Re: [ts-7000] mmap failing when trying to interface to some DIO; TS-7260

[Jim Jackson <>]

Check out the man page for mmap on a "full" linux system or on the web.
mmap can only be used to map to a page boundary. You then add suitable 
offsets, depending on usage, to this mmap'ed base pointer.

check out the ts7200io.c file in my adio program at

  http://www.comp.leeds.ac.uk/jj/linux/adio.tgz

This app note describes how this sort of stuff is done...

  http://www.simtec.co.uk/appnotes/AN0014/

Jim
----------------------------------------------------------------------------
HomePage:    http://www.comp.leeds.ac.uk/jj
TS7200 Page: http://www.comp.leeds.ac.uk/jj/linux/arm-sbc.html



On Fri, 6 Feb 2009, sean machin wrote:

> Hi All,
>
> I'm writing a driver which needs to interface to the digital I/O ports
> on my TS-7260.  The particular physical addresses
> I need access to are 0x80840014 for a data direction register and
> 0x80840004 for the data register.
>
> It looks like my call to mmap the address 0x80840014 is failing with
> errno 22 (invalid argument).  Anyone on the
> list got an idea why the call is failing?  Thanks.
>
> --------------------------------------------------------------------------------------------------------------
>    uint8_t* ddr_reg = mmap(0, getpagesize(), PROT_READ|PROT_WRITE,
> MAP_SHARED, fd, 0x80840014);
>    if (ddr_reg == MAP_FAILED) {
>        syslog(LOG_ERR, "mmap failed with errno %d", errno);
>    }
>
>


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