From: "David S. Miller" <davem@redhat.com>
To: Oliver.Neukum@lrz.uni-muenchen.de
Cc: roland@topspin.com, linux-kernel@vger.kernel.org
Subject: Re: PCI DMA to small buffers on cache-incoherent arch
Date: Sun, 09 Jun 2002 21:24:22 -0700 (PDT) [thread overview]
Message-ID: <20020609.212422.70462475.davem@redhat.com> (raw)
In-Reply-To: <200206090640.g596e6X14829@fachschaft.cup.uni-muenchen.de>
From: Oliver Neukum <Oliver.Neukum@lrz.uni-muenchen.de>
Date: Sun, 9 Jun 2002 08:45:49 +0200
Am Sonntag, 9. Juni 2002 07:29 schrieb David S. Miller:
> From: Roland Dreier <roland@topspin.com>
> Date: 08 Jun 2002 18:26:12 -0700
>
> Just to make sure I'm reading this correctly, you're saying that as
> long as a buffer is OK for DMA, it should be OK to use a
> sub-cache-line chunk as a DMA buffer via pci_map_single(), and
> accessing the rest of the cache line should be OK at any time before,
> during and after the DMA.
>
> Yes.
Does this mean that this piece of memory does have to be declared
uncacheable until DMA is finished ?
How else do you solve th problem of validity during DMA and
especially after DMA ?
You flush either before/after depending upon whether the cpu caches
are writeback in nature or not, and the cpu is not allowed to touch
those addresses while the device is doing the DMA.
next prev parent reply other threads:[~2002-06-10 4:28 UTC|newest]
Thread overview: 99+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-06-08 20:38 PCI DMA to small buffers on cache-incoherent arch Roland Dreier
2002-06-08 13:58 ` Anton Blanchard
2002-06-09 0:52 ` Roland Dreier
2002-06-08 23:03 ` David S. Miller
2002-06-09 0:40 ` Roland Dreier
2002-06-09 0:53 ` David S. Miller
2002-06-09 1:26 ` Roland Dreier
2002-06-09 5:29 ` David S. Miller
2002-06-09 6:16 ` Roland Dreier
2002-06-10 16:03 ` Roland Dreier
2002-06-11 14:04 ` David Woodhouse
2002-06-09 6:45 ` Oliver Neukum
2002-06-10 4:24 ` David S. Miller [this message]
2002-06-10 10:00 ` Oliver Neukum
2002-06-10 10:24 ` David S. Miller
2002-06-09 9:51 ` Paul Mackerras
2002-06-09 10:54 ` Benjamin Herrenschmidt
2002-06-10 4:27 ` David S. Miller
2002-06-10 15:59 ` Roland Dreier
2002-06-10 17:03 ` Tom Rini
2002-06-10 17:22 ` Oliver Neukum
2002-06-10 17:29 ` Tom Rini
2002-06-10 17:39 ` Oliver Neukum
2002-06-10 19:03 ` Roland Dreier
2002-06-10 19:14 ` Tom Rini
2002-06-10 19:21 ` Roland Dreier
2002-06-10 19:26 ` Tom Rini
2002-06-10 17:57 ` Russell King
2002-06-10 17:28 ` Roland Dreier
2002-06-10 18:07 ` William Jhun
2002-06-10 18:29 ` William Jhun
2002-06-10 18:33 ` Mark Zealey
2002-06-10 18:44 ` Oliver Neukum
2002-06-11 3:10 ` David S. Miller
2002-06-11 4:04 ` Roland Dreier
2002-06-11 4:16 ` Brad Hards
2002-06-11 4:24 ` Roland Dreier
2002-06-11 4:24 ` David S. Miller
2002-06-11 4:21 ` David S. Miller
2002-06-11 4:39 ` Roland Dreier
2002-06-11 4:38 ` David S. Miller
2002-06-11 6:23 ` Oliver Neukum
2002-06-11 6:38 ` David S. Miller
2002-06-11 7:38 ` Oliver Neukum
2002-06-11 7:36 ` David S. Miller
2002-06-11 7:43 ` David S. Miller
2002-06-11 8:07 ` Oliver Neukum
2002-06-11 8:15 ` David S. Miller
2002-06-11 12:06 ` Oliver Neukum
2002-06-11 12:04 ` David S. Miller
2002-06-11 14:23 ` Oliver Neukum
2002-06-14 4:14 ` David S. Miller
2002-06-11 18:26 ` Roland Dreier
2002-06-11 17:29 ` Benjamin Herrenschmidt
2002-06-12 12:02 ` Oliver Neukum
2002-06-11 20:06 ` Benjamin Herrenschmidt
2002-06-12 12:02 ` David S. Miller
2002-06-11 23:00 ` Thunder from the hill
2002-06-11 23:56 ` Roland Dreier
2002-06-12 0:09 ` Thunder from the hill
2002-06-11 15:57 ` William Jhun
2002-06-12 9:06 ` Pavel Machek
2002-06-12 20:16 ` David S. Miller
2002-06-12 11:47 ` David S. Miller
2002-06-12 12:08 ` Oliver Neukum
2002-06-14 4:41 ` David S. Miller
2002-06-12 16:09 ` William Jhun
2002-06-09 1:30 ` Albert D. Cahalan
2002-06-09 5:29 ` David S. Miller
2002-06-09 6:33 ` Albert D. Cahalan
2002-06-09 6:50 ` Oliver Neukum
2002-06-09 6:57 ` Albert D. Cahalan
2002-06-09 7:15 ` Oliver Neukum
2002-06-09 8:48 ` Russell King
2002-06-09 15:42 ` Albert D. Cahalan
2002-06-09 23:26 ` Oliver Neukum
-- strict thread matches above, loose matches on Subject: below --
2002-06-11 5:31 David Brownell
2002-06-11 5:44 ` David S. Miller
2002-06-11 15:12 ` David Brownell
2002-06-11 15:44 ` Oliver Neukum
2002-06-12 3:25 ` David S. Miller
2002-06-11 17:33 ` Benjamin Herrenschmidt
2002-06-12 9:42 ` David S. Miller
2002-06-12 14:14 ` David Brownell
2002-06-12 15:00 ` Benjamin Herrenschmidt
2002-06-12 18:44 ` Roland Dreier
2002-06-12 19:13 ` David Brownell
2002-06-12 19:58 ` Oliver Neukum
2002-06-12 22:51 ` David S. Miller
2002-06-12 23:17 ` Oliver Neukum
2002-06-13 4:57 ` David Brownell
2002-06-12 22:46 ` David S. Miller
2002-06-13 5:13 ` David Brownell
2002-06-13 9:38 ` David S. Miller
2002-06-12 22:50 ` David S. Miller
2002-06-12 6:25 ` David Brownell
2002-06-12 6:24 ` David S. Miller
2002-06-12 7:06 ` David Brownell
2002-06-12 9:22 ` David S. Miller
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