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lan743x: Fix TX Stall Issue

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It has been observed that tx queue stalls while downloading
from certain web sites (example www.speedtest.net)

The cause has been tracked down to a corner case where
dma descriptors where not setup properly. And there for a tx
completion interrupt was not signaled.

This fix corrects the problem by properly marking the end of
a multi descriptor transmission.

Fixes: 23f0703c12 ("lan743x: Add main source files for new lan743x driver")
Signed-off-by: Bryan Whitehead <Bryan.Whitehead@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Bryan Whitehead 2019-02-26 14:06:26 -05:00 committed by David S. Miller
parent d25ed413d5
commit 90490ef726
1 changed files with 12 additions and 4 deletions
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16
drivers/net/ethernet/microchip/lan743x_main.c
View File

@ -1400,7 +1400,8 @@ static int lan743x_tx_frame_start(struct lan743x_tx *tx,
}
static void lan743x_tx_frame_add_lso(struct lan743x_tx *tx,
unsigned int frame_length)
unsigned int frame_length,
int nr_frags)
{
/* called only from within lan743x_tx_xmit_frame.
* assuming tx->ring_lock has already been acquired.
@ -1410,6 +1411,10 @@ static void lan743x_tx_frame_add_lso(struct lan743x_tx *tx,
/* wrap up previous descriptor */
tx->frame_data0 |= TX_DESC_DATA0_EXT_;
if (nr_frags <= 0) {
tx->frame_data0 |= TX_DESC_DATA0_LS_;
tx->frame_data0 |= TX_DESC_DATA0_IOC_;
}
tx_descriptor = &tx->ring_cpu_ptr[tx->frame_tail];
tx_descriptor->data0 = tx->frame_data0;
@ -1514,8 +1519,11 @@ static void lan743x_tx_frame_end(struct lan743x_tx *tx,
u32 tx_tail_flags = 0;
/* wrap up previous descriptor */
tx->frame_data0 |= TX_DESC_DATA0_LS_;
tx->frame_data0 |= TX_DESC_DATA0_IOC_;
if ((tx->frame_data0 & TX_DESC_DATA0_DTYPE_MASK_) ==
TX_DESC_DATA0_DTYPE_DATA_) {
tx->frame_data0 |= TX_DESC_DATA0_LS_;
tx->frame_data0 |= TX_DESC_DATA0_IOC_;
}
tx_descriptor = &tx->ring_cpu_ptr[tx->frame_tail];
buffer_info = &tx->buffer_info[tx->frame_tail];
@ -1600,7 +1608,7 @@ static netdev_tx_t lan743x_tx_xmit_frame(struct lan743x_tx *tx,
}
if (gso)
lan743x_tx_frame_add_lso(tx, frame_length);
lan743x_tx_frame_add_lso(tx, frame_length, nr_frags);
if (nr_frags <= 0)
goto finish;