[okl4-developer] About register IRQ and ISR on Iguana application

[Carl van Schaik]

Hi Kashin,

Interrupts in OKL4 are registered against a handler thread and not a 
function. Ie. when an interrupt triggers, the kernel will send the 
handler thread an IPC message. Thus you can only register interrupts 
with a thread-id and not a function pointer. The message is sent from a 
virtual interrupt thread with thread number equal to interrupt number, 
eg  L4_GlobalId(irq, 1)

After registering for an interrupt, the handler thread can do something 
like L4_Wait(&from_tid) and needs to then check if from_tid is the 
thread-id of the interrupt source.

eg
 L4_Wait(&from_tid)
 // check for error here

 // check if interrupt recieved
 if (L4_ThreadNo(from_tid) == irq)
 {
    /// do somthing
     L4_Reply(from_tid);  // ack interrupt
 }


regards,
Carl


kashin Lin wrote:
> Hi,
>
> i noticed that there is a function named 
> "hardware_register_interrupt" which seems what i need.
> but the first parameter's type is "L4_ThreadId_t" not a function point 
> i expect, so i'm confused how to use it.
>
> can anyone show me a simple code snip about how to use it?
> for instance, the ISR "func_A" service the IRQ # "B"
>
> thanks for your help.
>
>
> best,
> kashin lin
>
>
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