[OpenWrt-Devel] [PATCHv2 2/2] ramips: ethernet: fix to interrupt handling

[Rosen Penev]

From: NeilBrown <neil at brown.name>

The current code acknowledged interrupts *after* polling.
This is the wrong way around, and could cause an interrupt to
be missed.
This is not likely to be fatal as another packet, and so another
interrupt, should come along soon.  But maybe it is causing
problems, so let's fix it anyway.

Signed-off-by: NeilBrown <neil at brown.name>
(Note that this matches the upstream driver.)
Signed-off-by: Rosen Penev <rosenp at gmail.com>
---
 v2: Added comment.
 .../drivers/net/ethernet/mediatek/mtk_eth_soc.c       | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/target/linux/ramips/files-4.14/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/target/linux/ramips/files-4.14/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index 91974a461c..5612e64eb1 100644
--- a/target/linux/ramips/files-4.14/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/target/linux/ramips/files-4.14/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -879,6 +879,8 @@ static int fe_poll_rx(struct napi_struct *napi, int budget,
 	struct fe_rx_dma *rxd, trxd;
 	int done = 0, pad;
 
+	fe_reg_w32(rx_intr, FE_REG_FE_INT_STATUS);
+
 	if (netdev->features & NETIF_F_RXCSUM)
 		checksum_bit = soc->checksum_bit;
 	else
@@ -971,9 +973,6 @@ release_desc:
 		done++;
 	}
 
-	if (done < budget)
-		fe_reg_w32(rx_intr, FE_REG_FE_INT_STATUS);
-
 	return done;
 }
 
@@ -989,6 +988,8 @@ static int fe_poll_tx(struct fe_priv *priv, int budget, u32 tx_intr,
 	u32 idx, hwidx;
 	struct fe_tx_ring *ring = &priv->tx_ring;
 
+	fe_reg_w32(tx_intr, FE_REG_FE_INT_STATUS);
+
 	idx = ring->tx_free_idx;
 	hwidx = fe_reg_r32(FE_REG_TX_DTX_IDX0);
 
@@ -1012,9 +1013,7 @@ static int fe_poll_tx(struct fe_priv *priv, int budget, u32 tx_intr,
 	if (idx == hwidx) {
 		/* read hw index again make sure no new tx packet */
 		hwidx = fe_reg_r32(FE_REG_TX_DTX_IDX0);
-		if (idx == hwidx)
-			fe_reg_w32(tx_intr, FE_REG_FE_INT_STATUS);
-		else
+		if (idx != hwidx)
 			*tx_again = 1;
 	} else {
 		*tx_again = 1;
-- 
2.23.0


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