RE: [PATCH v3 net-next 1/8] ptp: netc: use ioread64_lo_hi/iowrite64_lo_hi for 64-bit register access

quoted

@@ -500,22 +473,19 @@ static void netc_timer_handle_etts_event(struct

netc_timer *priv, int index,

quoted

 					 bool update_event)
 {
 	struct ptp_clock_event event;
-	u32 etts_l = 0, etts_h = 0;
+	u64 etts = 0;

-	while (netc_timer_rd(priv, NETC_TMR_STAT) & TMR_STAT_ETS_VLD(index))

{

quoted

-		etts_l = netc_timer_rd(priv, NETC_TMR_ETTS_L(index));
-		etts_h = netc_timer_rd(priv, NETC_TMR_ETTS_H(index));
-	}
+	while (netc_timer_rd(priv, NETC_TMR_STAT) & TMR_STAT_ETS_VLD(index))
+		etts = netc_timer_rd64(priv, NETC_TMR_ETTS_L(index));

 	/* Invalid time stamp */
-	if (!etts_l && !etts_h)
+	if (!etts)
 		return;

 	if (update_event) {
 		event.type = PTP_CLOCK_EXTTS;
 		event.index = index;
-		event.timestamp = (u64)etts_h << 32;
-		event.timestamp |= etts_l;
+		event.timestamp = etts;
 		ptp_clock_event(priv->clock, &event);
 	}
 }

[Severity: High]
This is a pre-existing issue, but does this loop discard all but the last
timestamp from the hardware FIFO?

The while loop successfully drains multiple timestamps from the TMR_ETTS
FIFO
if they accumulate before the interrupt is handled. However, because etts is
overwritten on each iteration and ptp_clock_event() is only called once
after the loop completes, it appears any prior external events in the batch
are silently lost.

This is a false positive, the intention is to get the last timestamp.