From: "Nate Edel" <mramfs@sfchat.org>
To: "Jason Luo" <abcd.bpmf@gmail.com>,
"Arjan van de Ven" <arjan@infradead.org>
Cc: <linux-kernel@vger.kernel.org>
Subject: Re: Can I get 200M contiguous physical memory?
Date: Thu, 10 Mar 2005 10:57:54 -0800 [thread overview]
Message-ID: <00b701c525a3$128c2ac0$6a004b0a@charlemagne> (raw)
In-Reply-To: <1110445030.6291.57.camel@laptopd505.fenrus.org>
From: "Arjan van de Ven" <arjan@infradead.org>
To: "Jason Luo" <abcd.bpmf@gmail.com>
>> A data acquisition card. In DMA mode, the card need 200M contiguous
>> memory for DMA.
>
> (or want to reserve memory at the boot commandline and then do really
> really evil hacks)
Such as booting the machine with "mem=(real memory - 200)M" and then
just doing an ioremap of the top 200M of memory.
It's not the most elegant way of doing things given that it requires
user intervention at boot time, but I'm not sure it counts as a "really
evil hack." Code-wise it's very simple - there's sample code in a
couple of the in-RAM MTD(*) drivers you can use as a model. I'm not sure
if this method will translate easily to non-x86 platforms if that's an
issue.
(* /drivers/mtd/devices/slram.c and /drivers/mtd/devices/mtdram.c ; I'm
not sure which of these is more up to date.)
next prev parent reply other threads:[~2005-03-10 19:16 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-03-10 8:10 Jason Luo
2005-03-10 8:16 ` Chris Wedgwood
2005-03-10 8:49 ` Jason Luo
2005-03-10 8:57 ` Arjan van de Ven
2005-03-10 18:57 ` Nate Edel [this message]
2005-03-10 19:02 ` Arjan van de Ven
2005-03-10 20:28 ` linux-os
2005-03-10 9:00 ` Chris Wedgwood
2005-03-10 8:43 ` Mario Holbe
2005-03-11 20:39 ` Bill Davidsen
[not found] <3Gr3R-5gH-23@gated-at.bofh.it>
[not found] ` <3Grdy-5nv-3@gated-at.bofh.it>
[not found] ` <3GrGK-5Ff-17@gated-at.bofh.it>
[not found] ` <3GrQf-5Vr-27@gated-at.bofh.it>
2005-03-11 2:20 ` Robert Hancock
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