diff options
| -rw-r--r-- | include/linux/irq.h | 3 | ||||
| -rw-r--r-- | kernel/irq/chip.c | 67 | ||||
| -rw-r--r-- | kernel/irq/manage.c | 34 |
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, |