On 03/01/2011 09:22 PM, Benjamin Herrenschmidt wrote:
diff --git a/arch/powerpc/include/asm/mpic.h b/arch/powerpc/include/asm/mpic.h
index e000cce..7e1be12 100644
--- a/arch/powerpc/include/asm/mpic.h
+++ b/arch/powerpc/include/asm/mpic.h
@@ -325,6 +325,8 @@ struct mpic
#ifdef CONFIG_PM
struct mpic_irq_save *save_data;
#endif
+
+ int cpu;
};
Why ? The MPIC isn't specifically associated with a CPU and whatever we
pick as default during boot isn't relevant later on, so I don't see why
we should have global permanent state here.
I agree. I shouldn't have cached that. We should probably introduce a
helper function to get the cpuid, though. The:
unsigned int cpu = 0;
if (mpic->flags & MPIC_PRIMARY)
cpu = hard_smp_processor_id();
code is scattered in three places: '_mpic_cpu_write', '_mpic_cpu_read',
and 'mpic_init'.
/* Check if we have one of those nice broken MPICs with a flipped endian on
@@ -622,6 +631,14 @@ static unsigned int mpic_is_ipi(struct mpic *mpic,
unsigned int irq)
return (src>= mpic->ipi_vecs[0]&& src<= mpic->ipi_vecs[3]);
}
+/* Determine if the linux irq is a timer interrupt */
+static unsigned int mpic_is_timer_interrupt(struct mpic *mpic, unsigned int
irq)
+{
+ unsigned int src = mpic_irq_to_hw(irq);
+
+ return (src>= mpic->timer_vecs[0]&& src<= mpic->timer_vecs[3]);
+}
+
/* Convert a cpu mask from logical to physical cpu numbers. */
static inline u32 mpic_physmask(u32 cpumask)
@@ -967,6 +984,15 @@ static int mpic_host_map(struct irq_host *h, unsigned int
virq,
if (hw>= mpic->irq_count)
return -EINVAL;
+ /* If the MPIC was reset, then all vectors have already been
+ * initialized. Otherwise, the appropriate vector needs to be
+ * initialized here to ensure that only used sources are setup with
+ * a vector.
+ */
+ if (mpic->flags& MPIC_NO_RESET)
+ if (!(mpic_is_ipi(mpic, hw) || mpic_is_timer_interrupt(mpic,
hw)))
+ mpic_init_vector(mpic, hw);
+
The above isn't useful. Of those two registers you want to initialize,
afaik, one (the destination) will be initialized by the core calling
into set_affinity when the interrupt is requested, and the other one is
AFAIK, we can't rely on 'set_affinity' always being called. I don't
think it is called at all when !defined(CONFIG_SMP) and if it was, then
that would be an error:
/* include/linux/irq.h */
#else /* CONFIG_SMP */
static inline int irq_set_affinity(unsigned int irq,
const struct cpumask *m)
{
return -EINVAL;
}
partially initialized in set_type, I'd say just modify set_type to
initialize the source as well, and problem solved, no ?
The priority has to be initialized as well. They could both be done in
'mpic_set_irq_type', but that seems like a weird place since it has
nothing to do with actually setting the type.
Since we already have 'mpic_irq_set_priority' and 'mpic_set_vector',
perhaps a better option is to add 'mpic_set_destination' and put the
following in 'mpic_host_map' (using the cpuid helper function suggested
above):
/* Lazy source init when MPIC_NO_RESET */
if (!mpic_is_ipi(mpic, hw) && (mpic->flags & MPIC_NO_RESET)) {
mpic_set_vector(virq, hw);
mpic_set_destination(virq, mpic_cpuid(mpic));
mpic_irq_set_priority(virq, 8);
}
It is more overhead, but it reads well. Thoughts?
Or is there a chance that the interrupt was left unmasked ?
There shouldn't be. The original idea was that either the boot program
would leave it masked or one of the AMP OSes would boot without
'pic-no-reset', which would mask everything. Most likely the boot program.
I think it would be kosher to mask it in set_type unconditionally, I don't
think it's ever supposed
to be called for an enabled interrupt.
I will look into that.
Thanks,
--
Meador Inge | meador_inge AT mentor.com
Mentor Embedded | http://www.mentor.com/embedded-software
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