Patch "net: stmmac: Fix TX timestamp calculation" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

net: stmmac: Fix TX timestamp calculation

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
net-stmmac-fix-tx-timestamp-calculation.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Fredrik Hallenberg <[email protected]>
Date: Mon, 18 Dec 2017 23:33:59 +0100
Subject: net: stmmac: Fix TX timestamp calculation

From: Fredrik Hallenberg <[email protected]>

[ Upstream commit 200922c93f008e03ddc804c6dacdf26ca1ba86d7 ]

When using GMAC4 the value written in PTP_SSIR should be shifted however the shifted value is also used in subsequent calculations which results in a bad timestamp value.

---
 drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

@@ -38,6 +38,7 @@ static u32 stmmac_config_sub_second_incr
 {
 	u32 value = readl(ioaddr + PTP_TCR);
 	unsigned long data;
+	u32 reg_value;
 
 	/* For GMAC3.x, 4.x versions, convert the ptp_clock to nano second
 	 *	formula = (1/ptp_clock) * 1000000000

@@ -54,10 +55,11 @@ static u32 stmmac_config_sub_second_incr
 
 	data &= PTP_SSIR_SSINC_MASK;
 
+	reg_value = data;
 	if (gmac4)
-		data = data << GMAC4_PTP_SSIR_SSINC_SHIFT;
+		reg_value <<= GMAC4_PTP_SSIR_SSINC_SHIFT;
 
-	writel(data, ioaddr + PTP_SSIR);
+	writel(reg_value, ioaddr + PTP_SSIR);
 
 	return data;
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/net-stmmac-fix-tx-timestamp-calculation.patch