[U-Boot] Fw: TFTP fails when using network switch

Loren A. Linden Levy
2009-01-20T16:55:47Z

Hi Jerry,

It looks to me like for the M%282 board the PHY address is determined
by querying the MII interface:

include/configs/M5282EVB.h

#define CONFIG_MCFFEC
#ifdef CONFIG_MCFFEC
# define CONFIG_NET_MULTI 1
# define CONFIG_MII 1
# define CFG_DISCOVER_PHY
...

This cause the code in ./drivers/net/mcffec.c specifically
mii_discover_phy to be run, I tried to enable the debugging in this
code:

//#undef ET_DEBUG
//#undef MII_DEBUG

but it does not seem to print anything (:(). One interesting feature is
that once my uClinux image has booted I can talk to it over the
switched network just fin. So the issue is really something in the
setup of the MII PHY interface in u-boot. Is there any build target to
allow me to try and debug this?

Thanks.

Alex

On Mon, 19 Jan 2009 20:14:07 -0500
Jerry Van Baren <gvb.uboot@gmail.com> wrote:

> Hi Loren,
>
> Please don't top post. It annoys us curmudgeons.
>
> Loren A. Linden Levy wrote:
> > Hi All,
> >
> > I still have not found a solution and I am a bit desperate. I did not
> > seem to be able to send any packets (using ping) from the FECO on the
> > M5282Lite board to the tftp host, however pings from the host were
> > answered and I saw packets going from the coldfire board to the host
> > in wireshark. I also get a strange error when I ask for mii info:
> >
> > uBOOT=>> mii device
> > MII devices: 'FEC0'
> > Current device: 'FEC0
> >
> > uBOOT=>> mii info
> > MII not complete
> > MII not complete
> > ...
> >
> > a dump gives me:
> >
> > uBOOT=>> mii dump
> > MII not complete
> > 0. (ffff) -- PHY control register --
> > (8000:8000) 0.15 = 1 reset
> > (4000:4000) 0.14 = 1 loopback
> > (2040:2040) 0. 6,13 = b11 speed selection = ??? Mbps
> > (1000:1000) 0.12 = 1 A/N enable
> > (0800:0800) 0.11 = 1 power-down
> > (0400:0400) 0.10 = 1 isolate
> > (0200:0200) 0. 9 = 1 restart A/N
> > (0100:0100) 0. 8 = 1 duplex = full
> > (0080:0080) 0. 7 = 1 collision test enable
> > (003f:003f) 0. 5- 0 = 63 (reserved)
>
> Note that ALL the bits are '1'. That is indicating your PHY is NOT
> DRIVING data on the MII data line (always idle high). Odds are really
> good that you are not driving your MII clock and data properly, your PHY
> isn't at the address you think it is at, or your hardware has problems.
> The only reason you are getting any ether activity is likely because
> your PHY is defaulting to a configuration that is mostly (not entirely)
> broken.
>
> * Double-check your MII clock and data pin configurations. Are you
> initializing them correctly? Error probability: 87%.
>
> * What address is your PHY strapped to? You need to know this. Error
> probability: 11% (your emails imply you don't know this - I bumped the
> probability up because of that impression).
>
> * Use a logic analyzer (preferred), o-scope (good) or a logic probe on
> your PHY's MII clock and data lines and verify they are receiving the
> right sequence (or at least wiggling when you do the MII commands).
> With a logic analyzer you should be able to read the data you are
> sending and verify the bit pattern. You can do this with an o-scope
> (especially a digital one) too, but a little trickier. This is likely a
> software error (above 87% + 11%) - hardware error probability: 2%
>
> * Oh yeah, you might be clocking the MII lines too fast. Pretty small
> probability, though.
>
> [snip]
>
> Good luck and happy probing,
> gvb
>
> P.S. I used mostly odd percentages because I read somewhere that made up
> percentages are more believable when they are odd. ;-)

--
--
---------------------------------------------
Loren A. Linden Levy
Department of Physics
390 UCB
University of Colorado
Boulder, CO 80309-0390
Tel: 303-735-6146 (CU) / +049 040 8998 4789 (DESY)
Fax: 303-492-3352 (CU) / +049 040 8998 4034 (DESY)
Cell: 303-332-2768 (U.S.) / +049 (0)151 5496 1831 (Germany)
Email: Loren.Lindenlevy at colorado.edu
url: http://up.colorado.edu/~lindenle
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