[okl4-developer] About jiffies in wombat

[Nelson Tam]

On 08/01/2008, at 3:09 AM, Geoffrey Lee wrote:

> On Mon, Jan 07, 2008 at 05:11:46PM +0800, kashin Lin wrote:
>>
>> but when i tried to use wombat as l4 application, it stop at "while  
>> (ticks
>> == jiffies) ;"  in src/linux/kernel-2.6.11-v2/init/calibrate.c.
>>
>> it seems the
>> "jiffies" doesn't change in this case. so i wonder what may cause  
>> this ?
>>
>> i guess it may related to timer driver in src/drivers/. (i port a  
>> timer
>> driver named "davinci_timer" too)
>>
>> if the
>> problem resulted from that driver, are there anything i should take  
>> care or
>> must implement when i write the timer driver ?
>
>
> At the very least you need to make sure that your timer driver can  
> correctly
> handle timeouts.  Try running the drivers example, that has code which
> does some basic tests for your timer.


Hi Kashin,

In particular, do make sure that when the drivers example calls
virtual_timer_current_time(), the return value is increasing over time.

Possible reasons why it isn't working:

1. the mapping isn't actually pointing to device registers (check your
physical address defined in device core)

2. timer needs to be enabled or setup properly (this really depends on  
your
hardware)

3. the mapping is mapped as cached (nasty, but I don't think this is  
your
problem)

Also like Geoff said, make sure that your driver is handling timeouts
correctly.

Enjoy,

Nelson.
--
(nt)