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