net: dsa: microchip: ptp: add packet transmission timestamping

This patch adds the routines for transmission of ptp packets. When the
ptp pdelay_req packet to be transmitted, it uses the deferred xmit
worker to schedule the packets.
During irq_setup, interrupt for Sync, Pdelay_req and Pdelay_rsp are
enabled. So interrupt is triggered for all three packets. But for
p2p1step, we require only time stamp of Pdelay_req packet. Hence to
avoid posting of the completion from ISR routine for Sync and
Pdelay_resp packets, ts_en flag is introduced. This controls which
packets need to processed for timestamp.
After the packet is transmitted, ISR is triggered. The time at which
packet transmitted is recorded to separate register.
This value is reconstructed to absolute time and posted to the user
application through socket error queue.

Signed-off-by: Christian Eggers <ceggers@arri.de>
Co-developed-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 137 insertions, 1 deletions

diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c
index b4e7d579ac51..5e1e5bd555d2 100644
--- a/drivers/net/dsa/microchip/ksz_common.c
+++ b/drivers/net/dsa/microchip/ksz_common.c
@@ -6,6 +6,7 @@
  */
 
 #include <linux/delay.h>
+#include <linux/dsa/ksz_common.h>
 #include <linux/export.h>
 #include <linux/gpio/consumer.h>
 #include <linux/kernel.h>
@@ -2539,6 +2540,17 @@ static enum dsa_tag_protocol ksz_get_tag_protocol(struct dsa_switch *ds,
 	return proto;
 }
 
+static int ksz_connect_tag_protocol(struct dsa_switch *ds,
+				    enum dsa_tag_protocol proto)
+{
+	struct ksz_tagger_data *tagger_data;
+
+	tagger_data = ksz_tagger_data(ds);
+	tagger_data->xmit_work_fn = ksz_port_deferred_xmit;
+
+	return 0;
+}
+
 static int ksz_port_vlan_filtering(struct dsa_switch *ds, int port,
 				   bool flag, struct netlink_ext_ack *extack)
 {
@@ -2954,6 +2966,7 @@ static int ksz_switch_detect(struct ksz_device *dev)
 
 static const struct dsa_switch_ops ksz_switch_ops = {
 	.get_tag_protocol	= ksz_get_tag_protocol,
+	.connect_tag_protocol   = ksz_connect_tag_protocol,
 	.get_phy_flags		= ksz_get_phy_flags,
 	.setup			= ksz_setup,
 	.teardown		= ksz_teardown,
@@ -2991,6 +3004,7 @@ static const struct dsa_switch_ops ksz_switch_ops = {
 	.get_ts_info		= ksz_get_ts_info,
 	.port_hwtstamp_get	= ksz_hwtstamp_get,
 	.port_hwtstamp_set	= ksz_hwtstamp_set,
+	.port_txtstamp		= ksz_port_txtstamp,
 	.port_rxtstamp		= ksz_port_rxtstamp,
 };
 
diff --git a/drivers/net/dsa/microchip/ksz_common.h b/drivers/net/dsa/microchip/ksz_common.h
index ec1bceb4efcc..c8b49c86dfe1 100644
--- a/drivers/net/dsa/microchip/ksz_common.h
+++ b/drivers/net/dsa/microchip/ksz_common.h
@@ -87,6 +87,7 @@ struct ksz_irq {
 struct ksz_ptp_irq {
 	struct ksz_port *port;
 	u16 ts_reg;
+	bool ts_en;
 	char name[16];
 	int num;
 };
@@ -116,6 +117,8 @@ struct ksz_port {
 	bool hwts_rx_en;
 	struct ksz_irq ptpirq;
 	struct ksz_ptp_irq ptpmsg_irq[3];
+	ktime_t tstamp_msg;
+	struct completion tstamp_msg_comp;
 #endif
 };
 
diff --git a/drivers/net/dsa/microchip/ksz_ptp.c b/drivers/net/dsa/microchip/ksz_ptp.c
index 29413fb608ed..6edce141cbd7 100644
--- a/drivers/net/dsa/microchip/ksz_ptp.c
+++ b/drivers/net/dsa/microchip/ksz_ptp.c
@@ -18,6 +18,8 @@
 
 #define ptp_caps_to_data(d) container_of((d), struct ksz_ptp_data, caps)
 #define ptp_data_to_ksz_dev(d) container_of((d), struct ksz_device, ptp_data)
+#define work_to_xmit_work(w) \
+		container_of((w), struct ksz_deferred_xmit_work, work)
 
 /* Sub-nanoseconds-adj,max * sub-nanoseconds / 40ns * 1ns
  * = (2^30-1) * (2 ^ 32) / 40 ns * 1 ns = 6249999
@@ -111,9 +113,15 @@ static int ksz_set_hwtstamp_config(struct ksz_device *dev,
 
 	switch (config->tx_type) {
 	case HWTSTAMP_TX_OFF:
+		prt->ptpmsg_irq[KSZ_SYNC_MSG].ts_en  = false;
+		prt->ptpmsg_irq[KSZ_XDREQ_MSG].ts_en = false;
+		prt->ptpmsg_irq[KSZ_PDRES_MSG].ts_en = false;
 		prt->hwts_tx_en = false;
 		break;
 	case HWTSTAMP_TX_ONESTEP_P2P:
+		prt->ptpmsg_irq[KSZ_SYNC_MSG].ts_en  = false;
+		prt->ptpmsg_irq[KSZ_XDREQ_MSG].ts_en = true;
+		prt->ptpmsg_irq[KSZ_PDRES_MSG].ts_en = false;
 		prt->hwts_tx_en = true;
 		break;
 	default:
@@ -232,6 +240,87 @@ out:
 	return false;
 }
 
+void ksz_port_txtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb)
+{
+	struct ksz_device *dev = ds->priv;
+	struct ptp_header *hdr;
+	struct sk_buff *clone;
+	struct ksz_port *prt;
+	unsigned int type;
+	u8 ptp_msg_type;
+
+	prt = &dev->ports[port];
+
+	if (!prt->hwts_tx_en)
+		return;
+
+	type = ptp_classify_raw(skb);
+	if (type == PTP_CLASS_NONE)
+		return;
+
+	hdr = ptp_parse_header(skb, type);
+	if (!hdr)
+		return;
+
+	ptp_msg_type = ptp_get_msgtype(hdr, type);
+
+	switch (ptp_msg_type) {
+	case PTP_MSGTYPE_PDELAY_REQ:
+		break;
+
+	default:
+		return;
+	}
+
+	clone = skb_clone_sk(skb);
+	if (!clone)
+		return;
+
+	/* caching the value to be used in tag_ksz.c */
+	KSZ_SKB_CB(skb)->clone = clone;
+}
+
+static void ksz_ptp_txtstamp_skb(struct ksz_device *dev,
+				 struct ksz_port *prt, struct sk_buff *skb)
+{
+	struct skb_shared_hwtstamps hwtstamps = {};
+	int ret;
+
+	/* timeout must include DSA master to transmit data, tstamp latency,
+	 * IRQ latency and time for reading the time stamp.
+	 */
+	ret = wait_for_completion_timeout(&prt->tstamp_msg_comp,
+					  msecs_to_jiffies(100));
+	if (!ret)
+		return;
+
+	hwtstamps.hwtstamp = prt->tstamp_msg;
+	skb_complete_tx_timestamp(skb, &hwtstamps);
+}
+
+void ksz_port_deferred_xmit(struct kthread_work *work)
+{
+	struct ksz_deferred_xmit_work *xmit_work = work_to_xmit_work(work);
+	struct sk_buff *clone, *skb = xmit_work->skb;
+	struct dsa_switch *ds = xmit_work->dp->ds;
+	struct ksz_device *dev = ds->priv;
+	struct ksz_port *prt;
+
+	prt = &dev->ports[xmit_work->dp->index];
+
+	clone = KSZ_SKB_CB(skb)->clone;
+
+	skb_shinfo(clone)->tx_flags |= SKBTX_IN_PROGRESS;
+
+	reinit_completion(&prt->tstamp_msg_comp);
+
+	dsa_enqueue_skb(skb, skb->dev);
+
+	ksz_ptp_txtstamp_skb(dev, prt, clone);
+
+	kfree(xmit_work);
+}
+
 static int _ksz_ptp_gettime(struct ksz_device *dev, struct timespec64 *ts)
 {
 	u32 nanoseconds;
@@ -488,7 +577,29 @@ void ksz_ptp_clock_unregister(struct dsa_switch *ds)
 
 static irqreturn_t ksz_ptp_msg_thread_fn(int irq, void *dev_id)
 {
-	return IRQ_NONE;
+	struct ksz_ptp_irq *ptpmsg_irq = dev_id;
+	struct ksz_device *dev;
+	struct ksz_port *port;
+	u32 tstamp_raw;
+	ktime_t tstamp;
+	int ret;
+
+	port = ptpmsg_irq->port;
+	dev = port->ksz_dev;
+
+	if (ptpmsg_irq->ts_en) {
+		ret = ksz_read32(dev, ptpmsg_irq->ts_reg, &tstamp_raw);
+		if (ret)
+			return IRQ_NONE;
+
+		tstamp = ksz_decode_tstamp(tstamp_raw);
+
+		port->tstamp_msg = ksz_tstamp_reconstruct(dev, tstamp);
+
+		complete(&port->tstamp_msg_comp);
+	}
+
+	return IRQ_HANDLED;
 }
 
 static irqreturn_t ksz_ptp_irq_thread_fn(int irq, void *dev_id)
@@ -633,6 +744,8 @@ int ksz_ptp_irq_setup(struct dsa_switch *ds, u8 p)
 						REG_PTP_PORT_TX_INT_STATUS__2);
 	snprintf(ptpirq->name, sizeof(ptpirq->name), "ptp-irq-%d", p);
 
+	init_completion(&port->tstamp_msg_comp);
+
 	ptpirq->domain = irq_domain_add_linear(dev->dev->of_node, ptpirq->nirqs,
 					       &ksz_ptp_irq_domain_ops, ptpirq);
 	if (!ptpirq->domain)
diff --git a/drivers/net/dsa/microchip/ksz_ptp.h b/drivers/net/dsa/microchip/ksz_ptp.h
index 9bb8fb059ac2..0b14aed71ec2 100644
--- a/drivers/net/dsa/microchip/ksz_ptp.h
+++ b/drivers/net/dsa/microchip/ksz_ptp.h
@@ -30,6 +30,8 @@ int ksz_get_ts_info(struct dsa_switch *ds, int port,
 		    struct ethtool_ts_info *ts);
 int ksz_hwtstamp_get(struct dsa_switch *ds, int port, struct ifreq *ifr);
 int ksz_hwtstamp_set(struct dsa_switch *ds, int port, struct ifreq *ifr);
+void ksz_port_txtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb);
+void ksz_port_deferred_xmit(struct kthread_work *work);
 bool ksz_port_rxtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb,
 		       unsigned int type);
 int ksz_ptp_irq_setup(struct dsa_switch *ds, u8 p);
@@ -64,6 +66,10 @@ static inline void ksz_ptp_irq_free(struct dsa_switch *ds, u8 p) {}
 
 #define ksz_port_rxtstamp NULL
 
+#define ksz_port_txtstamp NULL
+
+#define ksz_port_deferred_xmit NULL
+
 #endif	/* End of CONFIG_NET_DSA_MICROCHIP_KSZ_PTP */
 
 #endif