Add a facility for associating optional descriptions with active interrupt

handlers.  This is primarily intended as a way to allow devices that use
multiple interrupts (e.g. MSI) to meaningfully distinguish the various
interrupt handlers.
- Add a new BUS_DESCRIBE_INTR() method to the bus interface to associate
  a description with an active interrupt handler setup by BUS_SETUP_INTR.
  It has a default method (bus_generic_describe_intr()) which simply passes
  the request up to the parent device.
- Add a bus_describe_intr() wrapper around BUS_DESCRIBE_INTR() that supports
  printf(9) style formatting using var args.
- Reserve MAXCOMLEN bytes in the intr_handler structure to hold the name of
  an interrupt handler and copy the name passed to intr_event_add_handler()
  into that buffer instead of just saving the pointer to the name.
- Add a new intr_event_describe_handler() which appends a description string
  to an interrupt handler's name.
- Implement support for interrupt descriptions on amd64 and i386 by having
  the nexus(4) driver supply a custom bus_describe_intr method that invokes
  a new intr_describe() MD routine which in turn looks up the associated
  interrupt event and invokes intr_event_describe_handler().

Requested by:	many
Reviewed by:	scottl
MFC after:	2 weeks

1 files changed, 3 insertions, 1 deletions

diff --git a/sys/sys/interrupt.h b/sys/sys/interrupt.h
index 92c0f03..18f73d9 100644
--- a/sys/sys/interrupt.h
+++ b/sys/sys/interrupt.h
@@ -47,7 +47,7 @@ struct intr_handler {
 	driver_intr_t	*ih_handler;	/* Threaded handler function. */
 	void		*ih_argument;	/* Argument to pass to handlers. */
 	int		 ih_flags;
-	const char	*ih_name;	/* Name of handler. */
+	char		 ih_name[MAXCOMLEN]; /* Name of handler. */
 	struct intr_event *ih_event;	/* Event we are connected to. */
 	int		 ih_need;	/* Needs service. */
 	TAILQ_ENTRY(intr_handler) ih_next; /* Next handler for this event. */
@@ -172,6 +172,8 @@ int	intr_event_destroy(struct intr_event *ie);
 void	intr_event_execute_handlers(struct proc *p, struct intr_event *ie);
 int	intr_event_handle(struct intr_event *ie, struct trapframe *frame);
 int	intr_event_remove_handler(void *cookie);
+int	intr_event_describe_handler(struct intr_event *ie, void *cookie,
+	    const char *descr);
 int	intr_getaffinity(int irq, void *mask);
 void	*intr_handler_source(void *cookie);
 int	intr_setaffinity(int irq, void *mask);