diff options
Diffstat (limited to 'patches.at91/0111-net-macb-memory-barriers-cleanup.patch')
| -rw-r--r-- | patches.at91/0111-net-macb-memory-barriers-cleanup.patch | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/patches.at91/0111-net-macb-memory-barriers-cleanup.patch b/patches.at91/0111-net-macb-memory-barriers-cleanup.patch new file mode 100644 index 00000000000000..42240f7cc2c6ba --- /dev/null +++ b/patches.at91/0111-net-macb-memory-barriers-cleanup.patch @@ -0,0 +1,96 @@ +From ae87461f10e59a207038af4df8944fabc8c9ac55 Mon Sep 17 00:00:00 2001 +From: Havard Skinnemoen <havard@skinnemoen.net> +Date: Fri, 28 May 2010 17:13:33 +0200 +Subject: net/macb: memory barriers cleanup + +Remove a couple of unneeded barriers and document the remaining ones. + +Signed-off-by: Havard Skinnemoen <havard@skinnemoen.net> +[nicolas.ferre@atmel.com: split patch in topics] +Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com> +--- + 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 e9b909a..a4dcd11 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?) +-- +1.8.0.197.g5a90748 + |