From: Russell King Some ARM platforms have the ability to program the interrupt controller to detect various interrupt edges and/or levels. For some platforms, this is critical to setup correctly, particularly those which the setting is dependent on the device. Currently, ARM drivers do (eg) the following: err = request_irq(irq, ...); set_irq_type(irq, IRQT_RISING); However, if the interrupt has previously been programmed to be level sensitive (for whatever reason) then this will cause an interrupt storm. Hence, if we combine set_irq_type() with request_irq(), we can then safely set the type prior to unmasking the interrupt. The unfortunate problem is that in order to support this, these flags need to be visible outside of the ARM architecture - drivers such as smc91x need these flags and they're cross-architecture. Finally, the SA_TRIGGER_* flag passed to request_irq() should reflect the property that the device would like. The IRQ controller code should do its best to select the most appropriate supported mode. Signed-off-by: Russell King Signed-off-by: Andrew Morton --- arch/arm/kernel/irq.c | 14 ++++++++++++-- include/asm-arm/irq.h | 12 ++++++++---- include/linux/signal.h | 13 +++++++++++++ 3 files changed, 33 insertions(+), 6 deletions(-) diff -puN arch/arm/kernel/irq.c~irq-type-flags arch/arm/kernel/irq.c --- 25/arch/arm/kernel/irq.c~irq-type-flags Mon Dec 12 15:19:08 2005 +++ 25-akpm/arch/arm/kernel/irq.c Mon Dec 12 15:19:08 2005 @@ -684,8 +684,12 @@ int setup_irq(unsigned int irq, struct i spin_lock_irqsave(&irq_controller_lock, flags); p = &desc->action; if ((old = *p) != NULL) { - /* Can't share interrupts unless both agree to */ - if (!(old->flags & new->flags & SA_SHIRQ)) { + /* + * Can't share interrupts unless both agree to and are + * the same type. + */ + if (!(old->flags & new->flags & SA_SHIRQ) || + (~old->flags & new->flags) & SA_TRIGGER_MASK) { spin_unlock_irqrestore(&irq_controller_lock, flags); return -EBUSY; } @@ -705,6 +709,12 @@ int setup_irq(unsigned int irq, struct i desc->running = 0; desc->pending = 0; desc->disable_depth = 1; + + if (new->flags & SA_TRIGGER_MASK) { + unsigned int type = new->flags & SA_TRIGGER; + desc->chip->set_type(irq, type); + } + if (!desc->noautoenable) { desc->disable_depth = 0; desc->chip->unmask(irq); diff -puN include/asm-arm/irq.h~irq-type-flags include/asm-arm/irq.h --- 25/include/asm-arm/irq.h~irq-type-flags Mon Dec 12 15:19:08 2005 +++ 25-akpm/include/asm-arm/irq.h Mon Dec 12 15:19:08 2005 @@ -25,10 +25,14 @@ extern void disable_irq_nosync(unsigned extern void disable_irq(unsigned int); extern void enable_irq(unsigned int); -#define __IRQT_FALEDGE (1 << 0) -#define __IRQT_RISEDGE (1 << 1) -#define __IRQT_LOWLVL (1 << 2) -#define __IRQT_HIGHLVL (1 << 3) +/* + * These correspond with the SA_TRIGGER_* defines, and therefore the + * IRQRESOURCE_IRQ_* defines. + */ +#define __IRQT_RISEDGE (1 << 0) +#define __IRQT_FALEDGE (1 << 1) +#define __IRQT_HIGHLVL (1 << 2) +#define __IRQT_LOWLVL (1 << 3) #define IRQT_NOEDGE (0) #define IRQT_RISING (__IRQT_RISEDGE) diff -puN include/linux/signal.h~irq-type-flags include/linux/signal.h --- 25/include/linux/signal.h~irq-type-flags Mon Dec 12 15:19:08 2005 +++ 25-akpm/include/linux/signal.h Mon Dec 12 15:19:08 2005 @@ -18,6 +18,19 @@ #define SA_PROBE SA_ONESHOT #define SA_SAMPLE_RANDOM SA_RESTART #define SA_SHIRQ 0x04000000 +/* + * As above, these correspond to the IORESOURCE_IRQ_* defines in + * linux/ioport.h to select the interrupt line behaviour. When + * requesting an interrupt without specifying a SA_TRIGGER, the + * setting should be assumed to be "as already configured", which + * may be as per machine or firmware initialisation. + */ +#define SA_TRIGGER_LOW 0x00000008 +#define SA_TRIGGER_HIGH 0x00000004 +#define SA_TRIGGER_FALLING 0x00000002 +#define SA_TRIGGER_RISING 0x00000001 +#define SA_TRIGGER_MASK (SA_TRIGGER_HIGH|SA_TRIGGER_LOW|\ + SA_TRIGGER_RISING|SA_TRIGGER_FALLING) /* * Real Time signals may be queued. _