Re: [PATCH v1 2/3] scsi - a2091.c: convert m68k WD33C93 drivers to DMA API

[Michael Schmitz <schmitzmic@gmail.com>]

Hi Geert,

On 30/06/22 03:55, Geert Uytterhoeven wrote:
> Hi Michael,
>
> On Wed, Jun 29, 2022 at 9:27 AM Michael Schmitz <schmitzmic@gmail.com> 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)?

Cheers,

     Michael

>
> Gr{oetje,eeting}s,
>
>                          Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
>
> 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