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authorDavid Brownell <david-b@pacbell.net>2006-07-30 03:03:08 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-07-31 13:28:36 -0700
commit15a647eba94c3da27ccc666bea72e7cca06b2d19 (patch)
treeb4fbc1e78cb298a36d1106847be1433553d217c8
parent5e44ef238b7eb607532e89249e7b2523faf77a92 (diff)
downloadlinux-2.6.34-ux500-15a647eba94c3da27ccc666bea72e7cca06b2d19.tar.gz
[PATCH] genirq: {en,dis}able_irq_wake() need refcounting too
IRQs need refcounting and a state flag to track whether the the IRQ should be enabled or disabled as a "normal IRQ" source after a series of calls to {en,dis}able_irq(). For shared IRQs, the IRQ must be enabled so long as at least one driver needs it active. Likewise, IRQs need the same support to track whether the IRQ should be enabled or disabled as a "wakeup event" source after a series of calls to {en,dis}able_irq_wake(). For shared IRQs, the IRQ must be enabled as a wakeup source during sleep so long as at least one driver needs it. But right now they _don't have_ that refcounting ... which means sharing a wakeup-capable IRQ can't work correctly in some configurations. This patch adds the refcount and flag mechanisms to set_irq_wake() -- which is what {en,dis}able_irq_wake() call -- and minimal documentation of what the irq wake mechanism does. Drivers relying on the older (broken) "toggle" semantics will trigger a warning; that'll be a handful of drivers on ARM systems. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Acked-by: Ingo Molnar <mingo@elte.hu> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--include/linux/irq.h3
-rw-r--r--kernel/irq/manage.c28
2 files changed, 29 insertions, 2 deletions
diff --git a/include/linux/irq.h b/include/linux/irq.h
index b48eae32dc6..6e59ac05ef2 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -58,6 +58,7 @@
#define IRQ_NOREQUEST 0x04000000 /* IRQ cannot be requested */
#define IRQ_NOAUTOEN 0x08000000 /* IRQ will not be enabled on request irq */
#define IRQ_DELAYED_DISABLE 0x10000000 /* IRQ disable (masking) happens delayed. */
+#define IRQ_WAKEUP 0x20000000 /* IRQ triggers system wakeup */
struct proc_dir_entry;
@@ -124,6 +125,7 @@ struct irq_chip {
* @action: the irq action chain
* @status: status information
* @depth: disable-depth, for nested irq_disable() calls
+ * @wake_depth: enable depth, for multiple set_irq_wake() callers
* @irq_count: stats field to detect stalled irqs
* @irqs_unhandled: stats field for spurious unhandled interrupts
* @lock: locking for SMP
@@ -147,6 +149,7 @@ struct irq_desc {
unsigned int status; /* IRQ status */
unsigned int depth; /* nested irq disables */
+ unsigned int wake_depth; /* nested wake enables */
unsigned int irq_count; /* For detecting broken IRQs */
unsigned int irqs_unhandled;
spinlock_t lock;
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 4e461438e48..92be519eff2 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -137,16 +137,40 @@ EXPORT_SYMBOL(enable_irq);
* @irq: interrupt to control
* @on: enable/disable power management wakeup
*
- * Enable/disable power management wakeup mode
+ * Enable/disable power management wakeup mode, which is
+ * disabled by default. Enables and disables must match,
+ * just as they match for non-wakeup mode support.
+ *
+ * Wakeup mode lets this IRQ wake the system from sleep
+ * states like "suspend to RAM".
*/
int set_irq_wake(unsigned int irq, unsigned int on)
{
struct irq_desc *desc = irq_desc + irq;
unsigned long flags;
int ret = -ENXIO;
+ int (*set_wake)(unsigned, unsigned) = desc->chip->set_wake;
+ /* wakeup-capable irqs can be shared between drivers that
+ * don't need to have the same sleep mode behaviors.
+ */
spin_lock_irqsave(&desc->lock, flags);
- if (desc->chip->set_wake)
+ if (on) {
+ if (desc->wake_depth++ == 0)
+ desc->status |= IRQ_WAKEUP;
+ else
+ set_wake = NULL;
+ } else {
+ if (desc->wake_depth == 0) {
+ printk(KERN_WARNING "Unbalanced IRQ %d "
+ "wake disable\n", irq);
+ WARN_ON(1);
+ } else if (--desc->wake_depth == 0)
+ desc->status &= ~IRQ_WAKEUP;
+ else
+ set_wake = NULL;
+ }
+ if (set_wake)
ret = desc->chip->set_wake(irq, on);
spin_unlock_irqrestore(&desc->lock, flags);
return ret;