netdev - Re: [PATCH v2] net: fec: Fix the disabling of RX interrupt

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Message-ID: <CAOMZO5CRQeuF_ERZ0v2uocuADXRWscKLN0KqdDHfu+0Ub2MEhw@mail.gmail.com>
Date:	Mon, 18 Feb 2013 23:38:18 -0300
From:	Fabio Estevam <festevam@...il.com>
To:	Frank Li <lznuaa@...il.com>
Cc:	Fabio Estevam <fabio.estevam@...escale.com>, davem@...emloft.net,
	Frank.Li@...escale.com, shawn.guo@...aro.org, marex@...x.de,
	s.hauer@...gutronix.de, netdev@...r.kernel.org
Subject: Re: [PATCH v2] net: fec: Fix the disabling of RX interrupt

On Mon, Feb 18, 2013 at 10:54 PM, Frank Li <lznuaa@...il.com> wrote:

> This is not correct fix.
> Read, OR and write is not atomic. Need lock.
> But if use hw_lock, it cause dead lock.
> I spend some time to remove such lock.

Ok, could you please try the patch below? It avoids the kernel crash
on my mx53qsb:

 drivers/net/ethernet/freescale/fec.c |   23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/freescale/fec.c
b/drivers/net/ethernet/freescale/fec.c
index 0fe68c4..4df6518 100644
--- a/drivers/net/ethernet/freescale/fec.c
+++ b/drivers/net/ethernet/freescale/fec.c
@@ -804,6 +804,24 @@ rx_processing_done:
 	return pkt_received;
 }

+static void fec_control_rx(struct net_device *ndev, bool enable)
+{
+	struct fec_enet_private *fep = netdev_priv(ndev);
+	int reg;	
+	unsigned long flags;
+
+	spin_lock_irqsave(&fep->hw_lock, flags);
+	reg = readl(fep->hwp + FEC_IMASK);
+	if (enable)
+		reg |= FEC_ENET_RXF;
+	else
+		reg &= ~FEC_ENET_RXF;
+
+	writel(reg, fep->hwp + FEC_IMASK);
+
+	spin_unlock_irqrestore(&fep->hw_lock, flags);
+}
+
 static irqreturn_t
 fec_enet_interrupt(int irq, void *dev_id)
 {
@@ -821,8 +839,7 @@ fec_enet_interrupt(int irq, void *dev_id)

 			/* Disable the RX interrupt */
 			if (napi_schedule_prep(&fep->napi)) {
-				writel(FEC_RX_DISABLED_IMASK,
-					fep->hwp + FEC_IMASK);
+				fec_control_rx(ndev, false);
 				__napi_schedule(&fep->napi);
 			}
 		}
@@ -1628,7 +1645,7 @@ static int fec_enet_init(struct net_device *ndev)
 	ndev->netdev_ops = &fec_netdev_ops;
 	ndev->ethtool_ops = &fec_enet_ethtool_ops;

-	writel(FEC_RX_DISABLED_IMASK, fep->hwp + FEC_IMASK);
+	fec_control_rx(ndev, false);
 	netif_napi_add(ndev, &fep->napi, fec_enet_rx_napi, FEC_NAPI_WEIGHT);

 	/* Initialize the receive buffer descriptors. */
-- 
1.7.9.5
--
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