lkml.org 
[lkml]   [2013]   [Oct]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH] m68k/atari: Call paging_init() before nf_init()
From
On Sat, Oct 19, 2013 at 2:33 AM, Michael Schmitz
<schmitz@biophys.uni-duesseldorf.de> wrote:
>> With the DISCONTIGMEM memory model, the kernel must be stored in the
>> first memory block. As ST-RAM is before FastRAM in memory, you cannot
>> have the kernel in FastRAM without losing ST-RAM (as main memory ---
>> you can still e.g. ioremap() it for atafb, and use the rest of it as
>> swap through
>> a block device like z2ram. This is basically what we do on Amiga with Chip
>> RAM
>> and Z2 RAM).
>
> As long as we can ioremap() the ST-RAM frame buffer, we ought to be fine in
> the first instance. How useful ST-RAM as swap may be is debatable so I'd
> leave that aside for now.
>
> Main benefits would be for users of TTs that have been left out with recent
> kernel sizes.
>
> OK - how would I go about ioremaping a chunk of ST-RAM when that has been
> left out of the mm setup because it violates the discontigmem layout rules?
> Set up a kernel private mapping for all of ST-RAM, and make that available
> to the stram allocator?

Just call ioremap(), that takes care of the kernel private mapping.
ioremap() is meant to map anything that is not part of the mm setup.

>> With the SPARSEMEM memory model, you should be able to store the kernel
>> in FastRAM and have ST-RAM, too.
>
> I can still remember the headache I got when last playing with the mm code,
> I think I'll pass.

But "we" probably have to do that anyway, to please the Amiga BigRAM users.

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


\
 
 \ /
  Last update: 2013-10-19 10:21    [W:0.055 / U:1.172 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site