Re: [PATCH] q800: implement mac rom reset function for BIOS-less mode

[Jason A. Donenfeld]

On Thu, Jan 2, 2020 at 12:41 PM Laurent Vivier <address@hidden> wrote:
>
> Le 02/01/2020 à 12:10, Laurent Vivier a écrit :
> > Le 02/01/2020 à 11:36, Jason A. Donenfeld a écrit :
> >> On Linux, calling `reboot(RB_AUTOBOOT);` will result in
> >> arch/m68k/mac/misc.c's mac_reset function being called. That in turn
> >> looks at the rombase (or uses 0x40800000 is there's no rombase), adds
> >> 0xa, and jumps to that address. At the moment, there's nothing there, so
> >> the kernel just crashes when trying to reboot. So, this commit adds a
> >> very simple implementation at that location, which just writes to via2
> >> to power down.
> >>
> >> Signed-off-by: Jason A. Donenfeld <address@hidden>
> >> ---
> >
> > There are two cleaners solution to do that:
> > 1- catch the jump to the ROM address in QEMU and shutdown the machine, see
> >
> > https://github.com/vivier/qemu-m68k/commit/51cd57d1128059819038b9800455fbf794430c15
> >
> > 2- or as you do, write a fake ROM but use the VIA2 port B bit 3 to
> > shutdown the machine see hw/misc/mac_via.c mos6522_q800_via2_portB_write().
>
> OK, 2 is what you do, so I think we can take this.
>
> The assembly code is correct but not easy to read, could you use defined
> values (VIA_BASE) and add some comments?
>
> I think we don't need the BI_MAC_ROMBASE: in fact MACROM_ADDR is wrong,
> you can change its definition to 0x40800000.
>
> Thanks,
> Laurent

I've addressed your comments and submitted v2.