amd-xgbe: Prevent looping forever if timestamp update fails

Just to be on the safe side, should the update of the timestamp registers
not complete, issue a warning rather than looping forever waiting for the
update to complete.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/amd/xgbe/xgbe-dev.c

@@ -1497,26 +1497,37 @@ static void xgbe_rx_desc_init(struct xgbe_channel *channel)
 static void xgbe_update_tstamp_addend(struct xgbe_prv_data *pdata,
 				      unsigned int addend)
 {
+	unsigned int count = 10000;
+
 	/* Set the addend register value and tell the device */
 	XGMAC_IOWRITE(pdata, MAC_TSAR, addend);
 	XGMAC_IOWRITE_BITS(pdata, MAC_TSCR, TSADDREG, 1);
 
 	/* Wait for addend update to complete */
-	while (XGMAC_IOREAD_BITS(pdata, MAC_TSCR, TSADDREG))
+	while (--count && XGMAC_IOREAD_BITS(pdata, MAC_TSCR, TSADDREG))
 		udelay(5);
+
+	if (!count)
+		netdev_err(pdata->netdev,
+			   "timed out updating timestamp addend register\n");
 }
 
 static void xgbe_set_tstamp_time(struct xgbe_prv_data *pdata, unsigned int sec,
 				 unsigned int nsec)
 {
+	unsigned int count = 10000;
+
 	/* Set the time values and tell the device */
 	XGMAC_IOWRITE(pdata, MAC_STSUR, sec);
 	XGMAC_IOWRITE(pdata, MAC_STNUR, nsec);
 	XGMAC_IOWRITE_BITS(pdata, MAC_TSCR, TSINIT, 1);
 
 	/* Wait for time update to complete */
-	while (XGMAC_IOREAD_BITS(pdata, MAC_TSCR, TSINIT))
+	while (--count && XGMAC_IOREAD_BITS(pdata, MAC_TSCR, TSINIT))
 		udelay(5);
+
+	if (!count)
+		netdev_err(pdata->netdev, "timed out initializing timestamp\n");
 }
 
 static u64 xgbe_get_tstamp_time(struct xgbe_prv_data *pdata)