| Re: [hatari-devel] VME access |
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Hi,
On 1/3/21 12:33 PM, Thorsten Otto wrote:
On Sonntag, 3. Januar 2021 10:02:19 CET Thomas Huth wrote:
Couldn't you please try to come
up with enough VME emulation instead to fix Linux on the TT?
Thomas, it's about interrupt handling and based on
comments seems to e.g. redirect FDC interrupts:
https://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k.git/tree/arch/m68k/atari/config.c#n394
VME interrupts are set here:
https://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k.git/tree/arch/m68k/atari/ataints.c
And up to 16 VME interrupts are supported:
https://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k.git/tree/arch/m68k/include/asm/atariints.h#n24
I could add some pre-liminary code to setup
suitable SCU mask etc variables when corresponding
regs are written...
But I'm unfamiliar how the whole Hatari interrupt
handling works, and with need to reroute existing
interrupts to go through SCU that's something
I'll leave to you or Nicolas.
That would be the better direction.
Then there would be extra interrupts redundantly
emulated, which would just slow down things.
As Thorsten mentioned, all that would be useless
until some actual VME HW is also emulated.
Wouldn't it make more sense to pretend no VME is available?
Thorsten, that's what my patch adds support for.
To emulate VME,
you would need to specify which kind of VME card should be emulated (AFAIK
could be either memory expansion, or graphics-card, or network card). That
would be a pain.
[1] "--vme-errors" option would go away when
there's some real VME implementation, but
something more similar to --dsp option could
actually be future-proof:
"--vme <x>", where <x> is:
"none" - VME reg access causes errors
"dummy" - what's currently done, errors disabled
And in future:
"empty" -- VME interrupts working, no VME card
"net" -- VME network card emulation
Thomas, does that sound any better?
- Eero