request_threaded_irq(9) [centos man page]

REQUEST_THREADED_IRQ(9) 				     Public Functions Provided					   REQUEST_THREADED_IRQ(9)

NAME

       request_threaded_irq - allocate an interrupt line

SYNOPSIS

       int request_threaded_irq(unsigned int irq, irq_handler_t handler, irq_handler_t thread_fn, unsigned long irqflags, const char * devname,
				void * dev_id);

ARGUMENTS

       irq
	   Interrupt line to allocate

       handler
	   Function to be called when the IRQ occurs. Primary handler for threaded interrupts If NULL and thread_fn != NULL the default primary
	   handler is installed

       thread_fn
	   Function called from the irq handler thread If NULL, no irq thread is created

       irqflags
	   Interrupt type flags

       devname
	   An ascii name for the claiming device

       dev_id
	   A cookie passed back to the handler function

DESCRIPTION

       This call allocates interrupt resources and enables the interrupt line and IRQ handling. From the point this call is made your handler
       function may be invoked. Since your handler function must clear any interrupt the board raises, you must take care both to initialise your
       hardware and to set up the interrupt handler in the right order.

       If you want to set up a threaded irq handler for your device then you need to supply handler and thread_fn.  handler is still called in
       hard interrupt context and has to check whether the interrupt originates from the device. If yes it needs to disable the interrupt on the
       device and return IRQ_WAKE_THREAD which will wake up the handler thread and run thread_fn. This split handler design is necessary to
       support shared interrupts.

       Dev_id must be globally unique. Normally the address of the device data structure is used as the cookie. Since the handler receives this
       value it makes sense to use it.

       If your interrupt is shared you must pass a non NULL dev_id as this is required when freeing the interrupt.

FLAGS

       IRQF_SHARED Interrupt is shared IRQF_TRIGGER_* Specify active edge(s) or level

AUTHORS

       Thomas Gleixner <tglx@linutronix.de>
	   Author.

       Ingo Molnar <mingo@elte.hu>
	   Author.

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014						   REQUEST_THREADED_IRQ(9)

Check Out this Related Man Page

ddi_intr_hilevel(9F)					   Kernel Functions for Drivers 				      ddi_intr_hilevel(9F)

NAME

       ddi_intr_hilevel - indicate interrupt handler type

SYNOPSIS

       #include <sys/ddi.h>
       #include <sys/sunddi.h>

       int ddi_intr_hilevel(dev_info_t *dip, uint_t inumber);

INTERFACE LEVEL

       Solaris DDI specific (Solaris DDI).

PARAMETERS

       dip	       Pointer to dev_info structure.

       inumber	       Interrupt number.

DESCRIPTION

       ddi_intr_hilevel() returns non-zero if the specified interrupt is a "high level" interrupt.

       High  level interrupts must be handled without using system services that manipulate thread or process states, because these interrupts are
       not blocked by the scheduler.

       In addition, high level interrupt handlers must take care to do a minimum of work because they are not preemptable.

       A typical high level interrupt handler would put data into a circular buffer and schedule a soft interrupt  by  calling	 ddi_trigger_soft-
       intr(). The circular buffer could be protected by using a mutex that was properly initialized for the interrupt handler.

       ddi_intr_hilevel() can be used before calling  ddi_add_intr() to decide which type of interrupt handler should be used. Most device drivers
       are designed with the knowledge that the devices they support will always generate low level interrupts, however some devices, for  example
       those  using SBus or VME bus level 6 or 7 interrupts must use this test because on some machines those interrupts are high level (above the
       scheduler level) and on other machines they are not.

RETURN VALUES

       non-zero        indicates a high-level interrupt.

CONTEXT

       These functions can be called from user or interrupt context.

SEE ALSO

       ddi_add_intr(9F), mutex(9F)

       Writing Device Drivers

SunOS 5.10							    7 Jan 1992						      ddi_intr_hilevel(9F)

Linux and UNIX Man Pages

request_threaded_irq(9) [centos man page]

Check Out this Related Man Page