Re: [hatari-devel] SCU/VME register access?

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

Le 07/06/2024 à 14:51, Eero Tamminen a écrit :
> Hi,
>
> On 5.6.2024 12.46, Nicolas Pomarède wrote:
> > 4 years later, time to resurrect this old thread :)
> >
> > Are there any ready to use linux disk image I could use to check the 
> > boot process regarding SCU registers ?
>
> If you're using Debian, it's easy to build latest m68k Linux kernel.
>
> Just copy-paste the commands given in the "3. Building m68k kernel" 
> section of the Hatari "m68k-linux.txt" doc (with "/path/to/hatari" parts 
> replaced by path to your Hatari checkout).
>
> If you do not have Debian, I can mail you the kernel and its symbols 
> file (about 5MB uncompressed).
>
>
> Example in "6. Running Hatari" section tells how to run that Linux 
> kernel with Hatari.
>
> As TT SCU is accessed already at Linux boot, you do not need a disk 
> image i.e. you can drop the "--ide-master" option (besides replacing 
> "falcon" with "tt"). [1]
>
>
> > I know there's also the SysV disk images at http://www.atariunix.com/ 
> > but it seems they also rely on the RTC's internal timer interrupt, 
> > which is not emulated so far
> >
> > Or some other programs that modify SCU registers ? (apart from the TOS 
> > used in MegaSTE / TT)
>
> This is shown by "--trace vme" on latest m68k Linux v6.9:
> ---------------------------------------------------
> ...
> VME: SCU read  (0xff8e01): 0x00
> ...
> NR_IRQS: 141
> VME: SCU write (0xff8e01): 0x10 (system interrupt mask)
> VME: SCU write (0xff8e0d): 0x60 (VME interrupt mask)
> clocksource: mfp: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 
> 77769386670404 ns
> unexpected interrupt from 112
> Console: colour dummy device 80x25
> printk: legacy console [tty0] enabled
> unexpected interrupt from 112
> ...
> unexpected interrupt from 104
> ...
> ---------------------------------------------------
>
> (After which there are constant messages of both 104 & 112 interrupts.)
>
>
> Whereas with "--vme off", linux boots to user-space just fine under TT 
> emulation.
>
>
>      - Eero
>
> [1] Section "4. Building root file system" gives commands for building 
> two different root file systems from packages available on Debian, one 
> based one Busybox, and another based on klibc utilities.

Hi

using the linux image you sent me, I ran hatari with :

hatari  --machine tt --tos tos306fr.img --dsp off --fpu 68882 --mmu on 
-s 14 --ttram 64 --addr24 off -c lilo.cfg --lilo "debug=nfcon 
root=/dev/ram ro init=/init" --trace vme

then I see (this is a work in progress version with SCU support)

scu write sys_int mask ff8e01=0x10 pc=3aa022
scu write vme_int mask ff8e0d=0x60 pc=3aa028

writing 0x10 at ff8e01 allows vsync interrupt (but not hsync), but then 
the linux boot shows lots of line "unexpected interrupt from 112". And 
112 is 0x70, which is VBL interrupt.

so it's strange that linux allows vsync interrupt but then shows some 
errors about interrupt 112 (and in the source code at 
https://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k.git/tree/arch/m68k/atari/ataints.c#n304 
it says vbl is enabled for the cursor)

and when I run above line with --machine falcon and --tos tos404.img 
then I get a kernel crash with a dump of the backtrace.

Can you share the command you run in falcon mode to get a booting linux ?

Nicolas