[U-Boot] RMII ethernet problems on i.MX6 Solo

[Carolyn Smith]

On Thu, Sep 27, 2012 at 2:07 PM, Carolyn Smith <carolynsmi56 at gmail.com> wrote:
> On Thu, Sep 27, 2012 at 12:00 PM, Fabio Estevam <festevam at gmail.com> wrote:
>>
>> On Thu, Sep 27, 2012 at 3:27 PM, Carolyn Smith <carolynsmi56 at gmail.com> wrote:
>> > Hello,
>> >
>> > Has anyone had any success getting RMII ethernet to work on an i.MX6 Solo
>> > or DualLite? I am pretty confident I have the IOMUX registers set up
>> > properly and the clocking configured and working properly but am not seeing
>> > any activity on the TXEN line when trying to transmit a packet.I can access
>> > the PHY's registers so I think that means MDC and MDIO must be working.
>>
>> Which Ethernet PHY are you using and which board?
>>
>> Can you post your patches in the list for review, so that we can try
>> to understand the problem better?
>>
>> Regards,
>>
>> Fabio Estevam
>
>
> It's an SMSC LAN8720A PHY on a custom i.MX6 Solo board. I can't post
> all my patches at this point but I could provide register dumps of
> anything you think might be relevant.
>
> I did make a change to fec_mxc.c in the fec_open function. I #ifdef'ed
> out this section
>
> #ifdef FEC_QUIRK_ENET_MAC
>         {
>                 u32 ecr = readl(&fec->eth->ecntrl) & ~FEC_ECNTRL_SPEED;
>                 u32 rcr = (readl(&fec->eth->r_cntrl) &
>                                 ~(FEC_RCNTRL_RMII | FEC_RCNTRL_RMII_10T)) |
>                                 FEC_RCNTRL_RGMII | FEC_RCNTRL_MII_MODE;
>                 if (speed == _1000BASET)
>                         ecr |= FEC_ECNTRL_SPEED;
>                 else if (speed != _100BASET)
>                         rcr |= FEC_RCNTRL_RMII_10T;
>                 writel(ecr, &fec->eth->ecntrl);
>                 writel(rcr, &fec->eth->r_cntrl);
>         }
> #endif
>
> Since it seems to put the ENET_RCR register into RGMII mode which is
> not what I am using. I have ENET_RCR set to 0x05ee0124.
>
> Thanks,
> Carolyn

As it turns out, I found the magic bullet late last night and got
ethernet working on my board. The secret turned out to be the
IOMUXC_ENET_IPG_CLK_RMII_SELECT_INPUT daisy chain register. I had it
set incorrectly so the processor wasn't getting the ethernet clock.

Regards,
Carolyn