[uClinux-dev] questions on gpio in device driver

Garfield gmail2000 at 21cn.com
Tue Mar 25 07:26:15 EST 2003

Hello uclinux-dev-request,

Tuesday, March 25, 2003, 2:26:43 PM, you wrote:

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udruo> than "Re: Contents of uClinux-dev digest..."

udruo> Today's Topics:

udruo>    1. Re: uClinux on 68000 confusion (John Williams)
udruo>    2. Re: Coldfire serial port problems (Greg Ungerer)
udruo>    3. Re: Still having trouble with latest CVS and Arcturus uC5272 (Brad Clements)
udruo>    4. Re: Re: soft_irq() (John Williams)
udruo>    5. IDE on 20030305 dist (hn)
udruo>    6. Re: soft_irq() (Miles Bader)
udruo>    7. Re: uClinux on 68000 confusion (David McCullough)
udruo>    8. Tiny memory (John Williams)
udruo>    9. Re: Tiny memory (Miles Bader)
udruo>   10. execve (buc at larsen.st)
udruo>   11. Re: soft_irq() (Miles Bader)
udruo>   12. Re: execve (Andrae Muys)
udruo>   13. Re: execve (Matthew Natalier)
udruo>   14. Re: Re: Tiny memory (David McCullough)

udruo> --__--__--

udruo> Message: 1
udruo> Date: Tue, 25 Mar 2003 09:34:22 +1000
udruo> From: John Williams <jwilliams at itee.uq.edu.au>
udruo> Organization: ITEE, UNiversity of Queendland
udruo> To: uclinux-dev at uclinux.org
udruo> Subject: Re: [uClinux-dev] uClinux on 68000 confusion
udruo> Reply-To: uclinux-dev at uclinux.org

udruo> David McCullough wrote:
>> Jivin Jonathan L Long lays it down ...
>>>I am attempting to put uClinux on my 68000 board. However, I am a bit confused 
>>>about how to compile uClinux for the straight 68000. I have downloaded the 
>>>latest uClinux-dev tarball. There are arch subdirs for m68k and m68knommu; 
>>>what is the difference? Isn't uClinux only for systems without an MMU? Also, 
>> uClinux is a set of patches to support systems without an MMU,  it
>> doesn't remove support for systems with an MMU, although you wouldn't be
>> the first to make that assumption :-)

udruo> What are the consequences of just ignoring MMUs and running uClinux 
udruo> instead or regular linux?  Apart from what you lose (virtual memory 
udruo> etc), do you gain anything?

udruo> The hacker in me shouts "the ability for user code to do whatever it 
udruo> needs to without interference from the kernel!", but then 
udruo> software-engineer me quickly locks hacker-me back in the dungeon! :)

udruo> John

udruo> --__--__--

udruo> Message: 2
udruo> Date: Tue, 25 Mar 2003 10:07:53 +1000
udruo> From: Greg Ungerer <gerg at snapgear.com>
udruo> Organization: SnapGear
udruo> To: uclinux-dev at uclinux.org
udruo> CC: jean at mind.be
udruo> Subject: Re: [uClinux-dev] Coldfire serial port problems
udruo> Reply-To: uclinux-dev at uclinux.org

udruo> Hi Jean, Peter,

udruo> Peter Vandenabeele wrote:
>> We have a problem with the Coldfire serial port (RS485), using the 
>> 2.4.20-uc0 kernel on a coldfire 5407:
>> Under heavy load (high traffic) at high baudrate (115.2kbps) the 
>> 'read' from the application sometimes hangs until the tty timeout
>> expires. After the timeout everything is ok.
>> Any idea on this ? I was thinking about an interrupt (on RX and TX) 
>> problem.

udruo> My first thought would be too check what happens in
udruo> mcfserial.c if the flip buffer fills up. Maybe it
udruo> stalls, and for some reason doesn't start processing
udruo> RX data again once the buffer has been emptied.
udruo> Just a thought anyway...

>> I have seen a changelog to 2.5.63 from 
>> 'http://www.linuxhq.com/kernel/changelog/v2.5/63/', saying that:
>>><gerg at snapgear.com>
>>>      [PATCH] fix m68knommu/ColdFire serial port hang
>>>     This patches fixes a serial port "hang" on the m68knommu ColdFire
>>>      serial driver. It was erroneoulsy looking for a state bit that
>>>      is never set.
>> Could this fix our problem ? I will give it a try anyway.

udruo> No, this won't be it. This problem was specific to changes in
udruo> 2.5 kernels. 2.4.x kernels won't have this problem.

udruo> Regards
udruo> Greg

udruo> ------------------------------------------------------------------------
udruo> Greg Ungerer  --  Chief Software Wizard        EMAIL:  gerg at snapgear.com
udruo> SnapGear Pty Ltd                               PHONE:    +61 7 3435 2888
udruo> 825 Stanley St,                                  FAX:    +61 7 3891 3630
udruo> Woolloongabba, QLD, 4102, Australia              WEB:   www.SnapGear.com

udruo> --__--__--

udruo> Message: 3
udruo> From: "Brad Clements" <bkc at murkworks.com>
udruo> Organization: MurkWorks, Incorporated.
Dear All,

I am working on a device driver now.

While processing GPIO in my driver, I met some troubles.  Could
anybody give me an example on this field.

Thanx for your help in advance.

Best regards,
 Garfield                            mailto:gmail2000 at 21cn.com

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