From mboxrd@z Thu Jan 1 00:00:00 1970 From: Fredrik Hallenberg Subject: [PATCH 1/2] net: stmmac: Fix TX timestamp calculation Date: Mon, 18 Dec 2017 23:33:59 +0100 Message-ID: <20171218223400.29644-1-megahallon@gmail.com> Cc: Jose Abreu , "David S . Miller" , Giuseppe Cavallaro , Alexandre Torgue , Fredrik Hallenberg To: netdev@vger.kernel.org, linux-kernel@vger.kernel.org Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org 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. Signed-off-by: Fredrik Hallenberg --- drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c index 721b61655..08c19ebd5 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c @@ -34,6 +34,7 @@ static u32 stmmac_config_sub_second_increment(void __iomem *ioaddr, { 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 @@ -50,10 +51,11 @@ static u32 stmmac_config_sub_second_increment(void __iomem *ioaddr, 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; } -- 2.15.1