[PATCH 5.4 28/50] net: stmmac: reset Tx desc base address before restarting Tx

[Greg Kroah-Hartman]

From: Jongsung Kim <neidhard.kim@xxxxxxx>

commit f421031e3ff0dd288a6e1bbde9aa41a25bb814e6 upstream.

Refer to the databook of DesignWare Cores Ethernet MAC Universal:

6.2.1.5 Register 4 (Transmit Descriptor List Address Register

If this register is not changed when the ST bit is set to 0, then
the DMA takes the descriptor address where it was stopped earlier.

The stmmac_tx_err() does zero indices to Tx descriptors, but does
not reset HW current Tx descriptor address. To fix inconsistency,
the base address of the Tx descriptors should be rewritten before
restarting Tx.

Signed-off-by: Jongsung Kim <neidhard.kim@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: Macpaul Lin <macpaul.lin@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1987,6 +1987,8 @@ static void stmmac_tx_err(struct stmmac_
 	tx_q->cur_tx = 0;
 	tx_q->mss = 0;
 	netdev_tx_reset_queue(netdev_get_tx_queue(priv->dev, chan));
+	stmmac_init_tx_chan(priv, priv->ioaddr, priv->plat->dma_cfg,
+			    tx_q->dma_tx_phy, chan);
 	stmmac_start_tx_dma(priv, chan);
 
 	priv->dev->stats.tx_errors++;