i.MX Processors中的主题 Re: help about fec problem

help about fec problem

mehmet — Sun, 08 May 2011 12:05:33 GMT

Hi all,

I have a big problem that I couldn't understand. I have i.mx28 evk. I use default sb linux with sd card. I want to up eth0 and mount my host pc with nfs.

ifconfig eth0 122.122.122.149 netmask 255.255.255.0

eth0: Freescale FEC PHY driver [Generic PHY] (mii_bus:phy_addr=0:00, irq=-1)
root@freescale ~$ PHY: 0:00 - Link is Up - 100/Full

mount -t nfs -o nolock 122.122.122.141:/srv/nfs/share /mnt

Sometimes mounting is ok, sometimes it lates, but sometimes it cannot be mounted.

Mostly I see act led flashes very fast but there is no activity. I check with ifconfig, there is no increase on any packets and on ethernet switch act. led doesn't flash.

When I couldn't mount nfs, I tried down up like below and got error response;

ifconfig eth0 down

ifconfig eth0 up

FEC: MDIO read timeout

eth0: could not attach to PHY

ifconfig: SIOCSIFFLAGS: Connection timeout

Thanks.

Mehmet

Re: help about fec problem

mehmet — Thu, 12 May 2011 12:03:52 GMT

Hi all,

Someone should get same error. It is default images and evk.

Thanks.

Mehmet

Re: help about fec problem

wgeho — Mon, 20 Jun 2011 13:56:18 GMT

Hi all,

I have exactly the same problem (with or whithout nfs). Activity led flashes very fast but there is no activity.

I was not able to get any useful information from the freescale support team.

Re: help about fec problem

TimWoodham — Wed, 22 Jun 2011 14:37:55 GMT

there is a patch for the ethernet on the 2.6.35 BSP from freescale,

check out the thread on the freescale page,

http://forums.freescale.com/t5/i-MX-Microprocessors/i-mx28-evk-network-plug-unplug-problem/m-p/75101#M2948

Re: help about fec problem

wgeho — Thu, 23 Jun 2011 13:43:17 GMT

Hi Tim,

Thanks for your reply.

The described problem is not exactly the same.

Well, there are two problems:

- stopping ethernet is not working.

- the activity led flashes very fast but there is no activity (only happens sometimes).

The patch is a workaround for the first one, but there remains the second one.

However, for me it seems they are related. After calling the function fec_restart, there are no more interrupts.

Re: help about fec problem

BryanJI — Fri, 24 Jun 2011 06:30:49 GMT

I also use nfs, it just fine. Maybe you need to check your working network.

For later problem, the fec has this problem. Check the solution on freescale forum.

Re: help about fec problem

SamGandhi — Fri, 28 Oct 2011 21:28:59 GMT

Has this problem being fixed. We are running 3.1.0-rc5 kernel and see this often.

if one does if down eth0 and then if up eth0 then you see message:

FEC: MDIO read timeout
eth0: could not attach to PHY
ifconfig: SIOCSIFFLAGS: Connection timed out

Also when nfs booting sometimes the TX LED on the connector flashes really fast but actually board doesn't seem to be do rx/tx any packets.

[ BTW are freescale folks on imxcommunity.org? ]

Re: help about fec problem

Michael_McTerna — Sun, 30 Oct 2011 16:59:05 GMT

I took a look in the Freescale git tree on Friday, and it seemed that the bug was still there...

As pointed out elsewhere the 'fix' is a one liner in drivers/net/fec.c in fec_stop() - just remove the following lines:

/* Whack a reset. We should wait for this. */
writel(1, fep->hwp + FEC_ECNTRL);
udelay(10);

It would be nice if this could get fixed on mainline as the bug has been around for a long time now.

Re: help about fec problem

YiLi — Thu, 05 Jan 2012 15:33:32 GMT

Which revision of i.mx28 EVK board are you seeing this issue?

Re: help about fec problem

Michael_McTerna — Thu, 05 Jan 2012 15:38:32 GMT

Actually on a Karo TX28 module.

Re: help about fec problem

rogerio_silva — Fri, 06 Jan 2012 14:02:27 GMT

I got the same problem when testing another i.MX platform. It was solved by increasing the MDIO timeout on file linux/drivers/fec.c (The patch was already submitted on Freescale and Mainline repositories).

On this file, change the line:

#define FEC_MII_TIMEOUT 1000

#define FEC_MII_TIMEOUT 40000

Doesn't make sense to leave the timeout in 1000 usecs because the time resolution is 10ms. On my tests 40ms seems to work fine with the PHY I have used.

Let us know about your results.

Rgds,

Rogerio Pimentel

Re: help about fec problem

Michael_McTerna — Fri, 06 Jan 2012 16:55:12 GMT

Rogerio Pimentel said:

I got the same problem when testing another i.MX platform. It was solved by increasing the MDIO timeout on file linux/drivers/fec.c (The patch was already submitted on Freescale and Mainline repositories).
On this file, change the line:
#define FEC_MII_TIMEOUT 1000
to
#define FEC_MII_TIMEOUT 40000
Doesn't make sense to leave the timeout in 1000 usecs because the time resolution is 10ms. On my tests 40ms seems to work fine with the PHY I have used.
Let us know about your results.

I tested the timeout change on my MX28 and it doesn't fix the original problem, which I think is actually caused because the MII interface doesn't get sufficiently re-initialised after the reset in fec_stop() since fec_enet_interrupt() then never gets the FEC_ENET_MII & hence the similar but different timeout.

I also checked and FEC_MII_TIMEOUT is passed through usecs_to_jiffies(). I tested this and found it sensibly rounds up to 1 jiffy = 10ms on my board which seems plenty long enough in normal operation.

I haven't checked again, so maybe the problem's already been fixed by Freescale. It's certainly been around on the MX28 for long enough:

http://forums.freescale.com/t5/i-MX-Microprocessors/iMX28-eth0-Could-not-attach-to-PHY/m-p/65649

Re: help about fec problem

jackyliu — Mon, 16 Jan 2012 06:55:29 GMT

NFS use UDP as its default protocol.
UDP is not stable.
You can use "-o tcp" when mount, so it will use tcp to make connection. TCP is a stable connection.

Re: help about fec problem

PeterKardos — Tue, 17 Jan 2012 07:52:17 GMT

I don't what's the current status of this issue...

Please also make sure you have a MAC address assigned to your interface. I've had a similar experience with our project with i.mx253 + LAN8700(RMII). No other "tweaks" were necessary, everything runs out-of-box, with kernel 2.6.39.4...

Re: help about fec problem

PauliM — Thu, 09 Feb 2012 14:14:14 GMT

Hi, Just experienced this on a MX28EVK board running 2.6.35 kernel from freescale. What is the preferred way to fix or get around this problem?

Does the patch mentioned earlier work and if yes, how should it be applied?

Thanks

Pauli

Re: help about fec problem

Michael_McTerna — Thu, 09 Feb 2012 14:26:05 GMT

Pauli M said:

Hi, Just experienced this on a MX28EVK board running 2.6.35 kernel from freescale. What is the preferred way to fix or get around this problem?
Does the patch mentioned earlier work and if yes, how should it be applied?

I'm not sure what the preferred way is, but I removed the following lines from drivers/net/fec.c in fec_stop(), and this allows me to ifup/ifdown the net device repeatedly without problem on my i.MX28 with linux 2.6.38:

/* Whack a reset. We should wait for this. */
writel(1, fep->hwp + FEC_ECNTRL);
udelay(10);

Re: help about fec problem

DanieleDall_Acq — Thu, 09 Feb 2012 15:24:17 GMT

Actually I've fixed the "Led Blinking" problem (which occurs just on some networks) using the attached patch. For my understanding the PHY was continuosly processing speed auto negotiation packets, preventing it to work properly.

I've implemented this on top of the above mentioned patch.

Ciao

--daniele

Re: help about fec problem

DanieleDall_Acq — Thu, 09 Feb 2012 15:27:12 GMT

The patch :)

Re: help about fec problem

PauliM — Thu, 09 Feb 2012 15:27:18 GMT

Thanks. On a quick test commenting the two lines seems to work. Sad to see there is no official fix for this.

Regards

Pauli

Re: help about fec problem

CraigMcQueen — Thu, 29 Oct 2020 08:57:44 GMT

Daniele Dall'Acqua wrote:

The patch

Can anyone point me to documentation of how to integrate this patch into LTIB kernel builds?