EMAC driver: bf537 MAC multicast hash filtering patch

The bf537 Ethernet MAC driver in the 2007R1.1-RC3 kernel (and the
current kernel) do not implement multicast hash filtering. This
is a performance problem if you have lots of multicast on your network.

This patch plugs the right bits into the multicast hash registers.

Signed-off-by: Aidan Williams <aidan@nicta.com.au>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/bfin_mac.c b/drivers/net/bfin_mac.c
index ee39819..c6586cd 100644 (file)
--- a/drivers/net/bfin_mac.c
+++ b/drivers/net/bfin_mac.c
@@ -11,6 +11,7 @@
  * Description:
  *
  * Modified:
+ *             2006-12-19 Aidan Williams, multicast hash support
  *             Copyright 2004-2006 Analog Devices Inc.
  *
  * Bugs:       Enter bugs at http://blackfin.uclinux.org/
@@ -800,6 +801,39 @@ static void bf537mac_timeout(struct net_device *dev)
        netif_wake_queue(dev);
 }
 
+static void bf537mac_multicast_hash(struct net_device *dev)
+{
+       u32 emac_hashhi, emac_hashlo;
+       struct dev_mc_list *dmi = dev->mc_list;
+       char *addrs;
+       int i;
+       u32 crc;
+
+       emac_hashhi = emac_hashlo = 0;
+
+       for (i = 0; i < dev->mc_count; i++) {
+               addrs = dmi->dmi_addr;
+               dmi = dmi->next;
+
+               /* skip non-multicast addresses */
+               if (!(*addrs & 1))
+                       continue;
+
+               crc = ether_crc(ETH_ALEN, addrs);
+               crc >>= 26;
+
+               if (crc & 0x20)
+                       emac_hashhi |= 1 << (crc & 0x1f);
+               else
+                       emac_hashlo |= 1 << (crc & 0x1f);
+       }
+
+       bfin_write_EMAC_HASHHI(emac_hashhi);
+       bfin_write_EMAC_HASHLO(emac_hashlo);
+
+       return;
+}
+
 /*
  * This routine will, depending on the values passed to it,
  * either make it accept multicast packets, go into
@@ -815,11 +849,17 @@ static void bf537mac_set_multicast_list(struct net_device *dev)
                sysctl = bfin_read_EMAC_OPMODE();
                sysctl |= RAF;
                bfin_write_EMAC_OPMODE(sysctl);
-       } else if (dev->flags & IFF_ALLMULTI || dev->mc_count) {
+       } else if (dev->flags & IFF_ALLMULTI) {
                /* accept all multicast */
                sysctl = bfin_read_EMAC_OPMODE();
                sysctl |= PAM;
                bfin_write_EMAC_OPMODE(sysctl);
+       } else if (dev->mc_count) {
+               /* set up multicast hash table */
+               sysctl = bfin_read_EMAC_OPMODE();
+               sysctl |= HM;
+               bfin_write_EMAC_OPMODE(sysctl);
+               bf537mac_multicast_hash(dev);
        } else {
                /* clear promisc or multicast mode */
                sysctl = bfin_read_EMAC_OPMODE();