From 83510e3cc63b58e4f3831b5b001a3722af405903 Mon Sep 17 00:00:00 2001
From: Esben Haabendal <esben@geanix.com>
Date: Tue, 30 Apr 2019 09:17:59 +0200
Subject: [PATCH 1/4] net: ll_temac: Enable DMA when ready, not before
Git-commit: 73f7375d3ed6ad372f1e9404007a0c866063d773
Patch-mainline: v5.2-rc1
References: git-fixes
As soon as TAILDESCR_PTR is written, DMA transfers might start.
Let's ensure we are ready to receive DMA IRQ's before doing that.
Signed-off-by: Esben Haabendal <esben@geanix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Denis Kirjanov <denis.kirjanov@suse.com>
---
drivers/net/ethernet/xilinx/ll_temac_main.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/drivers/net/ethernet/xilinx/ll_temac_main.c b/drivers/net/ethernet/xilinx/ll_temac_main.c
index 357e7c104409..10a28cea72be 100644
--- a/drivers/net/ethernet/xilinx/ll_temac_main.c
+++ b/drivers/net/ethernet/xilinx/ll_temac_main.c
@@ -295,17 +295,21 @@ static int temac_dma_bd_init(struct net_device *ndev)
CHNL_CTRL_IRQ_IOE);
/* 0xff010283 */
- lp->dma_out(lp, RX_CURDESC_PTR, lp->rx_bd_p);
- lp->dma_out(lp, RX_TAILDESC_PTR,
- lp->rx_bd_p + (sizeof(*lp->rx_bd_v) * (RX_BD_NUM - 1)));
- lp->dma_out(lp, TX_CURDESC_PTR, lp->tx_bd_p);
-
/* Init descriptor indexes */
lp->tx_bd_ci = 0;
lp->tx_bd_next = 0;
lp->tx_bd_tail = 0;
lp->rx_bd_ci = 0;
+ /* Enable RX DMA transfers */
+ wmb();
+ lp->dma_out(lp, RX_CURDESC_PTR, lp->rx_bd_p);
+ lp->dma_out(lp, RX_TAILDESC_PTR,
+ lp->rx_bd_p + (sizeof(*lp->rx_bd_v) * (RX_BD_NUM - 1)));
+
+ /* Prepare for TX DMA transfer */
+ lp->dma_out(lp, TX_CURDESC_PTR, lp->tx_bd_p);
+
return 0;
out:
@@ -802,6 +806,7 @@ static int temac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
skb_tx_timestamp(skb);
/* Kick off the transfer */
+ wmb();
lp->dma_out(lp, TX_TAILDESC_PTR, tail_p); /* DMA start */
return NETDEV_TX_OK;
--
2.16.4