Re: I/O bus reset to fix CMD MSCP controllers (and probably others)

[Anders Magnusson <ragge%tethuvudet.se@localhost>]

    Den 2025-03-31 kl. 16:36, skrev Mouse:
> > > Data point: when I boot 1.4T under my emulator, I see only three I/O
> > > resets.  One is the emulator resetting itself during startup.  The
> > > other two are due to writes to IPR 55, which happen [in ROM code]
> > >         
> > Could you see if there are any writes to the IP register?  That would
> > be the software reset of just that controller.
> >       
> I see five writes to IP, from startup to single-user shell.  In terms
> of console output, they happen:
>
> (1) After "2.." and before "1..0..".
> (2) After "0..\r\n\n" and before "\n\r\r>> NetBSD/vax boot"
> (3) After "> boot -s\r\n" and before the twirler starts.
> (4) After "uba0 at ibus0: Q22\n\r\r" and before "uda0 at uba0".
> (5) After "mscpbus0 at uda0" and before ": version 0 model 0".
>     
    We can note here that it is the same uda/mscp code here in Mouse's
    emulator (running 1.4T) as it is in the current source.
    Also, the writing to IP are the same.  
    
    Something about odd controllers that I remember; I once got hold of
    an Emulex UC04 controller which I never got working, no matter what
    I tried.
    I got the feeling that it was timing-dependent to initialize it.
    
    BTW, Hans, have you tried fiddling with the DELAY() timer?  
    
    Also, since booting works where it will init the controller, I
    glanced at that code as well (ra.c).
    It do not have any delays at all; looks more or less like this:
    
            *ra_ip = 0; /* Start init */
    
            /* Init of this uda */
            while ((*ra_sa & MP_STEP1) == 0)
                    ;
            *ra_sw = 0x8000;
            while ((*ra_sa & MP_STEP2) == 0)
                    ;
            *ra_sw = johan;
            while ((*ra_sa & MP_STEP3) == 0)
                    ;
            *ra_sw = johan2;
            while ((*ra_sa & MP_STEP4) == 0)
                    ;
    
    -- Ragge