From: Steve Rossi <srossi@ccrl•mot.com>
To: Dan Malek <dan@netx4•com>
Cc: Embedded Linux PPC List <linuxppc-embedded@lists•linuxppc.org>
Subject: Re: allocating non-cacheable regions
Date: Wed, 31 May 2000 15:53:25 -0500 [thread overview]
Message-ID: <39357BC5.A0B3E713@ccrl.mot.com> (raw)
In-Reply-To: 3910838C.986942D6@embeddededge.com
I'm back on this ... with another question. Following the examples in
commproc.c and enet.c - does setting the _PAGE_NO_CACHE flag
for a page table entry also invalidate any cached data for that page?
I am observing a write-though behavior when I write to addresses in
the _PAGE_NO_CACHE page but when I read from addresses marked
as _PAGE_NO_CACHE it appears to be retrieving data from the cache
not from memory. Is this expected behavior? How can I make it so that
reads as well as writes to a particular page bypass the cache?
Thanks,
Steve
Dan Malek wrote:
> Steve Rossi wrote:
> >
> > How do I allocate a region of memory that is flagged as being
> > non-cacheable?
>
> For an example, look at the commproc.c or enet.c driver in the
> arch/ppc/8xx_io directory. When pages are allocated, the PTEs are
> tracked down and marked non-cache.
>
--
-------------------------------------------------------
Steven K. Rossi srossi@ccrl•mot.com
Staff Engineer
Multimedia Communications Research Laboratory
Motorola Labs
-------------------------------------------------------
** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
next prev parent reply other threads:[~2000-05-31 20:53 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2000-05-03 15:47 allocating non-cacheable regions Steve Rossi
2000-05-03 19:52 ` Dan Malek
2000-05-04 6:45 ` MPC860 enet driver dony
2000-05-31 20:53 ` Steve Rossi [this message]
2000-05-31 22:12 ` allocating non-cacheable regions Dan Malek
2000-05-31 22:39 ` Tom Roberts
2000-06-01 13:01 ` Steve Rossi
2000-06-01 20:10 ` Steve Rossi
2000-06-02 14:24 ` Steve Rossi
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