8139too: move wmb before TX DMA start
The write barrier should be used before starting a DMA transfer. This fixes
a problem, where almost all packets received on another machine had garbled
content. Tested with an RTL8100C on a MIPS machine.
Signed-off-by: Andreas Oberritter <obi@linuxtv.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/8139too.c b/drivers/net/8139too.c
index 32e66f0..0daf8c1 100644
--- a/drivers/net/8139too.c
+++ b/drivers/net/8139too.c
@@ -1723,13 +1723,18 @@
}
spin_lock_irqsave(&tp->lock, flags);
+ /*
+ * Writing to TxStatus triggers a DMA transfer of the data
+ * copied to tp->tx_buf[entry] above. Use a memory barrier
+ * to make sure that the device sees the updated data.
+ */
+ wmb();
RTL_W32_F (TxStatus0 + (entry * sizeof (u32)),
tp->tx_flag | max(len, (unsigned int)ETH_ZLEN));
dev->trans_start = jiffies;
tp->cur_tx++;
- wmb();
if ((tp->cur_tx - NUM_TX_DESC) == tp->dirty_tx)
netif_stop_queue (dev);