[PATCH 25/39] mv643xx_eth: massively simplify multicast address crc8 computation

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To: Dale Farnsworth <dale@...>
Cc: <netdev@...>
Date: Tuesday, June 3, 2008 - 7:02 am

Replace the 70-line crc8 computation (used for multicast address
filtering tables) by a 5-line version.

Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
---
 drivers/net/mv643xx_eth.c |   95 ++++++++++-----------------------------------
 1 files changed, 21 insertions(+), 74 deletions(-)

diff --git a/drivers/net/mv643xx_eth.c b/drivers/net/mv643xx_eth.c
index b3be8fe..beb4cf9 100644
--- a/drivers/net/mv643xx_eth.c
+++ b/drivers/net/mv643xx_eth.c
@@ -1132,16 +1132,29 @@ static int mv643xx_eth_set_mac_address(struct net_device *dev, void *addr)
 	return 0;
 }
 
+static int addr_crc(unsigned char *addr)
+{
+	int crc = 0;
+	int i;
+
+	for (i = 0; i < 6; i++) {
+		int j;
+
+		crc = (crc ^ addr[i]) << 8;
+		for (j = 7; j >= 0; j--) {
+			if (crc & (0x100 << j))
+				crc ^= 0x107 << j;
+		}
+	}
+
+	return crc;
+}
+
 static void mc_addr(struct mv643xx_eth_private *mep, unsigned char *addr)
 {
 	unsigned int port_num = mep->port_num;
-	unsigned int mac_h;
-	unsigned int mac_l;
-	unsigned char crc_result = 0;
 	int table;
-	int mac_array[48];
-	int crc[8];
-	int i;
+	int crc;
 
 	if ((addr[0] == 0x01) && (addr[1] == 0x00) &&
 	    (addr[2] == 0x5E) && (addr[3] == 0x00) && (addr[4] == 0x00)) {
@@ -1150,76 +1163,10 @@ static void mc_addr(struct mv643xx_eth_private *mep, unsigned char *addr)
 		return;
 	}
 
-	/* Calculate CRC-8 out of the given address */
-	mac_h = (addr[0] << 8) | (addr[1]);
-	mac_l = (addr[2] << 24) | (addr[3] << 16) |
-			(addr[4] << 8) | (addr[5] << 0);
-
-	for (i = 0; i < 32; i++)
-		mac_array[i] = (mac_l >> i) & 0x1;
-	for (i = 32; i < 48; i++)
-		mac_array[i] = (mac_h >> (i - 32)) & 0x1;
-
-	crc[0] = mac_array[45] ^ mac_array[43] ^ mac_array[40] ^ mac_array[39] ^
-		 mac_array[35] ^ mac_array[34] ^ mac_array[31] ^ mac_array[30] ^
-		 mac_array[28] ^ mac_array[23] ^ mac_array[21] ^ mac_array[19] ^
-		 mac_array[18] ^ mac_array[16] ^ mac_array[14] ^ mac_array[12] ^
-		 mac_array[8]  ^ mac_array[7]  ^ mac_array[6]  ^ mac_array[0];
-
-	crc[1] = mac_array[46] ^ mac_array[45] ^ mac_array[44] ^ mac_array[43] ^
-		 mac_array[41] ^ mac_array[39] ^ mac_array[36] ^ mac_array[34] ^
-		 mac_array[32] ^ mac_array[30] ^ mac_array[29] ^ mac_array[28] ^
-		 mac_array[24] ^ mac_array[23] ^ mac_array[22] ^ mac_array[21] ^
-		 mac_array[20] ^ mac_array[18] ^ mac_array[17] ^ mac_array[16] ^
-		 mac_array[15] ^ mac_array[14] ^ mac_array[13] ^ mac_array[12] ^
-		 mac_array[9]  ^ mac_array[6]  ^ mac_array[1]  ^ mac_array[0];
-
-	crc[2] = mac_array[47] ^ mac_array[46] ^ mac_array[44] ^ mac_array[43] ^
-		 mac_array[42] ^ mac_array[39] ^ mac_array[37] ^ mac_array[34] ^
-		 mac_array[33] ^ mac_array[29] ^ mac_array[28] ^ mac_array[25] ^
-		 mac_array[24] ^ mac_array[22] ^ mac_array[17] ^ mac_array[15] ^
-		 mac_array[13] ^ mac_array[12] ^ mac_array[10] ^ mac_array[8]  ^
-		 mac_array[6]  ^ mac_array[2]  ^ mac_array[1]  ^ mac_array[0];
-
-	crc[3] = mac_array[47] ^ mac_array[45] ^ mac_array[44] ^ mac_array[43] ^
-		 mac_array[40] ^ mac_array[38] ^ mac_array[35] ^ mac_array[34] ^
-		 mac_array[30] ^ mac_array[29] ^ mac_array[26] ^ mac_array[25] ^
-		 mac_array[23] ^ mac_array[18] ^ mac_array[16] ^ mac_array[14] ^
-		 mac_array[13] ^ mac_array[11] ^ mac_array[9]  ^ mac_array[7]  ^
-		 mac_array[3]  ^ mac_array[2]  ^ mac_array[1];
-
-	crc[4] = mac_array[46] ^ mac_array[45] ^ mac_array[44] ^ mac_array[41] ^
-		 mac_array[39] ^ mac_array[36] ^ mac_array[35] ^ mac_array[31] ^
-		 mac_array[30] ^ mac_array[27] ^ mac_array[26] ^ mac_array[24] ^
-		 mac_array[19] ^ mac_array[17] ^ mac_array[15] ^ mac_array[14] ^
-		 mac_array[12] ^ mac_array[10] ^ mac_array[8]  ^ mac_array[4]  ^
-		 mac_array[3]  ^ mac_array[2];
-
-	crc[5] = mac_array[47] ^ mac_array[46] ^ mac_array[45] ^ mac_array[42] ^
-		 mac_array[40] ^ mac_array[37] ^ mac_array[36] ^ mac_array[32] ^
-		 mac_array[31] ^ mac_array[28] ^ mac_array[27] ^ mac_array[25] ^
-		 mac_array[20] ^ mac_array[18] ^ mac_array[16] ^ mac_array[15] ^
-		 mac_array[13] ^ mac_array[11] ^ mac_array[9]  ^ mac_array[5]  ^
-		 mac_array[4]  ^ mac_array[3];
-
-	crc[6] = mac_array[47] ^ mac_array[46] ^ mac_array[43] ^ mac_array[41] ^
-		 mac_array[38] ^ mac_array[37] ^ mac_array[33] ^ mac_array[32] ^
-		 mac_array[29] ^ mac_array[28] ^ mac_array[26] ^ mac_array[21] ^
-		 mac_array[19] ^ mac_array[17] ^ mac_array[16] ^ mac_array[14] ^
-		 mac_array[12] ^ mac_array[10] ^ mac_array[6]  ^ mac_array[5]  ^
-		 mac_array[4];
-
-	crc[7] = mac_array[47] ^ mac_array[44] ^ mac_array[42] ^ mac_array[39] ^
-		 mac_array[38] ^ mac_array[34] ^ mac_array[33] ^ mac_array[30] ^
-		 mac_array[29] ^ mac_array[27] ^ mac_array[22] ^ mac_array[20] ^
-		 mac_array[18] ^ mac_array[17] ^ mac_array[15] ^ mac_array[13] ^
-		 mac_array[11] ^ mac_array[7]  ^ mac_array[6]  ^ mac_array[5];
-
-	for (i = 0; i < 8; i++)
-		crc_result = crc_result | (crc[i] << i);
+	crc = addr_crc(addr);
 
 	table = OTHER_MCAST_TABLE(port_num);
-	set_filter_table_entry(mep, table, crc_result);
+	set_filter_table_entry(mep, table, crc);
 }
 
 static void set_multicast_list(struct net_device *dev)
-- 
1.5.3.4

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Messages in current thread:
[PATCH 00/39] mv643xx_eth: complete overhaul, Lennert Buytenhek, (Tue Jun 3, 7:02 am)
[PATCH 29/39] mv643xx_eth: general cleanup, Lennert Buytenhek, (Tue Jun 3, 7:02 am)
Re: [PATCH 29/39] mv643xx_eth: general cleanup, Dale Farnsworth, (Thu Jun 5, 8:33 am)
Re: [PATCH 29/39] mv643xx_eth: general cleanup, Lennert Buytenhek, (Fri Jun 6, 4:24 am)
Re: [PATCH 29/39] mv643xx_eth: general cleanup, Dale Farnsworth, (Fri Jun 6, 6:59 am)
[PATCH 19/39] mv643xx_eth: kill -&gt;rx_resource_err, Lennert Buytenhek, (Tue Jun 3, 7:02 am)
Re: [PATCH 19/39] mv643xx_eth: kill -&gt;rx_resource_err, Dale Farnsworth, (Thu Jun 5, 7:48 am)
[PATCH 10/39] mv643xx_eth: clarify irq masking and unmasking, Lennert Buytenhek, (Tue Jun 3, 7:02 am)
[PATCH 02/39] mv643xx_eth: trim unnecessary includes, Lennert Buytenhek, (Tue Jun 3, 7:02 am)
Re: [PATCH 02/39] mv643xx_eth: trim unnecessary includes, Dale Farnsworth, (Thu Jun 5, 7:02 am)
Re: [PATCH 02/39] mv643xx_eth: trim unnecessary includes, Lennert Buytenhek, (Fri Jun 6, 4:18 am)
Re: [PATCH 02/39] mv643xx_eth: trim unnecessary includes, Dale Farnsworth, (Fri Jun 6, 6:55 am)
[PATCH 03/39] mv643xx_eth: shorten reg names, Lennert Buytenhek, (Tue Jun 3, 7:02 am)
[PATCH 18/39] mv643xx_eth: kill superfluous comments, Lennert Buytenhek, (Tue Jun 3, 7:02 am)
Re: [PATCH 18/39] mv643xx_eth: kill superfluous comments, Dale Farnsworth, (Thu Jun 5, 8:03 am)
Re: [PATCH 03/39] mv643xx_eth: shorten reg names, Dale Farnsworth, (Thu Jun 5, 7:21 am)
[PATCH 12/39] mv643xx_eth: get rid of RX_BUF_OFFSET, Lennert Buytenhek, (Tue Jun 3, 7:02 am)
Re: [PATCH 12/39] mv643xx_eth: get rid of RX_BUF_OFFSET, Dale Farnsworth, (Thu Jun 5, 7:37 am)
[PATCH 11/39] mv643xx_eth: move PHY wait defines into callers, Lennert Buytenhek, (Tue Jun 3, 7:02 am)
[PATCH 09/39] mv643xx_eth: remove unused DESC_SIZE define, Lennert Buytenhek, (Tue Jun 3, 7:02 am)
[PATCH 27/39] mv643xx_eth: split out tx queue state, Lennert Buytenhek, (Tue Jun 3, 7:02 am)
[PATCH 26/39] mv643xx_eth: split out rx queue state, Lennert Buytenhek, (Tue Jun 3, 7:02 am)
Re: [PATCH 26/39] mv643xx_eth: split out rx queue state, Dale Farnsworth, (Thu Jun 5, 8:39 am)
Re: [PATCH 27/39] mv643xx_eth: split out tx queue state, Dale Farnsworth, (Thu Jun 5, 8:09 am)
[PATCH 32/39] mv643xx_eth: allow multiple TX queues, Lennert Buytenhek, (Tue Jun 3, 7:02 am)
Re: [PATCH 32/39] mv643xx_eth: allow multiple TX queues, Dale Farnsworth, (Thu Jun 5, 8:41 am)
[PATCH 31/39] mv643xx_eth: allow multiple RX queues, Lennert Buytenhek, (Tue Jun 3, 7:02 am)
Re: [PATCH 31/39] mv643xx_eth: allow multiple RX queues, Dale Farnsworth, (Thu Jun 5, 8:35 am)
[PATCH 33/39] mv643xx_eth: work around TX hang hardware issue, Lennert Buytenhek, (Tue Jun 3, 7:02 am)
[PATCH 23/39] mv643xx_eth: kill FUNC_RET_STATUS/pkt_info, Lennert Buytenhek, (Tue Jun 3, 7:02 am)
[PATCH 30/39] mv643xx_eth: add tx rate control, Lennert Buytenhek, (Tue Jun 3, 7:02 am)
Re: [PATCH 30/39] mv643xx_eth: add tx rate control, Dale Farnsworth, (Thu Jun 5, 8:51 am)
[PATCH 25/39] mv643xx_eth: massively simplify multicast addr..., Lennert Buytenhek, (Tue Jun 3, 7:02 am)
[PATCH 36/39] mv643xx_eth: be more agressive about RX refill, Lennert Buytenhek, (Tue Jun 3, 7:02 am)
[PATCH 38/39] mv643xx_eth: add PHY-less mode, Lennert Buytenhek, (Tue Jun 3, 7:02 am)
Re: [PATCH 38/39] mv643xx_eth: add PHY-less mode, Dale Farnsworth, (Thu Jun 5, 8:49 am)