Porting ethernet driver from FREEBSD to rtems-libbsd

[Sebastian Huber]

It depends on the capabilities of the interrupt controller. Maybe you 
have to drop the support for nested interrupts. The 
bsp_interrupt_dispatch() function for a state of the art interrupt 
controller looks like this (arm-gic-irq.c):

void bsp_interrupt_dispatch(void)
{
   volatile gic_cpuif *cpuif = GIC_CPUIF;
   uint32_t icciar = cpuif->icciar;
   rtems_vector_number vector = GIC_CPUIF_ICCIAR_ACKINTID_GET(icciar);
   rtems_vector_number spurious = 1023;

   if (vector != spurious) {
     uint32_t psr = _ARMV4_Status_irq_enable();

     bsp_interrupt_handler_dispatch(vector);

     _ARMV4_Status_restore(psr);

     cpuif->icceoir = icciar;
   }
}

On 28/05/15 13:50, ragu nath wrote:
> Hi Sebastian,
>
> The problem is with rx interrupt. We are enabling rx interrupt before
> it is processed. The rtems server task do not get an opportunity to
> run.
>
> I found this might be the logical explanation of the issue.
> bsp_interrupt_dispatch() calls bsp_interrupt_server_trigger which
> disables the rx interrupt and creates BSP_INTERRUPT_EVENT .  For this
> event, bsp_interrupt_server_task() was supposed to call the actual
> interrupt handler and then enable the rx interrupt. But before the
> event is processed, we enable the rx interrupt in dispatch function.
> So again rx interrupt is generated and event is created and the cycle
> goes on. Server task is never executed in turn actual interrupt
> handler is never executed.
>
> Since we enable the interrupt, it occurs again and again as we never handle it.
>
> Is there any other possibility that I might need to look into?
>
>
> Thanks,
> Ragunath
>
> On Thu, May 28, 2015 at 4:58 PM, Sebastian Huber
> <sebastian.huber at embedded-brains.de> wrote:
>> Hello,
>>
>> the bsp_interrupt_dispatch() is quite complicated in the beagle BSP. Is the
>> interrupt controller of this chip really that broken? Sane interrupt
>> controllers block interrupts of equal or lower priority relative to the
>> currently pending interrupt.

-- 
Sebastian Huber, embedded brains GmbH

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