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* [Qemu-devel] [PATCH] irq: introduce qemu_irq_proxy()
@ 2011-09-18 12:58 Avi Kivity
  2011-09-18 13:37 ` Avi Kivity
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Avi Kivity @ 2011-09-18 12:58 UTC (permalink / raw)
  To: Richard Henderson, Anthony Liguori, qemu-devel

In some cases we have a circular dependency involving irqs - the irq
controller depends on a bus, which in turn depends on the irq controller.
Add qemu_irq_proxy() which acts as a passthrough, except that the target
irq may be set later on.

Signed-off-by: Avi Kivity <avi@redhat.com>
---

Turns out the circular dependency i8259->isa->pci->i8259 is widespread,
so introduce a general means of fixing it up.  I'll update the patchset to
make use of it everywhere it occurs.

 hw/irq.c |   14 ++++++++++++++
 hw/irq.h |    5 +++++
 2 files changed, 19 insertions(+), 0 deletions(-)

diff --git a/hw/irq.c b/hw/irq.c
index 60eabe8..62f766e 100644
--- a/hw/irq.c
+++ b/hw/irq.c
@@ -90,3 +90,17 @@ qemu_irq qemu_irq_split(qemu_irq irq1, qemu_irq irq2)
     s[1] = irq2;
     return qemu_allocate_irqs(qemu_splitirq, s, 1)[0];
 }
+
+static void proxy_irq_handler(void *opaque, int n, int level)
+{
+    qemu_irq **target = opaque;
+
+    if (*target) {
+        qemu_set_irq((*target)[n], level);
+    }
+}
+
+qemu_irq *qemu_irq_proxy(qemu_irq **target, int n)
+{
+    return qemu_allocate_irqs(proxy_irq_handler, target, n);
+}
diff --git a/hw/irq.h b/hw/irq.h
index 389ed7a..64da2fd 100644
--- a/hw/irq.h
+++ b/hw/irq.h
@@ -33,4 +33,9 @@ qemu_irq qemu_irq_invert(qemu_irq irq);
 /* Returns a new IRQ which feeds into both the passed IRQs */
 qemu_irq qemu_irq_split(qemu_irq irq1, qemu_irq irq2);
 
+/* Returns a new IRQ set which connects 1:1 to another IRQ set, which
+ * may be set later.
+ */
+qemu_irq *qemu_irq_proxy(qemu_irq **target, int n);
+
 #endif
-- 
1.7.6.3

^ permalink raw reply related	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2011-09-23 18:51 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2011-09-18 12:58 [Qemu-devel] [PATCH] irq: introduce qemu_irq_proxy() Avi Kivity
2011-09-18 13:37 ` Avi Kivity
2011-09-18 14:18 ` Richard Henderson
2011-09-23 18:51 ` Anthony Liguori

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