Re: Amiga Memory map

[Geert U. <ge...@li...>]

On Tue, 17 Oct 2000, Arno Griffioen wrote:
> In the 2.2.10 kernel in arch/ppc/mm/init.c it reads:
> 
> setbat(1, zTwoBase,   0x00000000, 0x01000000, IO_PAGE);
> 
> Which seems to indicate that the entire 16Mb lower block from 0x00000000
> up to 0x01000000 is mapped to 0x80000000 as IO_PAGE, which expands
> to:
> 
> 	PAGE_NO_CACHE
> 	PAGE_GUARDED
> 	PAGE_RW
> 
> Not sure what 'GUARDED' is. The others should be self-explanatory.

IIRC< `GUARDED' means that no reordering should be done on accesses to this
area.

> So CS-PPC access for you should probably happen to/from 0x80F40000+offset.
> (should be the same as ZTWO_VADDR(F40000 + offset))

Or `ZTWO_VADDR(0xF40000)+offset', so you have to use ZTWO_VADDR() only once.

The disadvantage of using plain 0x80F40000+offset is that it will break when
we change the mapping of Zorro II space :-)

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@li...

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds