[U-Boot] Ethernet receive issue in PPC440

[prathika <prathika@deeopl.com>]

Hi Stefan,
Thanks for that information. Will get back when  after analysing the 
received packets.

Thanks & Regards,
Prathika R

Stefan Roese wrote:
> On Wednesday 15 April 2009, prathika wrote:
>> I am using PowerPC 440 EP.  The PHY I am using is DP83848. I have
>> enabled RMII mode. I am making sure that all the registers are
>> configured for this mode only, by reading back the registers.
>>
>> First i tried enabling internal loopback in PowerPC by enabling the ILE
>> bit in EMAC0_MR1 register. There was no issue. Then I wanted to test
>> external loopback without RJ-45 cable. that is the data transmitted by
>> Power PC is loop backed by the PHY. So i disabled the ILE bit and
>> enabled FullDuplex FDE bit in EMAC0_MR1 register (As illustrated in the
>> PowerPC User Manual). I also enabled Internal Loopback in PHY.I had no
>> issues in this also. I was able to receive the looped back packets from
>> the PHY.
>>
>> Also to make sure that PHY has no issue, there is a built in test
>> facility avaiilable in the PHY. I also enabled that bit and cleared for
>> the passing of the Built In Test of the PHY.
>>
>> But i never tried doing loop back with the RJ-45 cable. But when i
>> cleared the loop back along the PHY path, should i also test looping
>> back with the cable??
> 
> Such an loopback test using an external shortcut RJ45 cable is more for a 
> factory test of the interface. I just mentioned it to check which loopback 
> test you were doing. You can better test with an PC connected to the 4xx 
> EMAC. And this is what you are doing.
> 
> So you should concentrate on the receive path of the 4xx driver and analyze 
> the errors that you are receiving.
> 
> Best regards,
> Stefan
> 
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