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Merge branch 'irq-threaded-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

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* 'irq-threaded-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  genirq: Do not mask oneshot edge type interrupts
  genirq: Support nested threaded irq handling
  genirq: Add buslock support
  genirq: Add oneshot support
This commit is contained in:
Linus Torvalds 2009-09-11 13:21:31 -07:00
commit d90a7e8640
5 changed files with 194 additions and 9 deletions
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4
include/linux/interrupt.h
View File

@ -50,6 +50,9 @@
* IRQF_IRQPOLL - Interrupt is used for polling (only the interrupt that is
* registered first in an shared interrupt is considered for
* performance reasons)
* IRQF_ONESHOT - Interrupt is not reenabled after the hardirq handler finished.
* Used by threaded interrupts which need to keep the
* irq line disabled until the threaded handler has been run.
*/
#define IRQF_DISABLED 0x00000020
#define IRQF_SAMPLE_RANDOM 0x00000040
@ -59,6 +62,7 @@
#define IRQF_PERCPU 0x00000400
#define IRQF_NOBALANCING 0x00000800
#define IRQF_IRQPOLL 0x00001000
#define IRQF_ONESHOT 0x00002000
/*
* Bits used by threaded handlers:

10
include/linux/irq.h
View File

@ -69,6 +69,8 @@ typedef void (*irq_flow_handler_t)(unsigned int irq,
#define IRQ_MOVE_PCNTXT 0x01000000 /* IRQ migration from process context */
#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)
@ -100,6 +102,9 @@ struct msi_desc;
* @set_type: set the flow type (IRQ_TYPE_LEVEL/etc.) of an IRQ
* @set_wake: enable/disable power-management wake-on of an IRQ
*
* @bus_lock: function to lock access to slow bus (i2c) chips
* @bus_sync_unlock: function to sync and unlock slow bus (i2c) chips
*
* @release: release function solely used by UML
* @typename: obsoleted by name, kept as migration helper
*/
@ -123,6 +128,9 @@ struct irq_chip {
int (*set_type)(unsigned int irq, unsigned int flow_type);
int (*set_wake)(unsigned int irq, unsigned int on);
void (*bus_lock)(unsigned int irq);
void (*bus_sync_unlock)(unsigned int irq);
/* Currently used only by UML, might disappear one day.*/
#ifdef CONFIG_IRQ_RELEASE_METHOD
void (*release)(unsigned int irq, void *dev_id);
@ -373,6 +381,8 @@ 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);

74
kernel/irq/chip.c
View File

@ -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
@ -382,7 +449,10 @@ handle_level_irq(unsigned int irq, struct irq_desc *desc)
spin_lock(&desc->lock);
desc->status &= ~IRQ_INPROGRESS;
if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
if (unlikely(desc->status & IRQ_ONESHOT))
desc->status |= IRQ_MASKED;
else if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
desc->chip->unmask(irq);
out_unlock:
spin_unlock(&desc->lock);
@ -572,6 +642,7 @@ __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
desc->chip = &dummy_irq_chip;
}
chip_bus_lock(irq, desc);
spin_lock_irqsave(&desc->lock, flags);
/* Uninstall? */
@ -591,6 +662,7 @@ __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
desc->chip->startup(irq);
}
spin_unlock_irqrestore(&desc->lock, flags);
chip_bus_sync_unlock(irq, desc);
}
EXPORT_SYMBOL_GPL(__set_irq_handler);

13
kernel/irq/internals.h
View File

@ -44,6 +44,19 @@ extern int irq_select_affinity_usr(unsigned int irq);
extern void irq_set_thread_affinity(struct irq_desc *desc);
/* Inline functions for support of irq chips on slow busses */
static inline void chip_bus_lock(unsigned int irq, struct irq_desc *desc)
{
if (unlikely(desc->chip->bus_lock))
desc->chip->bus_lock(irq);
}
static inline void chip_bus_sync_unlock(unsigned int irq, struct irq_desc *desc)
{
if (unlikely(desc->chip->bus_sync_unlock))
desc->chip->bus_sync_unlock(irq);
}
/*
* Debugging printout:
*/

102
kernel/irq/manage.c
View File

@ -230,9 +230,11 @@ void disable_irq_nosync(unsigned int irq)
if (!desc)
return;
chip_bus_lock(irq, desc);
spin_lock_irqsave(&desc->lock, flags);
__disable_irq(desc, irq, false);
spin_unlock_irqrestore(&desc->lock, flags);
chip_bus_sync_unlock(irq, desc);
}
EXPORT_SYMBOL(disable_irq_nosync);
@ -294,7 +296,8 @@ void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume)
* matches the last disable, processing of interrupts on this
* IRQ line is re-enabled.
*
* This function may be called from IRQ context.
* This function may be called from IRQ context only when
* desc->chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
*/
void enable_irq(unsigned int irq)
{
@ -304,9 +307,11 @@ void enable_irq(unsigned int irq)
if (!desc)
return;
chip_bus_lock(irq, desc);
spin_lock_irqsave(&desc->lock, flags);
__enable_irq(desc, irq, false);
spin_unlock_irqrestore(&desc->lock, flags);
chip_bus_sync_unlock(irq, desc);
}
EXPORT_SYMBOL(enable_irq);
@ -436,6 +441,26 @@ int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
return ret;
}
/*
* Default primary interrupt handler for threaded interrupts. Is
* assigned as primary handler when request_threaded_irq is called
* with handler == NULL. Useful for oneshot interrupts.
*/
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()) {
@ -451,6 +476,23 @@ static int irq_wait_for_interrupt(struct irqaction *action)
return -1;
}
/*
* Oneshot interrupts keep the irq line masked until the threaded
* handler finished. unmask if the interrupt has not been disabled and
* is marked MASKED.
*/
static void irq_finalize_oneshot(unsigned int irq, struct irq_desc *desc)
{
chip_bus_lock(irq, desc);
spin_lock_irq(&desc->lock);
if (!(desc->status & IRQ_DISABLED) && (desc->status & IRQ_MASKED)) {
desc->status &= ~IRQ_MASKED;
desc->chip->unmask(irq);
}
spin_unlock_irq(&desc->lock);
chip_bus_sync_unlock(irq, desc);
}
#ifdef CONFIG_SMP
/*
* Check whether we need to change the affinity of the interrupt thread.
@ -492,7 +534,7 @@ 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;
int wake, oneshot = desc->status & IRQ_ONESHOT;
sched_setscheduler(current, SCHED_FIFO, &param);
current->irqaction = action;
@ -518,6 +560,9 @@ static int irq_thread(void *data)
spin_unlock_irq(&desc->lock);
action->thread_fn(action->irq, action->dev_id);
if (oneshot)
irq_finalize_oneshot(action->irq, desc);
}
wake = atomic_dec_and_test(&desc->threads_active);
@ -565,7 +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)
@ -590,10 +635,32 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
rand_initialize_irq(irq);
}
/* Oneshot interrupts are not allowed with shared */
if ((new->flags & IRQF_ONESHOT) && (new->flags & IRQF_SHARED))
return -EINVAL;
/*
* Threaded handler ?
* Check whether the interrupt nests into another interrupt
* thread.
*/
if (new->thread_fn) {
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 && !nested) {
struct task_struct *t;
t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
@ -662,9 +729,12 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
desc->status |= IRQ_PER_CPU;
#endif
desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING | IRQ_ONESHOT |
IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
if (new->flags & IRQF_ONESHOT)
desc->status |= IRQ_ONESHOT;
if (!(desc->status & IRQ_NOAUTOEN)) {
desc->depth = 0;
desc->status &= ~IRQ_DISABLED;
@ -875,7 +945,14 @@ EXPORT_SYMBOL_GPL(remove_irq);
*/
void free_irq(unsigned int irq, void *dev_id)
{
struct irq_desc *desc = irq_to_desc(irq);
if (!desc)
return;
chip_bus_lock(irq, desc);
kfree(__free_irq(irq, dev_id));
chip_bus_sync_unlock(irq, desc);
}
EXPORT_SYMBOL(free_irq);
@ -884,6 +961,8 @@ EXPORT_SYMBOL(free_irq);
* @irq: Interrupt line to allocate
* @handler: Function to be called when the IRQ occurs.
* Primary handler for threaded interrupts
* If NULL and thread_fn != NULL the default
* primary handler is installed
* @thread_fn: Function called from the irq handler thread
* If NULL, no irq thread is created
* @irqflags: Interrupt type flags
@ -963,8 +1042,12 @@ int request_threaded_irq(unsigned int irq, irq_handler_t handler,
if (desc->status & IRQ_NOREQUEST)
return -EINVAL;
if (!handler)
return -EINVAL;
if (!handler) {
if (!thread_fn)
return -EINVAL;
handler = irq_default_primary_handler;
}
action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
if (!action)
@ -976,7 +1059,10 @@ int request_threaded_irq(unsigned int irq, irq_handler_t handler,
action->name = devname;
action->dev_id = dev_id;
chip_bus_lock(irq, desc);
retval = __setup_irq(irq, desc, action);
chip_bus_sync_unlock(irq, desc);
if (retval)
kfree(action);