Subject: Re: FEC_IEVENT_RFIFO_ERROR

From: "Dale Farnsworth" <[email-masked]>
Date: Thu, 3 Mar 2005 09:59:56 -0700

On Thu, Mar 03, 2005 at 01:14:54PM +0000, Babarovic Ivica wrote:
> I run 2.6.10-rc2 kernel (http://www.246tNt.com/mpc52xx/)
> for MPC5200 chip on a custom board that is almost lite5200 compatible.
> I noticed a couple of times I have a strange error at bootup.
> It was FEC_IEVENT_RFIFO_ERROR. Most of the times this
> went trough without problems but since today system just hangs.
> Sometimes with several printouts of this error.
> ---boot sequence ------
> FEC_IEVENT_RFIFO_ERROR
> FEC_IEVENT_RFIFO_ERROR
> FEC_IEVENT_RFIFO_ERROR
> ....
> 
> I traced a problem a bit and found that this happenes at
> mpc52xx_fec_probe() function in fec.c at this point:
> --------------------------------------------------------------------------
>       /* Get the IRQ we need one by one */
>                /* Control */
>        dev->irq = ocp->def->irq;
> -->       if (request_irq(dev->irq, &fec_interrupt, SA_INTERRUPT, 
>                        "mpc52xx_fec_ctrl", dev)) {
>                printk(KERN_ERR "mpc52xx_fec: ctrl interrupt request 
> failed\n");
>                ret = -EBUSY;
>                dev->irq = -1;  /* Don't try to free it */
>                goto probe_error;
>        }
> --------------------------------------------------------------------------

It looks like the bootloader left the FEC enabled.  You might try
the following (untested) patch which resets the FEC and disables
its interrupts before requesting the irq.

-Dale

===== drivers/net/fec_mpc52xx/fec.c 1.1 vs edited =====
--- 1.1/drivers/net/fec_mpc52xx/fec.c	2004-11-20 15:26:33 -07:00
+++ edited/drivers/net/fec_mpc52xx/fec.c	2005-03-03 09:43:08 -07:00
@@ -85,18 +85,13 @@
 	return 0;
 }
 
-/* This function is called to start or restart the FEC during a link
- * change.  This happens on fifo errors or when switching between half
- * and full duplex.
- */
-static void fec_restart(struct net_device *dev, int duplex)
+static void fec_reset(struct net_device *dev)
 {
 	struct fec_priv *priv = (struct fec_priv *)dev->priv;
 	struct mpc52xx_fec *fec = priv->fec;
-	u32 rcntrl;
-	u32 tcntrl;
 	int i;
 
+	out_be32(&priv->fec->imask, 0);		/* mask all interrupts */
 	out_be32(&fec->rfifo_status, in_be32(&fec->rfifo_status) & 0x700000);
 	out_be32(&fec->tfifo_status, in_be32(&fec->tfifo_status) & 0x700000);
 	out_be32(&fec->reset_cntrl, 0x1000000);
@@ -110,6 +105,20 @@
 	}
 	if (i == FEC_RESET_DELAY)
 		printk (KERN_ERR "FEC Reset timeout!\n");
+}
+
+/* This function is called to start or restart the FEC during a link
+ * change.  This happens on fifo errors or when switching between half
+ * and full duplex.
+ */
+static void fec_restart(struct net_device *dev, int duplex)
+{
+	struct fec_priv *priv = (struct fec_priv *)dev->priv;
+	struct mpc52xx_fec *fec = priv->fec;
+	u32 rcntrl;
+	u32 tcntrl;
+
+	fec_reset(dev);
 
 	/* Set station address. */
 	fec_set_paddr(dev, dev->dev_addr);
@@ -645,6 +654,8 @@
 	ret = sdma_fec_tx_init(priv->tx_sdma, priv->tx_fifo);
 	if (ret < 0)
 		goto probe_error;
+
+	fec_reset(dev);
 
 	/* Get the IRQ we need one by one */
 		/* Control */