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NAME

     BUS_SETUP_INTR, bus_setup_intr, BUS_TEARDOWN_INTR, bus_teardown_intr -
     create, attach and teardown an interrupt handler

SYNOPSIS

     #include <sys/param.h>
     #include <sys/bus.h>

     int
     BUS_SETUP_INTR(device_t dev, device_t child, struct resource *irq,
             int flags, driver_filter_t *filter, driver_intr_t *ithread,
             void *arg, void **cookiep);

     int
     bus_setup_intr(device_t dev, struct resource *r, int flags,
             driver_filter_t filter, driver_intr_t ithread, void *arg,
             void **cookiep);

     int
     BUS_TEARDOWN_INTR(device_t dev, device_t child, struct resource *irq,
             void *cookiep);

     int
     bus_teardown_intr(device_t dev, struct resource *r, void *cookiep);

DESCRIPTION

     The BUS_SETUP_INTR() method will create and attach an interrupt handler
     to an interrupt previously allocated by the resource manager’s
     BUS_ALLOC_RESOURCE(9) method.  The flags are found in and give the broad
     category of interrupt.  The flags also tell the interrupt handlers about
     certain device driver characteristics.  INTR_EXCL marks the handler as
     being an exclusive handler for this interrupt.  INTR_MPSAFE tells the
     scheduler that the interrupt handler is well behaved in a preemptive
     environment (‘‘SMP safe’’), and does not need to be protected by the
     ‘‘Giant Lock’’ mutex.  INTR_ENTROPY marks the interrupt as being a good
     source of entropy - this may be used by the entropy device /dev/random.

     To define a time-critical handler (previously known as INTR_FAST) that
     will not execute any potentially blocking operation, use the filter
     argument.  Otherwise, use the ithread argument.  The defined handler will
     be called with the value arg as its only argument.

     The cookiep argument is a pointer to a void * that BUS_SETUP_INTR() will
     write a cookie for the parent bus’ use to if it is successful in
     establishing an interrupt.  Driver writers may assume that this cookie
     will be non-zero.  The nexus driver will write 0 on failure to cookiep.

     The interrupt handler will be detached by BUS_TEARDOWN_INTR().  The
     cookie needs to be passed to BUS_TEARDOWN_INTR() in order to tear down
     the correct interrupt handler.  Once BUS_TEARDOWN_INTR() returns, it is
     guaranteed that the interrupt function is not active and will no longer
     be called.

     Mutexes are not allowed to be held across calls to these functions.

RETURN VALUES

     Zero is returned on success, otherwise an appropriate error is returned.

SEE ALSO

     random(4), device(9), driver(9)

AUTHORS

     This manual page was written by Jeroen Ruigrok van der Werven
     〈asmodai@FreeBSD.org〉 based on the manual pages for BUS_CREATE_INTR() and
     BUS_CONNECT_INTR() written by Doug Rabson 〈dfr@FreeBSD.org〉.