xref: /linux/rust/kernel/irq/flags.rs (revision 0851d34a8cc3a0a43acd79a5c4980d45c6471aab)
1 // SPDX-License-Identifier: GPL-2.0
2 // SPDX-FileCopyrightText: Copyright 2025 Collabora ltd.
3 
4 use crate::bindings;
5 use 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)]
27 pub struct Flags(c_ulong);
28 
29 impl 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 
105 impl 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 
112 impl 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 
119 impl core::ops::Not for Flags {
120     type Output = Self;
121     fn not(self) -> Self::Output {
122         Self(!self.0)
123     }
124 }
125