From: "Gerhard Pircher" <gerhard_pircher@gmx•net>
To: linuxppc-dev@ozlabs.org,debian-powerpc@lists•debian.org
Subject: Re: Unmapping pages from the linear addressing without HIGHMEM support
Date: Fri, 10 Mar 2006 14:31:01 +0100 (MET) [thread overview]
Message-ID: <7457.1141997461@www088.gmx.net> (raw)
In-Reply-To: 31042.1141997321@www088.gmx.net
> --- Ursprüngliche Nachricht ---
> Von: Dan Malek <dan@embeddedalley•com>
> An: "Gerhard Pircher" <gerhard_pircher@gmx•net>
> Kopie: debian-powerpc@lists•debian.org, linuxppc-dev@ozlabs•org, Benjamin
> Herrenschmidt <benh@kernel•crashing.org>
> Betreff: Re: Unmapping pages from the linear addressing without
> HIGHMEM support
> Datum: Fri, 10 Mar 2006 07:59:33 -0500
>
> On Mar 10, 2006, at 4:09 AM, Gerhard Pircher wrote:
>
> > That would mean I cannot reuse the code in dma-mapping.c, right?
>
> Sure you can. All you need to do is turn of BAT mapping, which
> is as easy as using the 'nobats' command line parameter and
> all of this code should just work for you.
Yes, that was the solution I would have used. The other solution is to
reserve a physical memory area for DMA operations that is not mapped by the
BATs (AFAIU nor by any page tables setup by the kernel). Therefore I doubt
that I can simply reuse the dma-mapping.c code for the latter approach!? Do
I mix something up here?
> > ... but I guess I have to setup my own page table for the reserved
> > DMA memory area and implement my own alloc_pages() function!?
>
> No, that's already done for you behind all of these functions.
But only, if the whole BAT mapping is killed, right?
Thanks!
Gerhard
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next parent reply other threads:[~2006-03-10 13:31 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <31042.1141997321@www088.gmx.net>
2006-03-10 13:31 ` Gerhard Pircher [this message]
2006-03-09 13:51 Unmapping pages from the linear addressing without HIGHMEM support Gerhard Pircher
2006-03-09 22:11 ` Benjamin Herrenschmidt
2006-03-10 9:09 ` Gerhard Pircher
2006-03-10 12:59 ` Dan Malek
2006-03-10 23:12 ` Benjamin Herrenschmidt
2006-03-10 23:13 ` Benjamin Herrenschmidt
2006-03-11 13:28 ` Gerhard Pircher
2006-03-12 0:07 ` Benjamin Herrenschmidt
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