1 files changed, 158 insertions, 26 deletions

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 50da67672901..bde4c667d24d 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -80,14 +80,22 @@ int irq_can_set_affinity(unsigned int irq)
         return 1;
 }
 
-void
-irq_set_thread_affinity(struct irq_desc *desc, const struct cpumask *cpumask)
+/**
+ *      irq_set_thread_affinity - Notify irq threads to adjust affinity
+ *      @desc:          irq descriptor which has affitnity changed
+ *
+ *      We just set IRQTF_AFFINITY and delegate the affinity setting
+ *      to the interrupt thread itself. We can not call
+ *      set_cpus_allowed_ptr() here as we hold desc->lock and this
+ *      code can be called from hard interrupt context.
+ */
+void irq_set_thread_affinity(struct irq_desc *desc)
 {
         struct irqaction *action = desc->action;
 
         while (action) {
                 if (action->thread)
-                        set_cpus_allowed_ptr(action->thread, cpumask);
+                        set_bit(IRQTF_AFFINITY, &action->thread_flags);
                 action = action->next;
         }
 }
@@ -112,7 +120,7 @@ int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask)
         if (desc->status & IRQ_MOVE_PCNTXT) {
                 if (!desc->chip->set_affinity(irq, cpumask)) {
                         cpumask_copy(desc->affinity, cpumask);
-                        irq_set_thread_affinity(desc, cpumask);
+                        irq_set_thread_affinity(desc);
                 }
         }
         else {
@@ -122,7 +130,7 @@ int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask)
 #else
         if (!desc->chip->set_affinity(irq, cpumask)) {
                 cpumask_copy(desc->affinity, cpumask);
-                irq_set_thread_affinity(desc, cpumask);
+                irq_set_thread_affinity(desc);
         }
 #endif
         desc->status |= IRQ_AFFINITY_SET;
@@ -176,7 +184,7 @@ int irq_select_affinity_usr(unsigned int irq)
         spin_lock_irqsave(&desc->lock, flags);
         ret = setup_affinity(irq, desc);
         if (!ret)
-                irq_set_thread_affinity(desc, desc->affinity);
+                irq_set_thread_affinity(desc);
         spin_unlock_irqrestore(&desc->lock, flags);
 
         return ret;
@@ -222,9 +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);
 
@@ -286,7 +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)
 {
@@ -296,9 +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);
 
@@ -428,6 +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()) {
@@ -444,6 +477,56 @@ static int irq_wait_for_interrupt(struct irqaction *action)
 }
 
 /*
+ * 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.
+ */
+static void
+irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
+{
+        cpumask_var_t mask;
+
+        if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
+                return;
+
+        /*
+         * In case we are out of memory we set IRQTF_AFFINITY again and
+         * try again next time
+         */
+        if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
+                set_bit(IRQTF_AFFINITY, &action->thread_flags);
+                return;
+        }
+
+        spin_lock_irq(&desc->lock);
+        cpumask_copy(mask, desc->affinity);
+        spin_unlock_irq(&desc->lock);
+
+        set_cpus_allowed_ptr(current, mask);
+        free_cpumask_var(mask);
+}
+#else
+static inline void
+irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
+#endif
+
+/*
  * Interrupt handler thread
  */
 static int irq_thread(void *data)
@@ -451,13 +534,15 @@ 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;
 
         while (!irq_wait_for_interrupt(action)) {
 
+                irq_thread_check_affinity(desc, action);
+
                 atomic_inc(&desc->threads_active);
 
                 spin_lock_irq(&desc->lock);
@@ -475,6 +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);
@@ -522,7 +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)
@@ -547,10 +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,
@@ -564,7 +674,6 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
                  */
                 get_task_struct(t);
                 new->thread = t;
-                wake_up_process(t);
         }
 
         /*
@@ -620,9 +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;
@@ -647,6 +759,7 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
                                 (int)(new->flags & IRQF_TRIGGER_MASK));
         }
 
+        new->irq = irq;
         *old_ptr = new;
 
         /* Reset broken irq detection when installing new handler */
@@ -664,7 +777,13 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
 
         spin_unlock_irqrestore(&desc->lock, flags);
 
-        new->irq = irq;
+        /*
+         * Strictly no need to wake it up, but hung_task complains
+         * when no hard interrupt wakes the thread up.
+         */
+        if (new->thread)
+                wake_up_process(new->thread);
+
         register_irq_proc(irq, desc);
         new->dir = NULL;
         register_handler_proc(irq, new);
@@ -718,7 +837,6 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
 {
         struct irq_desc *desc = irq_to_desc(irq);
         struct irqaction *action, **action_ptr;
-        struct task_struct *irqthread;
         unsigned long flags;
 
         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
@@ -766,9 +884,6 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
                         desc->chip->disable(irq);
         }
 
-        irqthread = action->thread;
-        action->thread = NULL;
-
         spin_unlock_irqrestore(&desc->lock, flags);
 
         unregister_handler_proc(irq, action);
@@ -776,12 +891,6 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
         /* Make sure it's not being used on another CPU: */
         synchronize_irq(irq);
 
-        if (irqthread) {
-                if (!test_bit(IRQTF_DIED, &action->thread_flags))
-                        kthread_stop(irqthread);
-                put_task_struct(irqthread);
-        }
-
 #ifdef CONFIG_DEBUG_SHIRQ
         /*
          * It's a shared IRQ -- the driver ought to be prepared for an IRQ
@@ -797,6 +906,13 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
                 local_irq_restore(flags);
         }
 #endif
+
+        if (action->thread) {
+                if (!test_bit(IRQTF_DIED, &action->thread_flags))
+                        kthread_stop(action->thread);
+                put_task_struct(action->thread);
+        }
+
         return action;
 }
 
@@ -829,7 +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);
 
@@ -838,6 +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
@@ -917,8 +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)
@@ -930,7 +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);