Re: /dev/vme*
Bolo <[email protected]> Wed, 13 Feb 2008 23:35:30 -0600
| Newsgroups | gmane.os.netbsd.ports.sun3,gmane.os.netbsd.ports.sun2 |
|---|---|
| Message-ID | <[email protected]> |
> > My guess is that they generate the alternate vmebus bus cycle codes > > needed to access vmebus devices with 16bit address/data regsiters. > > They just allow mapping a different range. That could be allowed for > /dev/mem directly as well. That's why I don't see the point in the > additional devices. My suns are off at the moment, and I don't have current source handy, but this may be applicable: 1) it would probably break SunOS executable compatability. The execs can't open the vme address space to access the vme resources there properly. 2) IIRC (and it has been a long time) parts of the address space of the suns are setup to access the VME bus with different widths. So, yes all it does is map a different range, but that lets the hardware do the accesses with the different widths. The sun sbus and perhaps mbus memory access may have similar weird mappings, but I never really had to deal with that. Bolo