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Commit | Line | Data |
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7f653662 GKH |
1 | From lars.persson@axis.com Wed Apr 17 22:13:54 2019 |
2 | From: Lars Persson <lars.persson@axis.com> | |
3 | Date: Mon, 15 Apr 2019 09:49:47 +0200 | |
4 | Subject: net: stmmac: Set dma ring length before enabling the DMA | |
5 | To: stable@vger.kernel.org | |
6 | Cc: peppe.cavallaro@st.com, alexandre.torgue@st.com, joabreu@synopsys.com, Lars Persson <larper@axis.com> | |
7 | Message-ID: <20190415074947.6144-1-larper@axis.com> | |
8 | ||
9 | From: Lars Persson <lars.persson@axis.com> | |
10 | ||
11 | This was fixed in upstream by commit 7d9e6c5afab6 ("net: stmmac: Integrate | |
12 | XGMAC into main driver flow") that is a new feature commit. | |
13 | ||
14 | We found a race condition in the DMA init sequence that hits if the | |
15 | PHY already has link up during stmmac_hw_setup. Since the ring length | |
16 | was programmed after enabling the RX path, we might receive a packet | |
17 | before the correct ring length is programmed. When that happened we | |
18 | could not get reliable interrupts for DMA RX and the MTL complained | |
19 | about RX FIFO overrun. | |
20 | ||
21 | Signed-off-by: Lars Persson <larper@axis.com> | |
22 | Cc: stable@vger.kernel.org # 4.14.x | |
23 | Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com> | |
24 | Cc: Alexandre Torgue <alexandre.torgue@st.com> | |
25 | Cc: Jose Abreu <joabreu@synopsys.com> | |
26 | Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
27 | ||
28 | --- | |
29 | drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 6 +++--- | |
30 | 1 file changed, 3 insertions(+), 3 deletions(-) | |
31 | ||
32 | --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | |
33 | +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | |
34 | @@ -2536,9 +2536,6 @@ static int stmmac_hw_setup(struct net_de | |
35 | netdev_warn(priv->dev, "%s: failed debugFS registration\n", | |
36 | __func__); | |
37 | #endif | |
38 | - /* Start the ball rolling... */ | |
39 | - stmmac_start_all_dma(priv); | |
40 | - | |
41 | priv->tx_lpi_timer = STMMAC_DEFAULT_TWT_LS; | |
42 | ||
43 | if ((priv->use_riwt) && (priv->hw->dma->rx_watchdog)) { | |
44 | @@ -2558,6 +2555,9 @@ static int stmmac_hw_setup(struct net_de | |
45 | priv->hw->dma->enable_tso(priv->ioaddr, 1, chan); | |
46 | } | |
47 | ||
48 | + /* Start the ball rolling... */ | |
49 | + stmmac_start_all_dma(priv); | |
50 | + | |
51 | return 0; | |
52 | } | |
53 |