qemu/include/hw/irq.h
Peter Maydell faf7c6de34 include/hw/irq.h: New function qemu_irq_is_connected()
Mostly devices don't need to care whether one of their output
qemu_irq lines is connected, because functions like qemu_set_irq()
silently do nothing if there is nothing on the other end.  However
sometimes a device might want to implement default behaviour for the
case where the machine hasn't wired the line up to anywhere.

Provide a function qemu_irq_is_connected() that devices can use for
this purpose.  (The test is trivial but encapsulating it in a
function makes it easier to see where we're doing it in case we need
to change the implementation later.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20200728103744.6909-2-peter.maydell@linaro.org
2020-08-03 17:55:03 +01:00

77 lines
2.2 KiB
C

#ifndef QEMU_IRQ_H
#define QEMU_IRQ_H
/* Generic IRQ/GPIO pin infrastructure. */
#define TYPE_IRQ "irq"
void qemu_set_irq(qemu_irq irq, int level);
static inline void qemu_irq_raise(qemu_irq irq)
{
qemu_set_irq(irq, 1);
}
static inline void qemu_irq_lower(qemu_irq irq)
{
qemu_set_irq(irq, 0);
}
static inline void qemu_irq_pulse(qemu_irq irq)
{
qemu_set_irq(irq, 1);
qemu_set_irq(irq, 0);
}
/* Returns an array of N IRQs. Each IRQ is assigned the argument handler and
* opaque data.
*/
qemu_irq *qemu_allocate_irqs(qemu_irq_handler handler, void *opaque, int n);
/*
* Allocates a single IRQ. The irq is assigned with a handler, an opaque
* data and the interrupt number.
*/
qemu_irq qemu_allocate_irq(qemu_irq_handler handler, void *opaque, int n);
/* Extends an Array of IRQs. Old IRQs have their handlers and opaque data
* preserved. New IRQs are assigned the argument handler and opaque data.
*/
qemu_irq *qemu_extend_irqs(qemu_irq *old, int n_old, qemu_irq_handler handler,
void *opaque, int n);
void qemu_free_irqs(qemu_irq *s, int n);
void qemu_free_irq(qemu_irq irq);
/* Returns a new IRQ with opposite polarity. */
qemu_irq qemu_irq_invert(qemu_irq irq);
/* Returns a new IRQ which feeds into both the passed IRQs.
* It's probably better to use the TYPE_SPLIT_IRQ device instead.
*/
qemu_irq qemu_irq_split(qemu_irq irq1, qemu_irq irq2);
/* For internal use in qtest. Similar to qemu_irq_split, but operating
on an existing vector of qemu_irq. */
void qemu_irq_intercept_in(qemu_irq *gpio_in, qemu_irq_handler handler, int n);
/**
* qemu_irq_is_connected: Return true if IRQ line is wired up
*
* If a qemu_irq has a device on the other (receiving) end of it,
* return true; otherwise return false.
*
* Usually device models don't need to care whether the machine model
* has wired up their outbound qemu_irq lines, because functions like
* qemu_set_irq() silently do nothing if there is nothing on the other
* end of the line. However occasionally a device model will want to
* provide default behaviour if its output is left floating, and
* it can use this function to identify when that is the case.
*/
static inline bool qemu_irq_is_connected(qemu_irq irq)
{
return irq != NULL;
}
#endif