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authorThomas Gleixner <tglx@linutronix.de>2015-10-09 23:28:58 +0200
committerThomas Gleixner <tglx@linutronix.de>2015-10-11 11:33:42 +0200
commite9849777d0e27cdd2902805be51da73e7c79578c (patch)
tree398bab5d6a91973d2e8a281bae6dff8ebd57ac8b
parentfcf8ab690e3decf8335c51fdabea773a3f5ea026 (diff)
genirq: Add flag to force mask in disable_irq[_nosync]()
If an irq chip does not implement the irq_disable callback, then we use a lazy approach for disabling the interrupt. That means that the interrupt is marked disabled, but the interrupt line is not immediately masked in the interrupt chip. It only becomes masked if the interrupt is raised while it's marked disabled. We use this to avoid possibly expensive mask/unmask operations for common case operations. Unfortunately there are devices which do not allow the interrupt to be disabled easily at the device level. They are forced to use disable_irq_nosync(). This can result in taking each interrupt twice. Instead of enforcing the non lazy mode on all interrupts of a irq chip, provide a settings flag, which can be set by the driver for that particular interrupt line. Reported-and-tested-by: Duc Dang <dhdang@apm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Jason Cooper <jason@lakedaemon.net> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1510092348370.6097@nanos
-rw-r--r--include/linux/irq.h4
-rw-r--r--kernel/irq/chip.c9
-rw-r--r--kernel/irq/manage.c1
-rw-r--r--kernel/irq/settings.h12
4 files changed, 25 insertions, 1 deletions
diff --git a/include/linux/irq.h b/include/linux/irq.h
index ba72b60b57b1..3c1c96786248 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -72,6 +72,7 @@ enum irqchip_irq_state;
* IRQ_IS_POLLED - Always polled by another interrupt. Exclude
* it from the spurious interrupt detection
* mechanism and from core side polling.
+ * IRQ_DISABLE_UNLAZY - Disable lazy irq disable
*/
enum {
IRQ_TYPE_NONE = 0x00000000,
@@ -97,13 +98,14 @@ enum {
IRQ_NOTHREAD = (1 << 16),
IRQ_PER_CPU_DEVID = (1 << 17),
IRQ_IS_POLLED = (1 << 18),
+ IRQ_DISABLE_UNLAZY = (1 << 19),
};
#define IRQF_MODIFY_MASK \
(IRQ_TYPE_SENSE_MASK | IRQ_NOPROBE | IRQ_NOREQUEST | \
IRQ_NOAUTOEN | IRQ_MOVE_PCNTXT | IRQ_LEVEL | IRQ_NO_BALANCING | \
IRQ_PER_CPU | IRQ_NESTED_THREAD | IRQ_NOTHREAD | IRQ_PER_CPU_DEVID | \
- IRQ_IS_POLLED)
+ IRQ_IS_POLLED | IRQ_DISABLE_UNLAZY)
#define IRQ_NO_BALANCING_MASK (IRQ_PER_CPU | IRQ_NO_BALANCING)
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 4aa00d325b8c..15206453b12a 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -241,6 +241,13 @@ void irq_enable(struct irq_desc *desc)
* disabled. If an interrupt happens, then the interrupt flow
* handler masks the line at the hardware level and marks it
* pending.
+ *
+ * If the interrupt chip does not implement the irq_disable callback,
+ * a driver can disable the lazy approach for a particular irq line by
+ * calling 'irq_set_status_flags(irq, IRQ_DISABLE_UNLAZY)'. This can
+ * be used for devices which cannot disable the interrupt at the
+ * device level under certain circumstances and have to use
+ * disable_irq[_nosync] instead.
*/
void irq_disable(struct irq_desc *desc)
{
@@ -248,6 +255,8 @@ void irq_disable(struct irq_desc *desc)
if (desc->irq_data.chip->irq_disable) {
desc->irq_data.chip->irq_disable(&desc->irq_data);
irq_state_set_masked(desc);
+ } else if (irq_settings_disable_unlazy(desc)) {
+ mask_irq(desc);
}
}
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 312f9cb12805..a71175ff98d5 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1463,6 +1463,7 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
/* If this was the last handler, shut down the IRQ line: */
if (!desc->action) {
+ irq_settings_clr_disable_unlazy(desc);
irq_shutdown(desc);
irq_release_resources(desc);
}
diff --git a/kernel/irq/settings.h b/kernel/irq/settings.h
index 3320b84cc60f..320579d89091 100644
--- a/kernel/irq/settings.h
+++ b/kernel/irq/settings.h
@@ -15,6 +15,7 @@ enum {
_IRQ_NESTED_THREAD = IRQ_NESTED_THREAD,
_IRQ_PER_CPU_DEVID = IRQ_PER_CPU_DEVID,
_IRQ_IS_POLLED = IRQ_IS_POLLED,
+ _IRQ_DISABLE_UNLAZY = IRQ_DISABLE_UNLAZY,
_IRQF_MODIFY_MASK = IRQF_MODIFY_MASK,
};
@@ -28,6 +29,7 @@ enum {
#define IRQ_NESTED_THREAD GOT_YOU_MORON
#define IRQ_PER_CPU_DEVID GOT_YOU_MORON
#define IRQ_IS_POLLED GOT_YOU_MORON
+#define IRQ_DISABLE_UNLAZY GOT_YOU_MORON
#undef IRQF_MODIFY_MASK
#define IRQF_MODIFY_MASK GOT_YOU_MORON
@@ -154,3 +156,13 @@ static inline bool irq_settings_is_polled(struct irq_desc *desc)
{
return desc->status_use_accessors & _IRQ_IS_POLLED;
}
+
+static inline bool irq_settings_disable_unlazy(struct irq_desc *desc)
+{
+ return desc->status_use_accessors & _IRQ_DISABLE_UNLAZY;
+}
+
+static inline void irq_settings_clr_disable_unlazy(struct irq_desc *desc)
+{
+ desc->status_use_accessors &= ~_IRQ_DISABLE_UNLAZY;
+}

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