net: moxa: clear DESC1 on ndo_start_xmit()

TX buffer length is not cleared on ndo_start_xmit().
Failing to do so can bug/hang the controller and
cause TX interrupts to stop altogether.

Remove the readl() and compute a new value for DESC1.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=69031

Signed-off-by: Jonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 4 deletions

diff --git a/drivers/net/ethernet/moxa/moxart_ether.c b/drivers/net/ethernet/moxa/moxart_ether.c
index 5020fd47825d..eed70d9f0d9d 100644
--- a/drivers/net/ethernet/moxa/moxart_ether.c
+++ b/drivers/net/ethernet/moxa/moxart_ether.c
@@ -346,10 +346,9 @@ static int moxart_mac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
                 len = ETH_ZLEN;
         }
 
-        txdes1 = readl(desc + TX_REG_OFFSET_DESC1);
-        txdes1 |= TX_DESC1_LTS | TX_DESC1_FTS;
-        txdes1 &= ~(TX_DESC1_FIFO_COMPLETE | TX_DESC1_INTR_COMPLETE);
-        txdes1 |= (len & TX_DESC1_BUF_SIZE_MASK);
+        txdes1 = TX_DESC1_LTS | TX_DESC1_FTS | (len & TX_DESC1_BUF_SIZE_MASK);
+        if (tx_head == TX_DESC_NUM_MASK)
+                txdes1 |= TX_DESC1_END;
         writel(txdes1, desc + TX_REG_OFFSET_DESC1);
         writel(TX_DESC0_DMA_OWN, desc + TX_REG_OFFSET_DESC0);