[PATCH net v2 1/2] net: ethernet: mtk_eth_soc: reset all TX queues on DMA free

[Daniel Golle]

The purpose of resetting the TX queue is to reset the byte and packet
count as well as to clear the software flow control XOFF bit.

MediaTek developers pointed out that netdev_reset_queue would only
resets queue 0 of the network device.

Queues that are not reset may cause unexpected issues.

Packets may stop being sent after reset and "transmit timeout" log may
be displayed.

Import fix from MediaTek's SDK to resolve this issue.

Link: https://git01.mediatek.com/plugins/gitiles/openwrt/feeds/mtk-openwrt-feeds/+/319c0d9905579a46dc448579f892f364f1f84818
Fixes: f63959c7eec31 ("net: ethernet: mtk_eth_soc: implement multi-queue support for per-port queues")
Signed-off-by: Daniel Golle <daniel at makrotopia.org>
---
v2: Use netdev_tx_reset_subqueue()

 drivers/net/ethernet/mediatek/mtk_eth_soc.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index 8fda4ce80d811..53c39561b6d9a 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -3186,11 +3186,19 @@ static int mtk_dma_init(struct mtk_eth *eth)
 static void mtk_dma_free(struct mtk_eth *eth)
 {
 	const struct mtk_soc_data *soc = eth->soc;
-	int i;
+	int i, j, txqs = 1;
+
+	if (MTK_HAS_CAPS(eth->soc->caps, MTK_QDMA))
+		txqs = MTK_QDMA_NUM_QUEUES;
+
+	for (i = 0; i < MTK_MAX_DEVS; i++) {
+		if (!eth->netdev[i])
+			continue;
+
+		for (j = 0; j < txqs; j++)
+			netdev_tx_reset_subqueue(eth->netdev[i], j);
+	}
 
-	for (i = 0; i < MTK_MAX_DEVS; i++)
-		if (eth->netdev[i])
-			netdev_reset_queue(eth->netdev[i]);
 	if (!MTK_HAS_CAPS(soc->caps, MTK_SRAM) && eth->scratch_ring) {
 		dma_free_coherent(eth->dma_dev,
 				  MTK_QDMA_RING_SIZE * soc->tx.desc_size,
-- 
2.49.0