Re: PowerUP SCSI driver.

[F. H. <fh...@at...>]

On Mon, Jun 26, 2000 at 09:53:20AM +0200, Michel D?nzer wrote:
> "F. Heitkamp" wrote:
> > 
> > I'm still at a loss to figure out why the cache test
> > is failing on the 53c770.c driver.  I have been comparing
> > the code in 53C770.c with that in the SYM53X8XX.c driver
> > and the ncr_snooptest() routines are pretty much the same.
> 
> Two things:
> 
> 1. Fred please join as a developer and share your code! :)

Are there any folks out there that want to help work on
this driver?  Last I checked either no one had the same
hardware as I, or did not, have the time, or simply wasn't
interested.

> 
> 2. Is there still no support for the 53c770 in the 2.3 kernel? There are even
> two 53c7xx drivers now...

Hmmm.  I'll have a look.  I think the 770 chip may have been
used in some UNIXes or RAID controllers, but since it doesn't
have a PCI bus interface, it was probably not used in PCs.

> 
> 
> > From looking at the code it seems like the ncr_snooptest()
> > is copying the SCSI scripts code to the cache and then
> > trying to execute that code.  Since that execution fails
> > the cache test fails.
> > [...]
> > ncr_snooptest(): CACHE TEST FAILED: timeout.
> > CACHE INCORRECTLY CONFIGURED.
>   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> Have you checked the cache configuration options? ;)
> 
> What cache is this about?

I am, by no means, an expert on these drivers but I 
think the cache is a place in memory for the SCSI chip
to store and execute its scripts.  It may also be a
common area for the host processor and the SCSI chip
to share data.  Any insight would be appreciated.

The cache seems to be got by using check_region/request_region,
which are standard kernel API calls AFAICT. The check_region
call succeeds, and according to the "Linux Device Drivers"
book the request_region will never fail if the check_region
succeeds.

There could be a problem with alignment of the cache, but I'm
not sure how to check that out.  I guess I am going to peer
at some of the other SCSI drivers and see what they do.


-- 
Fred