[PATCH v3 3/4] genirq: Add support for IRQF_COND_ONESHOT

Jan Kiszka
2010-12-13T23:00:21Z

From: Jan Kiszka <jan.kiszka@siemens.com>

Provide an adaptive version of IRQF_ONESHOT: If the line is exclusively used,
IRQF_COND_ONESHOT provides the same semantics as IRQF_ONESHOT. If it is
shared, the line will be unmasked directly after the hardirq handler, just as
if IRQF_COND_ONESHOT was not provided.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
include/linux/interrupt.h | 3 +++
kernel/irq/manage.c | 19 ++++++++++++++++---
2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 12e5fc0..bbb16f4 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -56,6 +56,8 @@
* irq line disabled until the threaded handler has been run.
* IRQF_NO_SUSPEND - Do not disable this IRQ during suspend
* IRQF_ADAPTIVE - Request notification about upcoming interrupt line sharing
+ * IRQF_COND_ONESHOT - If line is not shared, keep interrupt disabled after
+ * hardirq handler finshed.
*
*/
#define IRQF_DISABLED 0x00000020
@@ -69,6 +71,7 @@
#define IRQF_ONESHOT 0x00002000
#define IRQF_NO_SUSPEND 0x00004000
#define IRQF_ADAPTIVE 0x00008000
+#define IRQF_COND_ONESHOT 0x00010000

#define IRQF_TIMER (__IRQF_TIMER | IRQF_NO_SUSPEND)

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 2dd4eef..9a73633 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -583,7 +583,7 @@ static int irq_thread(void *data)
struct sched_param param = { .sched_priority = MAX_USER_RT_PRIO/2, };
struct irqaction *action = data;
struct irq_desc *desc = irq_to_desc(action->irq);
- int wake, oneshot = desc->status & IRQ_ONESHOT;
+ int wake, oneshot;

sched_setscheduler(current, SCHED_FIFO, &param);
current->irqaction = action;
@@ -606,6 +606,7 @@ static int irq_thread(void *data)
desc->status |= IRQ_PENDING;
raw_spin_unlock_irq(&desc->lock);
} else {
+ oneshot = desc->status & IRQ_ONESHOT;
raw_spin_unlock_irq(&desc->lock);

action->thread_fn(action->irq, action->dev_id);
@@ -759,6 +760,15 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
shared = 1;

desc->irq_data.drv_status |= IRQS_SHARED;
+ desc->status &= ~IRQ_ONESHOT;
+
+ /* Unmask if the interrupt was masked due to oneshot mode. */
+ if ((desc->status &
+ (IRQ_INPROGRESS | IRQ_DISABLED | IRQ_MASKED)) ==
+ IRQ_MASKED) {
+ desc->irq_data.chip->irq_unmask(&desc->irq_data);
+ desc->status &= ~IRQ_MASKED;
+ }
}

if (!shared) {
@@ -783,7 +793,7 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING | IRQ_ONESHOT |
IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);

- if (new->flags & IRQF_ONESHOT)
+ if (new->flags & (IRQF_ONESHOT | IRQF_COND_ONESHOT))
desc->status |= IRQ_ONESHOT;

if (!(desc->status & IRQ_NOAUTOEN)) {
@@ -934,8 +944,11 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
desc->irq_data.chip->irq_shutdown(&desc->irq_data);
else
desc->irq_data.chip->irq_disable(&desc->irq_data);
- } else if (!desc->action->next)
+ } else if (!desc->action->next) {
single_handler = true;
+ if (desc->action->flags & IRQF_COND_ONESHOT)
+ desc->status |= IRQ_ONESHOT;
+ }

#ifdef CONFIG_SMP
/* make sure affinity_hint is cleaned up */
--
1.7.1