[ECOS] FIQ on ARM processor

[Andrew Lunn]

> If not, is there an other way to do ?

We have only one source generating FIQ interrupts. So we sidestep ecos
all together and install a VSR on the FIQ. That puts our code directly
onto the FIQ vector. You have to take the usual precausions, save
registers etc before jumping into C code. Also you cannot call any
eCos functions since your not in an eCos ISR. Only a few of our FIQ
interrupts require eCos to do something. When that happens we use a
software controlled interrupt to trigger an IRQ interrupt which eCos
then handles.

        Andrew