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[PATCH v2 3/4] irq/of/ARM: Enhance irq iteration capability of irq_domai

To: Thomas Gleixner <tglx@linutronix.de>, devicetree-discuss@lists.ozlabs.org, Grant Likely <grant.likely@secretlab.ca>, Rob Herring <rob.herring@calxeda.com>
Subject: [PATCH v2 3/4] irq/of/ARM: Enhance irq iteration capability of irq_domain code.
From: David Daney <ddaney.cavm@gmail.com>
Date: Wed, 14 Dec 2011 18:32:09 -0800
Cc: linux-kernel@vger.kernel.org, linux-mips@linux-mips.org, David Daney <david.daney@cavium.com>
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From: David Daney <david.daney@cavium.com>

Not all irq_domain have linear sequences of irq numbers, so add hooks
for domain specific iteration of the irqs in the domain.

There is an optional function in irq_domain_ops (each_irq) that iterates over 
the
irqs in the domain calling a callback function on each one.  If it is
not present, the new helper functions irq_domain_each_irq() and
irq_domain_each_hwirq() iterate using the existing semantics.

arch/arm/common/gic.c had to be modified to use the new iteration
method as part of the change.

Signed-off-by: David Daney <david.daney@cavium.com>
---
 arch/arm/common/gic.c     |   32 ++++++++++-------
 include/linux/irqdomain.h |   14 +++++---
 kernel/irq/irqdomain.c    |   84 ++++++++++++++++++++++++++++++++------------
 3 files changed, 89 insertions(+), 41 deletions(-)

diff --git a/arch/arm/common/gic.c b/arch/arm/common/gic.c
index 171061f..2e091b7 100644
--- a/arch/arm/common/gic.c
+++ b/arch/arm/common/gic.c
@@ -345,6 +345,24 @@ void __init gic_cascade_irq(unsigned int gic_nr, unsigned 
int irq)
        irq_set_chained_handler(irq, gic_handle_cascade_irq);
 }
 
+static int __init gic_dist_init_domain_cb(struct irq_domain *domain,
+                                         unsigned int irq,
+                                         unsigned int hwirq)
+{
+       if (hwirq < 32) {
+               irq_set_percpu_devid(irq);
+               irq_set_chip_and_handler(irq, &gic_chip,
+                                        handle_percpu_devid_irq);
+               set_irq_flags(irq, IRQF_VALID | IRQF_NOAUTOEN);
+       } else {
+               irq_set_chip_and_handler(irq, &gic_chip,
+                                        handle_fasteoi_irq);
+               set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
+       }
+       irq_set_chip_data(irq, gic);
+       return 0;
+}
+
 static void __init gic_dist_init(struct gic_chip_data *gic)
 {
        unsigned int i, irq;
@@ -392,19 +410,7 @@ static void __init gic_dist_init(struct gic_chip_data *gic)
        /*
         * Setup the Linux IRQ subsystem.
         */
-       irq_domain_for_each_irq(domain, i, irq) {
-               if (i < 32) {
-                       irq_set_percpu_devid(irq);
-                       irq_set_chip_and_handler(irq, &gic_chip,
-                                                handle_percpu_devid_irq);
-                       set_irq_flags(irq, IRQF_VALID | IRQF_NOAUTOEN);
-               } else {
-                       irq_set_chip_and_handler(irq, &gic_chip,
-                                                handle_fasteoi_irq);
-                       set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
-               }
-               irq_set_chip_data(irq, gic);
-       }
+       irq_domain_each_irq(domain, gic_dist_init_domain_cb);
 
        writel_relaxed(1, base + GIC_DIST_CTRL);
 }
diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
index 16ba5a9..68d031b 100644
--- a/include/linux/irqdomain.h
+++ b/include/linux/irqdomain.h
@@ -27,12 +27,16 @@ struct irq_domain;
  * @to_irq: (optional) given a local hardware irq number, return the linux
  *          irq number.  If to_irq is not implemented, then the irq_domain
  *          will use this translation: irq = (domain->irq_base + hwirq)
+ * @each_irq: (optional) call the cb function for each irq that is a
+ *            member of the domain.
  * @dt_translate: Given a device tree node and interrupt specifier, decode
  *                the hardware irq number and linux irq type value.
  */
 struct irq_domain_ops {
        unsigned int (*to_irq)(struct irq_domain *d, unsigned int hwirq);
-
+       int (*each_irq)(struct irq_domain *d,
+                       int (*cb)(struct irq_domain *d,
+                                 unsigned int irq, unsigned int hwirq));
 #ifdef CONFIG_OF
        int (*dt_translate)(struct irq_domain *d, struct device_node *node,
                            const u32 *intspec, unsigned int intsize,
@@ -81,10 +85,10 @@ static inline unsigned int irq_domain_to_irq(struct 
irq_domain *d,
        return d->irq_base + hwirq - d->hwirq_base;
 }
 
-#define irq_domain_for_each_irq(d, hw, irq) \
-       for (hw = d->hwirq_base, irq = irq_domain_to_irq(d, hw); \
-            hw < d->hwirq_base + d->nr_irq; \
-            hw++, irq = irq_domain_to_irq(d, hw))
+extern int irq_domain_each_irq(struct irq_domain *d,
+                              int (*cb)(struct irq_domain *d,
+                                        unsigned int irq,
+                                        unsigned int hwirq));
 
 extern void irq_domain_add(struct irq_domain *domain);
 extern void irq_domain_del(struct irq_domain *domain);
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index 7bae422..c9cec12 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -9,6 +9,25 @@
 static LIST_HEAD(irq_domain_list);
 static DEFINE_MUTEX(irq_domain_mutex);
 
+static int irq_domain_add_per_irq(struct irq_domain *domain, unsigned int irq,
+                                 unsigned int hwirq)
+{
+       struct irq_data *d = irq_get_irq_data(irq);
+
+       if (!d) {
+               WARN(1, "error: assigning domain to non existant irq_desc");
+               return 1;
+       }
+       if (d->domain) {
+               /* things are broken; just report, don't clean up */
+               WARN(1, "error: irq_desc already assigned to a domain");
+               return 1;
+       }
+       d->domain = domain;
+       d->hwirq = hwirq;
+       return 0;
+}
+
 /**
  * irq_domain_add() - Register an irq_domain
  * @domain: ptr to initialized irq_domain structure
@@ -19,52 +38,71 @@ static DEFINE_MUTEX(irq_domain_mutex);
  */
 void irq_domain_add(struct irq_domain *domain)
 {
-       struct irq_data *d;
-       unsigned int hwirq, irq;
-
        /*
         * This assumes that the irq_domain owner has already allocated
         * the irq_descs.  This block will be removed when support for dynamic
         * allocation of irq_descs is added to irq_domain.
         */
-       irq_domain_for_each_irq(domain, hwirq, irq) {
-               d = irq_get_irq_data(irq);
-               if (!d) {
-                       WARN(1, "error: assigning domain to non existant 
irq_desc");
-                       return;
-               }
-               if (d->domain) {
-                       /* things are broken; just report, don't clean up */
-                       WARN(1, "error: irq_desc already assigned to a domain");
-                       return;
-               }
-               d->domain = domain;
-               d->hwirq = hwirq;
-       }
+       irq_domain_each_irq(domain, irq_domain_add_per_irq);
 
        mutex_lock(&irq_domain_mutex);
        list_add(&domain->list, &irq_domain_list);
        mutex_unlock(&irq_domain_mutex);
 }
 
+static int irq_domain_del_per_irq(struct irq_domain *domain, unsigned int irq,
+                                 unsigned int hwirq)
+{
+       struct irq_data *d = irq_get_irq_data(irq);
+
+       d->domain = NULL;
+       return 0;
+}
+
 /**
  * irq_domain_del() - Unregister an irq_domain
  * @domain: ptr to registered irq_domain.
  */
 void irq_domain_del(struct irq_domain *domain)
 {
-       struct irq_data *d;
-       unsigned int hwirq, irq;
-
        mutex_lock(&irq_domain_mutex);
        list_del(&domain->list);
        mutex_unlock(&irq_domain_mutex);
 
        /* Clear the irq_domain assignments */
-       irq_domain_for_each_irq(domain, hwirq, irq) {
-               d = irq_get_irq_data(irq);
-               d->domain = NULL;
+       irq_domain_each_irq(domain, irq_domain_del_per_irq);
+}
+
+/**
+ * irq_domain_each_irq() - Iterate over each irq in an irq_domain
+ * @d: Pointer to the irq_domain to iterate over.
+ * @cb: Pointer to a function to be called for each irq in the
+ *      irq_domain.
+ *
+ * The cb() function is called for each irq in the irq_domain.  If it
+ * returns non-zero, the iteration is stopped.
+ *
+ * Returns: The value returned by the last invocation of cb().
+ */
+int irq_domain_each_irq(struct irq_domain *d,
+                       int (*cb)(struct irq_domain *d, unsigned int irq,
+                                 unsigned int hwirq))
+{
+       unsigned int hw, irq;
+       int ret = 0;
+
+       if (d->ops->each_irq)
+               return d->ops->each_irq(d, cb);
+
+       for (hw = d->hwirq_base, irq = irq_domain_to_irq(d, hw);
+            hw < d->hwirq_base + d->nr_irq;
+            hw++, irq = irq_domain_to_irq(d, hw)) {
+               ret = cb(d, irq, hw);
+               if (ret)
+                       break;
        }
+
+       return ret;
 }
 
 #if defined(CONFIG_OF_IRQ)
-- 
1.7.2.3


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