Merge branch 'irq-threaded-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
authorLinus Torvalds <torvalds@linux-foundation.org>
Fri, 11 Sep 2009 20:21:31 +0000 (13:21 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 11 Sep 2009 20:21:31 +0000 (13:21 -0700)
* '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

include/linux/interrupt.h
include/linux/irq.h
kernel/irq/chip.c
kernel/irq/internals.h
kernel/irq/manage.c

index 35e7df1..1ac57e5 100644 (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:
index 9e9eb76..ae9653d 100644 (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);
 
index 13c68e7..c166019 100644 (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);
 
index e70ed55..1b5d742 100644 (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:
  */
index 0ec9ed8..bde4c66 100644 (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;
+
+       /*
+        * 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;
+       }
+
        /*
-        * Threaded 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,
@@ -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);