Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758586Ab2J3KSZ (ORCPT ); Tue, 30 Oct 2012 06:18:25 -0400 Received: from eusmtp01.atmel.com ([212.144.249.242]:36956 "EHLO eusmtp01.atmel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758313Ab2J3KSW (ORCPT ); Tue, 30 Oct 2012 06:18:22 -0400 From: Nicolas Ferre To: , , CC: , , , , , , Nicolas Ferre Subject: [PATCH v3 02/10] net/macb: memory barriers cleanup Date: Tue, 30 Oct 2012 11:17:54 +0100 Message-ID: X-Mailer: git-send-email 1.8.0 In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2755 Lines: 98 From: Havard Skinnemoen Remove a couple of unneeded barriers and document the remaining ones. Signed-off-by: Havard Skinnemoen [nicolas.ferre@atmel.com: split patch in topics] Signed-off-by: Nicolas Ferre --- 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 0931cb7..e7f554d 100644 --- a/drivers/net/ethernet/cadence/macb.c +++ b/drivers/net/ethernet/cadence/macb.c @@ -373,7 +373,9 @@ 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))) @@ -416,7 +418,10 @@ 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; } @@ -437,12 +442,14 @@ 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++; @@ -462,6 +469,8 @@ 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(); /* @@ -480,7 +489,9 @@ 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; @@ -675,6 +686,8 @@ 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); @@ -783,9 +796,6 @@ 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/