Webserver Woes with mcf5235 (BCC) and rtems 4.7.1

[Paul Whitfield]

CWolfe at motioncontrol.org wrote:
> Hi All,
> 	I recently fixed the network driver for the bsp, and would like to use the GoAhead 
> webserver, but I have been having issues with serving pages. For some unknown reason, 
> illegal characters are being injected into/showing up in the http responses. While I feel 
> confident that It is a driver/configuration issue, I am not sure where to start. I have attempted 
> changing buffer descriptor alignment, MTU size, mbuf and mbuf cluster sizes, Usecs per tick 
> and some other random odds and ends. At one poijnt yesterday, for a few hours, the problem 
> vanished mysteriously, and the webserver was running correctly, though such is not the case 
> now. I have checked the contents of the files in flash, and they are correct, so the erors are 
> definitely being produced by the network driver/stack, but i don't know why. From ethereal, I 
> have noticed that the checksums are bad in all of the packets sent out from the board, but I 
> don't know how much that helps or not. I would appreciate any advice anyone could give.
> Best Regards,
> Christopher Wolfe

One thing that caught me on a different variant of the coldfire(5270)
is that the buffer descriptors must be aligned to certain boundaries.
The from memory the symptoms were similar.

Looking in the 5235 manual it says:

"Buffer descriptor rings *must* start on a 32-bit boundary; however, it 
is recommended they are made 128-bit aligned."

You could try making the bd be alligned on a 128 bit boundary?

The other thing that "bit" me was interactions between the
cache and the FEC, to fix it I invalidated the cache in the FEC ISR.


All of this is on a different processor variant, so YMMV.


Hope that helps

Regards

Paul Whitfield.

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