From: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
To: Ed Okerson <ed.okerson@gmail.com>
Cc: linux-mips@linux-mips.org
Subject: Re: mmap KSEG1
Date: Fri, 4 Dec 2009 19:33:09 +0100 [thread overview]
Message-ID: <20091204183309.GA10383@alpha.franken.de> (raw)
In-Reply-To: <83f0348b0912040952h40d4d151n79ca5fc33a830ee2@mail.gmail.com>
On Fri, Dec 04, 2009 at 11:52:03AM -0600, Ed Okerson wrote:
> Is it possible to mmap an address in KSEG1 so a user space app can
> read/write to an IO device uncached?
well not exactly to KSEG1, since that is kernel exclusive address space,
but it's possible to map the physical address of the device:
Try
fd = open("/dev/mem", O_RDWR|O_SYNC);
io = mmap (NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, ioaddr);
where ioaddr is the physical address of the io device.
Thomas.
--
Crap can work. Given enough thrust pigs will fly, but it's not necessary a
good idea. [ RFC1925, 2.3 ]
prev parent reply other threads:[~2009-12-04 18:33 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-04 17:52 mmap KSEG1 Ed Okerson
2009-12-04 18:12 ` David Daney
2009-12-04 18:33 ` Thomas Bogendoerfer [this message]
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