io.h question

Arnd Bergmann arnd at arndb.de
Fri Jan 6 23:03:55 EST 2006


On Thursday 05 January 2006 21:00, mcnernbm at notes.udayton.edu wrote:
> I finally noticed out_8 and in_8 and what not are located in the
> ppc io.h file in the kernel development download.  But when I 
> tried to do a io.h with in my program I added #include <asm/io.h> 
> and it seems to find it with not problems but it can not find the
> functions with in that file.  Am i missing a define I need to set
> or something so I can see the right files with in io.h I am
> compiling for a ppc405 on a xilinx virtex 4 board.      

The definitions in that file are only usable from inside the kernel,
you can not use them in a user space application.

The correct way to solve your problem (which you did not explain, so
I can only guess) would be to write a kernel device driver for
the peripherial you want to drive, at least if it does not exist yet.

For prototyping, you can play with mmap() on /dev/mem in a user
application, but that is often not very reliable.

	Arnd <><



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