[Etherboot-developers] 3c900 not working ...

[Paul M. <pa...@as...>]

Hi,

I've been trying to get an old 3c900(B?) combo card working with
etherboot-5.0.8, initially via a floppy boot.

Etherboot detected the card correctly, chose to use the UTP media option
and got as far as attempting to send its first ethernet frame (DHCP
discovery) before hanging.

Being of an inquisitive nature, I tracked the problem down to line 206 of
3c595.c If I understand this correctly, this is a tight loop that waits
for the FIFO buffer to become sufficiently free that it has space for the
first packet.  The problem is FREE_TX is always returning 0 :^/

I was using the Linux driver as a comparison (to try and figure out how
things worked) and I noticed something odd.  In 2.4.19 (what I had to
hand), there's a discrepancy between what Linux uses for the offset and
what etherboot does.  In Linux (3c59x.c line 626)

> /* Register window 1 offsets, the window used in normal operation.
>    On the Vortex this window is always mapped at offsets 0x10-0x1f. */
> enum Window1 {
>         TX_FIFO = 0x10,  RX_FIFO = 0x10,  RxErrors = 0x14,
>         RxStatus = 0x18,  Timer=0x1A, TxStatus = 0x1B,
>         TxFree = 0x1C, /* Remaining free bytes in Tx buffer. */
> };

Also, the Linux driver never sets the Window to 1.  So Window 1 could be
repeated, at the slightly higher offsets for (my) Boomerang card, not just
the Vortex.

Whereas, in etherboot, there's (3c595.h line 137 onwards)
> /*
>  * Window 1 registers. Operating Set.
>  */
[...]
> #define VX_W1_FREE_TX           0x0c

The etherboot driver *does* change the Window to 1. This could explain the 
discrepancy in offsets. 

I tried changing VX_W1_FREE_TX to 0x1c, but the card still returned 0x0
for each query of FREE_TX.

Any suggestions?

Cheers,

Paul.

PS
The card works perfectly under Linux, btw.

PPS
Please CC emails to me as I'm not subscribed to the list


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Particle Physics (Theory & Experimental) Groups                   Paul Millar 
Department of Physics and Astronomy                     pa...@as...
University of Glasgow                                 pa...@ph...
Glasgow, G12 8QQ, Scotland             http://www.astro.gla.ac.uk/users/paulm 
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