Module: xenomai-head
Branch: master
Commit: d740688e53232491f6572637f95ee15a4df094c0

Author: Philippe Gerum <>
Date:   Tue Apr 28 11:01:10 2009 +0200

Introduce PIC mute support, initially for powerpc.

Some I-pipe patches may allow to tell the embedded PICs to mute the
low priority interrupt channels, i.e. all IRQs which are not of any
interest to a heading pipeline domain like Xenomai (typically,
Linux-handled device interrupts).

When available, this feature prevents the real-time activity to be
preempted by non-related interrupt events, even for the short time
needed by the I-pipe to log them.

When this support is available from the I-pipe, the Xenomai scheduler
will request all PICs to mute the low priority interrupts when
entering the Xenomai domain, and conversely unmute them when leaving

NOTE: not all platforms may provide such feature, since it depends on
the characteristics of the embedded PICs (typically, how
straightforward it is to mask or lower the priority of a subset of
interrupt sources), and whether the I-pipe implements this feature.


 include/asm-generic/hal.h      |    7 +++++++
 include/asm-powerpc/bits/pod.h |    2 ++
 2 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/include/asm-generic/hal.h b/include/asm-generic/hal.h
index 7628fff..b37e476 100644
--- a/include/asm-generic/hal.h
+++ b/include/asm-generic/hal.h
@@ -161,6 +161,13 @@ typedef spinlock_t rthal_spinlock_t;
 #define rthal_send_ipi(irq,cpus)       ipipe_send_ipi(irq,cpus)
 #define rthal_lock_irq(dom,cpu,irq)    __ipipe_lock_irq(dom,cpu,irq)
 #define rthal_unlock_irq(dom,irq)      __ipipe_unlock_irq(dom,irq)
+#define rthal_mute_pic()               ipipe_mute_pic()
+#define rthal_unmute_pic()             ipipe_unmute_pic()
+#else /* !__IPIPE_FEATURE_PIC_MUTE */
+#define rthal_mute_pic()               do { } while(0)
+#define rthal_unmute_pic()             do { } while(0)
+#endif /* __IPIPE_FEATURE_PIC_MUTE */
 #define rthal_processor_id()           ipipe_processor_id()
diff --git a/include/asm-powerpc/bits/pod.h b/include/asm-powerpc/bits/pod.h
index c335ccc..f412d0c 100644
--- a/include/asm-powerpc/bits/pod.h
+++ b/include/asm-powerpc/bits/pod.h
@@ -59,6 +59,7 @@ void xnpod_delete_thread(struct xnthread *);
 static inline void xnarch_leave_root(xnarchtcb_t * rootcb)
+       rthal_mute_pic();
        /* Remember the preempted Linux task pointer. */
        rootcb->user_task = rootcb->active_task = current;
        rootcb->tsp = &current->thread;
@@ -80,6 +81,7 @@ static inline void xnarch_enter_root(xnarchtcb_t * rootcb)
        if (!rootcb->mm)
                set_ti_thread_flag(rootcb->tip, TIF_MMSWITCH_INT);
+       rthal_unmute_pic();
 struct xnlock;

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