On Tuesday 01 November 2005 10:49, you wrote:

> > In that case, the nucleus must keep track of all the irqs, i.e.
> > some_struct irqs[IPIPE_NR_IRQS]. Ok, the rthal_realtime_irq[] may be
> > removed here from hal.
> > But there is already the per-irq array in ipipe_domain struct. Having got
> > [1] and [2] merged, we would have this array as the only one and avoid
> > the use of rthal_realtime_irq[] at all. Although, the ipipe_domain would
> > become a bit more heavy :) Well, but [2] into [3] is leeeess intrusive on
> > the other hand.
> Due to the intrusiveness, I would vote for a [2]->[3] merge.

Yep, obviously.

What about something like this:


struct rthal_realtime_irq_t {

        struct xnintr_t *handlers; // or xnqueue_t handlers;
        unsigned long hits[RTHAL_NR_CPUS];

        // maybe something else

} rthal_realtime_irq[IPIPE_NR_IRQS];

either this array should be exported so to be available from the nucleus layer 
or should be moved into the nucleus layer completely, but so far I like the 
idea the HAL handles basic irq-related chores, if no then e.g. what to do 
with rthal_linux_irq, apc counterparts.

struct xnintr_t is extended as follows:

unsigned flags;         // e.g. IRQ_SHARED
const char *name;
struct xnintr_t *next; // or xnholder_t hlink;

actually, xniack_t iack field should gone or a policy on its use should be 
established. e.g. what if a few handlers that share the same irq want to set 
up its own iack handler. I see that it's not a part of the rtdm's 
request_irq() interface (always NULL so that the default one is used) but a 
part of the native and posix skins' interfaces (e.g. rt_intr_create).

Another thing is how different return values of ISR handlers should be 

first handler reports CHAINED, the second one - HANDLED and some of them - 


xnintr_irq_handler(unsigned irq, void *cookie) -> xnintr_irq_handler(unsigned 

Thus, it may be passed into rthal_virtualize_irq() and called directly from 
the ipipe layer (we don't need that hal::irq_trampoline() any more).

xnintr_irq_handler(unsigned irq)
- xnintr_t *intr = (xnintr_t *)cookie;
+ xnintr_t *handlers = hal_realtime_irq(irq)->handlers; // or get a queue 
- s = intr->isr(intr);
+ iterate through all the handlers

err, hopefully that looks not like a complete mess, anyway that's what on the 
top of my head at the moment :)

> One issue remains in any case: the HAL currently maintains a /proc entry
> for the registered IRQs. It reports if a handler is registered and the
> IRQ hits per CPU. As I think this entry should also report the
> registered driver names in the future, we have to hand the management
> over to whatever part traces all registered handlers. Is this acceptable
> from the layering point of view?

But the same can be done from the HAL if we're still going to keep the per-irq 
array there as well as basic realtime-irq-related chores. Just in that case, 
the HAL would be aware about some extended information, like names.

> Jan

Best regards,

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