[PATCH net-next v8 1/2] net: ethernet: ti: am65-cpts: Enable RX HW timestamp for PTP packets using CPTS FIFO

From: Chintan Vankar
Date: Fri Apr 19 2024 - 04:27:39 EST


Add a new function "am65_cpts_rx_timestamp()" which checks for PTP
packets from header and timestamps them.

Add another function "am65_cpts_find_rx_ts()" which finds CPTS FIFO
Event to get the timestamp of received PTP packet.

Signed-off-by: Chintan Vankar <c-vankar@xxxxxx>
---

Link to v7:
https://lore.kernel.org/r/20240417120913.3811519-2-c-vankar@xxxxxx/

Changes from v7 to v8:
- No changes.

drivers/net/ethernet/ti/am65-cpts.c | 84 ++++++++++++++++++++++++++---
drivers/net/ethernet/ti/am65-cpts.h | 6 +++
2 files changed, 83 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/ti/am65-cpts.c b/drivers/net/ethernet/ti/am65-cpts.c
index c66618d91c28..599454c1d19f 100644
--- a/drivers/net/ethernet/ti/am65-cpts.c
+++ b/drivers/net/ethernet/ti/am65-cpts.c
@@ -275,15 +275,13 @@ static bool am65_cpts_fifo_pop_event(struct am65_cpts *cpts,
return true;
}

-static int am65_cpts_fifo_read(struct am65_cpts *cpts)
+static int __am65_cpts_fifo_read(struct am65_cpts *cpts)
{
struct ptp_clock_event pevent;
struct am65_cpts_event *event;
bool schedule = false;
int i, type, ret = 0;
- unsigned long flags;

- spin_lock_irqsave(&cpts->lock, flags);
for (i = 0; i < AM65_CPTS_FIFO_DEPTH; i++) {
event = list_first_entry_or_null(&cpts->pool,
struct am65_cpts_event, list);
@@ -312,8 +310,7 @@ static int am65_cpts_fifo_read(struct am65_cpts *cpts)
event->tmo = jiffies +
msecs_to_jiffies(AM65_CPTS_EVENT_RX_TX_TIMEOUT);

- list_del_init(&event->list);
- list_add_tail(&event->list, &cpts->events);
+ list_move_tail(&event->list, &cpts->events);

dev_dbg(cpts->dev,
"AM65_CPTS_EV_TX e1:%08x e2:%08x t:%lld\n",
@@ -356,14 +353,24 @@ static int am65_cpts_fifo_read(struct am65_cpts *cpts)
}

out:
- spin_unlock_irqrestore(&cpts->lock, flags);
-
if (schedule)
ptp_schedule_worker(cpts->ptp_clock, 0);

return ret;
}

+static int am65_cpts_fifo_read(struct am65_cpts *cpts)
+{
+ unsigned long flags;
+ int ret = 0;
+
+ spin_lock_irqsave(&cpts->lock, flags);
+ ret = __am65_cpts_fifo_read(cpts);
+ spin_unlock_irqrestore(&cpts->lock, flags);
+
+ return ret;
+}
+
static u64 am65_cpts_gettime(struct am65_cpts *cpts,
struct ptp_system_timestamp *sts)
{
@@ -906,6 +913,69 @@ static int am65_skb_get_mtype_seqid(struct sk_buff *skb, u32 *mtype_seqid)
return 1;
}

+static u64 am65_cpts_find_rx_ts(struct am65_cpts *cpts, u32 skb_mtype_seqid)
+{
+ struct list_head *this, *next;
+ struct am65_cpts_event *event;
+ unsigned long flags;
+ u32 mtype_seqid;
+ u64 ns = 0;
+
+ spin_lock_irqsave(&cpts->lock, flags);
+ __am65_cpts_fifo_read(cpts);
+ list_for_each_safe(this, next, &cpts->events) {
+ event = list_entry(this, struct am65_cpts_event, list);
+ if (time_after(jiffies, event->tmo)) {
+ list_move(&event->list, &cpts->pool);
+ continue;
+ }
+
+ mtype_seqid = event->event1 &
+ (AM65_CPTS_EVENT_1_MESSAGE_TYPE_MASK |
+ AM65_CPTS_EVENT_1_SEQUENCE_ID_MASK |
+ AM65_CPTS_EVENT_1_EVENT_TYPE_MASK);
+
+ if (mtype_seqid == skb_mtype_seqid) {
+ ns = event->timestamp;
+ list_move(&event->list, &cpts->pool);
+ break;
+ }
+ }
+ spin_unlock_irqrestore(&cpts->lock, flags);
+
+ return ns;
+}
+
+void am65_cpts_rx_timestamp(struct am65_cpts *cpts, struct sk_buff *skb)
+{
+ struct am65_cpts_skb_cb_data *skb_cb = (struct am65_cpts_skb_cb_data *)skb->cb;
+ struct skb_shared_hwtstamps *ssh;
+ int ret;
+ u64 ns;
+
+ /* am65_cpts_rx_timestamp() is called before eth_type_trans(), so
+ * skb MAC Hdr properties are not configured yet. Hence need to
+ * reset skb MAC header here
+ */
+ skb_reset_mac_header(skb);
+ ret = am65_skb_get_mtype_seqid(skb, &skb_cb->skb_mtype_seqid);
+ if (!ret)
+ return; /* if not PTP class packet */
+
+ skb_cb->skb_mtype_seqid |= (AM65_CPTS_EV_RX << AM65_CPTS_EVENT_1_EVENT_TYPE_SHIFT);
+
+ dev_dbg(cpts->dev, "%s mtype seqid %08x\n", __func__, skb_cb->skb_mtype_seqid);
+
+ ns = am65_cpts_find_rx_ts(cpts, skb_cb->skb_mtype_seqid);
+ if (!ns)
+ return;
+
+ ssh = skb_hwtstamps(skb);
+ memset(ssh, 0, sizeof(*ssh));
+ ssh->hwtstamp = ns_to_ktime(ns);
+}
+EXPORT_SYMBOL_GPL(am65_cpts_rx_timestamp);
+
/**
* am65_cpts_tx_timestamp - save tx packet for timestamping
* @cpts: cpts handle
diff --git a/drivers/net/ethernet/ti/am65-cpts.h b/drivers/net/ethernet/ti/am65-cpts.h
index 6e14df0be113..90296968a75c 100644
--- a/drivers/net/ethernet/ti/am65-cpts.h
+++ b/drivers/net/ethernet/ti/am65-cpts.h
@@ -22,6 +22,7 @@ void am65_cpts_release(struct am65_cpts *cpts);
struct am65_cpts *am65_cpts_create(struct device *dev, void __iomem *regs,
struct device_node *node);
int am65_cpts_phc_index(struct am65_cpts *cpts);
+void am65_cpts_rx_timestamp(struct am65_cpts *cpts, struct sk_buff *skb);
void am65_cpts_tx_timestamp(struct am65_cpts *cpts, struct sk_buff *skb);
void am65_cpts_prep_tx_timestamp(struct am65_cpts *cpts, struct sk_buff *skb);
void am65_cpts_rx_enable(struct am65_cpts *cpts, bool en);
@@ -48,6 +49,11 @@ static inline int am65_cpts_phc_index(struct am65_cpts *cpts)
return -1;
}

+static inline void am65_cpts_rx_timestamp(struct am65_cpts *cpts,
+ struct sk_buff *skb)
+{
+}
+
static inline void am65_cpts_tx_timestamp(struct am65_cpts *cpts,
struct sk_buff *skb)
{
--
2.34.1