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Re: FIQ on ARM


David Airlie wrote:
> 
> Hi all,
> 
> I see eCos supports the FIQ on ARM as just another IRQ line, is there any
> way to make it use the FIQ as a prioritised interrupt line? I have an IRQ
> interrupt that holds the system for a long time and I'd like to allow a
> serial FIQ to interrupt it ... but all eCos does is return if the IRQ is
> active an allow eCos to service it ..
> 
> my current thinking is to remove the return .. but I'm wondering how
> re-entrant eCos is at this level, will it handle the situation well..

For a start, if you do that you'll stomp on __exception_stack. You'll need
to make a separate __FIQ_exception_stack. After that it may not be too bad
because it shouldn't be terribly different from a nested interrupt. But
there could well be fiddly bits with the mode registers.

Jifl
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