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Date: Fri, 07 Mar 2014 17:00:04 +0100
From: Stefan Wahren <stefan.wahren@...e.com>
To: "fugang.duan@...escale.com" <fugang.duan@...escale.com>,
Frank Li <lznuaa@...il.com>, Fabio Estevam <festevam@...il.com>
CC: David Miller <davem@...emloft.net>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
"linux-arm-kernel@...ts.arm.linux.org.uk"
<linux-arm-kernel@...ts.arm.linux.org.uk>,
Shawn Guo <shawn.guo@...aro.org>,
"Fabio.Estevam@...escale.com" <Fabio.Estevam@...escale.com>,
"Frank.Li@...escale.com" <Frank.Li@...escale.com>,
Sascha Hauer <kernel@...gutronix.de>
Subject: Re: [Bug] net/fec on i.MX28: promiscuous mode lost after reconnecting
network cable
Hi,
Am 07.03.2014 03:10, schrieb fugang.duan@...escale.com:
> From: Frank Li <lznuaa@...il.com>
> Data: Friday, March 07, 2014 1:43 AM
>
>> To: Fabio Estevam
>> Cc: Stefan Wahren; David Miller; netdev@...r.kernel.org; linux-arm-
>> kernel@...ts.arm.linux.org.uk; Shawn Guo; Estevam Fabio-R49496; Li Frank-B20596;
>> Duan Fugang-B38611; Sascha Hauer
>> Subject: Re: [Bug] net/fec on i.MX28: promiscuous mode lost after reconnecting
>> network cable
>>
>> On Thu, Mar 6, 2014 at 4:30 AM, Fabio Estevam <festevam@...il.com> wrote:
>>> Adding some more folks on Cc.
>>>
>>> On Thu, Mar 6, 2014 at 6:29 AM, Stefan Wahren <stefan.wahren@...e.com> wrote:
>>>> Hello,
>>>>
>>>> i'm using a i.MX28 custom board (I2SE Duckbill) with 2 different
>>>> Ethernet interfaces. Both interfaces should be used as bridge using
>>>> bridge utils. One Ethernet interface is the buildin fec and the other
>>>> is connect by spi. The board runs under Linux mainline 3.10. But the
>>>> following problem still occurs on 3.14-rc4.
>>>>
>>>> Here is the problem, if i disconnect and reconnect the Ethernet cable
>>>> on the buildin fec (eth0), the bridge says the port comes up, but it doesn't
>> work.
>>>> After that any traffic to the fec is okay, but traffic "through" the
>>>> bridge is lost. But i expect no traffic is lost, after reconnect the network
>> cable.
>>>> If i reset the board without disconnecting the cables, the traffic "through"
>>>> the bridge works. If i force the promiscuous mode on the fec (eth0)
>>>> after the reconnect, the bridge works too:
>>>>
>>>> ifconfig eth0 promisc
>>>>
>>>> After that, i made some research and probably found the cause of the
>>>> problem. In the case that the bridge works (link state connected
>>>> since
>>>> reboot) the register HW_ENET_MAC_RCR of the i.MX28 returns 0x45EE011C
>>>> (PROM=1, promiscuous mode on). Then I disconnect the ethernet cable
>>>> and reconnect it. After that the register returns 0x45EE0114 (PROM=0,
>>>> promiscuous mode off) and the bridge doesn't work.
>>>>
>>>> Based on this information, i created a patch against Linux 3.10. I'm
>>>> not sure it's a good solution but it works. After a fec reset all
>>>> register values of HW_ENET_MAC_RCR must be restored, but fec_restart
>>>> do not handle them at all. So set_multicast_list is called after
>>>> fec_restart to restore the promiscuous mode of the fec.
>>>>
>>>> diff --git a/drivers/net/ethernet/freescale/fec_main.c
>>>> b/drivers/net/ethernet/freescale/fec_main.c
>>>> index d48099f..cb6b66e 100644
>>>> --- a/drivers/net/ethernet/freescale/fec_main.c
>>>> +++ b/drivers/net/ethernet/freescale/fec_main.c
>>>> @@ -1063,6 +1063,8 @@ static void fec_get_mac(struct net_device
>>>> *ndev)
>>>>
>>>> /*
>>>> ---------------------------------------------------------------------
>>>> ---- */
>>>>
>>>> +static void set_multicast_list(struct net_device *ndev);
>>>> +
>>>> /*
>>>> * Phy section
>>>> */
>>>> @@ -1093,8 +1095,10 @@ static void fec_enet_adjust_link(struct
>>>> net_device
>>>> *ndev)
>>>> }
>>>>
>>>> /* if any of the above changed restart the FEC */
>>>> - if (status_change)
>>>> + if (status_change) {
>>>> fec_restart(ndev, phy_dev->duplex);
>>>> + set_multicast_list(ndev);
>>>> + }
>>>> } else {
>>>> if (fep->link) {
>>>> fec_stop(ndev);
>>>>
>>>> Is this solution correct?
>> There are many places to call fec_resart.
>> I suggest call set_multicase_list in fec_restart function.
>>
> Yes, we had called set_multicase_list() in fec_restart() function.
> The patch is redundant.
thanks for the review. I didn't look too long at the linux-3.14-rc4, so
i didn't see that. I only know that my problem is still reproducable in
linux-3.14-rc5.
But i think i know why the problem still occurs. Both functions
set_multicast_list() and fec_restart() write into the register
FEC_R_CNTRL. The call of set_multicast_list() is too soon and has no
effect in my case. The reason is that the register FEC_R_CNTRL is
completly overwritten by the local variable rcntl of fec_restart.
Here is a patch against linux-3.14-rc5 which fixes my problem. I moved
the function call to set_multicast_list() behind the register write to
FEC_R_CNTRL.
--- linux-3.14-rc5-old/drivers/net/ethernet/freescale/fec_main.c
2014-03-03 03:56:16.000000000 +0100
+++ linux-3.14-rc5/drivers/net/ethernet/freescale/fec_main.c 2014-03-07
16:38:16.564026150 +0100
@@ -527,13 +527,6 @@
/* Clear any outstanding interrupt. */
writel(0xffc00000, fep->hwp + FEC_IEVENT);
- /* Setup multicast filter. */
- set_multicast_list(ndev);
-#ifndef CONFIG_M5272
- writel(0, fep->hwp + FEC_HASH_TABLE_HIGH);
- writel(0, fep->hwp + FEC_HASH_TABLE_LOW);
-#endif
-
/* Set maximum receive buffer size. */
writel(PKT_MAXBLR_SIZE, fep->hwp + FEC_R_BUFF_SIZE);
@@ -654,6 +647,13 @@
writel(rcntl, fep->hwp + FEC_R_CNTRL);
+ /* Setup multicast filter. */
+ set_multicast_list(ndev);
+#ifndef CONFIG_M5272
+ writel(0, fep->hwp + FEC_HASH_TABLE_HIGH);
+ writel(0, fep->hwp + FEC_HASH_TABLE_LOW);
+#endif
+
if (id_entry->driver_data & FEC_QUIRK_ENET_MAC) {
/* enable ENET endian swap */
ecntl |= (1 << 8);
Is this better? If so i'll create a proper patch.
BR Stefan
>>>> Do you need more information?
>>>>
>>>> Best regards
>>>> Stefan Wahren
>>>> --
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