kernel/irq/
flags.rs

1// SPDX-License-Identifier: GPL-2.0
2// SPDX-FileCopyrightText: Copyright 2025 Collabora ltd.
3
4use crate::bindings;
5use crate::prelude::*;
6
7/// Flags to be used when registering IRQ handlers.
8///
9/// Flags can be used to request specific behaviors when registering an IRQ
10/// handler, and can be combined using the `|`, `&`, and `!` operators to
11/// further control the system's behavior.
12///
13/// A common use case is to register a shared interrupt, as sharing the line
14/// between devices is increasingly common in modern systems and is even
15/// required for some buses. This requires setting [`Flags::SHARED`] when
16/// requesting the interrupt. Other use cases include setting the trigger type
17/// through `Flags::TRIGGER_*`, which determines when the interrupt fires, or
18/// controlling whether the interrupt is masked after the handler runs by using
19/// [`Flags::ONESHOT`].
20///
21/// If an invalid combination of flags is provided, the system will refuse to
22/// register the handler, and lower layers will enforce certain flags when
23/// necessary. This means, for example, that all the
24/// [`crate::irq::Registration`] for a shared interrupt have to agree on
25/// [`Flags::SHARED`] and on the same trigger type, if set.
26#[derive(Clone, Copy, PartialEq, Eq)]
27pub struct Flags(c_ulong);
28
29impl Flags {
30    /// Use the interrupt line as already configured.
31    pub const TRIGGER_NONE: Flags = Flags::new(bindings::IRQF_TRIGGER_NONE);
32
33    /// The interrupt is triggered when the signal goes from low to high.
34    pub const TRIGGER_RISING: Flags = Flags::new(bindings::IRQF_TRIGGER_RISING);
35
36    /// The interrupt is triggered when the signal goes from high to low.
37    pub const TRIGGER_FALLING: Flags = Flags::new(bindings::IRQF_TRIGGER_FALLING);
38
39    /// The interrupt is triggered while the signal is held high.
40    pub const TRIGGER_HIGH: Flags = Flags::new(bindings::IRQF_TRIGGER_HIGH);
41
42    /// The interrupt is triggered while the signal is held low.
43    pub const TRIGGER_LOW: Flags = Flags::new(bindings::IRQF_TRIGGER_LOW);
44
45    /// Allow sharing the IRQ among several devices.
46    pub const SHARED: Flags = Flags::new(bindings::IRQF_SHARED);
47
48    /// Set by callers when they expect sharing mismatches to occur.
49    pub const PROBE_SHARED: Flags = Flags::new(bindings::IRQF_PROBE_SHARED);
50
51    /// Flag to mark this interrupt as timer interrupt.
52    pub const TIMER: Flags = Flags::new(bindings::IRQF_TIMER);
53
54    /// Interrupt is per CPU.
55    pub const PERCPU: Flags = Flags::new(bindings::IRQF_PERCPU);
56
57    /// Flag to exclude this interrupt from irq balancing.
58    pub const NOBALANCING: Flags = Flags::new(bindings::IRQF_NOBALANCING);
59
60    /// Interrupt is used for polling (only the interrupt that is registered
61    /// first in a shared interrupt is considered for performance reasons).
62    pub const IRQPOLL: Flags = Flags::new(bindings::IRQF_IRQPOLL);
63
64    /// Interrupt is not re-enabled after the hardirq handler finished. Used by
65    /// threaded interrupts which need to keep the irq line disabled until the
66    /// threaded handler has been run.
67    pub const ONESHOT: Flags = Flags::new(bindings::IRQF_ONESHOT);
68
69    /// Do not disable this IRQ during suspend. Does not guarantee that this
70    /// interrupt will wake the system from a suspended state.
71    pub const NO_SUSPEND: Flags = Flags::new(bindings::IRQF_NO_SUSPEND);
72
73    /// Force enable it on resume even if [`Flags::NO_SUSPEND`] is set.
74    pub const FORCE_RESUME: Flags = Flags::new(bindings::IRQF_FORCE_RESUME);
75
76    /// Interrupt cannot be threaded.
77    pub const NO_THREAD: Flags = Flags::new(bindings::IRQF_NO_THREAD);
78
79    /// Resume IRQ early during syscore instead of at device resume time.
80    pub const EARLY_RESUME: Flags = Flags::new(bindings::IRQF_EARLY_RESUME);
81
82    /// If the IRQ is shared with a [`Flags::NO_SUSPEND`] user, execute this
83    /// interrupt handler after suspending interrupts. For system wakeup devices
84    /// users need to implement wakeup detection in their interrupt handlers.
85    pub const COND_SUSPEND: Flags = Flags::new(bindings::IRQF_COND_SUSPEND);
86
87    /// Don't enable IRQ or NMI automatically when users request it. Users will
88    /// enable it explicitly by `enable_irq` or `enable_nmi` later.
89    pub const NO_AUTOEN: Flags = Flags::new(bindings::IRQF_NO_AUTOEN);
90
91    /// Exclude from runnaway detection for IPI and similar handlers, depends on
92    /// `PERCPU`.
93    pub const NO_DEBUG: Flags = Flags::new(bindings::IRQF_NO_DEBUG);
94
95    pub(crate) fn into_inner(self) -> c_ulong {
96        self.0
97    }
98
99    const fn new(value: u32) -> Self {
100        build_assert!(value as u64 <= c_ulong::MAX as u64);
101        Self(value as c_ulong)
102    }
103}
104
105impl core::ops::BitOr for Flags {
106    type Output = Self;
107    fn bitor(self, rhs: Self) -> Self::Output {
108        Self(self.0 | rhs.0)
109    }
110}
111
112impl core::ops::BitAnd for Flags {
113    type Output = Self;
114    fn bitand(self, rhs: Self) -> Self::Output {
115        Self(self.0 & rhs.0)
116    }
117}
118
119impl core::ops::Not for Flags {
120    type Output = Self;
121    fn not(self) -> Self::Output {
122        Self(!self.0)
123    }
124}
kernel/irq/flags.rs

kernel/irq/
flags.rs
