Hi,
As of 2.6.14, in include/linux/irq.h, there are two definitions as below.
As you see, hw_interrupt_type accepts irq numbers for each irq,
whereas irq_desc does not seem to keep a unique number. How are the
two matched to each other then? Is it the irq_desc array offset that
uniquely identifies each irq?
I am asking because on some (e.g. smp) architectures, there are
multiple irq controllers and each irq number does `not' represent a
primary key for each irq, because there are multiple instances of the
same irq number on the system, for different irqs.
Thanks,
Bahadir
/*
* Interrupt controller descriptor. This is all we need
* to describe about the low-level hardware.
*/
struct hw_interrupt_type {
const char * typename;
unsigned int (*startup)(unsigned int irq);
void (*shutdown)(unsigned int irq);
void (*enable)(unsigned int irq);
void (*disable)(unsigned int irq);
void (*ack)(unsigned int irq);
/*...*/
};
/*
* This is the "IRQ descriptor", which contains various information
* about the irq, including what kind of hardware handling it has,
* whether it is disabled etc etc.
*/
typedef struct irq_desc {
hw_irq_controller *handler;
void *handler_data;
struct irqaction *action; /* IRQ action list */
unsigned int status; /* IRQ status */
unsigned int depth; /* nested irq disables */
unsigned int irq_count; /* For detecting broken interrupts */
unsigned int irqs_unhandled;
spinlock_t lock;
/* ... */
}
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