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-rw-r--r--include/linux/irq.h3
-rw-r--r--kernel/irq/chip.c67
-rw-r--r--kernel/irq/manage.c34
3 files changed, 101 insertions, 3 deletions
diff --git a/include/linux/irq.h b/include/linux/irq.h
index ce8171bc6fa..8778ee99393 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -70,6 +70,7 @@ typedef void (*irq_flow_handler_t)(unsigned int irq,
#define IRQ_AFFINITY_SET 0x02000000 /* IRQ affinity was set from userspace*/
#define IRQ_SUSPENDED 0x04000000 /* IRQ has gone through suspend sequence */
#define IRQ_ONESHOT 0x08000000 /* IRQ is not unmasked after hardirq */
+#define IRQ_NESTED_THREAD 0x10000000 /* IRQ is nested into another, no own handler thread */
#ifdef CONFIG_IRQ_PER_CPU
# define CHECK_IRQ_PER_CPU(var) ((var) & IRQ_PER_CPU)
@@ -386,6 +387,8 @@ set_irq_chained_handler(unsigned int irq,
__set_irq_handler(irq, handle, 1, NULL);
}
+extern void set_irq_nested_thread(unsigned int irq, int nest);
+
extern void set_irq_noprobe(unsigned int irq);
extern void set_irq_probe(unsigned int irq);
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index f856330e684..5765aad9499 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -222,6 +222,34 @@ int set_irq_chip_data(unsigned int irq, void *data)
}
EXPORT_SYMBOL(set_irq_chip_data);
+/**
+ * set_irq_nested_thread - Set/Reset the IRQ_NESTED_THREAD flag of an irq
+ *
+ * @irq: Interrupt number
+ * @nest: 0 to clear / 1 to set the IRQ_NESTED_THREAD flag
+ *
+ * The IRQ_NESTED_THREAD flag indicates that on
+ * request_threaded_irq() no separate interrupt thread should be
+ * created for the irq as the handler are called nested in the
+ * context of a demultiplexing interrupt handler thread.
+ */
+void set_irq_nested_thread(unsigned int irq, int nest)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+ unsigned long flags;
+
+ if (!desc)
+ return;
+
+ spin_lock_irqsave(&desc->lock, flags);
+ if (nest)
+ desc->status |= IRQ_NESTED_THREAD;
+ else
+ desc->status &= ~IRQ_NESTED_THREAD;
+ spin_unlock_irqrestore(&desc->lock, flags);
+}
+EXPORT_SYMBOL_GPL(set_irq_nested_thread);
+
/*
* default enable function
*/
@@ -299,6 +327,45 @@ static inline void mask_ack_irq(struct irq_desc *desc, int irq)
}
}
+/*
+ * handle_nested_irq - Handle a nested irq from a irq thread
+ * @irq: the interrupt number
+ *
+ * Handle interrupts which are nested into a threaded interrupt
+ * handler. The handler function is called inside the calling
+ * threads context.
+ */
+void handle_nested_irq(unsigned int irq)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+ struct irqaction *action;
+ irqreturn_t action_ret;
+
+ might_sleep();
+
+ spin_lock_irq(&desc->lock);
+
+ kstat_incr_irqs_this_cpu(irq, desc);
+
+ action = desc->action;
+ if (unlikely(!action || (desc->status & IRQ_DISABLED)))
+ goto out_unlock;
+
+ desc->status |= IRQ_INPROGRESS;
+ spin_unlock_irq(&desc->lock);
+
+ action_ret = action->thread_fn(action->irq, action->dev_id);
+ if (!noirqdebug)
+ note_interrupt(irq, desc, action_ret);
+
+ spin_lock_irq(&desc->lock);
+ desc->status &= ~IRQ_INPROGRESS;
+
+out_unlock:
+ spin_unlock_irq(&desc->lock);
+}
+EXPORT_SYMBOL_GPL(handle_nested_irq);
+
/**
* handle_simple_irq - Simple and software-decoded IRQs.
* @irq: the interrupt number
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 0a3fd5b524c..e485cea04bf 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -451,6 +451,16 @@ static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
return IRQ_WAKE_THREAD;
}
+/*
+ * Primary handler for nested threaded interrupts. Should never be
+ * called.
+ */
+static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
+{
+ WARN(1, "Primary handler called for nested irq %d\n", irq);
+ return IRQ_NONE;
+}
+
static int irq_wait_for_interrupt(struct irqaction *action)
{
while (!kthread_should_stop()) {
@@ -600,7 +610,7 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
struct irqaction *old, **old_ptr;
const char *old_name = NULL;
unsigned long flags;
- int shared = 0;
+ int nested, shared = 0;
int ret;
if (!desc)
@@ -630,9 +640,27 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
return -EINVAL;
/*
- * Threaded handler ?
+ * Check whether the interrupt nests into another interrupt
+ * thread.
+ */
+ nested = desc->status & IRQ_NESTED_THREAD;
+ if (nested) {
+ if (!new->thread_fn)
+ return -EINVAL;
+ /*
+ * Replace the primary handler which was provided from
+ * the driver for non nested interrupt handling by the
+ * dummy function which warns when called.
+ */
+ new->handler = irq_nested_primary_handler;
+ }
+
+ /*
+ * Create a handler thread when a thread function is supplied
+ * and the interrupt does not nest into another interrupt
+ * thread.
*/
- if (new->thread_fn) {
+ if (new->thread_fn && !nested) {
struct task_struct *t;
t = kthread_create(irq_thread, new, "irq/%d-%s", irq,