Re: mmap KSEG1

[Thomas Bogendoerfer <tsbogend@alpha.franken.de>]

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.

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