[PATCH 02/10] net/macb: memory barriers cleanup
From: Nicolas Ferre <hidden>
Date: 2012-09-05 08:25:39
Also in:
linux-arm-kernel, lkml
Subsystem:
atmel macb ethernet driver, networking drivers, the rest · Maintainers:
Théo Lebrun, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Havard Skinnemoen <redacted> Remove a couple of unneeded barriers and document the remaining ones. Signed-off-by: Havard Skinnemoen <redacted> [nicolas.ferre@atmel.com: split patch in topics] Signed-off-by: Nicolas Ferre <redacted> --- drivers/net/ethernet/cadence/macb.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c
index 9a10f69..26ca01e 100644
--- a/drivers/net/ethernet/cadence/macb.c
+++ b/drivers/net/ethernet/cadence/macb.c@@ -372,7 +372,9 @@ static void macb_tx(struct macb *bp) BUG_ON(skb == NULL); + /* Make hw descriptor updates visible to CPU */ rmb(); + bufstat = bp->tx_ring[tail].ctrl; if (!(bufstat & MACB_BIT(TX_USED)))
@@ -415,7 +417,10 @@ static int macb_rx_frame(struct macb *bp, unsigned int first_frag, if (frag == last_frag) break; } + + /* Make descriptor updates visible to hardware */ wmb(); + return 1; }
@@ -436,12 +441,14 @@ static int macb_rx_frame(struct macb *bp, unsigned int first_frag, frag_len); offset += RX_BUFFER_SIZE; bp->rx_ring[frag].addr &= ~MACB_BIT(RX_USED); - wmb(); if (frag == last_frag) break; } + /* Make descriptor updates visible to hardware */ + wmb(); + skb->protocol = eth_type_trans(skb, bp->dev); bp->stats.rx_packets++;
@@ -461,6 +468,8 @@ static void discard_partial_frame(struct macb *bp, unsigned int begin, for (frag = begin; frag != end; frag = NEXT_RX(frag)) bp->rx_ring[frag].addr &= ~MACB_BIT(RX_USED); + + /* Make descriptor updates visible to hardware */ wmb(); /*
@@ -479,7 +488,9 @@ static int macb_rx(struct macb *bp, int budget) for (; budget > 0; tail = NEXT_RX(tail)) { u32 addr, ctrl; + /* Make hw descriptor updates visible to CPU */ rmb(); + addr = bp->rx_ring[tail].addr; ctrl = bp->rx_ring[tail].ctrl;
@@ -674,6 +685,8 @@ static int macb_start_xmit(struct sk_buff *skb, struct net_device *dev) bp->tx_ring[entry].addr = mapping; bp->tx_ring[entry].ctrl = ctrl; + + /* Make newly initialized descriptor visible to hardware */ wmb(); entry = NEXT_TX(entry);
@@ -782,9 +795,6 @@ static void macb_init_rings(struct macb *bp) static void macb_reset_hw(struct macb *bp) { - /* Make sure we have the write buffer for ourselves */ - wmb(); - /* * Disable RX and TX (XXX: Should we halt the transmission * more gracefully?)
--
1.7.10