Re: dummy help on io
From: Randy.Dunlap (rddunlap_at_osdl.org)
Date: 12/13/04
- Previous message: frahm_at_irsamc.ups-tlse.fr: "Re: [Fwd: 2.6.10-rc3: tulip-driver: tulip_stop_rxtx() failed]"
- In reply to: Gene Heskett: "Re: dummy help on io"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
Date: Sun, 12 Dec 2004 18:16:38 -0800 To: gene.heskett@verizon.net
Gene Heskett wrote:
> 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.
Sure, just look at it on-screen (or print very selected
pages of it).
>>>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?
A kernel driver (whether built into vmlinux or a loadable
module) cannot use them and does not 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.
-- ~Randy - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
- Previous message: frahm_at_irsamc.ups-tlse.fr: "Re: [Fwd: 2.6.10-rc3: tulip-driver: tulip_stop_rxtx() failed]"
- In reply to: Gene Heskett: "Re: dummy help on io"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
Relevant Pages
|
|
