On Tue, 2005-02-15 at 12:04, [EMAIL PROTECTED] wrote:
> On Tue, 15 Feb 2005, Michael Neuhauser wrote:
>
> > On Tue, 2005-02-15 at 09:29, [EMAIL PROTECTED] wrote:
> > >
> > > I can for-see a couple of points that would need some careful thinking:
> > >
> > > 1. pending (to Linux). How is it done - a) for each new irq it is added to
> > > a queue and then they are delivered exactly in this order, or b) each new
> > > irq is marked pending (e.g. in a bit-mask) and then they are delivered in
> > > arbitrary order? If a), then 1 per irq or possibly multiple entries per
> > > irq?
> >
> > It is b), kind of:
> [snip]
> > The decision what interrupt to deliver next is done
> > by__adeos_sync_stage() (with no relation to the order they happened):
> > the function flnz() favours the high numbered irqs (and has the
> > advantage of being only one assembler statement ("clz") for >= ARMv5.
>
> This might be a problem. After lots of testing, over-thinking we've landed
> with some version of a)... Will have to see how it goes now.
This is so fundamental to Adeos on all platforms, that I don't think it
would be easy to change.
> > > 2. mask-/ack-ing. Is only RTAI using real hardware irq-operations for all
> > > irqs, or only for real-time irqs and further domains are allowed to mask
> > > / ack themselves?
> >
> > When pipelining is enabled, Adeos replaces the mask, unmaks & mask_ack
> > slots in the linux irq_desc[] with its own
> > __adeos_override_irq_mask/unmas/mask_ack functions. These functions
> > disable interrupts hard to protect the PIC and call the original Linux
> > functions.
> >
> > __adeos_handle_irq() calls the irq acknowledge function (which actually
> > does mask-ack) before calling any domain's irq-handler. Unmasking the
> > irq (or doing irq-source specific clearing) is left to the irq handler.
>
> Did I understand you right, that each Linux interrupt will be mask_acked
> twice?
No, as the mask_ack() call in Linux' do_IRQ() is modified like this:
#ifdef CONFIG_ADEOS_CORE
if (!adp_pipelined)
#endif /* CONFIG_ADEOS_CORE */
desc->mask_ack(irq);
i.e. don't do it if pipelining is active.
Mike
--
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Firmix Software GmbH fax: +43 1 789 08 49 - 55
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