On Thu, Jan 12, 2012 at 06:31:28PM -0600, Rob Herring wrote:

Adding lakml...

On 01/11/2012 03:27 PM, Grant Likely wrote:

quoted

On Wed, Jan 11, 2012 at 2:15 PM, Rob Herring [off-list ref] wrote:

quoted

Grant,

On 01/11/2012 02:22 PM, Grant Likely wrote:

quoted

This patch removes the simplistic implementation of irq_domains and enables
the powerpc infrastructure for all irq_domain users.  The powerpc
infrastructure includes support for complex mappings between Linux and
hardware irq numbers, and can manage allocation of irq_descs.

This patch also converts the few users of irq_domain_add()/irq_domain_del()
to call irq_domain_add_legacy() instead.

So what is the non-legacy way? Legacy implies we don't want to do it
that way. I guess until we remove all non-DT platforms with GIC we are
stuck with legacy. That seems like it could be a ways out until we get
there.

Non-legacy is letting the irq_domain manage the irq_desc allocations.
Some of the controllers will be easy to convert, some will be more
difficult.  The primary thing that really blocks getting away from the
legacy method is anything that expects hardcoded #defined irq numbers.
 The goal is to convert all users over to the linear revmap method.

So I gave this a spin on highbank. I ran into a couple problems.

I had to revert "irqdesc: Consolidate irq reservation logic" which is in
your branch, but not this series. irq_alloc_desc_from was returning -EEXIST.

Gah, I flubbed that patch too.  Try this on top of it:

---

diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index 8a9e2ec..11feb2f 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c

@@ -375,6 +375,9 @@ __irq_reserve_irqs(int irq, unsigned int from, unsigned int cnt)
 	}
 
 	bitmap_set(allocated_irqs, start, cnt);
+	mutex_unlock(&sparse_irq_lock);
+	return start;
+
 err:
 	mutex_unlock(&sparse_irq_lock);
 	return ret;

@@ -408,7 +411,8 @@ EXPORT_SYMBOL_GPL(__irq_alloc_descs);
  */
 int irq_reserve_irqs(unsigned int from, unsigned int cnt)
 {
-	return __irq_reserve_irqs(from, from, cnt);
+	int start = __irq_reserve_irqs(from, from, cnt);
+	return start < 0 ? start : 0;
 }
 
 /**