Hi Michael,
On Wed, Jun 29, 2022 at 10:48 PM Michael Schmitz <schmitzmic@xxxxxxxxx> wrote:
> On 30/06/22 03:55, Geert Uytterhoeven wrote:
> > On Wed, Jun 29, 2022 at 9:27 AM Michael Schmitz <schmitzmic@xxxxxxxxx> wrote:
> >> Most users will opt for loading the kernel to a RAM chunk at a higher
> >> physical address, making the lower chunk unusable (except as chip RAM),
> >> meaning allocating a bounce buffer within the first 16 MB will most
> >> likely fail anyway AIUI (but Geert would know that for sure).
> > Exactly. On Zorro III-capable machines, Zorro II RAM is not mapped
> > for general use, but can be used by the z2ram block device.
> Is there any DMA capable memory other than chip and ZorroII RAM on these
> machines?
> > Note that you can use it as a bounce buffer, by looking for and marking
> > free chunks in the zorro_unused_z2ram bitmap.
>
> That would be similar to what amiga_chip_alloc() does, right? Any
> advantages over using chip RAM (faster, perhaps)?
Yes, Z2RAM is faster, as Amiga custom chip DMA does not steal cycles
from Z2RAM.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
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
