sh_eth: read MAC address registers only once

The code reading the MAHR/MALR registers in read_mac_address() is terribly
ineffective -- it reads MAHR 4 times and MALR 2 times, while it's enough to
read each register only once.  Use the local variables to achieve that,
somewhat beautifying the code while at it...

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c
index 7f3c610..2406ad4 100644 (file)
--- a/drivers/net/ethernet/renesas/sh_eth.c
+++ b/drivers/net/ethernet/renesas/sh_eth.c
@@ -989,12 +989,15 @@ static void read_mac_address(struct net_device *ndev, unsigned char *mac)
        if (mac[0] || mac[1] || mac[2] || mac[3] || mac[4] || mac[5]) {
                memcpy(ndev->dev_addr, mac, ETH_ALEN);
        } else {
-               ndev->dev_addr[0] = (sh_eth_read(ndev, MAHR) >> 24);
-               ndev->dev_addr[1] = (sh_eth_read(ndev, MAHR) >> 16) & 0xFF;
-               ndev->dev_addr[2] = (sh_eth_read(ndev, MAHR) >> 8) & 0xFF;
-               ndev->dev_addr[3] = (sh_eth_read(ndev, MAHR) & 0xFF);
-               ndev->dev_addr[4] = (sh_eth_read(ndev, MALR) >> 8) & 0xFF;
-               ndev->dev_addr[5] = (sh_eth_read(ndev, MALR) & 0xFF);
+               u32 mahr = sh_eth_read(ndev, MAHR);
+               u32 malr = sh_eth_read(ndev, MALR);
+
+               ndev->dev_addr[0] = (mahr >> 24) & 0xFF;
+               ndev->dev_addr[1] = (mahr >> 16) & 0xFF;
+               ndev->dev_addr[2] = (mahr >>  8) & 0xFF;
+               ndev->dev_addr[3] = (mahr >>  0) & 0xFF;
+               ndev->dev_addr[4] = (malr >>  8) & 0xFF;
+               ndev->dev_addr[5] = (malr >>  0) & 0xFF;
        }
 }