linux-kernel - [PATCH net v3 11/12] net/sonic: Fix CAM initialization

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Message-Id: <16c5c444451ae30a6b64d41a48851ec9cafbe003.1579730846.git.fthain@telegraphics.com.au>
Date:   Thu, 23 Jan 2020 09:07:26 +1100
From:   Finn Thain <fthain@...egraphics.com.au>
To:     "David S. Miller" <davem@...emloft.net>
Cc:     Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Chris Zankel <chris@...kel.net>,
        Laurent Vivier <laurent@...ier.eu>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Eric Dumazet <eric.dumazet@...il.com>,
        Stephen Hemminger <stephen@...workplumber.org>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH net v3 11/12] net/sonic: Fix CAM initialization

Section 4.3.1 of the datasheet says,

    This bit [TXP] must not be set if a Load CAM operation is in
    progress (LCAM is set). The SONIC will lock up if both bits are
    set simultaneously.

Testing has shown that the driver sometimes attempts to set LCAM
while TXP is set. Avoid this by waiting for command completion
before and after giving the LCAM command.

After issuing the Load CAM command, poll for !SONIC_CR_LCAM rather than
SONIC_INT_LCD, because the SONIC_CR_TXP bit can't be used until
!SONIC_CR_LCAM.

When in reset mode, take the opportunity to reset the CAM Enable
register.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Tested-by: Stan Johnson <userm57@...oo.com>
Signed-off-by: Finn Thain <fthain@...egraphics.com.au>
---
Changed since v2:
 - Finish conversion to spin_lock_irqsave/spin_unlock_irqrestore.
---
 drivers/net/ethernet/natsemi/sonic.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/natsemi/sonic.c b/drivers/net/ethernet/natsemi/sonic.c
index 914cec2ccc28..27b6f6585527 100644
--- a/drivers/net/ethernet/natsemi/sonic.c
+++ b/drivers/net/ethernet/natsemi/sonic.c
@@ -634,6 +634,8 @@ static void sonic_multicast_list(struct net_device *dev)
 		    (netdev_mc_count(dev) > 15)) {
 			rcr |= SONIC_RCR_AMC;
 		} else {
+			unsigned long flags;
+
 			netif_dbg(lp, ifup, dev, "%s: mc_count %d\n", __func__,
 				  netdev_mc_count(dev));
 			sonic_set_cam_enable(dev, 1);  /* always enable our own address */
@@ -647,9 +649,14 @@ static void sonic_multicast_list(struct net_device *dev)
 				i++;
 			}
 			SONIC_WRITE(SONIC_CDC, 16);
-			/* issue Load CAM command */
 			SONIC_WRITE(SONIC_CDP, lp->cda_laddr & 0xffff);
+
+			/* LCAM and TXP commands can't be used simultaneously */
+			spin_lock_irqsave(&lp->lock, flags);
+			sonic_quiesce(dev, SONIC_CR_TXP);
 			SONIC_WRITE(SONIC_CMD, SONIC_CR_LCAM);
+			sonic_quiesce(dev, SONIC_CR_LCAM);
+			spin_unlock_irqrestore(&lp->lock, flags);
 		}
 	}
 
@@ -675,6 +682,9 @@ static int sonic_init(struct net_device *dev)
 	SONIC_WRITE(SONIC_ISR, 0x7fff);
 	SONIC_WRITE(SONIC_CMD, SONIC_CR_RST);
 
+	/* While in reset mode, clear CAM Enable register */
+	SONIC_WRITE(SONIC_CE, 0);
+
 	/*
 	 * clear software reset flag, disable receiver, clear and
 	 * enable interrupts, then completely initialize the SONIC
@@ -785,14 +795,7 @@ static int sonic_init(struct net_device *dev)
 	 * load the CAM
 	 */
 	SONIC_WRITE(SONIC_CMD, SONIC_CR_LCAM);
-
-	i = 0;
-	while (i++ < 100) {
-		if (SONIC_READ(SONIC_ISR) & SONIC_INT_LCD)
-			break;
-	}
-	netif_dbg(lp, ifup, dev, "%s: CMD=%x, ISR=%x, i=%d\n", __func__,
-		  SONIC_READ(SONIC_CMD), SONIC_READ(SONIC_ISR), i);
+	sonic_quiesce(dev, SONIC_CR_LCAM);
 
 	/*
 	 * enable receiver, disable loopback
-- 
2.24.1