From: Flavio Leitner <fleitner@redhat.com>
Date: Wed, 7 Oct 2009 16:21:49 -0300
Subject: [net] bnx2: apply BROKEN_STATS workaround to 5706/5708
Message-id: 20091007192149.GA2096@redhat.com
O-Subject: [RHEL5.5 patch] Apply BROKEN_STATS workaround to 5706 and 5708.
Bugzilla: 527748
RH-Acked-by: John Feeney <jfeeney@redhat.com>
RH-Acked-by: Jiri Pirko <jpirko@redhat.com>
RH-Acked-by: David Miller <davem@redhat.com>

RHBZ#: https://bugzilla.redhat.com/show_bug.cgi?id=527748

Description:
=============
The network utilization graphics in ganglia report shows peaks
of petabytes, when the network interface is just Gigabit eth.

Broadcom developer (Michael Chan) confirmed that NIC BCM5706 and
BCM5708 are very similar in design so BCM5706 could suffer the same
problem described below:

The statistics block DMA on 5708 can be messed up occasionally on the
average of about once per hour.  If the user is reading the counters
within one second after the corruption, the counters will be all
messed up.  One second later, the counters will be ok again until the
next corruption occurs.

The workaround is to disable the periodic statistics DMA.  Instead,
we manually trigger the DMA once a second in bnx2_timer().  This
manual trigger of the DMA avoids the problem.

Upstream:
==========
Applied on net-next-2.6:
http://git.kernel.org/?p=linux/kernel/git/davem/net-next-2.6.git;a=commit;h=61d9e3fa7eacabfb7879e3da91709f1a5420c507

commit 61d9e3fa7eacabfb7879e3da91709f1a5420c507
Author: Michael Chan <mchan@broadcom.com>
Date:   Fri Aug 21 16:20:46 2009 +0000

    bnx2: Apply BROKEN_STATS workaround to 5706 and 5708.

    Add flag to expand the workaround to both chips.

    Signed-off-by: Michael Chan <mchan@broadcom.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>

Test Build at:
===============
http://brewweb.devel.redhat.com/brew/taskinfo?taskID=2018178

Proposed Patch:
================

It's a simple backport of the above upstream patch.

Signed-off-by: Flavio Leitner <fleitner@redhat.com>

diff --git a/drivers/net/bnx2.c b/drivers/net/bnx2.c
index 9ca4bcb..e870bfb 100644
--- a/drivers/net/bnx2.c
+++ b/drivers/net/bnx2.c
@@ -4901,7 +4901,7 @@ bnx2_init_chip(struct bnx2 *bp)
 	REG_WR(bp, BNX2_HC_CMD_TICKS,
 	       (bp->cmd_ticks_int << 16) | bp->cmd_ticks);
 
-	if (CHIP_NUM(bp) == CHIP_NUM_5708)
+	if (bp->flags & BNX2_FLAG_BROKEN_STATS)
 		REG_WR(bp, BNX2_HC_STATS_TICKS, 0);
 	else
 		REG_WR(bp, BNX2_HC_STATS_TICKS, bp->stats_ticks);
@@ -6038,7 +6038,7 @@ bnx2_timer(unsigned long data)
 		bnx2_reg_rd_ind(bp, BNX2_FW_RX_DROP_COUNT);
 
 	/* workaround occasional corrupted counters */
-	if (CHIP_NUM(bp) == CHIP_NUM_5708 && bp->stats_ticks)
+	if ((bp->flags & BNX2_FLAG_BROKEN_STATS) && bp->stats_ticks)
 		REG_WR(bp, BNX2_HC_COMMAND, bp->hc_cmd |
 					    BNX2_HC_COMMAND_STATS_NOW);
 
@@ -6980,7 +6980,7 @@ bnx2_set_coalesce(struct net_device *dev, struct ethtool_coalesce *coal)
 		0xff;
 
 	bp->stats_ticks = coal->stats_block_coalesce_usecs;
-	if (CHIP_NUM(bp) == CHIP_NUM_5708) {
+	if (bp->flags & BNX2_FLAG_BROKEN_STATS) {
 		if (bp->stats_ticks != 0 && bp->stats_ticks != USEC_PER_SEC)
 			bp->stats_ticks = USEC_PER_SEC;
 	}
@@ -7761,6 +7761,7 @@ bnx2_init_board(struct pci_dev *pdev, struct net_device *dev)
 			rc = -EIO;
 			goto err_out_unmap;
 		}
+		bp->flags |= BNX2_FLAG_BROKEN_STATS;
 	}
 
 	if (CHIP_NUM(bp) == CHIP_NUM_5709 && CHIP_REV(bp) != CHIP_REV_Ax) {
diff --git a/drivers/net/bnx2.h b/drivers/net/bnx2.h
index 2650627..4109b4c 100644
--- a/drivers/net/bnx2.h
+++ b/drivers/net/bnx2.h
@@ -6708,6 +6708,7 @@ struct bnx2 {
 					 BNX2_FLAG_USING_MSIX)
 #define BNX2_FLAG_JUMBO_BROKEN		0x00000800
 #define BNX2_FLAG_CAN_KEEP_VLAN		0x00001000
+#define BNX2_FLAG_BROKEN_STATS		0x00002000
 
 	struct bnx2_napi	bnx2_napi[BNX2_MAX_MSIX_VEC];