1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
|
//! IMPLEMENTATION DETAILS. DO NOT USE ANYTHING IN THIS MODULE
#[cfg(not(debug_assertions))]
use core::hint;
use core::{cell::Cell, ptr, u8};
#[cfg(armv7m)]
use cortex_m::register::basepri;
pub use cortex_m::{
asm::wfi, interrupt, peripheral::scb::SystemHandler, peripheral::syst::SystClkSource,
peripheral::Peripherals,
};
pub use heapless::consts;
use heapless::spsc::{Queue, SingleCore};
#[cfg(feature = "timer-queue")]
pub use crate::tq::{isr as sys_tick, NotReady, TimerQueue};
pub type FreeQueue<N> = Queue<u8, N, usize, SingleCore>;
pub type ReadyQueue<T, N> = Queue<(T, u8), N, usize, SingleCore>;
#[cfg(armv7m)]
#[inline(always)]
pub fn run<F>(f: F)
where
F: FnOnce(),
{
let initial = basepri::read();
f();
unsafe { basepri::write(initial) }
}
#[cfg(not(armv7m))]
#[inline(always)]
pub fn run<F>(f: F)
where
F: FnOnce(),
{
f();
}
// Newtype over `Cell` that forbids mutation through a shared reference
pub struct Priority {
inner: Cell<u8>,
}
impl Priority {
#[inline(always)]
pub unsafe fn new(value: u8) -> Self {
Priority { inner: Cell::new(value)}
}
// these two methods are used by claim (see below) but can't be used from the RTFM application
#[inline(always)]
fn set(&self, value: u8) {
self.inner.set(value)
}
#[inline(always)]
fn get(&self) -> u8 {
self.inner.get()
}
}
// TODO(MaybeUninit) Until core::mem::MaybeUninit is stabilized we use our own (inefficient)
// implementation
pub struct MaybeUninit<T> {
value: Option<T>,
}
impl<T> MaybeUninit<T> {
pub const fn uninitialized() -> Self {
MaybeUninit { value: None }
}
pub unsafe fn get_ref(&self) -> &T {
if let Some(x) = self.value.as_ref() {
x
} else {
match () {
// Try to catch UB when compiling in release with debug assertions enabled
#[cfg(debug_assertions)]
() => unreachable!(),
#[cfg(not(debug_assertions))]
() => hint::unreachable_unchecked(),
}
}
}
pub unsafe fn get_mut(&mut self) -> &mut T {
if let Some(x) = self.value.as_mut() {
x
} else {
match () {
// Try to catch UB when compiling in release with debug assertions enabled
#[cfg(debug_assertions)]
() => unreachable!(),
#[cfg(not(debug_assertions))]
() => hint::unreachable_unchecked(),
}
}
}
pub fn set(&mut self, val: T) {
// NOTE(volatile) we have observed UB when this uses a plain `ptr::write`
unsafe { ptr::write_volatile(&mut self.value, Some(val)) }
}
}
#[inline(always)]
pub fn assert_send<T>()
where
T: Send,
{
}
#[inline(always)]
pub fn assert_sync<T>()
where
T: Sync,
{
}
#[cfg(armv7m)]
#[inline(always)]
pub unsafe fn claim<T, R, F>(
ptr: *mut T,
priority: &Priority,
ceiling: u8,
nvic_prio_bits: u8,
f: F,
) -> R
where
F: FnOnce(&mut T) -> R,
{
let current = priority.get();
if priority.get() < ceiling {
if ceiling == (1 << nvic_prio_bits) {
priority.set(u8::MAX);
let r = interrupt::free(|_| f(&mut *ptr));
priority.set(current);
r
} else {
priority.set(ceiling);
basepri::write(logical2hw(ceiling, nvic_prio_bits));
let r = f(&mut *ptr);
basepri::write(logical2hw(current, nvic_prio_bits));
priority.set(current);
r
}
} else {
f(&mut *ptr)
}
}
#[cfg(not(armv7m))]
#[inline(always)]
pub unsafe fn claim<T, R, F>(
ptr: *mut T,
priority: &Priority,
ceiling: u8,
_nvic_prio_bits: u8,
f: F,
) -> R
where
F: FnOnce(&mut T) -> R,
{
let current = priority.get();
if priority.get() < ceiling {
priority.set(u8::MAX);
let r = interrupt::free(|_| f(&mut *ptr));
priority.set(current);
r
} else {
f(&mut *ptr)
}
}
#[cfg(armv7m)]
#[inline]
fn logical2hw(logical: u8, nvic_prio_bits: u8) -> u8 {
((1 << nvic_prio_bits) - logical) << (8 - nvic_prio_bits)
}
|
