[U-Boot] LXT972 issue on MPC8247: tx error

[Jerry Van Baren <gerald.vanbaren@ge.com>]

Hi Sauce.Cheng,

Sauce.Cheng wrote:
> my code run on the board reveal the info as following:
> 
> Board: Motorola MPC8272ADS
> DRAM:  32 MB
> FLASH: 512 kB
> In:    serial
> Out:   serial
> Err:   serial
> Net:   FCC1 ETHERNET
> bb_miiphy_write()
> Hit any key to stop autoboot:  0 
> =>
> 
> after i enter words like "ping 192.168.0.100",show something like this
> PS. the line start as "chengmo" are debug infos 
> 
> chengmo : fec_init
> chengmo 0 : rtx.txbd[0].cbd_sc : 00004c00
> chengmo 1 : rtx.txbd[1].cbd_sc : 00004c00
> Using FCC1 ETHERNET device
> chengmo : fec_send
> chengmo_b : rtx.txbd[0].cbd_sc : 00004c00
> chengmo_a : rtx.txbd[0].cbd_sc : 0000ec00
> fec: tx error
> chengmo : fec_send
> fec: tx buffer not ready
> ping failed; host 192.168.0.100 is not alive
> 
> eventually, show me that "fec: tx buffer not ready."
> this prompt is in fec_send() in ether_fcc.c

[snip]

> where the mistakes could happen ? i really cant find it.

Your FEC (Tx) most likely is not being clocked.  Check your QE clock 
configurations, verify that your PHY/MAC/??? is generating the correct 
clocks, etc.

FWIIW, I had this happen on my board because the H/W designer strapped 
the PHY to power up with the clocks disabled (lowers power).  I have to 
flip a bit in a PHY register to enable clocks.  (I'm using a different 
processor and different PHY, YMMV.)

HTH,
gvb