Re: [PATCH, RESEND] microblaze: Fix level interrupt ACKing

From: Michal Simek
Date: Fri Nov 20 2009 - 06:07:31 EST


Hi Steve,

steve@xxxxxxxxxxxxxxx wrote:
Level interrupts need to be ack'd in the unmask handler, as in powerpc. Among other issues, this bug causes the system clock to appear to run at double-speed.

Can you send me any step-by-step manual how to demonstrate me this fault? If system clock runs at double-speed, then I should be able able to see that time is two times faster. Or do you mean different behavior?

Thanks,
Michal




Signed-off-by: Steven J. Magnani <steve@xxxxxxxxxxxxxxx>
---
diff -uprN a/arch/microblaze/kernel/intc.c b/arch/microblaze/kernel/intc.c
--- a/arch/microblaze/kernel/intc.c 2009-06-02 15:26:28.000000000 -0500
+++ b/arch/microblaze/kernel/intc.c 2009-06-02 15:27:39.000000000 -0500
@@ -41,8 +41,16 @@ unsigned int nr_irq;
static void intc_enable_or_unmask(unsigned int irq)
{
+ unsigned long mask = 1 << irq;
pr_debug("enable_or_unmask: %d\n", irq);
- out_be32(INTC_BASE + SIE, 1 << irq);
+ out_be32(INTC_BASE + SIE, mask);
+
+ /* ack level irqs because they can't be acked during
+ * ack function since the handle_level_irq function
+ * acks the irq before calling the interrupt handler
+ */
+ if (irq_desc[irq].status & IRQ_LEVEL)
+ out_be32(INTC_BASE + IAR, mask);
}
static void intc_disable_or_mask(unsigned int irq)

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--
Michal Simek, Ing. (M.Eng)
w: www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel 2.6 Microblaze Linux - http://www.monstr.eu/fdt/
Microblaze U-BOOT custodian
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