[U-Boot] Ethernet receive issue in PPC440

[Stefan Roese]

On Friday 10 April 2009, prathika wrote:
> i am porting uboot in PowerPC 440.
> i tried using the ping command.i have connected my board to PC via cross
> cable.
> When i monitor on the PC side using Network Monitor,
> the PC receives the ARP request packet and the PC is replying with
> acknowledgement.
> I verified reading the receive status register in PPC, it shows there
> was FCS error and the EMAC rejects the received packet.

Which 440 variant are you using? And which PHY (in which connection mode, MII, 
RGMII...)?

> Actually i enabled external loop back in PowerPC and made appropriate
> configuration in PPC and in the PHY chip.I have no issues in receiving
> the packet.things work absolutely fine.

Are you doing an internal loopback test (using the loopback test mode of the 
EMAC, or such a test mode of the PHY) or are you using an real external 
loopback test, using an external RJ45 loopback connector?

You might want to take a look at the 4xx POST ethernet driver and tests. It's 
possible to use internal and external loopback tests here (see 
CONFIG_SYS_POST_ETHER_EXT_LOOPBACK).

> but when it comes to peer to 
> peer communication, i have problem.. should i doubt on my hardware??

Sure. If it's not working then it's always possible that such problems result 
from hardware issues.

> what 
> can be the possibilities?? has anyone faced such an issue?

I suggest you check your PHY and it's components. Sometimes a wrong resistor 
or capacitor can cause such or similar problems.

Best regards,
Stefan

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