From: Lars Persson Date: Mon, 15 Apr 2019 07:49:47 +0000 (+0200) Subject: net: stmmac: Set dma ring length before enabling the DMA X-Git-Tag: MMI-QSB30.62-17~983^2~20^2~3 X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=5661213956662f592979925eab1e4dfff955ba05;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git net: stmmac: Set dma ring length before enabling the DMA This was fixed in upstream by commit 7d9e6c5afab6 ("net: stmmac: Integrate XGMAC into main driver flow") that is a new feature commit. We found a race condition in the DMA init sequence that hits if the PHY already has link up during stmmac_hw_setup. Since the ring length was programmed after enabling the RX path, we might receive a packet before the correct ring length is programmed. When that happened we could not get reliable interrupts for DMA RX and the MTL complained about RX FIFO overrun. Signed-off-by: Lars Persson Cc: stable@vger.kernel.org # 4.14.x Cc: Giuseppe Cavallaro Cc: Alexandre Torgue Cc: Jose Abreu Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index 4a9dbee6f054..f2429ec07b57 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -2536,9 +2536,6 @@ static int stmmac_hw_setup(struct net_device *dev, bool init_ptp) netdev_warn(priv->dev, "%s: failed debugFS registration\n", __func__); #endif - /* Start the ball rolling... */ - stmmac_start_all_dma(priv); - priv->tx_lpi_timer = STMMAC_DEFAULT_TWT_LS; if ((priv->use_riwt) && (priv->hw->dma->rx_watchdog)) { @@ -2558,6 +2555,9 @@ static int stmmac_hw_setup(struct net_device *dev, bool init_ptp) priv->hw->dma->enable_tso(priv->ioaddr, 1, chan); } + /* Start the ball rolling... */ + stmmac_start_all_dma(priv); + return 0; }