Subject: Re: [PATCH 2/2] net: ti cpsw ethernet: set IFCTL_{A,B} bits for RMII mode

From: Daniel Mack <[email-masked]>
Date: Thu, 27 Sep 2012 13:42:43 +0200

On 26.09.2012 20:50, N, Mugunthan V wrote:
>> For RMII mode operation in 100Mbps, the CPSW needs to set the
>> IFCTL_A / IFCTL_B bits in the MACCONTROL register.
>>
>> Signed-off-by: Daniel Mack <[email-masked]>
>> Cc: Mugunthan V N <[email-masked]>
>> Cc: Vaibhav Hiremath <[email-masked]>
>> Cc: David S. Miller <[email-masked]>
>> ---
>>  drivers/net/ethernet/ti/cpsw.c | 6 ++++++
>>  1 file changed, 6 insertions(+)
>>
>> diff --git a/drivers/net/ethernet/ti/cpsw.c
>> b/drivers/net/ethernet/ti/cpsw.c
>> index 3d7594e..d88dbfa 100644
>> --- a/drivers/net/ethernet/ti/cpsw.c
>> +++ b/drivers/net/ethernet/ti/cpsw.c
>> @@ -386,6 +386,12 @@ static void _cpsw_adjust_link(struct cpsw_slave
>> *slave,
>>  			mac_control |= BIT(7);	/* GIGABITEN	*/
>>  		if (phy->duplex)
>>  			mac_control |= BIT(0);	/* FULLDUPLEXEN	*/
>> +
>> +		/* set speed_in input in case RMII mode is used in >10Mbps
>> */
>> +		if (phy->speed > 10 && slave->slave_num < 2 &&
>> +		    phy->interface == PHY_INTERFACE_MODE_RMII)
>> +			mac_control |= BIT(15 + slave->slave_num);
> 
> Mac control register is separate for both the slaves and has same bit definitions,
> Bit 15 has to be set for 100Mbps link for RMII and RGMII Phy interface to control
> the RMII/RGMII gasket and in GMII this bit is Un-used by CPSW.
> For slave 1, Bit 16 is set with the above code which is not used control the
> RMII/RGMII gasket control. So it is not required to pass the Phy mode from DT.
> This patch has to be reworked to set Bit 15 with any Phy mode connected.

Hmm, that's interesting. I read the datasheet differently, but I believe
you're right.

> The original driver present was tested with GMII (Beagle Bone A5) and
> RGMII (AM3358 EVM) phy , but CPSW works fine without setting this bit in
> RGMII phymode so this issue was not caught in testing.

Yes, it used to work fine for me too until the hardware was reworked
from RGMII to RMII :)

Thanks a lot for the review - I just tested that setting bit 15 for all
PHY interface modes works for me as well, so I'm fine with that
solution. Will repost a new patch.

Daniel