[Xenomai-help] Handling a interrupt from user space on PPC405

[Xenomai-help] Handling a interrupt from user space on PPC405

[Niklaus Giger]

Hi

I tried to use the FIT (Fixed Interrupt Timer) on my PPC405GPr board, which 
uses 0x1010 as its interrupt vector in a user space (vxworks-skin) 
application.
<..>
  RT_INTR FITnterrupt;
  res = rt_intr_create(&FITnterrupt, 0, 0x1010, I_NOAUTOENA);
<..>
But I got -22 EINVAL as error.
Could somebody please tell me, what is wrong with my example.
I would like to have as little as possible code in the kernel and handling the 
whole interrupt in a RT (vxworks-skin) user space task.

And how do I have to handle the case, where my interrupt handler is only 
interested in one of external interrupts of the PPC405?

A good answer would enable me to publish afterwards a working example code.

Best regards.

-- 
Niklaus Giger

Re: [Xenomai-help] Handling a interrupt from user space on PPC405

[Heikki Lindholm]

Niklaus Giger kirjoitti:
> Hi
> 
> I tried to use the FIT (Fixed Interrupt Timer) on my PPC405GPr board, which 
> uses 0x1010 as its interrupt vector in a user space (vxworks-skin) 
> application.
> <..>
>   RT_INTR FITnterrupt;
>   res = rt_intr_create(&FITnterrupt, 0, 0x1010, I_NOAUTOENA);
> <..>
> But I got -22 EINVAL as error.
> Could somebody please tell me, what is wrong with my example.

The 0x1010 is the HW interrupt vector, but the argument should be the 
interrupt _line_. Besides, last time I checked, the ppc405 FIT isn't 
even 'wired' in the kernel; actually, there's no space for the interrupt 
prologue code, which basically results that no handler is called when 
the FIT interrupt occurs.

-- Heikki Lindholm

Re: [Xenomai-help] Handling a interrupt from user space on PPC405

[Wolfgang Grandegger]

Heikki Lindholm wrote:
> Niklaus Giger kirjoitti:
>> Hi
>>
>> I tried to use the FIT (Fixed Interrupt Timer) on my PPC405GPr board, 
>> which uses 0x1010 as its interrupt vector in a user space 
>> (vxworks-skin) application.
>> <..>
>>   RT_INTR FITnterrupt;
>>   res = rt_intr_create(&FITnterrupt, 0, 0x1010, I_NOAUTOENA);
>> <..>
>> But I got -22 EINVAL as error.
>> Could somebody please tell me, what is wrong with my example.
> 
> The 0x1010 is the HW interrupt vector, but the argument should be the 
> interrupt _line_. Besides, last time I checked, the ppc405 FIT isn't 
> even 'wired' in the kernel; actually, there's no space for the interrupt 
> prologue code, which basically results that no handler is called when 
> the FIT interrupt occurs.

Yes, in head_4xx.c there is the following note:

   /* NOTE:
    * FIT and WDT handlers are not implemented yet.
    */

But the relevant code could be copied from the PIT interrupt.

   /* 0x1000 - Programmable Interval Timer (PIT) Exception */
         START_EXCEPTION(0x1000, Decrementer)
         NORMAL_EXCEPTION_PROLOG
         lis     r0,TSR_PIS@h
         mtspr   SPRN_TSR,r0             /* Clear the PIT exception */
         addi    r3,r1,STACK_FRAME_OVERHEAD
   #ifdef CONFIG_IPIPE
         EXC_XFER_IPIPE(0x1000, __ipipe_grab_timer)
   #else /* !CONFIG_IPIPE */
         EXC_XFER_LITE(0x1000, timer_interrupt)
   #endif /* CONFIG_IPIPE */

and modified accordingly.

Wolfgang.


Wolfgang.

Re: [Xenomai-help] Handling a interrupt from user space on PPC405

[Heikki Lindholm]

Wolfgang Grandegger kirjoitti:
> Heikki Lindholm wrote:
> 
>> Niklaus Giger kirjoitti:
>>
>>> Hi
>>>
>>> I tried to use the FIT (Fixed Interrupt Timer) on my PPC405GPr board, 
>>> which uses 0x1010 as its interrupt vector in a user space 
>>> (vxworks-skin) application.
>>> <..>
>>>   RT_INTR FITnterrupt;
>>>   res = rt_intr_create(&FITnterrupt, 0, 0x1010, I_NOAUTOENA);
>>> <..>
>>> But I got -22 EINVAL as error.
>>> Could somebody please tell me, what is wrong with my example.
>>
>>
>> The 0x1010 is the HW interrupt vector, but the argument should be the 
>> interrupt _line_. Besides, last time I checked, the ppc405 FIT isn't 
>> even 'wired' in the kernel; actually, there's no space for the 
>> interrupt prologue code, which basically results that no handler is 
>> called when the FIT interrupt occurs.
> 
> 
> Yes, in head_4xx.c there is the following note:
> 
>   /* NOTE:
>    * FIT and WDT handlers are not implemented yet.
>    */
> 
> But the relevant code could be copied from the PIT interrupt.
> 
>   /* 0x1000 - Programmable Interval Timer (PIT) Exception */
>         START_EXCEPTION(0x1000, Decrementer)
>         NORMAL_EXCEPTION_PROLOG
>         lis     r0,TSR_PIS@h
>         mtspr   SPRN_TSR,r0             /* Clear the PIT exception */
>         addi    r3,r1,STACK_FRAME_OVERHEAD
>   #ifdef CONFIG_IPIPE
>         EXC_XFER_IPIPE(0x1000, __ipipe_grab_timer)
>   #else /* !CONFIG_IPIPE */
>         EXC_XFER_LITE(0x1000, timer_interrupt)
>   #endif /* CONFIG_IPIPE */
> 
> and modified accordingly.

But one should note that the decrementer vector is at 0x1000 and the FIT 
vector at 0x1010. The decrementer exception prologue is obviously bigger 
than 0x10 (16) bytes and thus needs to be moved elsewhere (and branched 
to from the decr vector.) It might be feasible to unite the handlers, 
though, by passing some variable to the C-language handler, telling 
which happened.

-- Heikki Lindholm

Re: [Xenomai-help] Handling a interrupt from user space on PPC405

[Wolfgang Grandegger]

Heikki Lindholm wrote:
> Wolfgang Grandegger kirjoitti:
>> Heikki Lindholm wrote:
>>
>>> Niklaus Giger kirjoitti:
>>>
>>>> Hi
>>>>
>>>> I tried to use the FIT (Fixed Interrupt Timer) on my PPC405GPr 
>>>> board, which uses 0x1010 as its interrupt vector in a user space 
>>>> (vxworks-skin) application.
>>>> <..>
>>>>   RT_INTR FITnterrupt;
>>>>   res = rt_intr_create(&FITnterrupt, 0, 0x1010, I_NOAUTOENA);
>>>> <..>
>>>> But I got -22 EINVAL as error.
>>>> Could somebody please tell me, what is wrong with my example.
>>>
>>>
>>> The 0x1010 is the HW interrupt vector, but the argument should be the 
>>> interrupt _line_. Besides, last time I checked, the ppc405 FIT isn't 
>>> even 'wired' in the kernel; actually, there's no space for the 
>>> interrupt prologue code, which basically results that no handler is 
>>> called when the FIT interrupt occurs.
>>
>>
>> Yes, in head_4xx.c there is the following note:
>>
>>   /* NOTE:
>>    * FIT and WDT handlers are not implemented yet.
>>    */
>>
>> But the relevant code could be copied from the PIT interrupt.
>>
>>   /* 0x1000 - Programmable Interval Timer (PIT) Exception */
>>         START_EXCEPTION(0x1000, Decrementer)
>>         NORMAL_EXCEPTION_PROLOG
>>         lis     r0,TSR_PIS@h
>>         mtspr   SPRN_TSR,r0             /* Clear the PIT exception */
>>         addi    r3,r1,STACK_FRAME_OVERHEAD
>>   #ifdef CONFIG_IPIPE
>>         EXC_XFER_IPIPE(0x1000, __ipipe_grab_timer)
>>   #else /* !CONFIG_IPIPE */
>>         EXC_XFER_LITE(0x1000, timer_interrupt)
>>   #endif /* CONFIG_IPIPE */
>>
>> and modified accordingly.
> 
> But one should note that the decrementer vector is at 0x1000 and the FIT 
> vector at 0x1010. The decrementer exception prologue is obviously bigger 
> than 0x10 (16) bytes and thus needs to be moved elsewhere (and branched 
> to from the decr vector.) It might be feasible to unite the handlers, 
> though, by passing some variable to the C-language handler, telling 
> which happened.

The above code snippet has to be modified for the FIT exception, of 
course, which calls _ipipe_grap_fit(). Here is what is basically needed:

   __ipipe_init_platform()
     calls fit_virq = ipipe_alloc_virq();

   __ipipe_grap_fit(regs)
     calls __ipipe_handle_irq(IPIPE_FIT_VIRQ, regs);

And the FIT timer has to be programed properly elsewhere.

Wolfgang.

Re: [Xenomai-help] Handling a interrupt from user space on PPC405

[Niklaus Giger]

Am Donnerstag, 14. Dezember 2006 08:05 schrieb Heikki Lindholm:
> Niklaus Giger kirjoitti:
> > Hi
> >
> > I tried to use the FIT (Fixed Interrupt Timer) on my PPC405GPr board,
> > which uses 0x1010 as its interrupt vector in a user space (vxworks-skin)
> > application.
> > <..>
> >   RT_INTR FITnterrupt;
> >   res = rt_intr_create(&FITnterrupt, 0, 0x1010, I_NOAUTOENA);
> > <..>
> > But I got -22 EINVAL as error.
> > Could somebody please tell me, what is wrong with my example.
>
> The 0x1010 is the HW interrupt vector, but the argument should be the
> interrupt _line_. Besides, last time I checked, the ppc405 FIT isn't
> even 'wired' in the kernel; actually, there's no space for the interrupt
> prologue code, which basically results that no handler is called when
> the FIT interrupt occurs.
>
Thanks a lot for your tip. 
I did now test using IPIPE_TRAP_UNKNOWN, where my main test routine looks like 
this.
>   int res, j;
>   RT_INTR FITnterrupt;
>   printf("\n%s:", __FUNCTION__);
>   // res = rt_intr_create(&FITnterrupt, "sysAuxClk", 0x1010, I_NOAUTOENA);
>   // returns -22 EINVAL
>   res = rt_intr_create(&FITnterrupt, 0, IPIPE_TRAP_UNKNOWN, I_NOAUTOENA);
>   perror("rt_intr_create returned " );
>   printf("%s: rt_intr_create return %d errno %s\n", __FUNCTION__, res,
> strerror(res)); if (res != 0) exit(1);
>
>   res = rt_intr_enable(&FITnterrupt);
>   printf("%s: rt_intr_enable return %d errno %s\n", __FUNCTION__, res,
> strerror(res));
>
>   for (j=0; j < 3; j++)
>   {
>     /* Timeout is one second in timer jiffies, as with vxworks we have the
> periodic time */ res = rt_intr_wait(&FITnterrupt, sysClkRateGet());
>     printf("%s: rt_intr_wait return %d errno %s\n", __FUNCTION__, res,
> strerror(res)); }
>   res = rt_intr_disable(&FITnterrupt);
>   printf("%s: rt_intr_disable return %d errno %s\n", __FUNCTION__, res,
> strerror(res));
>
>   res = rt_intr_delete(&FITnterrupt);
>   printf("%s: rt_intr_delete return %d errno %s\n", __FUNCTION__, res,
> strerror(res)); exit(0);

My output at the target now looks like.
> __xeno_user_init: rt_intr_enable return 0 errno Success
> __xeno_user_init: rt_intr_wait return -110 errno Unknown error 4294967186
> __xeno_user_init: rt_intr_wait return -110 errno Unknown error 4294967186
> __xeno_user_init: rt_intr_wait return -110 errno Unknown error 4294967186
> __xeno_user_init: rt_intr_disable return 0 errno Success
> __xeno_user_init: rt_intr_delete return 0 errno Success

This is what I expect, as this interrupt should not occur.
IPIPE_TRAP_UNKNOWN however cannot be found in any *.h exported 
to /usr/xenomai/include. I found it in include/asm-ppc/ipipe.h in the patched 
Linux kernel.
So I suppose, that some how Xenomai should export this definition to user 
space, too. 

Dealing with FIT and other interrupts will take some more time. But I would 
like to thank you and Wolfgang for your help, as your answers helped me a lot 
to see the problem.

Best regards

-- 
Niklaus Giger

Re: [Xenomai-help] Handling a interrupt from user space on PPC405

[Wolfgang Grandegger]

Niklaus Giger wrote:
> Hi
> 
> I tried to use the FIT (Fixed Interrupt Timer) on my PPC405GPr board, which 
> uses 0x1010 as its interrupt vector in a user space (vxworks-skin) 
> application.
> <..>
>   RT_INTR FITnterrupt;
>   res = rt_intr_create(&FITnterrupt, 0, 0x1010, I_NOAUTOENA);
> <..>
> But I got -22 EINVAL as error.
> Could somebody please tell me, what is wrong with my example.

The FIT exception is not an external interrupt and cannot be used with 
the the above function. And 0x1010 is not a valid IRQ number anyhow 
(it's actually the jump address of the FIT exception).

> I would like to have as little as possible code in the kernel and handling the 
> whole interrupt in a RT (vxworks-skin) user space task.
> 
> And how do I have to handle the case, where my interrupt handler is only 
> interested in one of external interrupts of the PPC405?
> 
> A good answer would enable me to publish afterwards a working example code.

The right thing to do is to handle the expection as VIRQ like the 
decrementer (or the PIT on the AMCC 405). Unfortunately, this requires 
various modifications to the ADEOS-IPIPE patch, but it's feasible, of 
course. Search for CONFIG_IPIPE in head_4xx.c,

Wolfgang.