microblaze: avoid interrupt race conditions

The interrupt acknowledge action have to run after the
registered interrupt handler. So we have a chance to
bear out the corresponding interrupt request in the
corresponding controller hardware.

With this reordering, we optain a proper interrupt
handling for level triggered interrupt sources -- for
example the new axi_timer v1.02.a introduced in ISE 13.2.

Signed-off-by: Stephan Linz <linz@li-pro.net>
Acked-by: Michal Simek <monstr@monstr.eu>

diff --git a/arch/microblaze/cpu/interrupts.c b/arch/microblaze/cpu/interrupts.c
index 5a13211..e7ca859 100644 (file)
--- a/arch/microblaze/cpu/interrupts.c
+++ b/arch/microblaze/cpu/interrupts.c
@@ -155,8 +155,6 @@ void interrupt_handler (void)
 #endif
        struct irq_action *act = vecs + irqs;
 
-       intc->iar = mask << irqs;
-
 #ifdef DEBUG_INT
        printf
            ("Jumping to interrupt handler rutine addr %x,count %x,arg %x\n",
@@ -165,6 +163,8 @@ void interrupt_handler (void)
        act->handler (act->arg);
        act->count++;
 
+       intc->iar = mask << irqs;
+
 #ifdef DEBUG_INT
        printf ("Dump INTC reg, isr %x, ier %x, iar %x, mer %x\n", intc->isr,
                intc->ier, intc->iar, intc->mer);