Try to create some sort of consistency in how the routings to find the

multicast hash are written.  There are still two distinct algorithms used,
and there actually isn't any reason each driver should have its own copy
of this function as they could all share one copy of it (if it grew an
additional argument).

1 files changed, 28 insertions, 27 deletions

diff --git a/sys/dev/xe/if_xe.c b/sys/dev/xe/if_xe.c
index 9609410..3e51011 100644
--- a/sys/dev/xe/if_xe.c
+++ b/sys/dev/xe/if_xe.c
@@ -22,13 +22,7 @@
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
- *
- *	$Id: if_xe.c,v 1.20 1999/06/13 19:17:40 scott Exp $
  */
-
-#include <sys/cdefs.h>
-__FBSDID("$FreeBSD$");
-
 /*
  * Portions of this software were derived from Werner Koch's xirc2ps driver
  * for Linux under the terms of the following license (from v1.30 of the
@@ -62,6 +56,9 @@ __FBSDID("$FreeBSD$");
  * OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
 /*		
  * FreeBSD device driver for Xircom CreditCard PCMCIA Ethernet adapters.  The
  * following cards are currently known to work with the driver:
@@ -166,7 +163,7 @@ static void      xe_enable_intr		(struct xe_softc *scp);
 static void      xe_disable_intr	(struct xe_softc *scp);
 static void      xe_set_multicast	(struct xe_softc *scp);
 static void      xe_set_addr		(struct xe_softc *scp, u_int8_t* addr, unsigned idx);
-static void      xe_set_hash		(struct xe_softc *scp, u_int8_t* addr);
+static void      xe_mchash		(struct xe_softc *scp, caddr_t addr);
 static int       xe_pio_write_packet	(struct xe_softc *scp, struct mbuf *mbp);
 
 /*
@@ -1302,7 +1299,7 @@ xe_set_multicast(struct xe_softc *scp) {
     else
       if (scp->mohawk)
 	/* Use hash filter on Mohawk and Dingo */
-	xe_set_hash(scp, LLADDR((struct sockaddr_dl *)maddr->ifma_addr));
+	xe_mchash(scp, LLADDR((struct sockaddr_dl *)maddr->ifma_addr));
       else
 	/* Nowhere else to put them on CE2 */
 	break;
@@ -1415,46 +1412,50 @@ xe_set_addr(struct xe_softc *scp, u_int8_t* addr, unsigned idx) {
  * address.
  */
 static void
-xe_set_hash(struct xe_softc* scp, u_int8_t* addr) {
+xe_mchash(struct xe_softc* scp, caddr_t addr) {
   u_int32_t crc = 0xffffffff;
-  u_int8_t bit, byte, crc31, idx;
-  unsigned i, j;
+  int idx, bit;
+  u_int8_t carry, byte, data, crc31, hash;
 
   /* Compute CRC of the address -- standard Ethernet CRC function */
-  for (i = 0; i < 6; i++) {
-    byte = addr[i];
-    for (j = 1; j <= 8; j++) {
+  for (data = *addr++, idx = 0; idx < 6; idx++, data >>= 1) {
+    for (bit = 1; bit <= 8; bit++) {
       if (crc & 0x80000000)
 	crc31 = 0x01;
       else
 	crc31 = 0;
-      bit = crc31 ^ (byte & 0x01);
+      carry = crc31 ^ (data & 0x01);
       crc <<= 1;
-      byte >>= 1;
-      if (bit)
-	crc = (crc ^ XE_CRC_POLY)|1;
+      data >>= 1;
+	crc = (crc ^ XE_CRC_POLY) | (carry|0x1);
     }
   }
 
   DEVPRINTF(3, (scp->dev, "set_hash: CRC = 0x%08x\n", crc));
 
-  /* Hash table index = 6 msbs of CRC, reversed */
-  for (i = 0, idx = 0; i < 6; i++) {
-    idx >>= 1;
+  /*
+   * Convert a CRC into an index into the multicast hash table.  What we do is
+   * take the most-significant 6 bits of the CRC, reverse them, and use that as
+   * the bit number in the hash table.  Bits 5:3 of the result give the byte
+   * within the table (0-7); bits 2:0 give the bit number within that byte (also
+   * 0-7), ie. the number of shifts needed to get it into the lsb position.
+   */
+  for (idx = 0, hash = 0; idx < 6; idx++) {
+    hash >>= 1;
     if (crc & 0x80000000) {
-      idx |= 0x20;
+      hash |= 0x20;
     }
     crc <<= 1;
   }
 
-  /* Top 3 bits of idx give register - 8, bottom 3 give bit within register */
-  byte = idx >> 3 | 0x08;
-  bit = 0x01 << (idx & 0x07);
+  /* Top 3 bits of hash give register - 8, bottom 3 give bit within register */
+  byte = hash >> 3 | 0x08;
+  carry = 0x01 << (hash & 0x07);
 
-  DEVPRINTF(3, (scp->dev, "set_hash: idx = 0x%02x, byte = 0x%02x, bit = 0x%02x\n", idx, byte, bit));
+  DEVPRINTF(3, (scp->dev, "set_hash: hash = 0x%02x, byte = 0x%02x, carry = 0x%02x\n", hash, byte, carry));
 
   XE_SELECT_PAGE(0x58);
-  XE_OUTB(byte, XE_INB(byte) | bit);
+  XE_OUTB(byte, XE_INB(byte) | carry);
 }