Re: dummy help on io

[Gene Heskett]

On Sunday 12 December 2004 19:11, Randy.Dunlap wrote:
>Gene Heskett wrote:
>> Greetings;
>>
>> I've ordered the device drivers book from O-Reilly but it will be
>> a few days getting here.
>
>Get it online:
>http://lwn.net/Kernel/LDD2/

Thanks, but my printer is down, I mde the mistake of installing
cups-1.1.22.  But I'll go get it anyway.
>
>> I'm trying to mod the GPL'd archive PIO.tar.gz, so it will build a
>> driver for a pci card with 3 each 82C55's on it, and I *think* I'd
>> have it working with the first of the 3 chips if I could figure
>> out what to do about using the call "iopl(3);" on installing
>> the driver, and conversely an "iopl(0);" at rmmod time.
>
>Where is that coming from?  I don't see it in the tarball
>or the web site (if I'm looking at the right place).
>   http://ieee.uow.edu.au/~daniel/software/robotd/

<http://ieee.uow.edu.au/~daniel/software/PIO/>

>> I'm told this is required to gain access perms to addresses above
>> 0x3FF.  The call "ioperm" is used below that I've been told.
>
>iopl() and ioperm() are userspace calls that call (g)libc.
>The kernel doesn't call them.

So my driver module does need them?

>> Unforch, an "insmod PIO io=0xf100" (where the card is addressed
>> at currently) is spitting out an "unresolved symbol" error for the
>> iopl call.
>>
>> Being a rank beginner at "pc" hardware, can someone give me a
>> checklist of things I've probably left out please?
>
>Can you put the iopl() call into your app instead?

I can try it in the examples demo.c which I've modified to run
the motor 10 revolutions, if it runs.  1 step/sec.  That runs
without any errors *if* I take the iopl() back out of the driver
and insmod it.

>or into a shell script that forks the app (since the iopl
>man page says:  Permissions are inherited by fork and exec.)
>
>> Kernel is 2.4.25-adeos.  With the module "rtai" inserted when emc
>> is running for realtime control purposes.
>>
>> The card is pure hardware, no bios, only address decoding that
>> can set the base address anyplace in the first 64k of address
>> space in a step of 4 sequence from 0xnn00-0xnn0C for the 4
>> ports of chip 1, 0xnn10-1C for chip 2, etc, where the nn is the
>> dipswitch setting.

-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
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Yahoo.com attorneys please note, additions to this message
by Gene Heskett are:
Copyright 2004 by Maurice Eugene Heskett, all rights reserved.

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