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-rw-r--r--include/linux/irq.h6
-rw-r--r--kernel/irq/chip.c2
-rw-r--r--kernel/irq/internals.h13
-rw-r--r--kernel/irq/manage.c19
4 files changed, 39 insertions, 1 deletions
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 5e7c6ee..ce8171b 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -101,6 +101,9 @@ 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
*/
@@ -124,6 +127,9 @@ 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);
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index b08c0d2..f856330 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -580,6 +580,7 @@ __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? */
@@ -599,6 +600,7 @@ __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);
diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index e70ed55..1b5d742 100644
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -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:
*/
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index d7f7b5f..0a3fd5b 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -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);
@@ -468,12 +473,14 @@ static int irq_wait_for_interrupt(struct irqaction *action)
*/
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
@@ -904,7 +911,14 @@ 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);
@@ -1011,7 +1025,10 @@ 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);