From: Jose Abreu <Jose.Abreu@synopsys.com>
Date: Mon, 17 Sep 2018 09:22:57 +0100
Subject: net: stmmac: Fixup the tail addr setting in xmit path
Git-commit: 0431100b3d82c509729ece1ab22ada2484e209c1
Patch-mainline: v4.19-rc6
References: networking-stable-18_10_16
Currently we are always setting the tail address of descriptor list to
the end of the pre-allocated list.
According to databook this is not correct. Tail address should point to
the last available descriptor + 1, which means we have to update the
tail address everytime we call the xmit function.
This should make no impact in older versions of MAC but in newer
versions there are some DMA features which allows the IP to fetch
descriptors in advance and in a non sequential order so its critical
that we set the tail address correctly.
Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Fixes: f748be531d70 ("stmmac: support new GMAC4")
Cc: David S. Miller <davem@davemloft.net>
Cc: Joao Pinto <jpinto@synopsys.com>
Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -2187,8 +2187,7 @@ static int stmmac_init_dma_engine(struct
priv->plat->dma_cfg,
tx_q->dma_tx_phy, chan);
- tx_q->tx_tail_addr = tx_q->dma_tx_phy +
- (DMA_TX_SIZE * sizeof(struct dma_desc));
+ tx_q->tx_tail_addr = tx_q->dma_tx_phy;
priv->hw->dma->set_tx_tail_ptr(priv->ioaddr,
tx_q->tx_tail_addr,
chan);
@@ -2953,6 +2952,8 @@ static netdev_tx_t stmmac_tso_xmit(struc
netdev_tx_sent_queue(netdev_get_tx_queue(dev, queue), skb->len);
+ tx_q->tx_tail_addr = tx_q->dma_tx_phy + (tx_q->cur_tx * sizeof(*desc));
+ tx_q->tx_tail_addr = tx_q->dma_tx_phy + (tx_q->cur_tx * sizeof(*desc));
priv->hw->dma->set_tx_tail_ptr(priv->ioaddr, tx_q->tx_tail_addr,
queue);