ENGR00288342 net:fec_ptp: fix the potential issue for storing timestamp

The timestamps generated in the i.MX drivers are generated by the
nanoseconds part coming from the 1588 clock. But the number of seconds
are maintained in a private structure of the interface. Those are
updated in a 1588 clock rollover interrupt.

The timestamp is generated right before a rollover of a second and the
timestamp value is constructed afterwards. Therefore the bigger part of
the timestamp is wrong (the second).

Suggested solution (pseudo-code):
If( actual-time.nsec < timestamp.nsec )
	Timestamp.sec = fpp->prtc -1;
Else
	Timestamp.sec = fpp->prtc;

Signed-off-by: Fugang Duan <B38611@freescale.com>

diff --git a/drivers/net/ethernet/freescale/fec_ptp.c b/drivers/net/ethernet/freescale/fec_ptp.c
index 33f73df95b44b54c03949c340ec0f78f74fe84ad..2d6997bea89a58d5e4326b8c4bb24ece246d62f6 100644 (file)
--- a/drivers/net/ethernet/freescale/fec_ptp.c
+++ b/drivers/net/ethernet/freescale/fec_ptp.c
@@ -362,6 +362,7 @@ void fec_ptp_store_txstamp(struct fec_enet_private *priv,
 {
        struct fec_ptp_ts_data tmp_tx_time;
        struct bufdesc_ex *bdp_ex = NULL;
+       struct ptp_rtc_time curr_time;
        u8 *ptp_loc;
        u16 eth_type;
 
@@ -389,7 +390,11 @@ void fec_ptp_store_txstamp(struct fec_enet_private *priv,
                memcpy(tmp_tx_time.ident.spid, &ptp_loc[PTP_SPID_OFFS],
                                                PTP_SOURCE_PORT_LENGTH);
                /* store tx timestamp */
-               tmp_tx_time.ts.sec = priv->prtc;
+               fec_get_curr_cnt(priv, &curr_time);
+               if (curr_time.rtc_time.nsec < bdp_ex->ts)
+                       tmp_tx_time.ts.sec = priv->prtc - 1;
+               else
+                       tmp_tx_time.ts.sec = priv->prtc;
                tmp_tx_time.ts.nsec = bdp_ex->ts;
                /* insert timestamp in circular buffer */
                fec_ptp_insert(&(priv->tx_timestamps), &tmp_tx_time);
@@ -402,6 +407,7 @@ void fec_ptp_store_rxstamp(struct fec_enet_private *priv,
 {
        struct fec_ptp_ts_data tmp_rx_time;
        struct bufdesc_ex *bdp_ex = NULL;
+       struct ptp_rtc_time curr_time;
        u8 *ptp_loc;
        u16 eth_type;
 
@@ -429,7 +435,11 @@ void fec_ptp_store_rxstamp(struct fec_enet_private *priv,
                memcpy(tmp_rx_time.ident.spid, &ptp_loc[PTP_SPID_OFFS],
                                                PTP_SOURCE_PORT_LENGTH);
                /* store rx timestamp */
-               tmp_rx_time.ts.sec = priv->prtc;
+               fec_get_curr_cnt(priv, &curr_time);
+               if (curr_time.rtc_time.nsec < bdp_ex->ts)
+                       tmp_rx_time.ts.sec = priv->prtc - 1;
+               else
+                       tmp_rx_time.ts.sec = priv->prtc;
                tmp_rx_time.ts.nsec = bdp_ex->ts;
 
                /* insert timestamp in circular buffer */