[uClinux-dev] BDM operational oddities

Kendrick G. Hamilton hamilton at SEDSystems.ca
Fri Nov 2 09:28:38 EST 2001


On Fri, 2 Nov 2001, Bruce Paterson wrote:

> Bruce Paterson wrote:
> >
> > > Is the console printing anything? I did not write this code, M. Leslie
> >
> > No. It seems it's the low level driver used at startup that is hanging.
>
> OK. Some success at last !
> I tracked it down by going through all the registers required for the
> SMC1 to work one
> by one till I found what was wrong. It was pretty obsure.
>
> The code in arch/m68knommu/kernel/setup.c assumed an oscilator prescaler
> of 128 prior to
> the PLL, whereas our card doesn't use the prescaler. I hard coded it for
> now removing the /128, but
> a better fix would be to look at the prescaler bit in the pll register
> and apply the appropriate
> division. Thsi wrong value for the system_clock resulted in a rubbish
> (-ve) value for the Baud
> rate generators in BRG0 (for SMC1).
>

I have that fix in the CVS repository.


> Now I get the text at last. yay !!
>
> Problem is, I crash out with:
> ...
> Ramdisk driver initialised: 16 ramdisks of 4096K size
> ...
> Blkmem 0 disk images:
> ...
> arena open of 0 failed
> VFS: cannot open root fs (1f:00)
>
> I'm using the mleslie supplied romfs.img and 2.0.38 kernel (for now). I
> have _ramfs setup at
> 0x99000 in RAM (instead of immediately after the text section) since
> it's easier for me to
> manipulate the s19 files at the moment.
> I'm using "make linux.s19", "make romfs.s19", editing the 2 together to
> make a single s19 file
> that is d/l using bdm (or the bootrom using tftp).
> The romfs does end up at 99000 as required as I can see "-rom1fs-" there
> using gdb.
> It also says that location = _ramfs, which I think is correct.
>
> I'll start looking at the fs code, but anyone got a better idea where I
> should go from here ?
>


> Cheers,
> Bruce
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-- 
Kendrick Hamilton E.I.T.
SED Systems, a division of Calian Ltd.
18 Innovation Blvd.
PO Box 1464
Saskatoon, Saskatchewan
Canada
S7N 3R1

Hamilton at sedsystems.ca
Tel: (306) 933-1453
Fax: (306) 933-1486

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