[U-Boot] Ethernet receive issue in PPC440

[U-Boot] Ethernet receive issue in PPC440

[prathika]

hi all,
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.

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. but when it comes to peer to 
peer communication, i have problem.. should i doubt on my hardware??what 
can be the possibilities?? has anyone faced such an issue?

Someone please help me in this regard.

Thanks & Regards,
Prathika R

[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

=====================================================================
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de
=====================================================================

[U-Boot] Ethernet receive issue in PPC440

[prathika]

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??

Thanks for your response.

Thanks & Regards,
Prathika R

Stefan Roese wrote:
> 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
> 
> =====================================================================
> DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
> Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de
> =====================================================================

[U-Boot] Ethernet receive issue in PPC440

[Stefan Roese]

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

=====================================================================
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de
=====================================================================

[U-Boot] Ethernet receive issue in PPC440

[prathika]

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
> 
> =====================================================================
> DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
> Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de
> =====================================================================