netdev - [PATCH net-next v4 1/2] net: systemport: only update UMAC

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Message-Id: <1399666599-19398-2-git-send-email-f.fainelli@gmail.com>
Date:	Fri,  9 May 2014 13:16:38 -0700
From:	Florian Fainelli <f.fainelli@...il.com>
To:	netdev@...r.kernel.org
Cc:	davem@...emloft.net, Florian Fainelli <f.fainelli@...il.com>
Subject: [PATCH net-next v4 1/2] net: systemport: only update UMAC_CMD if something changed

The link adjustment callback can be called as frequently as desired by
the PHY library, as such, let's avoid doing a Read/Modify/Write sequence
if nothing changed, which is more than likely since we are interfaced
with a switch device.

Signed-off-by: Florian Fainelli <f.fainelli@...il.com>
---
Changes in v4:
- re-align 2nd and 3rd lines properly according to the network style

Changes in v3:
- attempted to re-align the CMD_HD_EN lines but failed miserably

Changes in v2:
- respin

 drivers/net/ethernet/broadcom/bcmsysport.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bcmsysport.c b/drivers/net/ethernet/broadcom/bcmsysport.c
index 4dc8d1e9829b..ac42a9e91f3a 100644
--- a/drivers/net/ethernet/broadcom/bcmsysport.c
+++ b/drivers/net/ethernet/broadcom/bcmsysport.c
@@ -959,15 +959,16 @@ static void bcm_sysport_adj_link(struct net_device *dev)
 	if (!phydev->pause)
 		cmd_bits |= CMD_RX_PAUSE_IGNORE | CMD_TX_PAUSE_IGNORE;
 
-	reg = umac_readl(priv, UMAC_CMD);
-	reg &= ~((CMD_SPEED_MASK << CMD_SPEED_SHIFT) |
+	if (changed) {
+		reg = umac_readl(priv, UMAC_CMD);
+		reg &= ~((CMD_SPEED_MASK << CMD_SPEED_SHIFT) |
 			CMD_HD_EN | CMD_RX_PAUSE_IGNORE |
 			CMD_TX_PAUSE_IGNORE);
-	reg |= cmd_bits;
-	umac_writel(priv, reg, UMAC_CMD);
+		reg |= cmd_bits;
+		umac_writel(priv, reg, UMAC_CMD);
 
-	if (changed)
 		phy_print_status(priv->phydev);
+	}
 }
 
 static int bcm_sysport_init_tx_ring(struct bcm_sysport_priv *priv,
-- 
1.9.1

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