From: Clemens Koller <clemens.koller@anagramm.de>
To: Manu Abraham <abraham.manu@gmail.com>
Cc: Nobin Mathew <nobin.mathew@gmail.com>,
"vraghavan3@mail.gatech.edu" <vraghavan3@mail.gatech.edu>,
linux-kernel@vger.kernel.org
Subject: Re: Reading a physical memory location
Date: Wed, 11 Jul 2007 12:00:50 +0200 [thread overview]
Message-ID: <4694AA52.6040207@anagramm.de> (raw)
In-Reply-To: <1a297b360707110150x56e8ad6cu64ab768e7d3ce6ed@mail.gmail.com>
Manu Abraham schrieb:
> On 7/11/07, Nobin Mathew <nobin.mathew@gmail.com> wrote:
>> See this in the documentation
>>
>> The returned virtual address is a current CPU mapping for the memory
>> address given. It is only valid to use this function on addresses that
>> have a kernel mapping
>>
>> This function does not handle bus mappings for DMA transfers. In
>> almost all conceivable cases a device driver should not be using this
>> function
>>
>
> To get a better idea, look here
> http://tldp.org/LDP/khg/HyperNews/get/devices/addrxlate.html
Very nice! I have two more questions:
1. Is the document up to date?
2. Can anybody give an example how to "map" lots of pages (which
got filled by i.e. a scatter gather DMA chain) from a driver
(kernel space) to userspace?
Thanks
--
Clemens Koller
__________________________________
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next prev parent reply other threads:[~2007-07-11 10:01 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-09 19:47 Reading a physical memory location vraghavan3
2007-07-09 22:39 ` Nobin Mathew
2007-07-10 18:12 ` vraghavan3
2007-07-10 22:02 ` Manu Abraham
2007-07-11 5:43 ` Nobin Mathew
2007-07-11 8:11 ` Manu Abraham
2007-07-11 8:14 ` Nobin Mathew
2007-07-11 8:50 ` Manu Abraham
2007-07-11 8:57 ` Nobin Mathew
2007-07-11 10:00 ` Clemens Koller [this message]
2007-07-24 12:48 ` Helge Hafting
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