[parisc-linux] Re: NCR53c720

Matthew Wilcox willy@debian.org
Tue, 30 Sep 2003 15:32:50 +0100

On Tue, Sep 30, 2003 at 03:59:32PM +0200, Rene Brothuhn wrote:
> I have looked in the ncr53c8xx driver from 2.6 and there is mentioned that 
> "interrupt on the fly" is not working correctly for 720. Also 
> sym53c8xx_defs.h is included and so the registerset from a 810 is used, 
> but the 720/770 registers are slightly different.
> Is the NCR_Q720 or zalon driver working?

Yes, they're both working fine.

I went over the 770 register definitions the other night and only found
one difference between the names of the definitions in the sym53c8xx_defs
file and the 770 PDF and that was:

-/*3a*/  u_char    nc_sbr;
+/*3a*/  u_char    nc_sbr; /* dwt on 720 */

This is the DMA watchdog timer, but it's not actually used by the driver.
It's a `scratch byte register' on the 895.  Some of the `reserved'
fields in the 770 register definition have names, but they were only
ever touched if the chip was a sufficiently recent revision.

BTW, I couldn't see a document for the 720 chip on the LSI site -- only
the 710 and 770.  I presume I won't go far wrong treating them the same.

> > - Someone implements the non-coherent DMA interfaces for PowerPC.
> So, maybe I can do that at least for APUS, because some of the needed 
> interfaces I already created as a "dirty-hack" inside the 53c770 driver. 
> But the mean problem is, that there is no working 2.6 kernel for APUS... 
> The other problem is time, but maybe I find some hours on weekend...

Yeah, no hurry.  I don't think we have to get this done before 2.6.0 is
out -- after all, it's only a driver.

"It's not Hollywood.  War is real, war is primarily not about defeat or
victory, it is about death.  I've seen thousands and thousands of dead bodies.
Do you think I want to have an academic debate on this subject?" -- Robert Fisk