struct phy *serdes;
 
 	struct ocelot_port_tc tc;
+
+	u8 ptp_cmd;
+	struct list_head skbs;
+	u8 ts_id;
+};
+
+struct ocelot_skb {
+	struct list_head head;
+	struct sk_buff *skb;
+	u8 id;
 };
 
 u32 __ocelot_read_ix(struct ocelot *ocelot, u32 reg, u32 offset);
@@ -517,4 +553,7 @@ extern struct notifier_block ocelot_netdevice_nb;
 extern struct notifier_block ocelot_switchdev_nb;
 extern struct notifier_block ocelot_switchdev_blocking_nb;
 
+int ocelot_ptp_gettime64(struct ptp_clock_info *ptp, struct timespec64 *ts);
+void ocelot_get_hwtimestamp(struct ocelot *ocelot, struct timespec64 *ts);
+
 #endif

drivers/net/ethernet/mscc/ocelot_board.c

@@ -31,6 +31,8 @@ static int ocelot_parse_ifh(u32 *_ifh, struct frame_info *info)
 
 	info->len = OCELOT_BUFFER_CELL_SZ * wlen + llen - 80;
 
+	info->timestamp = IFH_EXTRACT_BITFIELD64(ifh[0], 21, 32);
+
 	info->port = IFH_EXTRACT_BITFIELD64(ifh[1], 43, 4);
 
 	info->tag_type = IFH_EXTRACT_BITFIELD64(ifh[1], 16,  1);
@@ -92,13 +94,14 @@ static irqreturn_t ocelot_xtr_irq_handler(int irq, void *arg)
 		return IRQ_NONE;
 
 	do {
-		struct sk_buff *skb;
+		struct skb_shared_hwtstamps *shhwtstamps;
+		u64 tod_in_ns, full_ts_in_ns;
+		struct frame_info info = {};
 		struct net_device *dev;
-		u32 *buf;
+		u32 ifh[4], val, *buf;
+		struct timespec64 ts;
 		int sz, len, buf_len;
-		u32 ifh[4];
-		u32 val;
-		struct frame_info info;
+		struct sk_buff *skb;
 
 		for (i = 0; i < IFH_LEN; i++) {
 			err = ocelot_rx_frame_word(ocelot, grp, true, &ifh[i]);
@@ -145,6 +148,22 @@ static irqreturn_t ocelot_xtr_irq_handler(int irq, void *arg)
 			break;
 		}
 
+		if (ocelot->ptp) {
+			ocelot_ptp_gettime64(&ocelot->ptp_info, &ts);
+
+			tod_in_ns = ktime_set(ts.tv_sec, ts.tv_nsec);
+			if ((tod_in_ns & 0xffffffff) < info.timestamp)
+				full_ts_in_ns = (((tod_in_ns >> 32) - 1) << 32) |
+						info.timestamp;
+			else
+				full_ts_in_ns = (tod_in_ns & GENMASK_ULL(63, 32)) |
+						info.timestamp;
+
+			shhwtstamps = skb_hwtstamps(skb);
+			memset(shhwtstamps, 0, sizeof(struct skb_shared_hwtstamps));
+			shhwtstamps->hwtstamp = full_ts_in_ns;
+		}
+
 		/* Everything we see on an interface that is in the HW bridge
 		 * has already been forwarded.
 		 */
@@ -164,6 +183,66 @@ static irqreturn_t ocelot_xtr_irq_handler(int irq, void *arg)
 	return IRQ_HANDLED;
 }
 
+static irqreturn_t ocelot_ptp_rdy_irq_handler(int irq, void *arg)
+{
+	int budget = OCELOT_PTP_QUEUE_SZ;
+	struct ocelot *ocelot = arg;
+
+	while (budget--) {
+		struct skb_shared_hwtstamps shhwtstamps;
+		struct list_head *pos, *tmp;
+		struct sk_buff *skb = NULL;
+		struct ocelot_skb *entry;
+		struct ocelot_port *port;
+		struct timespec64 ts;
+		u32 val, id, txport;
+
+		val = ocelot_read(ocelot, SYS_PTP_STATUS);
+
+		/* Check if a timestamp can be retrieved */
+		if (!(val & SYS_PTP_STATUS_PTP_MESS_VLD))
+			break;
+
+		WARN_ON(val & SYS_PTP_STATUS_PTP_OVFL);
+
+		/* Retrieve the ts ID and Tx port */
+		id = SYS_PTP_STATUS_PTP_MESS_ID_X(val);
+		txport = SYS_PTP_STATUS_PTP_MESS_TXPORT_X(val);
+
+		/* Retrieve its associated skb */
+		port = ocelot->ports[txport];
+
+		list_for_each_safe(pos, tmp, &port->skbs) {
+			entry = list_entry(pos, struct ocelot_skb, head);
+			if (entry->id != id)
+				continue;
+
+			skb = entry->skb;
+
+			list_del(pos);
+			kfree(entry);
+		}
+
+		/* Next ts */
+		ocelot_write(ocelot, SYS_PTP_NXT_PTP_NXT, SYS_PTP_NXT);
+
+		if (unlikely(!skb))
+			continue;
+
+		/* Get the h/w timestamp */
+		ocelot_get_hwtimestamp(ocelot, &ts);
+
+		/* Set the timestamp into the skb */
+		memset(&shhwtstamps, 0, sizeof(shhwtstamps));
+		shhwtstamps.hwtstamp = ktime_set(ts.tv_sec, ts.tv_nsec);
+		skb_tstamp_tx(skb, &shhwtstamps);
+
+		dev_kfree_skb_any(skb);
+	}
+
+	return IRQ_HANDLED;
+}
+
 static const struct of_device_id mscc_ocelot_match[] = {
 	{ .compatible = "mscc,vsc7514-switch" },
 	{ }
@@ -172,12 +251,12 @@ MODULE_DEVICE_TABLE(of, mscc_ocelot_match);
 
 static int mscc_ocelot_probe(struct platform_device *pdev)
 {
-	int err, irq;
-	unsigned int i;
 	struct device_node *np = pdev->dev.of_node;
 	struct device_node *ports, *portnp;
+	int err, irq_xtr, irq_ptp_rdy;
 	struct ocelot *ocelot;
 	struct regmap *hsio;
+	unsigned int i;
 	u32 val;
 
 	struct {
@@ -232,16 +311,29 @@ static int mscc_ocelot_probe(struct platform_device *pdev)
 	if (err)
 		return err;
 
-	irq = platform_get_irq_byname(pdev, "xtr");
-	if (irq < 0)
+	irq_xtr = platform_get_irq_byname(pdev, "xtr");
+	if (irq_xtr < 0)
 		return -ENODEV;
 
-	err = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+	err = devm_request_threaded_irq(&pdev->dev, irq_xtr, NULL,
 					ocelot_xtr_irq_handler, IRQF_ONESHOT,
 					"frame extraction", ocelot);
 	if (err)
 		return err;
 
+	irq_ptp_rdy = platform_get_irq_byname(pdev, "ptp_rdy");
+	if (irq_ptp_rdy > 0 && ocelot->targets[PTP]) {
+		err = devm_request_threaded_irq(&pdev->dev, irq_ptp_rdy, NULL,
+						ocelot_ptp_rdy_irq_handler,
+						IRQF_ONESHOT, "ptp ready",
+						ocelot);
+		if (err)
+			return err;
+
+		/* Both the PTP interrupt and the PTP bank are available */
+		ocelot->ptp = 1;
+	}
+
 	regmap_field_write(ocelot->regfields[SYS_RESET_CFG_MEM_INIT], 1);
 	regmap_field_write(ocelot->regfields[SYS_RESET_CFG_MEM_ENA], 1);