From: Adrian Cox <adrian@humboldt.co.uk>
To: Brad Boyer <flar@allandria.com>
Cc: John Whitney <jwhitney-linuxppc@sands-edge.com>,
"Michael R. Zucca" <mrz5149@acm.org>,
Linux/PPC Development <linuxppc-dev@lists.linuxppc.org>
Subject: Re: Problems with dma_alloc_coherent()
Date: Sun, 04 Apr 2004 09:15:13 +0100 [thread overview]
Message-ID: <1081066513.7999.830.camel@newt> (raw)
In-Reply-To: <20040403173358.GA19686@pants.nu>
On Sat, 2004-04-03 at 18:33, Brad Boyer wrote:
> It's generally better not to decide this sort of thing at compile time
> if you want it to be portable. If you want an example of a kernel that
> can do everything, try compiling Linux for m68k sometime. You can have
> one kernel that can support Amigas, Ataris, Macs, and a few others all
> at once. I'm sure it goes without saying that pretty much everything
> other than the base CPU is different on each platform. In fact, even
> just with 68k based Macs, Apple changed stuff so often that any two
> models may have almost nothing in common.
In the sort of embedded systems which have these DMA controllers, there
is generally no way for Linux to tell which hardware it is running on.
For example, there is no way to tell that this MPC8260 board was made by
North American Veeblefetzer, or that GPIO 15 is the MII clock and GPIO
21 is the MII data, or that those two lines were reassigned on the next
revision of the board. We're already stuck with compiling for a very
specific model, and we're frequently trying to save space in the boot
flash.
- Adrian Cox
** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/
next prev parent reply other threads:[~2004-04-04 8:15 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-04-01 15:59 Problems with dma_alloc_coherent() John Whitney
2004-04-01 16:30 ` John Whitney
2004-04-01 16:51 ` Dan Malek
2004-04-01 17:01 ` Tom Rini
2004-04-01 17:05 ` Matt Porter
2004-04-01 17:51 ` John Whitney
2004-04-01 18:16 ` Matt Porter
2004-04-01 18:19 ` Eugene Surovegin
2004-04-01 18:33 ` Eugene Surovegin
2004-04-01 18:33 ` John Whitney
2004-04-01 18:40 ` Eugene Surovegin
2004-04-01 18:48 ` John Whitney
2004-04-01 18:55 ` Dan Malek
2004-04-01 18:59 ` Eugene Surovegin
2004-04-01 19:10 ` John Whitney
2004-04-01 19:17 ` Eugene Surovegin
2004-04-01 19:35 ` John Whitney
2004-04-01 20:52 ` Michael R. Zucca
2004-04-01 22:00 ` Eugene Surovegin
2004-04-01 22:39 ` Michael R. Zucca
2004-04-02 16:50 ` John Whitney
2004-04-02 18:50 ` Michael R. Zucca
2004-04-02 19:27 ` John Whitney
2004-04-02 20:20 ` Michael R. Zucca
2004-04-02 21:01 ` John Whitney
2004-04-03 7:54 ` Adrian Cox
2004-04-03 12:43 ` John Whitney
2004-04-05 9:05 ` Adrian Cox
2004-04-03 17:33 ` Brad Boyer
2004-04-03 23:17 ` Paul Mackerras
2004-04-04 8:15 ` Adrian Cox [this message]
2004-04-02 22:54 ` Paul Mackerras
2004-04-03 7:33 ` Adrian Cox
2004-04-04 22:56 ` Benjamin Herrenschmidt
2004-04-02 5:45 ` Christoph Hellwig
2004-04-01 20:49 ` Matt Porter
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